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Rawlings AM, Sang Y, Sharrett AR, Coresh J, Griswold M, Kucharska-Newton AM, Palta P, Wruck LM, Gross AL, Deal JA, Power MC, Bandeen-Roche KJ. Multiple imputation of cognitive performance as a repeatedly measured outcome. Eur J Epidemiol 2016; 32:55-66. [PMID: 27619926 DOI: 10.1007/s10654-016-0197-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 09/02/2016] [Indexed: 12/26/2022]
Abstract
Longitudinal studies of cognitive performance are sensitive to dropout, as participants experiencing cognitive deficits are less likely to attend study visits, which may bias estimated associations between exposures of interest and cognitive decline. Multiple imputation is a powerful tool for handling missing data, however its use for missing cognitive outcome measures in longitudinal analyses remains limited. We use multiple imputation by chained equations (MICE) to impute cognitive performance scores of participants who did not attend the 2011-2013 exam of the Atherosclerosis Risk in Communities Study. We examined the validity of imputed scores using observed and simulated data under varying assumptions. We examined differences in the estimated association between diabetes at baseline and 20-year cognitive decline with and without imputed values. Lastly, we discuss how different analytic methods (mixed models and models fit using generalized estimate equations) and choice of for whom to impute result in different estimands. Validation using observed data showed MICE produced unbiased imputations. Simulations showed a substantial reduction in the bias of the 20-year association between diabetes and cognitive decline comparing MICE (3-4 % bias) to analyses of available data only (16-23 % bias) in a construct where missingness was strongly informative but realistic. Associations between diabetes and 20-year cognitive decline were substantially stronger with MICE than in available-case analyses. Our study suggests when informative data are available for non-examined participants, MICE can be an effective tool for imputing cognitive performance and improving assessment of cognitive decline, though careful thought should be given to target imputation population and analytic model chosen, as they may yield different estimands.
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Affiliation(s)
- Andreea Monica Rawlings
- Department of Epidemiology, Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins Bloomberg School of Public Health, 2024 E. Monument Street, Suite 2-600, Baltimore, MD, 21287, USA.
| | - Yingying Sang
- Department of Epidemiology, Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins Bloomberg School of Public Health, 2024 E. Monument Street, Suite 2-600, Baltimore, MD, 21287, USA
| | - Albert Richey Sharrett
- Department of Epidemiology, Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins Bloomberg School of Public Health, 2024 E. Monument Street, Suite 2-600, Baltimore, MD, 21287, USA
| | - Josef Coresh
- Department of Epidemiology, Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins Bloomberg School of Public Health, 2024 E. Monument Street, Suite 2-600, Baltimore, MD, 21287, USA
| | - Michael Griswold
- Center of Biostatistics and Bioinformatics, University of Mississippi Medical Center, Jackson, MS, USA
| | | | - Priya Palta
- Department of Epidemiology, University of North Carolina, Chapel Hill, NC, USA
| | - Lisa Miller Wruck
- Department of Biostatistics, University of North Carolina, Chapel Hill, NC, USA
| | - Alden Lawrence Gross
- Department of Epidemiology, Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins Bloomberg School of Public Health, 2024 E. Monument Street, Suite 2-600, Baltimore, MD, 21287, USA
| | - Jennifer Anne Deal
- Department of Epidemiology, Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins Bloomberg School of Public Health, 2024 E. Monument Street, Suite 2-600, Baltimore, MD, 21287, USA
| | - Melinda Carolyn Power
- Department of Epidemiology, Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins Bloomberg School of Public Health, 2024 E. Monument Street, Suite 2-600, Baltimore, MD, 21287, USA.,Department of Epidemiology and Biostatistics, George Washington University Milken Institute of Public Health, Washington, DC, USA
| | - Karen Jean Bandeen-Roche
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
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302
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Mayeda ER, Tchetgen Tchetgen EJ, Power MC, Weuve J, Jacqmin-Gadda H, Marden JR, Vittinghoff E, Keiding N, Glymour MM. A Simulation Platform for Quantifying Survival Bias: An Application to Research on Determinants of Cognitive Decline. Am J Epidemiol 2016; 184:378-87. [PMID: 27578690 DOI: 10.1093/aje/kwv451] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 12/22/2015] [Indexed: 11/14/2022] Open
Abstract
Bias due to selective mortality is a potential concern in many studies and is especially relevant in cognitive aging research because cognitive impairment strongly predicts subsequent mortality. Biased estimation of the effect of an exposure on rate of cognitive decline can occur when mortality is a common effect of exposure and an unmeasured determinant of cognitive decline and in similar settings. This potential is often represented as collider-stratification bias in directed acyclic graphs, but it is difficult to anticipate the magnitude of bias. In this paper, we present a flexible simulation platform with which to quantify the expected bias in longitudinal studies of determinants of cognitive decline. We evaluated potential survival bias in naive analyses under several selective survival scenarios, assuming that exposure had no effect on cognitive decline for anyone in the population. Compared with the situation with no collider bias, the magnitude of bias was higher when exposure and an unmeasured determinant of cognitive decline interacted on the hazard ratio scale to influence mortality or when both exposure and rate of cognitive decline influenced mortality. Bias was, as expected, larger in high-mortality situations. This simulation platform provides a flexible tool for evaluating biases in studies with high mortality, as is common in cognitive aging research.
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Liang FW, Chan W, Chen PJ, Zimmerman C, Waring S, Doody R. Cognitively-Related Basic Activities of Daily Living Impairment Greatly Increases the Risk of Death in Alzheimers Disease. PLoS One 2016; 11:e0160671. [PMID: 27571265 PMCID: PMC5003345 DOI: 10.1371/journal.pone.0160671] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 07/22/2016] [Indexed: 11/23/2022] Open
Abstract
INTRODUCTION Some Alzheimer's disease (AD) patients die without ever developing cognitively impaired basic activities of daily living (basic ADL), which may reflect slower disease progression or better compensatory mechanisms. Although impaired basic ADL is related to disease severity, it may exert an independent risk for death. This study examined the association between impaired basic ADL and survival of AD patients, and proposed a multistate approach for modeling the time to death for patients who demonstrate different patterns of progression of AD that do or do not include basic ADL impairment. METHODS 1029 patients with probable AD at the Baylor College of Medicine Alzheimer's Disease and Memory Disorders Center met the criteria for this study. Two complementary definitions were used to define development of basic ADL impairment using the Physical Self-Maintenance Scale score. A weighted Cox regression model, including a time-dependent covariate (development of basic ADL impairment), and a multistate survival model were applied to examine the effect of basic ADL impairment on survival. RESULTS As expected decreased ability to perform basic ADL at baseline, age at initial visit, years of education, and sex were all associated with significantly higher mortality risk. In those unimpaired at baseline, the development of basic ADL impairment was also associated with a much greater risk of death (hazard ratios 1.77-4.06) over and above the risk conferred by loss of MMSE points. A multi-state Cox model, controlling for those other variables quantified the substantive increase in hazard ratios for death conferred by the development of basic ADL impairment by two definitions and can be applied to calculate the short term risk of mortality in individual patients. CONCLUSIONS The current study demonstrates that the presence of basic ADL impairment or the development of such impairments are important predictors of death in AD patients, regardless of severity.
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Affiliation(s)
- Fu-Wen Liang
- Department of Public Health, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, No.1, University Road, Tainan City 701, Taiwan
| | - Wenyaw Chan
- Department of Biostatistics, University of Texas-Health Science Center at Houston, 1200 Pressler Street, E827, Houston, Texas 77030, United States of America
| | - Ping-Jen Chen
- Department of Geriatrics and Gerontology, Chi-Mei Medical Center, 901, Zhong-Hua Rd., Yong-Kang Dist., Tainan City 710, Taiwan
| | - Carissa Zimmerman
- Department of Psychology, Rice University, 6100 Main MS-27, Houston, Texas 77005, United States of America
| | - Stephen Waring
- Essentia Institute of Rural Health, 502 East Second Street, Duluth, MN 55805, United States of America
| | - Rachelle Doody
- Alzheimer's Disease and Memory Disorders Center, Baylor College of Medicine,7200 Cambridge Street, A9.210, Houston, Texas 77030, United States of America
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304
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Garcia-Larsen V, Potts JF, Del Giacco S, Bustos P, Diaz PV, Amigo H, Oyarzun M, Rona RJ. Changes in symptoms of asthma and rhinitis by sensitization status over ten years in a cohort of young Chilean adults. BMC Pulm Med 2016; 16:116. [PMID: 27503476 PMCID: PMC4977698 DOI: 10.1186/s12890-016-0273-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 06/10/2016] [Indexed: 11/11/2022] Open
Abstract
Background We investigated the net changes in prevalence of symptoms of asthma and rhinitis over 10 years in a cohort of young by baseline sensitization status. Methods One thousand one hundred ninety three Chilean adults subjects aged 22–28 living in a semi-rural area of central Chile answered a lifestyle and the European Community Respiratory Health Survey (ECRHS) questionnaires. Bronchial hyper-responsiveness (BHR) and skin prick test (SPT) to eight allergens were measured at baseline in 2001. Ten years later, 772 participants completed the questionnaires again. Estimates of adjusted net changes in prevalence of symptoms by sensitization status at baseline and association between sensitization status at baseline and respiratory symptoms ten years later were assessed. Results A quarter of the participants were sensitized to at least one allergen in 2001. Prevalence of wheeze had a net change per year of −0.37 % (95 % Confidence Interval −0.71 to 0.02 %; p = 0.067). Self-reported nasal allergies in the last 12 months increased by 0.83 % per year (95 % CI 0.49 to 1.17 %; p < 0.001). Those sensitized to either cat fur (OR 1.76; CI 1.01 to 3.05), cockroach, (OR 2.09; 1.13 to 3.86) blend of grass and pollens (1.78; 95 % CI 1.08 to 2.92), or weeds (OR 1.77; 95 % CI 1.01 to 3.12) in 2001 were more likely to have wheeze in the last 12 months 10 years later. Conclusion Symptoms of asthma remained stable or slightly changed over 10 years in adults, whilst rhinitis and nasal allergies greatly increased. Being sensitized to at least one allergen is a risk factor for persistent symptoms of asthma and rhinitis, but not for determining net changes of symptoms over time. The underlying causes for the contrasting trends between asthma and nasal allergy are unknown. Electronic supplementary material The online version of this article (doi:10.1186/s12890-016-0273-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Vanessa Garcia-Larsen
- Respiratory Epidemiology, Occupational Medicine, and Public Health Group, National Heart & Lung Institute, Imperial College London, Emmanuel Kaye Building, Manresa Road, London, SW3 6LR, UK.
| | - James F Potts
- Respiratory Epidemiology, Occupational Medicine, and Public Health Group, National Heart & Lung Institute, Imperial College London, Emmanuel Kaye Building, Manresa Road, London, SW3 6LR, UK
| | - Stefano Del Giacco
- Department of Medical Sciences "M Aresu", University of Cagliari, Asse Didattico "E1" - Cittadella Universitaria, Monserrato, Cagliari, 09042, Italy
| | - Patricia Bustos
- Department of Nutrition, Faculty of Medicine, University of Chile, Independencia 1027, Santiago, Chile
| | - Patricia V Diaz
- Institute of Bio-Medical Science, Faculty of Medicine, University of Chile, Independencia 1027, Santiago, Chile
| | - Hugo Amigo
- Department of Nutrition, Faculty of Medicine, University of Chile, Independencia 1027, Santiago, Chile
| | - Manuel Oyarzun
- Institute of Bio-Medical Science, Faculty of Medicine, University of Chile, Independencia 1027, Santiago, Chile
| | - Roberto J Rona
- Department of Psychological Medicine, Weston Education Centre, King's College London, Cutcombe Road, London, SE5 9RJ, UK
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305
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Węziak-Białowolska D, Białowolski P. Cultural events - does attendance improve health? Evidence from a Polish longitudinal study. BMC Public Health 2016; 16:730. [PMID: 27495252 PMCID: PMC4974712 DOI: 10.1186/s12889-016-3433-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 08/03/2016] [Indexed: 01/23/2023] Open
Abstract
Background Although there is strong advocacy for uptake of both the arts and creative activities as determinants of individual health conditions, studies evaluating causal influence of attendance at cultural events on population health using individual population data on health are scarce. If available, results are often only of an associative nature. In this light, this study investigated causative impact of attendance at cultural events on self-reported and physical health in the Polish population. Methods Four recent waves (2009, 2011, 2013 and 2015) of the biennial longitudinal Polish household panel study, Social Diagnosis, were analysed. The data, representative for the Polish population aged over 16, with respect to age, gender, classes of place of residence and NUTS 2 regions, were collected from self-report questionnaires. Causative influence of cultural attendance on population health was established using longitudinal population representative data. To account for unobserved heterogeneity of individuals and to mitigate issues caused by omitted variables, a panel data model with a fixed effects estimator was applied. The endogeneity problem (those who enjoy good health are more likely to participate in cultural activities more frequently) was circumvented by application of instrumental variables. Results Results confirmed positive association between cultural attendance and self-reported health. However, in contrast to the often suggested positive causative relationship, such a link was not confirmed by the study. Additionally, no evidence was found to corroborate a positive impact from cultural attendance on physical health. Both findings were substantiated by augmentation in the longitudinal perspective and causal link. Conclusions We showed the relation between attendance at cultural events and self-reported health could only be confirmed as associational. Therefore, this study provided little justification to encourage use of passive cultural participation as a measure of health promotion (improvement). Our study did not confirm any identifiable benefit to physical health from passive participation in culture. Future research should investigate the causative influence of active participation in creative activities on health outcomes as, in contrast to passive attendance, it may be influential.
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Affiliation(s)
- Dorota Węziak-Białowolska
- European Commission, Joint Research Centre (JRC), Directorate I. Competences, Modelling, Indicators and Impact Evaluation Unit, Via E. Fermi 2749, 21027, Ispra (VA), Italy.
| | - Piotr Białowolski
- Department of Economics, Social Studies, Applied Mathematics and Statistics, University of Turin, corso Unione Sovietica 218bis, 10134, Torino, Italy
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Lutsey PL, Norby FL, Gottesman RF, Mosley T, MacLehose RF, Punjabi NM, Shahar E, Jack CR, Alonso A. Sleep Apnea, Sleep Duration and Brain MRI Markers of Cerebral Vascular Disease and Alzheimer's Disease: The Atherosclerosis Risk in Communities Study (ARIC). PLoS One 2016; 11:e0158758. [PMID: 27415826 PMCID: PMC4944966 DOI: 10.1371/journal.pone.0158758] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 06/21/2016] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND A growing body of literature has suggested that obstructive sleep apnea (OSA) and habitual short sleep duration are linked to poor cognitive function. Neuroimaging studies may provide insight into this relation. OBJECTIVE We tested the hypotheses that OSA and habitual short sleep duration, measured at ages 54-73 years, would be associated with adverse brain morphology at ages 67-89 years. METHODS Included in this analysis are 312 ARIC study participants who underwent in-home overnight polysomnography in 1996-1998 and brain MRI scans about 15 years later (2012-2013). Sleep apnea was quantified by the apnea-hypopnea index and categorized as moderate/severe (≥15.0 events/hour), mild (5.0-14.9 events/hour), or normal (<5.0 events/hour). Habitual sleep duration was categorized, in hours, as <7, 7 to <8, ≥8. MRI outcomes included number of infarcts (total, subcortical, and cortical) and white matter hyperintensity (WMH) and Alzheimer's disease signature region volumes. Multivariable adjusted logistic and linear regression models were used. All models incorporated inverse probability weighting, to adjust for potential selection bias. RESULTS At the time of the sleep study participants were 61.7 (SD: 5.0) years old and 54% female; 19% had moderate/severe sleep apnea. MRI imaging took place 14.8 (SD: 1.0) years later, when participants were 76.5 (SD: 5.2) years old. In multivariable models which accounted for body mass index, neither OSA nor abnormal sleep duration were statistically significantly associated with odds of cerebral infarcts, WMH brain volumes or regional brain volumes. CONCLUSIONS In this community-based sample, mid-life OSA and habitually short sleep duration were not associated with later-life cerebral markers of vascular dementia and Alzheimer's disease. However, selection bias may have influenced our results and the modest sample size led to relatively imprecise associations.
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Affiliation(s)
- Pamela L. Lutsey
- University of Minnesota, Minneapolis, MN, United States of America
| | - Faye L. Norby
- University of Minnesota, Minneapolis, MN, United States of America
| | | | - Thomas Mosley
- University of Mississippi Medical Center, Jackson, MS, United States of America
| | | | | | - Eyal Shahar
- University of Arizona, Tucson, AZ, United States of America
| | | | - Alvaro Alonso
- Emory University, Atlanta, GA, United States of America
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307
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Weuve J, Kaufman JD, Szpiro AA, Curl C, Puett RC, Beck T, Evans DA, Mendes de Leon CF. Exposure to Traffic-Related Air Pollution in Relation to Progression in Physical Disability among Older Adults. ENVIRONMENTAL HEALTH PERSPECTIVES 2016; 124:1000-8. [PMID: 27022889 PMCID: PMC4937863 DOI: 10.1289/ehp.1510089] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 11/02/2015] [Accepted: 02/25/2016] [Indexed: 05/18/2023]
Abstract
BACKGROUND Physical disability is common though not inevitable in older age and has direct bearing on a person's ability to perform activities essential for self-care and independent living. Air pollution appears to increase the risk of several chronic diseases that contribute to the progression of disability. OBJECTIVE We evaluated long-term exposure to traffic-related air pollution (TRAP) in relation to progression in physical disability. METHODS We conducted our investigation within the Chicago Health and Aging Project. We measured participants' exposures to TRAP using two surrogates: residential proximity to major roads (1993 onwards) and ambient concentrations of oxides of nitrogen (NOX; 1999 onwards), predicted via a geographic information systems-based spatiotemporal smoothing model (cross-validation R2 = 0.87) that incorporated community-based monitoring and resolved intraurban exposure gradients at a spatial scale of tens of meters. Participants' lower-extremity physical ability was assessed every 3 years (1993-2012) via tandem stand, chair stand, and timed walking speed. RESULTS In multivariable-adjusted analyses (n = 5,708), higher long-term NOX exposure was associated with significantly faster progression in disability. Compared with the 5-year decline in physical ability score among participants in the lowest quartile of NOX exposure, decline among those in the highest exposure quartile was 1.14 units greater (95% confidence interval [CI]: -1.86, -0.42), equivalent to 3 additional years of decline among those in the lowest exposure quartile. The association was linear across the continuum of NOX exposure: per 10-ppb increment in exposure, the 5-year decline in physical ability score was 0.87 unit greater (95% CI: -1.35, -0.39). Proximity to a major road was not associated with disability progression (n = 9,994). CONCLUSIONS These data join a growing body of evidence suggesting that TRAP exposures may accelerate aging-related declines in health. CITATION Weuve J, Kaufman JD, Szpiro AA, Curl C, Puett RC, Beck T, Evans DA, Mendes de Leon CF. 2016. Exposure to traffic-related air pollution in relation to progression in physical disability among older adults. Environ Health Perspect 124:1000-1008; http://dx.doi.org/10.1289/ehp.1510089.
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Affiliation(s)
- Jennifer Weuve
- Rush Institute for Healthy Aging, Department of Internal Medicine, Rush University Medical Center, Chicago, Illinois, USA
- Address correspondence to J. Weuve, Boston University School of Public Health, Department of Epidemiology, 715 Albany St., T331E, Boston, MA 02118 USA. Telephone: (617) 638-8384. E-mail:
| | - Joel D. Kaufman
- Department of Environmental and Occupational Health Sciences, and
- Department of Epidemiology, University of Washington School of Public Health, Seattle, Washington, USA
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Adam A. Szpiro
- Department of Biostatistics, University of Washington School of Public Health, Seattle, Washington, USA
| | - Cynthia Curl
- Department of Environmental and Occupational Health Sciences, and
- Department of Community and Environmental Health, College of Health Sciences, Boise State University, Boise, Idaho, USA
| | - Robin C. Puett
- Maryland Institute of Applied Environmental Health, School of Public Heath, University of Maryland, College Park, Maryland, USA
| | - Todd Beck
- Rush Institute for Healthy Aging, Department of Internal Medicine, Rush University Medical Center, Chicago, Illinois, USA
| | - Denis A. Evans
- Rush Institute for Healthy Aging, Department of Internal Medicine, Rush University Medical Center, Chicago, Illinois, USA
| | - Carlos F. Mendes de Leon
- Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, Michigan, USA
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Assari S. Combined Racial and Gender Differences in the Long-Term Predictive Role of Education on Depressive Symptoms and Chronic Medical Conditions. J Racial Ethn Health Disparities 2016; 4:385-396. [PMID: 27270925 DOI: 10.1007/s40615-016-0239-7] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 04/15/2016] [Accepted: 04/21/2016] [Indexed: 01/25/2023]
Abstract
BACKGROUND Despite a well-established literature on the protective effect of education on health, less is known about group differences in the mechanisms underlying this association. Using a life course approach and cumulative advantage theory, this study compared Black men, Black women, White men, and White women to assess the long-term gradient (education as a continuous measure) and threshold (>12 years) effects of baseline education on change in chronic medical conditions (CMC) and depressive symptoms (DS) from baseline to 25 years later. METHODS Data came from the Americans' Changing Lives Study, 1986-2011. The study followed Black and White respondents for up to 25 years, among whom 1271 individuals who had survived and were under follow-up were interviewed in 2011 and reported their number of chronic medical conditions and depressive symptoms (Center for Epidemiological Studies-Depression; CES-D 11). Multi-group structural equation modeling was used to compare gradient and threshold effects of education on change in chronic medical conditions and depressive symptoms from baseline (1986) to 25 years later (2011) among Black men, Black women, White men, and White women. RESULTS There were group differences in the long-term association between education measured as a gradient and the change in depressive symptoms and chronic medical conditions during the follow-up, and in the association between education measured at the threshold of 12 years on change in depressive symptoms from baseline to follow-up. However, the association between education measured at this threshold and change in chronic medical conditions did not differ across race-gender groups. With the exception of Black men, who showed a gradient protective effect for baseline education against increase in the number of chronic medical associations (threshold or gradient) with change in chronic medical conditions. Among White men and White women, education had a threshold protective effect against increase in depressive symptoms from baseline to 25 years later. Black men and women showed a gradient protective effect of baseline education against an increase in depressive symptoms over the 25-year follow-up period, but unexpectedly, a threshold effect of education was also found to be associated with an increase in depressive symptoms over the follow-up period among Black men. This finding suggests that although Black men benefit from each incremental increase in education, those who graduated from high school were at an additional risk of depressive symptoms over a 25-year period. CONCLUSION Findings suggest that the intersection of race and gender influences how education is associated with long-term changes in physical and mental health of individuals from baseline to 25 years later. As the shape of the association between education and health depends on the intersection of race and gender, these groups may vary for operant mechanisms by which education operates as a main social determinant of health.
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Affiliation(s)
- Shervin Assari
- Department of Psychiatry, University of Michigan, 4250 Plymouth Road, SPC 5763, Ann Arbor, MI, 48109-2700, USA.
- Center for Research on Ethnicity, Culture and Health, School of Public Health, University of Michigan, 4250 Plymouth Road, SPC 5763, Ann Arbor, MI, 48109-2700, USA.
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309
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Life-course blood pressure in relation to brain volumes. Alzheimers Dement 2016; 12:890-9. [PMID: 27139841 DOI: 10.1016/j.jalz.2016.03.012] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 03/14/2016] [Accepted: 03/24/2016] [Indexed: 11/21/2022]
Abstract
INTRODUCTION The impact of blood pressure on brain volumes may be time-dependent or pattern-dependent. METHODS Of 1678 participants from the Atherosclerosis Risk in Communities Neurocognitive Study, we quantified the association between measures and patterns of blood pressure over three time points (∼24 or ∼15 years prior and concurrent with neuroimaging) with late life brain volumes. RESULTS Higher diastolic blood pressure ∼24 years prior, higher systolic and pulse pressure ∼15 years prior, and consistently elevated or rising systolic blood pressure from ∼15 years prior to concurrent with neuroimaging, but not blood pressures measured concurrent with neuroimaging, were associated with smaller volumes. The pattern of hypertension ∼15 years prior and hypotension concurrent with neuroimaging was associated with smaller volumes in regions preferentially affected by Alzheimer's disease (e.g., hippocampus: -0.27 standard units, 95% CI: -0.51, -0.03). DISCUSSION Hypertension 15 to 24 years prior is relevant to current brain volumes. Hypertension followed by hypotension appears particularly detrimental.
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310
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Lê-Scherban F, Albrecht SS, Bertoni A, Kandula N, Mehta N, Diez Roux AV. Immigrant status and cardiovascular risk over time: results from the Multi-Ethnic Study of Atherosclerosis. Ann Epidemiol 2016; 26:429-435.e1. [PMID: 27221804 DOI: 10.1016/j.annepidem.2016.04.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 03/28/2016] [Accepted: 04/11/2016] [Indexed: 12/21/2022]
Abstract
PURPOSE Despite cross-sectional evidence that foreign-born United States (US) residents often have better health than US-born residents of similar race and/or ethnicity, we know little about overall cardiovascular risk progression over time among immigrants as they age in the US. METHODS Using longitudinal data from the Multiethnic Study of Atherosclerosis on 6446 adults aged 45-84 years at baseline, we examined how nativity and length of US residence related to change in cardiovascular health (CVH) and cardiovascular event incidence over 11-year follow-up. CVH was measured using the American Heart Association's CVH measure (range, 0-14; higher is better). RESULTS Immigrants, particularly those with shorter US residence, had better baseline CVH and lower cardiovascular event incidence than the US born. Baseline CVH scores ranged from 8.67 (8.42-8.92) among immigrants living in the US less than 10 years to 7.86 (7.76-7.97) among the US born. However, recent immigrants experienced the largest CVH declines over time: 10-year declines ranged from -1.04 (-1.27 to -0.80) among immigrants living in the US less than 10 years at baseline to -0.47 (-0.52 to -0.42) among the US born. CONCLUSIONS Public health prevention efforts targeting new immigrants may help slow the deterioration of CVH and reduce future cardiovascular risk.
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Affiliation(s)
- Félice Lê-Scherban
- Department of Epidemiology and Biostatistics, Dornsife School of Public Health, Drexel University, Philadelphia, PA.
| | - Sandra S Albrecht
- Department of Nutrition, Carolina Population Center, University of North Carolina at Chapel Hill, Chapel Hill
| | - Alain Bertoni
- Division of Public Health Sciences, Department of Epidemiology & Prevention, Wake Forest University, Winston-Salem, NC
| | | | - Neil Mehta
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA
| | - Ana V Diez Roux
- Department of Epidemiology and Biostatistics, Dornsife School of Public Health, Drexel University, Philadelphia, PA
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Oudin A, Forsberg B, Adolfsson AN, Lind N, Modig L, Nordin M, Nordin S, Adolfsson R, Nilsson LG. Traffic-Related Air Pollution and Dementia Incidence in Northern Sweden: A Longitudinal Study. ENVIRONMENTAL HEALTH PERSPECTIVES 2016; 124:306-12. [PMID: 26305859 PMCID: PMC4786976 DOI: 10.1289/ehp.1408322] [Citation(s) in RCA: 228] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 07/28/2015] [Indexed: 05/18/2023]
Abstract
BACKGROUND Exposure to ambient air pollution is suspected to cause cognitive effects, but a prospective cohort is needed to study exposure to air pollution at the home address and the incidence of dementia. OBJECTIVES We aimed to assess the association between long-term exposure to traffic-related air pollution and dementia incidence in a major city in northern Sweden. METHODS Data on dementia incidence over a 15-year period were obtained from the longitudinal Betula study. Traffic air pollution exposure was assessed using a land-use regression model with a spatial resolution of 50 m × 50 m. Annual mean nitrogen oxide levels at the residential address of the participants at baseline (the start of follow-up) were used as markers for long-term exposure to air pollution. RESULTS Out of 1,806 participants at baseline, 191 were diagnosed with Alzheimer's disease during follow-up, and 111 were diagnosed with vascular dementia. Participants in the group with the highest exposure were more likely than those in the group with the lowest exposure to be diagnosed with dementia (Alzheimer's disease or vascular dementia), with a hazard ratio (HR) of 1.43 (95% CI: 0.998, 2.05 for the highest vs. the lowest quartile). The estimates were similar for Alzheimer's disease (HR 1.38) and vascular dementia (HR 1.47). The HR for dementia associated with the third quartile versus the lowest quartile was 1.48 (95% CI: 1.03, 2.11). A subanalysis that excluded a younger sample that had been retested after only 5 years of follow-up suggested stronger associations with exposure than were present in the full cohort (HR = 1.71; 95% CI: 1.08, 2.73 for the highest vs. the lowest quartile). CONCLUSIONS If the associations we observed are causal, then air pollution from traffic might be an important risk factor for vascular dementia and Alzheimer's disease.
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Affiliation(s)
- Anna Oudin
- Occupational and Environmental Medicine, Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
| | - Bertil Forsberg
- Occupational and Environmental Medicine, Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
- Address correspondence to B. Forsberg, Occupational and Environmental Medicine, Department of Public Health and Clinical Medicine, Umeå University, SE 901 87 Umeå, Sweden. Telephone: 46907852751. E-mail:
| | | | - Nina Lind
- Department of Psychology, Umeå University, Umeå, Sweden
| | - Lars Modig
- Occupational and Environmental Medicine, Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
| | - Maria Nordin
- Department of Psychology, Umeå University, Umeå, Sweden
| | - Steven Nordin
- Department of Psychology, Umeå University, Umeå, Sweden
| | - Rolf Adolfsson
- Division of Psychiatry, Department of Clinical Sciences, and
| | - Lars-Göran Nilsson
- ARC (Aging Research Centre), Karolinska Institutet, Stockholm, Sweden
- Umeå Center for Functional Brain Imaging, Umeå University, Umeå, Sweden
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312
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Lung function decline over 25 years of follow-up among black and white adults in the ARIC study cohort. Respir Med 2016; 113:57-64. [PMID: 26905512 DOI: 10.1016/j.rmed.2016.02.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 02/01/2016] [Accepted: 02/07/2016] [Indexed: 11/22/2022]
Abstract
BACKGROUND Interpretation of longitudinal information about lung function decline from middle to older age has been limited by loss to follow-up that may be correlated with baseline lung function or the rate of decline. We conducted these analyses to estimate age-related decline in lung function across groups of race, sex, and smoking status while accounting for dropout from the Atherosclerosis Risk in Communities Study. METHODS We analyzed data from 13,896 black and white participants, aged 45-64 years at the 1987-1989 baseline clinical examination. Using spirometry data collected at baseline and two follow-up visits, we estimated annual population-averaged mean changes in forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) by race, sex, and smoking status using inverse-probability-weighted independence estimating equations conditioning-on-being-alive. RESULTS Estimated rates of FEV1 decline estimated using inverse-probability-weighted independence estimating equations conditioning on being alive were higher among white than black participants at age 45 years (e.g., male never smokers: black: -29.5 ml/year; white: -51.9 ml/year), but higher among black than white participants by age 75 (black: -51.2 ml/year; white: -26). Observed differences by race were more pronounced among men than among women. By smoking status, FEV1 declines were larger among current than former or never smokers at age 45 across all categories of race and sex. By age 60, FEV1 decline was larger among former and never than current smokers. Estimated annual declines generated using unweighted generalized estimating equations were smaller for current smokers at younger ages in all four groups of race and sex compared with results from weighted analyses that accounted for attrition. CONCLUSIONS Using methods accounting for dropout from an approximately 25-year health study, estimated rates of lung function decline varied by age, race, sex, and smoking status, with largest declines observed among current smokers at younger ages.
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313
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Lutsey PL, Bengtson LGS, Punjabi NM, Shahar E, Mosley TH, Gottesman RF, Wruck LM, MacLehose RF, Alonso A. Obstructive Sleep Apnea and 15-Year Cognitive Decline: The Atherosclerosis Risk in Communities (ARIC) Study. Sleep 2016; 39:309-16. [PMID: 26446113 DOI: 10.5665/sleep.5434] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 08/28/2015] [Indexed: 12/31/2022] Open
Abstract
STUDY OBJECTIVES Prospective data evaluating abnormal sleep quality and quantity with cognitive decline are limited because most studies used subjective data and/or had short follow-up. We hypothesized that, over 15 y of follow-up, participants with objectively measured obstructive sleep apnea (OSA) and other indices of poor sleep quantity and quality would experience greater decline in cognitive functioning than participants with normal sleep patterns. METHODS ARIC participants (n = 966; mean age 61 y, 55% women) with in-home polysomnography (1996-1998) and repeated cognitive testing were followed for 15 y. Three cognitive tests (Delayed Word Recall, Word Fluency, and Digit Symbol Substitution) were administered at two time points (1996-1998 and 2011-2013). Ten additional cognitive tests were administered at the 2011-2013 neurocognitive examination. OSA was modeled using established clinical OSA severity categories. Multivariable linear regression was used to explore associations of OSA and other sleep indices with change in cognitive tests between the two assessments. RESULTS A median of 14.9 y (max: 17.3) passed between the two cognitive assessments. OSA category and additional indices of sleep (other measures of hypoxemia and disordered breathing, sleep fragmentation, sleep duration) were not associated with change in any cognitive test. Analyses of OSA severity categories and 10 cognitive tests administered only in 2011-2013 also showed little evidence of an association. CONCLUSIONS Overall, abnormal sleep quality and quantity at midlife was not related to cognitive decline and later-life cognition. The effect of adverse sleep quality and quantity on cognitive decline among the elderly remains to be determined.
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314
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Banack HR, Kaufman JS. Estimating the Time-Varying Joint Effects of Obesity and Smoking on All-Cause Mortality Using Marginal Structural Models. Am J Epidemiol 2016; 183:122-9. [PMID: 26656480 DOI: 10.1093/aje/kwv168] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 06/22/2015] [Indexed: 12/21/2022] Open
Abstract
Obesity and smoking are independently associated with a higher mortality risk, but previous studies have reported conflicting results about the relationship between these 2 time-varying exposures. Using prospective longitudinal data (1987-2007) from the Atherosclerosis Risk in Communities Study, our objective in the present study was to estimate the joint effects of obesity and smoking on all-cause mortality and investigate whether there were additive or multiplicative interactions. We fit a joint marginal structural Poisson model to account for time-varying confounding affected by prior exposure to obesity and smoking. The incidence rate ratios from the joint model were 2.00 (95% confidence interval (CI): 1.79, 2.24) for the effect of smoking on mortality among nonobese persons, 1.31 (95% CI: 1.13, 1.51) for the effect of obesity on mortality among nonsmokers, and 1.97 (95% CI: 1.73, 2.22) for the joint effect of smoking and obesity on mortality. The negative product term from the exponential model revealed a submultiplicative interaction between obesity and smoking (β = -0.28, 95% CI: -0.45, -0.11; P < 0.001). The relative excess risk of interaction was -0.34 (95% CI: -0.60, -0.07), indicating the presence of subadditive interaction. These results provide important information for epidemiologists, clinicians, and public health practitioners about the harmful impact of smoking and obesity.
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315
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Rehkopf DH, Domingue BW, Cullen MR. The Geographic Distribution of Genetic Risk as Compared to Social Risk for Chronic Diseases in the United States. BIODEMOGRAPHY AND SOCIAL BIOLOGY 2016; 62:126-142. [PMID: 27050037 PMCID: PMC4899969 DOI: 10.1080/19485565.2016.1141353] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
There is an association between chronic disease and geography, and there is evidence that the environment plays a critical role in this relationship. Yet at the same time, there is known to be substantial geographic variation by ancestry across the United States. Resulting geographic genetic variation-that is, the extent to which single nucleotide polymorphisms (SNPs) related to chronic disease vary spatially-could thus drive some part of the association between geography and disease. We describe the variation in chronic disease genetic risk by state of birth by taking risk SNPs from genome-wide association study meta-analyses for coronary artery disease, diabetes, and ischemic stroke and creating polygenic risk scores. We compare the amount of variability across state of birth in these polygenic scores to the variability in parental education, own education, earnings, and wealth. Our primary finding is that the polygenic risk scores are only weakly differentially distributed across U.S. states. The magnitude of the differences in geographic distribution is very small in comparison to the distribution of social and economic factors and thus is not likely sufficient to have a meaningful effect on geographic disease differences by U.S. state.
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Affiliation(s)
- David H Rehkopf
- a School of Medicine, Division of General Medical Disciplines , Stanford University , Stanford , California , USA
| | - Benjamin W Domingue
- b Graduate School of Education , Stanford University , Stanford , California , USA
| | - Mark R Cullen
- a School of Medicine, Division of General Medical Disciplines , Stanford University , Stanford , California , USA
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316
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Tampubolon G. Cognitive Ageing in Great Britain in the New Century: Cohort Differences in Episodic Memory. PLoS One 2015; 10:e0144907. [PMID: 26713627 PMCID: PMC4699214 DOI: 10.1371/journal.pone.0144907] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Accepted: 11/26/2015] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Dementias in high income countries are set to be the third major burden of disease even as older people are increasingly required to think for themselves how to provide for their lives in retirement. Meanwhile the period of older age continues to extend with increase in life expectancy. This challenge demands an understanding of how cognition changes over an extended period in later life. But studying cognitive ageing in the population faces a difficulty from the fact that older respondents are liable to leave (attrite) before study completion. This study tested three hypotheses: trajectories of cognitive ageing in Britain show an improvement beyond the age of 50; and they are lifted by secular improvement in cognition across cohorts; lastly they are susceptible to distortion due to attrition. METHODS AND FINDINGS Using the English Longitudinal Study of Ageing, this paper studied trajectories of episodic memory of Britons aged 50-89 from 2002 to 2013 (N = 5931). Using joint models the analysis found that levels of episodic memory follow a curvilinear shape, not a steady decline, in later life. The findings also revealed secular improvement in cognitive ageing such that as a cohort is being replaced episodic memory levels in the population improve. The analysis lastly demonstrated that failure to simultaneously model attrition can produce distorted pictures of cognitive ageing. CONCLUSION Old age in this century is not necessarily a period dominated by cognitive decline. In identifying behavioural factors associated with better cognitive ageing, such as social connections of traditional and online kinds, the paper raises possibilities of mustering an adequate response to the cognition challenge.
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Affiliation(s)
- Gindo Tampubolon
- Cathie Marsh Institute for Social Research, University of Manchester, Manchester, United Kingdom
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317
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Weisskopf MG, Sparrow D, Hu H, Power MC. Biased Exposure-Health Effect Estimates from Selection in Cohort Studies: Are Environmental Studies at Particular Risk? ENVIRONMENTAL HEALTH PERSPECTIVES 2015; 123:1113-22. [PMID: 25956004 PMCID: PMC4629739 DOI: 10.1289/ehp.1408888] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 05/06/2015] [Indexed: 05/17/2023]
Abstract
BACKGROUND The process of creating a cohort or cohort substudy may induce misleading exposure-health effect associations through collider stratification bias (i.e., selection bias) or bias due to conditioning on an intermediate. Studies of environmental risk factors may be at particular risk. OBJECTIVES We aimed to demonstrate how such biases of the exposure-health effect association arise and how one may mitigate them. METHODS We used directed acyclic graphs and the example of bone lead and mortality (all-cause, cardiovascular, and ischemic heart disease) among 835 white men in the Normative Aging Study (NAS) to illustrate potential bias related to recruitment into the NAS and the bone lead substudy. We then applied methods (adjustment, restriction, and inverse probability of attrition weighting) to mitigate these biases in analyses using Cox proportional hazards models to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs). RESULTS Analyses adjusted for age at bone lead measurement, smoking, and education among all men found HRs (95% CI) for the highest versus lowest tertile of patella lead of 1.34 (0.90, 2.00), 1.46 (0.86, 2.48), and 2.01 (0.86, 4.68) for all-cause, cardiovascular, and ischemic heart disease mortality, respectively. After applying methods to mitigate the biases, the HR (95% CI) among the 637 men analyzed were 1.86 (1.12, 3.09), 2.47 (1.23, 4.96), and 5.20 (1.61, 16.8), respectively. CONCLUSIONS Careful attention to the underlying structure of the observed data is critical to identifying potential biases and methods to mitigate them. Understanding factors that influence initial study participation and study loss to follow-up is critical. Recruitment of population-based samples and enrolling participants at a younger age, before the potential onset of exposure-related health effects, can help reduce these potential pitfalls. CITATION Weisskopf MG, Sparrow D, Hu H, Power MC. 2015. Biased exposure-health effect estimates from selection in cohort studies: are environmental studies at particular risk? Environ Health Perspect 123:1113-1122; http://dx.doi.org/10.1289/ehp.1408888.
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Affiliation(s)
- Marc G Weisskopf
- Department of Epidemiology and Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
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Associations of adolescent cannabis use with academic performance and mental health: A longitudinal study of upper middle class youth. Drug Alcohol Depend 2015; 156:207-212. [PMID: 26409752 PMCID: PMC4633365 DOI: 10.1016/j.drugalcdep.2015.09.010] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 09/10/2015] [Accepted: 09/12/2015] [Indexed: 11/21/2022]
Abstract
BACKGROUND There is a hypothesis that low socioeconomic status (SES) may explain the link between cannabis use and poorer academic performance and mental health. A key question, therefore, is whether adolescent cannabis use is associated with poorer academic performance and mental health in high SES communities where there is reduced potential for confounding. METHODS Youth (n=254) from an upper middle class community were followed prospectively through the four years of high school (from age 14/15 to age 17/18). Past-year frequency of cannabis use was assessed annually. Official school records of academic performance and self-reported mental health symptoms (externalizing and internalizing symptoms) were assessed in grades 9 and 12. RESULTS Persistent cannabis use across the four years of high school was associated with lower grade-point average (β=-0.18, p=.006), lower Scholastic Aptitude Test (SAT) score (β=-0.13, p=.038), and greater externalizing symptoms (β=0.29, p<.001) in 12th grade, but not with greater internalizing symptoms (β=0.04, p=.53). Moreover, persistent cannabis use was associated with lower grade-point average (β=-0.13, p=.014) and greater externalizing symptoms (β=0.24, p=.002) in 12th grade, even after controlling for 9th grade levels of these outcomes. Similar associations were observed for persistent alcohol and tobacco use. Effects for persistent cannabis use became non-significant after controlling for persistent alcohol and tobacco use, reflecting the difficulties of disentangling effects of cannabis from effects of alcohol and tobacco. CONCLUSIONS Low SES cannot fully explain associations between cannabis use and poorer academic performance and mental health.
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319
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Effect of health risk assessment and counselling on health behaviour and survival in older people: a pragmatic randomised trial. PLoS Med 2015; 12:e1001889. [PMID: 26479077 PMCID: PMC4610679 DOI: 10.1371/journal.pmed.1001889] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 09/11/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Potentially avoidable risk factors continue to cause unnecessary disability and premature death in older people. Health risk assessment (HRA), a method successfully used in working-age populations, is a promising method for cost-effective health promotion and preventive care in older individuals, but the long-term effects of this approach are unknown. The objective of this study was to evaluate the effects of an innovative approach to HRA and counselling in older individuals for health behaviours, preventive care, and long-term survival. METHODS AND FINDINGS This study was a pragmatic, single-centre randomised controlled clinical trial in community-dwelling individuals aged 65 y or older registered with one of 19 primary care physician (PCP) practices in a mixed rural and urban area in Switzerland. From November 2000 to January 2002, 874 participants were randomly allocated to the intervention and 1,410 to usual care. The intervention consisted of HRA based on self-administered questionnaires and individualised computer-generated feedback reports, combined with nurse and PCP counselling over a 2-y period. Primary outcomes were health behaviours and preventive care use at 2 y and all-cause mortality at 8 y. At baseline, participants in the intervention group had a mean ± standard deviation of 6.9 ± 3.7 risk factors (including unfavourable health behaviours, health and functional impairments, and social risk factors) and 4.3 ± 1.8 deficits in recommended preventive care. At 2 y, favourable health behaviours and use of preventive care were more frequent in the intervention than in the control group (based on z-statistics from generalised estimating equation models). For example, 70% compared to 62% were physically active (odds ratio 1.43, 95% CI 1.16-1.77, p = 0.001), and 66% compared to 59% had influenza vaccinations in the past year (odds ratio 1.35, 95% CI 1.09-1.66, p = 0.005). At 8 y, based on an intention-to-treat analysis, the estimated proportion alive was 77.9% in the intervention and 72.8% in the control group, for an absolute mortality difference of 4.9% (95% CI 1.3%-8.5%, p = 0.009; based on z-test for risk difference). The hazard ratio of death comparing intervention with control was 0.79 (95% CI 0.66-0.94, p = 0.009; based on Wald test from Cox regression model), and the number needed to receive the intervention to prevent one death was 21 (95% CI 12-79). The main limitations of the study include the single-site study design, the use of a brief self-administered questionnaire for 2-y outcome data collection, the unavailability of other long-term outcome data (e.g., functional status, nursing home admissions), and the availability of long-term follow-up data on mortality for analysis only in 2014. CONCLUSIONS This is the first trial to our knowledge demonstrating that a collaborative care model of HRA in community-dwelling older people not only results in better health behaviours and increased use of recommended preventive care interventions, but also improves survival. The intervention tested in our study may serve as a model of how to implement a relatively low-cost but effective programme of disease prevention and health promotion in older individuals. TRIAL REGISTRATION International Standard Randomized Controlled Trial Number: ISRCTN 28458424.
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320
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Shah AM, Claggett B, Folsom AR, Lutsey PL, Ballantyne CM, Heiss G, Solomon SD. Ideal Cardiovascular Health During Adult Life and Cardiovascular Structure and Function Among the Elderly. Circulation 2015; 132:1979-89. [PMID: 26350059 DOI: 10.1161/circulationaha.115.017882] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 08/31/2015] [Indexed: 11/16/2022]
Abstract
BACKGROUND A higher American Heart Association cardiovascular health score (CVHS) predicts a lower incidence of cardiovascular disease (CVD). However, the relationship of CVHS attainment through midlife to late life with CVD prevalence and cardiovascular structure and function in late life is not well described. METHODS AND RESULTS The following 6 ideal cardiovascular health metrics were assessed in the Atherosclerosis Risk in Communities (ARIC) study participants at 5 examination visits between 1987 and 2013: nonsmoking, body mass index <25 kg/m(2), untreated total cholesterol <200 mg/dL, untreated blood pressure <120/<80 mm Hg, fasting blood glucose <100 mg/dL, and ideal physical activity. Attainment over time was assessed as the percentage of maximum possible CVHS metrics achieved at visits 1 through 5, the slope of change in CVHS per decade of follow-up, and CVHS trajectory through follow-up. At visit 5, participant groups were characterized with respect to CVD prevalence (n=6520) and echocardiographic measures of cardiac structure and function (n=5903 free of CVD). CVHS was low at baseline and declined with age. Both greater CVHS attainment and improvement in CVHS during follow-up were associated with a lower prevalence of CVD and better left ventricular structure and systolic and diastolic function at visit 5. CONCLUSIONS Greater attainment of, and improvements in, ideal cardiovascular health through midlife to late life are associated with lower CVD prevalence and better cardiovascular structure and function when elderly. These findings highlight the importance of consistent primordial and primary prevention efforts throughout midlife to late life as a potential intervention to decrease the burden of CVD among the elderly.
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Affiliation(s)
- Amil M Shah
- From Division of Cardiovascular Medicine, Brigham and Women's Hospital, Boston, MA (A.M.S., B.C., S.D.S.); Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis (A.R.F., P.L.L.); Section of Cardiology, Baylor College of Medicine and Methodist DeBakey Heart and Vascular Center, Houston, TX (C.M.B.); and University of North Carolina Gillings School of Global Public Health, Chapel Hill (G.H.).
| | - Brian Claggett
- From Division of Cardiovascular Medicine, Brigham and Women's Hospital, Boston, MA (A.M.S., B.C., S.D.S.); Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis (A.R.F., P.L.L.); Section of Cardiology, Baylor College of Medicine and Methodist DeBakey Heart and Vascular Center, Houston, TX (C.M.B.); and University of North Carolina Gillings School of Global Public Health, Chapel Hill (G.H.)
| | - Aaron R Folsom
- From Division of Cardiovascular Medicine, Brigham and Women's Hospital, Boston, MA (A.M.S., B.C., S.D.S.); Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis (A.R.F., P.L.L.); Section of Cardiology, Baylor College of Medicine and Methodist DeBakey Heart and Vascular Center, Houston, TX (C.M.B.); and University of North Carolina Gillings School of Global Public Health, Chapel Hill (G.H.)
| | - Pamela L Lutsey
- From Division of Cardiovascular Medicine, Brigham and Women's Hospital, Boston, MA (A.M.S., B.C., S.D.S.); Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis (A.R.F., P.L.L.); Section of Cardiology, Baylor College of Medicine and Methodist DeBakey Heart and Vascular Center, Houston, TX (C.M.B.); and University of North Carolina Gillings School of Global Public Health, Chapel Hill (G.H.)
| | - Christie M Ballantyne
- From Division of Cardiovascular Medicine, Brigham and Women's Hospital, Boston, MA (A.M.S., B.C., S.D.S.); Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis (A.R.F., P.L.L.); Section of Cardiology, Baylor College of Medicine and Methodist DeBakey Heart and Vascular Center, Houston, TX (C.M.B.); and University of North Carolina Gillings School of Global Public Health, Chapel Hill (G.H.)
| | - Gerardo Heiss
- From Division of Cardiovascular Medicine, Brigham and Women's Hospital, Boston, MA (A.M.S., B.C., S.D.S.); Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis (A.R.F., P.L.L.); Section of Cardiology, Baylor College of Medicine and Methodist DeBakey Heart and Vascular Center, Houston, TX (C.M.B.); and University of North Carolina Gillings School of Global Public Health, Chapel Hill (G.H.)
| | - Scott D Solomon
- From Division of Cardiovascular Medicine, Brigham and Women's Hospital, Boston, MA (A.M.S., B.C., S.D.S.); Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis (A.R.F., P.L.L.); Section of Cardiology, Baylor College of Medicine and Methodist DeBakey Heart and Vascular Center, Houston, TX (C.M.B.); and University of North Carolina Gillings School of Global Public Health, Chapel Hill (G.H.)
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Weuve J, Proust-Lima C, Power MC, Gross AL, Hofer SM, Thiébaut R, Chêne G, Glymour MM, Dufouil C. Guidelines for reporting methodological challenges and evaluating potential bias in dementia research. Alzheimers Dement 2015; 11:1098-109. [PMID: 26397878 PMCID: PMC4655106 DOI: 10.1016/j.jalz.2015.06.1885] [Citation(s) in RCA: 161] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 06/05/2015] [Accepted: 06/17/2015] [Indexed: 01/26/2023]
Abstract
Clinical and population research on dementia and related neurologic conditions, including Alzheimer's disease, faces several unique methodological challenges. Progress to identify preventive and therapeutic strategies rests on valid and rigorous analytic approaches, but the research literature reflects little consensus on "best practices." We present findings from a large scientific working group on research methods for clinical and population studies of dementia, which identified five categories of methodological challenges as follows: (1) attrition/sample selection, including selective survival; (2) measurement, including uncertainty in diagnostic criteria, measurement error in neuropsychological assessments, and practice or retest effects; (3) specification of longitudinal models when participants are followed for months, years, or even decades; (4) time-varying measurements; and (5) high-dimensional data. We explain why each challenge is important in dementia research and how it could compromise the translation of research findings into effective prevention or care strategies. We advance a checklist of potential sources of bias that should be routinely addressed when reporting dementia research.
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Affiliation(s)
- Jennifer Weuve
- Rush Institute for Healthy Aging, Rush University Medical Center, Chicago, IL, USA
| | - Cécile Proust-Lima
- INSERM U897, Epidemiology and Biostatistics Center, Bordeaux School of Public Health, Bordeaux University, Bordeaux, France
| | - Melinda C Power
- Department of Epidemiology, Johns Hopkins School of Public Health, Baltimore, MD, USA
| | - Alden L Gross
- Department of Epidemiology, Johns Hopkins School of Public Health, Baltimore, MD, USA; Johns Hopkins Center on Aging and Health, Baltimore, MD, USA
| | - Scott M Hofer
- Department of Psychology and Centre on Aging, University of Victoria, Victoria, BC, Canada
| | - Rodolphe Thiébaut
- INSERM U897, Epidemiology and Biostatistics Center, Bordeaux School of Public Health, Bordeaux University, Bordeaux, France; Clinical Investigation Center-Clinical Epidemiology-CIC-1401 of INSERM U897, Bordeaux, France; Bordeaux University Hospital (Public Health Department), Bordeaux, France
| | - Geneviève Chêne
- INSERM U897, Epidemiology and Biostatistics Center, Bordeaux School of Public Health, Bordeaux University, Bordeaux, France; Clinical Investigation Center-Clinical Epidemiology-CIC-1401 of INSERM U897, Bordeaux, France; Bordeaux University Hospital (Public Health Department), Bordeaux, France
| | - M Maria Glymour
- Department of Social and Behavioral Sciences, Harvard School of Public Heath, Boston, MA, USA; Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, USA
| | - Carole Dufouil
- INSERM U897, Epidemiology and Biostatistics Center, Bordeaux School of Public Health, Bordeaux University, Bordeaux, France; Clinical Investigation Center-Clinical Epidemiology-CIC-1401 of INSERM U897, Bordeaux, France; Bordeaux University Hospital (Public Health Department), Bordeaux, France.
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Folsom AR, Shah AM, Lutsey PL, Roetker NS, Alonso A, Avery CL, Miedema MD, Konety S, Chang PP, Solomon SD. American Heart Association's Life's Simple 7: Avoiding Heart Failure and Preserving Cardiac Structure and Function. Am J Med 2015; 128:970-6.e2. [PMID: 25908393 PMCID: PMC4554769 DOI: 10.1016/j.amjmed.2015.03.027] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 03/24/2015] [Accepted: 03/24/2015] [Indexed: 11/28/2022]
Abstract
BACKGROUND Many people may underappreciate the role of lifestyle in avoiding heart failure. We estimated whether greater adherence in middle age to American Heart Association's Life's Simple 7 guidelines—on smoking, body mass, physical activity, diet, cholesterol, blood pressure, and glucose—is associated with lower lifetime risk of heart failure and greater preservation of cardiac structure and function in old age. METHODS We studied the population-based Atherosclerosis Risk in Communities Study cohort of 13,462 adults ages 45-64 years in 1987-1989. From the 1987-1989 risk factor measurements, we created a Life's Simple 7 score (range 0-14, giving 2 points for ideal, 1 point for intermediate, and 0 points for poor components). We identified 2218 incident heart failure events using surveillance of hospital discharge and death codes through 2011. In addition, in 4855 participants free of clinical cardiovascular disease in 2011-2013, we performed echocardiography from which we quantified left ventricular hypertrophy and diastolic dysfunction. RESULTS One in four participants (25.5%) developed heart failure through age 85 years. Yet, this lifetime heart failure risk was 14.4% for those with a middle-age Life's Simple 7 score of 10-14 (optimal), 26.8% for a score of 5-9 (average), and 48.6% for a score of 0-4 (inadequate). Among those with no clinical cardiovascular event, the prevalence of left ventricular hypertrophy in late life was approximately 40% as common, and diastolic dysfunction was approximately 60% as common, among those with an optimal middle-age Life's Simple 7 score, compared with an inadequate score. CONCLUSIONS Greater achievement of American Heart Association's Life's Simple 7 in middle age is associated with a lower lifetime occurrence of heart failure and greater preservation of cardiac structure and function.
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Affiliation(s)
- Aaron R Folsom
- Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis.
| | - Amil M Shah
- Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Boston, Mass
| | - Pamela L Lutsey
- Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis
| | - Nicholas S Roetker
- Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis
| | - Alvaro Alonso
- Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis
| | - Christy L Avery
- Department of Epidemiology, University of North Carolina, Chapel Hill
| | - Michael D Miedema
- Minneapolis Heart Institute and Minneapolis Heart Institute Foundation, Minneapolis, Minn
| | - Suma Konety
- Cardiology Division, University of Minnesota Medical School, Minneapolis
| | - Patricia P Chang
- Division of Cardiology, Department of Medicine, University of North Carolina, Chapel Hill
| | - Scott D Solomon
- Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Boston, Mass
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323
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Suemoto CK, Gilsanz P, Mayeda ER, Glymour MM. Body mass index and cognitive function: the potential for reverse causation. Int J Obes (Lond) 2015; 39:1383-9. [PMID: 25953125 PMCID: PMC4758694 DOI: 10.1038/ijo.2015.83] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 04/13/2015] [Accepted: 04/22/2015] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Higher late life body mass index (BMI) is unrelated to or even predicts lower risk of dementia in late life, a phenomenon that may be explained by reverse causation due to weight loss during preclinical phases of dementia. We aim to investigate the association of baseline BMI and changes in BMI with dementia in a large prospective cohort, and to examine whether weight loss predicts cognitive function. METHODS Using a national cohort of adults average age 58 years at baseline in 1994 (n=7029), we investigated the associations between baseline BMI in 1994 and memory scores from 2000 to 2010. We also examined the association of BMI change from 1994 to 1998 with memory scores from 2000 to 2010. Last, to investigate reverse causation, we examined whether memory scores in 1996 predicted BMI trajectories from 2000 to 2010. RESULTS Baseline overweight predicted better memory scores 6 to 16 years later (β=0.012, 95% confidence interval (CI)=0.001; 0.023). Decline in BMI predicted lower memory scores over the subsequent 12 years (β=-0.026, 95% CI= -0.041; -0.011). Lower memory scores at mean age 60 years in 1996 predicted faster annual rate of BMI decline during follow-up (β=-0.158 kg m(-2) per year, 95% CI= -0.223; -0.094). CONCLUSION Consistent with reverse causation, greater decline in BMI over the first 4 years of the study was associated with lower memory scores over the next decade and lower memory scores was associated with a decline in BMI. These findings suggest that preclinical dementia predicts weight loss for people as early as their late 50s.
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Affiliation(s)
- C K Suemoto
- Department of Social and Behavioral Sciences, Harvard School of Public Health, Boston, MA, USA
- Discipline of Geriatrics, University of Sao Paulo Medical School, Sao Paulo, SP, Brazil
| | - P Gilsanz
- Department of Social and Behavioral Sciences, Harvard School of Public Health, Boston, MA, USA
| | - E R Mayeda
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, USA
| | - M M Glymour
- Department of Social and Behavioral Sciences, Harvard School of Public Health, Boston, MA, USA
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, USA
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324
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Wu Q, Tchetgen Tchetgen EJ, Osypuk T, Weuve J, White K, Mujahid M, Glymour MM. Estimating the cognitive effects of prevalent diabetes, recent onset diabetes, and the duration of diabetes among older adults. Dement Geriatr Cogn Disord 2015; 39:239-49. [PMID: 25613323 DOI: 10.1159/000368654] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/24/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Little evidence is available on the effects of incident diabetes or diabetes duration on cognitive aging. METHODS We evaluated the effects of prevalent and incident diabetes on deteriorations in cognitive function, based on participants (n = 8,671) aged 65+ in the Health and Retirement Study in 2000. Inverse probability weighting was used to account for selective attrition and time-varying confounding of incident diabetes. RESULTS Prevalent diabetes predicted higher odds of dementia [odds ratio 1.27; 95% confidence interval (CI) 1.03-1.58] and worse memory (-0.06 in z-score units; 95% CI -0.10 to -0.02), but incident diabetes or diabetes duration up to 8 years of follow-up was not predictive. CONCLUSION Prevalent diabetes predicted lower cognition but not recent onset diabetes.
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Affiliation(s)
- Qiong Wu
- Institute of Social Science Survey, Peking University, Beijing, China
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325
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Abstract
Estimating causal effects is a frequent goal of epidemiologic studies. Traditionally, there have been three established systematic threats to consistent estimation of causal effects. These three threats are bias due to confounders, selection, and measurement error. Confounding, selection, and measurement bias have typically been characterized as distinct types of biases. However, each of these biases can also be characterized as missing data problems that can be addressed with missing data solutions. Here we describe how the aforementioned systematic threats arise from missing data as well as review methods and their related assumptions for reducing each bias type. We also link the assumptions made by the reviewed methods to the missing completely at random (MCAR) and missing at random (MAR) assumptions made in the missing data framework that allow for valid inferences to be made based on the observed, incomplete data.
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326
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Bédard A, Garcia-Aymerich J, Sanchez M, Le Moual N, Clavel-Chapelon F, Boutron-Ruault MC, Maccario J, Varraso R. Confirmatory Factor Analysis Compared with Principal Component Analysis to Derive Dietary Patterns: A Longitudinal Study in Adult Women. J Nutr 2015; 145:1559-68. [PMID: 25995279 DOI: 10.3945/jn.114.204479] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 04/29/2015] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Principal component analysis (PCA) has been used extensively to derive dietary patterns. We proposed to use confirmatory factor analysis (CFA) in the same context as PCA--as a one-step approach--to derive dietary patterns. OBJECTIVES The first aim of this study was methodologic and was to compare dietary patterns derived with the use of PCA and CFA, used as equivalent one-step approaches. The second aim of this study was to study these patterns in association with individual characteristics and new adult-onset asthma. METHODS We included 30,589 French women from the E3N (epidemiologic prospective cohort study of women from the MGEN national insurance plan) with 1177 reported cases of adult-onset asthma between 1993 and 2005. PCA and CFA were used in the same context, on 27 food groups, to derive dietary patterns. Associations between dietary patterns and adult-onset asthma were assessed by Cox proportional hazards models. RESULTS Whether we used PCA or CFA, 3 similar factors were found and labeled "Prudent," "Western," and "Aperitif." Correlations between patterns derived with the use of PCA and CFA were high. For the "Prudent" and "Aperitif" patterns, we observed comparable patterns in terms of associations with food groups, individual characteristics, and the onset of asthma. For the "Western" patterns, the one derived with the use of CFA was more related to an unhealthy diet than the one derived with the use of PCA, with higher correlations with the food groups "processed meat" (0.73 vs. 0.51) and "dough and pastry" (0.63 vs. 0.40), and negative associations with physical activity and with having parents who were farmers. Regarding associations with adult-onset asthma, a significant positive association was observed for the "Western" pattern derived with the use of CFA [multivariate RR for highest vs. lowest quintile: 1.30 (1.02, 1.67), P-trend: 0.03], whereas no association was reported when using PCA [RR: 1.14 (0.89, 1.47), P-trend: 0.40]. CONCLUSION Although quite similar dietary patterns were derived with the use of PCA and CFA, this study supports the alternative use of CFA to PCA for the identification of dietary patterns in epidemiologic studies.
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Affiliation(s)
- Annabelle Bédard
- INSERM U1168, Aging and chronic diseases-Epidemiological and public health approaches, Villejuif, France; UVSQ, UMR-S 1168, Université Versailles St-Quentin-en-Yvelines, France;
| | - Judith Garcia-Aymerich
- Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain; IMIM, Hospital del Mar Research Institute, Barcelona, Spain; CIBER en Epidemiologia y Salud Pública (CIBERESP), Barcelona, Spain; Department of Experimental and Health Sciences, Pompeu Fabra University, Barcelona, Spain
| | - Margaux Sanchez
- INSERM U1168, Aging and chronic diseases-Epidemiological and public health approaches, Villejuif, France; UVSQ, UMR-S 1168, Université Versailles St-Quentin-en-Yvelines, France
| | - Nicole Le Moual
- INSERM U1168, Aging and chronic diseases-Epidemiological and public health approaches, Villejuif, France; UVSQ, UMR-S 1168, Université Versailles St-Quentin-en-Yvelines, France
| | - Françoise Clavel-Chapelon
- INSERM, Centre for Research in Epidemiology and Population Health (CESP), U1018, Gustave Roussy Institute, Villejuif, France; and University of Paris-Sud, UMRS 1018, Villejuif, France
| | - Marie-Christine Boutron-Ruault
- INSERM, Centre for Research in Epidemiology and Population Health (CESP), U1018, Gustave Roussy Institute, Villejuif, France; and University of Paris-Sud, UMRS 1018, Villejuif, France
| | - Jean Maccario
- INSERM U1168, Aging and chronic diseases-Epidemiological and public health approaches, Villejuif, France; UVSQ, UMR-S 1168, Université Versailles St-Quentin-en-Yvelines, France
| | - Raphaëlle Varraso
- INSERM U1168, Aging and chronic diseases-Epidemiological and public health approaches, Villejuif, France; UVSQ, UMR-S 1168, Université Versailles St-Quentin-en-Yvelines, France
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Albanese E, Davis B, Jonsson PV, Chang M, Aspelund T, Garcia M, Harris T, Gudnason V, Launer LJ. Overweight and Obesity in Midlife and Brain Structure and Dementia 26 Years Later: The AGES-Reykjavik Study. Am J Epidemiol 2015; 181:672-9. [PMID: 25810457 DOI: 10.1093/aje/kwu331] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 10/27/2014] [Indexed: 01/17/2023] Open
Abstract
High adiposity in midlife might increase risk for late-life brain pathology, including dementia. Using data from the prospective Age, Gene/Environment Susceptibility-Reykjavik Study of men and women (born 1907-1935), we studied the associations of overweight and obesity at midlife (mean age, 50 (standard deviation, 4.7) years) with 1.5-T brain magnetic resonance imaging measures of infarct-like brain lesions, cerebral microbleeds, total brain volume, and white matter lesions volume, as well as dementia, in late life (mean age, 76 (standard deviation, 5.2) years). We used linear and Poisson models to estimate associations in 3,864 persons after adjustment for sociodemographic, health, and lifestyle characteristics. In midlife, the prevalence of overweight was 39% and that of obesity was 8%. After a mean follow-up of 26.2 (standard deviation, 4.9) years, midlife overweight and obesity were not associated with infarct-like brain lesions (relative risk (RR) = 0.82, 95% confidence interval (CI): 0.61, 1.10), cerebral microbleeds (RR = 0.69, 95% CI: 0.37, 1.32), total brain volume (β = 0.05, 95% CI: -0.34, 0.45), white matter lesions volume (β = -0.10, 95% CI: -0.20, 0.01), or dementia (RR = 0.91, 95% CI: 0.49, 1.72) compared with normal weight. These findings do not support the hypothesis that high body mass index in midlife modulates the risk for dementia.
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329
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Deckers K, van Boxtel MPJ, Schiepers OJG, de Vugt M, Muñoz Sánchez JL, Anstey KJ, Brayne C, Dartigues JF, Engedal K, Kivipelto M, Ritchie K, Starr JM, Yaffe K, Irving K, Verhey FRJ, Köhler S. Target risk factors for dementia prevention: a systematic review and Delphi consensus study on the evidence from observational studies. Int J Geriatr Psychiatry 2015; 30:234-46. [PMID: 25504093 DOI: 10.1002/gps.4245] [Citation(s) in RCA: 304] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 10/17/2014] [Accepted: 11/05/2014] [Indexed: 01/30/2023]
Abstract
OBJECTIVE Dementia has a multifactorial etiology, but the importance of individual health and lifestyle related risk factors is often uncertain or based on few studies. The goal of this paper is to identify the major modifiable risk factors for dementia as a first step in developing an effective preventive strategy and promoting healthy late life cognitive functioning. METHODS A mixed-method approach combined findings from a systematic literature review and a Delphi consensus study. The literature search was conducted in PubMed and updated an earlier review by the United States National Institutes of Health from 2010. We reviewed the available evidence from observational epidemiological studies. The online Delphi study asked eight international experts to rank and weigh each risk factor for its importance for dementia prevention. RESULTS Out of 3127 abstracts, 291 were included in the review. There was good agreement between modifiable risk factors identified in the literature review and risk factors named spontaneously by experts. After triangulation of both methods and re-weighting by experts, strongest support was found for depression, (midlife) hypertension, physical inactivity, diabetes, (midlife) obesity, hyperlipidemia, and smoking, while more research is needed for coronary heart disease, renal dysfunction, diet, and cognitive activity. CONCLUSIONS Findings provide good support for several somatic and lifestyle factors and will be used to inform the design of a new multicenter trial into dementia prevention.
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Affiliation(s)
- Kay Deckers
- Maastricht University, School for Mental Health and Neuroscience, Alzheimer Centrum Limburg, Maastricht, The Netherlands
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330
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Power MC, Deal JA, Sharrett AR, Jack CR, Knopman D, Mosley TH, Gottesman RF. Smoking and white matter hyperintensity progression: the ARIC-MRI Study. Neurology 2015; 84:841-8. [PMID: 25632094 DOI: 10.1212/wnl.0000000000001283] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
OBJECTIVE Our objective was to examine the link between smoking and smoking history, including smoking intensity and cessation, overall and by race, in a biracial prospective cohort study. METHODS A subset of Atherosclerosis Risk in Communities Study participants (n = 972, 49% black) completed brain MRI scans twice (1993-1995 and 2004-2006). We defined white matter hyperintensity (WMH) progression as an increase of ≥2 points on the 9-point Cardiovascular Health Study scale across scans. Participants reported information on smoking behavior at the baseline MRI and at 2 prior study visits, approximately 3 and 6 years before baseline. We used adjusted logistic regression to evaluate the association between smoking variables and WMH progression in the total sample and separately by race (black and white). RESULTS We found WMH progression in 23% of participants (30% of black participants, 17% of white participants). Overall, being a current smoker 6 years before baseline was associated with WMH progression. In race-stratified analyses, we found adverse associations with smoking status at multiple time points and persistent smoking in white but not in black participants. However, we found no statistical support for effect modification by race for most of these analyses. Increasing pack-years of smoking was associated with greater risk of WMH progression, while time since quitting and age at smoking initiation were not associated with WMH progression, with little indication of differences in these associations by race. CONCLUSIONS Our findings concur with previous studies suggesting a relationship between smoking and WMH progression, and further demonstrate a dose-dependent association.
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Affiliation(s)
- Melinda C Power
- From the Department of Neurology, Johns Hopkins University School of Medicine (R.F.G.), and Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health (M.C.P., J.A.D., A.R.S., R.F.G.), Baltimore, MD; Departments of Radiology (C.R.J.) and Neurology (D.K.), Mayo Clinic, Rochester, MN; and Department of Medicine (T.H.M.), University of Mississippi Medical Center, Jackson.
| | - Jennifer A Deal
- From the Department of Neurology, Johns Hopkins University School of Medicine (R.F.G.), and Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health (M.C.P., J.A.D., A.R.S., R.F.G.), Baltimore, MD; Departments of Radiology (C.R.J.) and Neurology (D.K.), Mayo Clinic, Rochester, MN; and Department of Medicine (T.H.M.), University of Mississippi Medical Center, Jackson
| | - A Richey Sharrett
- From the Department of Neurology, Johns Hopkins University School of Medicine (R.F.G.), and Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health (M.C.P., J.A.D., A.R.S., R.F.G.), Baltimore, MD; Departments of Radiology (C.R.J.) and Neurology (D.K.), Mayo Clinic, Rochester, MN; and Department of Medicine (T.H.M.), University of Mississippi Medical Center, Jackson
| | - Clifford R Jack
- From the Department of Neurology, Johns Hopkins University School of Medicine (R.F.G.), and Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health (M.C.P., J.A.D., A.R.S., R.F.G.), Baltimore, MD; Departments of Radiology (C.R.J.) and Neurology (D.K.), Mayo Clinic, Rochester, MN; and Department of Medicine (T.H.M.), University of Mississippi Medical Center, Jackson
| | - David Knopman
- From the Department of Neurology, Johns Hopkins University School of Medicine (R.F.G.), and Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health (M.C.P., J.A.D., A.R.S., R.F.G.), Baltimore, MD; Departments of Radiology (C.R.J.) and Neurology (D.K.), Mayo Clinic, Rochester, MN; and Department of Medicine (T.H.M.), University of Mississippi Medical Center, Jackson
| | - Thomas H Mosley
- From the Department of Neurology, Johns Hopkins University School of Medicine (R.F.G.), and Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health (M.C.P., J.A.D., A.R.S., R.F.G.), Baltimore, MD; Departments of Radiology (C.R.J.) and Neurology (D.K.), Mayo Clinic, Rochester, MN; and Department of Medicine (T.H.M.), University of Mississippi Medical Center, Jackson
| | - Rebecca F Gottesman
- From the Department of Neurology, Johns Hopkins University School of Medicine (R.F.G.), and Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health (M.C.P., J.A.D., A.R.S., R.F.G.), Baltimore, MD; Departments of Radiology (C.R.J.) and Neurology (D.K.), Mayo Clinic, Rochester, MN; and Department of Medicine (T.H.M.), University of Mississippi Medical Center, Jackson
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Rawlings AM, Sharrett AR, Schneider ALC, Coresh J, Albert M, Couper D, Griswold M, Gottesman RF, Wagenknecht LE, Windham BG, Selvin E. Diabetes in midlife and cognitive change over 20 years: a cohort study. Ann Intern Med 2014; 161:785-93. [PMID: 25437406 PMCID: PMC4432464 DOI: 10.7326/m14-0737] [Citation(s) in RCA: 275] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Type 2 diabetes is associated with dementia risk, but evidence is limited for possible associations of diabetes and prediabetes with cognitive decline. OBJECTIVE To determine whether diabetes in midlife is associated with 20-year cognitive decline and to characterize long-term cognitive decline across clinical categories of hemoglobin A1c (HbA1c) levels. DESIGN Prospective cohort study. SETTING The community-based ARIC (Atherosclerosis Risk in Communities) study. PARTICIPANTS 13,351 black and white adults aged 48 to 67 years at baseline (1990 to 1992). MEASUREMENTS Diabetes was defined by self-reported physician diagnosis or medication use or HbA1c level of 6.5% or greater. Undiagnosed diabetes, prediabetes, and glucose control in persons with diagnosed diabetes were defined by clinical categories of HbA1c level. Delayed word recall, digit symbol substitution, and word fluency tests were used to assess cognitive performance and were summarized with a global Z score. RESULTS Diabetes in midlife was associated with a 19% greater cognitive decline over 20 years (adjusted global Z-score difference, -0.15 [;95% CI, -0.22 to -0.08];) compared with no diabetes. Cognitive decline was significantly greater among persons with prediabetes (HbA1c level of 5.7% to 6.4%) than among those with an HbA1c level less than 5.7%. Participants with poorly controlled diabetes (HbA1c level ≥ 7.0%) had greater decline than those whose diabetes was controlled (adjusted global Z-score difference, -0.16; P = 0.071). Longer-duration diabetes was also associated with greater late-life cognitive decline (P for trend < 0.001). Rates of decline did not differ significantly between white and black persons (P for interaction = 0.44). LIMITATION Single HbA1c measurement at baseline, 1 test per cognitive domain, and potential geographic confounding of race comparisons. CONCLUSION Diabetes prevention and glucose control in midlife may protect against late-life cognitive decline. PRIMARY FUNDING SOURCE National Institutes of Health.
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Gottesman RF, Schneider AL, Albert M, Alonso A, Bandeen-Roche K, Coker L, Coresh J, Knopman D, Power MC, Rawlings A, Sharrett AR, Wruck LM, Mosley TH. Midlife hypertension and 20-year cognitive change: the atherosclerosis risk in communities neurocognitive study. JAMA Neurol 2014; 71:1218-27. [PMID: 25090106 PMCID: PMC4226067 DOI: 10.1001/jamaneurol.2014.1646] [Citation(s) in RCA: 322] [Impact Index Per Article: 32.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
IMPORTANCE Hypertension is a treatable potential cause of cognitive decline and dementia, but its greatest influence on cognition may occur in middle age. OBJECTIVE To evaluate the association between midlife (48-67 years of age) hypertension and the 20-year change in cognitive performance. DESIGN, SETTING, AND PARTICIPANTS The Atherosclerosis Risk in Communities cohort (1990-1992 through 2011-2013) underwent evaluation at field centers in Washington County, Maryland, Forsyth County, North Carolina, Jackson, Mississippi, and the Minneapolis, Minnesota, suburbs. Of 13 476 African American and white participants with baseline cognitive data, 58.0% of living participants completed the 20-year cognitive follow-up. EXPOSURES Hypertension, prehypertension, or normal blood pressure (BP) at visit 2 (1990-1992) constituted the primary exposure. Systolic BP at visit 2 or 5 (2011-2013) and indication for treatment at visit 2 based on the Eighth Joint National Committee (JNC-8) hypertension guidelines constituted the secondary exposures. MAIN OUTCOMES AND MEASURES Prespecified outcomes included the 20-year change in scores on the Delayed Word Recall Test, Digit Symbol Substitution Test, and Word Fluency Test and in global cognition. RESULTS During 20 years, baseline hypertension was associated with an additional decline of 0.056 global z score points (95% CI, -0.100 to -0.012) and prehypertension was associated nonsignificantly with 0.040 more global z score points of decline (95% CI, -0.085 to 0.005) compared with normal BP. Individuals with hypertension who used antihypertensives had less decline during the 20 years than untreated individuals with hypertension (-0.050 [95% CI, -0.003 to -0.097] vs -0.079 [95% CI, -0.156 to -0.002] global z score points). Having a JNC-8-specified indication for initiating antihypertensive treatment at baseline was associated with a greater 20-year decline (-0.044 [95% CI, -0.085 to -0.003] global z score points) than not having an indication. We observed effect modification by race for the continuous systolic BP analyses (P = .01), with each 20-mm Hg increment at baseline associated with an additional decline of 0.048 (95% CI, -0.074 to -0.022) points in global cognitive z score in whites but not in African Americans (decline, -0.020 [95% CI, -0.026 to 0.066] points). Systolic BP at the end of follow-up was not associated with the preceding 20 years of cognitive change in either group. Methods to account for bias owing to attrition strengthened the magnitude of some associations. CONCLUSIONS AND RELEVANCE Midlife hypertension and elevated midlife but not late-life systolic BP was associated with more cognitive decline during the 20 years of the study. Greater decline is found with higher midlife BP in whites than in African Americans.
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Affiliation(s)
- Rebecca F. Gottesman
- Departments of Neurology, Johns Hopkins University School of Medicine
- Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
| | | | - Marilyn Albert
- Departments of Neurology, Johns Hopkins University School of Medicine
| | - Alvaro Alonso
- Division of Epidemiology and Community Health, University of Minnesota, Minneapolis, MN
| | - Karen Bandeen-Roche
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
| | - Laura Coker
- Division of Public Health Sciences, Wake Forest School of Medicine, Winston-Salem, NC
| | - Josef Coresh
- Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
| | | | - Melinda C. Power
- Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
| | - Andreea Rawlings
- Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
| | - A. Richey Sharrett
- Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
| | - Lisa M. Wruck
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Thomas H. Mosley
- Department of Medicine; University of Mississippi Medical Center, Jackson, MS
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Espeland MA, Rapp SR, Bray GA, Houston DK, Johnson KC, Kitabchi AE, Hergenroeder AL, Williamson J, Jakicic JM, van Dorsten B, Kritchevsky SB. Long-term impact of behavioral weight loss intervention on cognitive function. J Gerontol A Biol Sci Med Sci 2014; 69:1101-8. [PMID: 24619151 PMCID: PMC4158413 DOI: 10.1093/gerona/glu031] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 02/04/2014] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND It is unknown whether intentional weight loss provides long-term benefits for cognitive function. METHODS An ancillary study to a randomized controlled clinical trial was conducted in overweight and obese individuals (N = 978), aged 45-76 years at enrollment, with type 2 diabetes. An intensive behavioral intervention designed to promote and maintain weight loss through caloric restriction and increased physical activity was compared with diabetes support and education. Standardized assessments of cognitive function were collected an average of 8.1 years after trial enrollment. RESULTS Participants assigned to intensive lifestyle intervention lost a mean (SE) 11.1% (0.4%) and 7.2% (0.5%) of weight at Years 1 and 8, respectively, compared with 1.0% (0.2%) and 3.3% (0.5%) in the control group (p < .001). Covariate-adjusted mean composite cognitive function test scores were similar for the two groups (p = .69), and no significant differences were found for any individual cognitive test. There was some evidence of a differential effect (nominal interaction p = .008) for a prespecified comparison: Intensive lifestyle intervention was associated with a relative mean benefit for composite cognitive function of 0.276 (95% confidence interval: 0.033, 0.520) SDs among individuals with body mass index less than 30 kg/m(2) at baseline compared with a relative mean deficit of 0.086 (-0.021, 0.194) SDs among individuals with body mass more than or equal to 30 kg/m(2). CONCLUSIONS Eight years of intensive lifestyle intervention did not alter cognitive function in obese adults with type 2 diabetes; however, there was evidence for benefit among overweight but not obese individuals. Changes in cognition were not assessed in this cross-sectional study.
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Affiliation(s)
| | - Stephen R Rapp
- Department of Psychiatry and Behavioral Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - George A Bray
- Pennington Biomedical Research Center, Louisiana State University, Baton Rouge
| | - Denise K Houston
- Section on Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | | | - Abbas E Kitabchi
- Department of Medicine, University of Tennessee Health Science Center, Memphis
| | | | - Jeff Williamson
- Section on Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina. Kulynych Center for Memory and Cognition Research, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - John M Jakicic
- Department of Health and Physical Activity, University of Pittsburgh, Pennsylvania
| | | | - Stephen B Kritchevsky
- Section on Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina
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Weuve J. Invited commentary: how exposure to air pollution may shape dementia risk, and what epidemiology can say about it. Am J Epidemiol 2014; 180:367-71. [PMID: 24966217 DOI: 10.1093/aje/kwu153] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The number of Americans with Alzheimer's disease (AD) dementia is expected to triple by 2050. No effective treatments exist, and prevention research has focused on behaviors and medical conditions, which have been difficult to modify at the population level. Cardiovascular disease epidemiology can inform the search for AD risk factors; exposure to fine particulate matter (PM) air pollution increases cardiovascular risk, pollutant regulations appear to reduce cardiovascular deaths, and vascular pathology influences dementia risk. In this issue of the Journal, Ailshire and Crimmins (Am J Epidemiol. 2014;180(4):359-366) report analyses of data from 14,000 older adults living across the United States, indicating an inverse association between exposure to PM and cognitive function, an outcome related to AD by virtue of the long period of cognitive decline that precedes clinical disease. Their work joins a growing body of data linking PM exposure to AD risk. If these data reflect causality, PM exposure would be 1 of few AD risk factors that are not only widespread, but that also can be modified at the population level using regulatory intervention. Active collaboration between air pollution and dementia epidemiologists will be critical for refining the available evidence and filling fundamental gaps, including the lack of studies on AD itself.
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Elbejjani M, Fuhrer R, Abrahamowicz M, Mazoyer B, Crivello F, Tzourio C, Dufouil C. Hippocampal atrophy and subsequent depressive symptoms in older men and women: results from a 10-year prospective cohort. Am J Epidemiol 2014; 180:385-93. [PMID: 25086051 PMCID: PMC4128769 DOI: 10.1093/aje/kwu132] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 04/29/2014] [Indexed: 11/12/2022] Open
Abstract
Several studies have reported smaller hippocampal volume in patients with depression. However, the temporality of the association is undetermined. One hypothesis is that hippocampal atrophy might be a susceptibility factor for depression. In the present study, we assessed whether hippocampal atrophy was associated with subsequent depressive symptoms in a cohort of older French adults (n = 1,309) who were 65-80 years of age and enrolled into the study in 1999-2001 in Dijon, France. Subjects were followed for more than 10 years. Participants underwent 2 cerebral magnetic resonance imaging scans, one at baseline and one at the 4-year follow-up. We used linear mixed models to estimate the associations of hippocampal atrophy with 1) the average depressive symptom scores over follow-up (using the Center for Epidemiologic Studies-Depression scale) measured biennially over the subsequent 6 years and 2) changes in symptom scores over follow-up. In women, a 2-standard-deviation increase in annual hippocampal atrophy was associated with a 1.67-point (95% confidence interval: 0.59, 2.77) increase in the average depressive symptom score over follow-up and with a 1.97-point (95% confidence interval: 0.68, 3.24) increase in scores over the 2 subsequent years but not with later changes in symptoms. No association was detected in men. Accounting for potential selective attrition (using inverse probability weights) did not alter results. Hippocampal atrophy was associated with more subsequent depressive symptoms and with shorter-term worsening of symptoms in women.
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Affiliation(s)
| | - Rebecca Fuhrer
- Correspondence to Dr. Rebecca Fuhrer, Department of Epidemiology, Biostatistics, and Occupational Health, McGill University Faculty of Medicine, 1020 Pine Avenue West, Montreal, Quebec H3A 1A2 (e-mail: )
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Rosso AL, Lee BK, Stefanick ML, Kroenke CH, Coker LH, Woods NF, Michael YL. Caregiving frequency and physical function: the Women's Health Initiative. J Gerontol A Biol Sci Med Sci 2014; 70:210-5. [PMID: 25060315 DOI: 10.1093/gerona/glu104] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Informal caregiving is common for older women and can negatively affect health, but its impact on physical function remains unclear. Using inverse probability weighting methods, we quantified the association of caregiving with physical function over 6 years. METHODS Study participants were 5,649 women aged 65 years and older at baseline of the Woman's Health Initiative Clinical Trial (multicenter recruitment, 1993-1998) with complete caregiving data and function at baseline and at least one follow-up. Caregiving was self-reported (low-frequency if ≤2 times per week and high-frequency if ≥3 times per week). Performance-based measures of physical function including timed walk (meters/second), grip strength (kilograms), and chair stands (number) were measured at baseline and years 1, 3, and 6. Associations and 95% confidence intervals of baseline caregiving with physical function were estimated by generalized estimating equations with inverse probability weighting by propensity and attrition scores, calculated by logistic regression of baseline health and demographic characteristics. RESULTS Over follow-up, low-frequency caregivers had higher grip strength when compared with noncaregivers (mean difference = 0.63kg, confidence interval: 0.24, 1.01). There were no observed differences between high-frequency caregivers and noncaregivers on grip strength or for either caregiver group when compared with noncaregivers on walk speed or chair stands. Rates of change in physical function measures did not differ by caregiving status. CONCLUSIONS Caregiving was not associated with poorer physical function in this sample of older women. Low-frequency caregiving was associated with better grip strength at baseline which persisted through follow-up. This study supports the concept that informal caregiving may not have universally negative health consequences.
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Affiliation(s)
- Andrea L Rosso
- Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pennsylvania.
| | - Brian K Lee
- Department of Epidemiology and Biostatistics, School of Public Health, Drexel University, Philadelphia, Pennsylvania
| | - Marcia L Stefanick
- Stanford Prevention Research Center, Stanford University, School of Medicine, Palo Alto, California
| | | | - Laura H Coker
- Department of Social Sciences and Health Policy, Wake Forest School of Medicine, Winston Salem, North Carolina
| | - Nancy F Woods
- School of Nursing, University of Washington, Seattle
| | - Yvonne L Michael
- Department of Epidemiology and Biostatistics, School of Public Health, Drexel University, Philadelphia, Pennsylvania
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Wlazlo N, van Greevenbroek MMJ, Ferreira I, Feskens EJM, van der Kallen CJH, Schalkwijk CG, Bravenboer B, Stehouwer CDA. Complement factor 3 is associated with insulin resistance and with incident type 2 diabetes over a 7-year follow-up period: the CODAM Study. Diabetes Care 2014; 37:1900-9. [PMID: 24760264 DOI: 10.2337/dc13-2804] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Immune dysregulation can affect insulin resistance (IR) and β-cell function and hence contribute to development of type 2 diabetes mellitus (T2DM). The complement system, as a regulator of immune and inflammatory homeostasis, may be a relevant contributor therein. However, longitudinal studies focusing on complement as a determinant of T2DM and IR are scarce. Therefore, we prospectively investigated the association of plasma complement factor 3 (C3) with (estimates of) IR in muscle, liver, and adipocytes, as well as with glucose tolerance, including incident T2DM. RESEARCH DESIGN AND METHODS Fasting C3, nonesterified fatty acids, glucose, and insulin (the latter two during oral glucose tolerance tests) were measured at baseline (n = 545) and after 7 years of follow-up (n = 394) in a prospective cohort study. RESULTS Over the 7-year period, C3 levels (per 0.1 g/L) were longitudinally associated with higher homeostasis model assessment of IR (HOMA2-IR; β = 15.2% [95% CI 12.9-17.6]), hepatic IR (β = 6.1% [95% CI 4.7-7.4]), adipocyte IR (β = 16.0% [95% CI 13.0-19.1]), fasting glucose (β = 1.8% [95% CI 1.2-2.4]), 2-h glucose (β = 5.2% [95% CI 3.7-6.7]), and area under the curve for glucose (β = 3.6% [95% CI 2.7-4.6]). In addition, greater changes in C3 (per 0.1 g/L) were associated with greater changes in HOMA2-IR (β = 0.08 [95% CI 0.02-0.15]) and greater changes in hepatic IR (β = 0.87 [95% CI 0.12-1.61]) over 7 years, but not glucose tolerance. Moreover, baseline C3 was associated with the 7-year incidence of T2DM (odds ratio 1.5 [95% CI 1.1-2.0]). CONCLUSIONS Changes in C3 were associated with changes in several measures of IR and may reflect progression of metabolic dysregulation, which eventually leads to abnormalities in glucose tolerance and T2DM.
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Affiliation(s)
- Nick Wlazlo
- Department of Internal Medicine, Catharina Hospital, Eindhoven, the NetherlandsCARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, the NetherlandsDepartment of Internal Medicine/Laboratory for Metabolism and Vascular Medicine, Maastricht University Medical Centre, Maastricht, the Netherlands
| | - Marleen M J van Greevenbroek
- CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, the NetherlandsDepartment of Internal Medicine/Laboratory for Metabolism and Vascular Medicine, Maastricht University Medical Centre, Maastricht, the Netherlands
| | - Isabel Ferreira
- CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, the NetherlandsDepartment of Internal Medicine/Laboratory for Metabolism and Vascular Medicine, Maastricht University Medical Centre, Maastricht, the NetherlandsDepartment of Clinical Epidemiology and Medical Technology Assessment, Maastricht University Medical Centre, Maastricht, the NetherlandsCAPHRI School for Public Health and Primary Care, Maastricht University Medical Centre, Maastricht, the Netherlands
| | - Edith J M Feskens
- Division of Human Nutrition, Section of Nutrition and Epidemiology, Wageningen University, Wageningen, the Netherlands
| | - Carla J H van der Kallen
- CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, the NetherlandsDepartment of Internal Medicine/Laboratory for Metabolism and Vascular Medicine, Maastricht University Medical Centre, Maastricht, the Netherlands
| | - Casper G Schalkwijk
- CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, the NetherlandsDepartment of Internal Medicine/Laboratory for Metabolism and Vascular Medicine, Maastricht University Medical Centre, Maastricht, the Netherlands
| | - Bert Bravenboer
- Department of Internal Medicine, Catharina Hospital, Eindhoven, the Netherlands
| | - Coen D A Stehouwer
- CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, the NetherlandsDepartment of Internal Medicine/Laboratory for Metabolism and Vascular Medicine, Maastricht University Medical Centre, Maastricht, the Netherlands
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Darsie B, Shlipak MG, Sarnak MJ, Katz R, Fitzpatrick AL, Odden MC. Kidney function and cognitive health in older adults: the Cardiovascular Health Study. Am J Epidemiol 2014; 180:68-75. [PMID: 24844846 DOI: 10.1093/aje/kwu102] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Recent evidence has demonstrated the importance of kidney function in healthy aging. We examined the association between kidney function and change in cognitive function in 3,907 participants in the Cardiovascular Health Study who were recruited from 4 US communities and studied from 1992 to 1999. Kidney function was measured by cystatin C-based estimated glomerular filtration rate (eGFRcys). Cognitive function was assessed using the Modified Mini-Mental State Examination and the Digit Symbol Substitution Test, which were administered up to 7 times during annual visits. There was an association between eGFRcys and change in cognitive function after adjustment for confounders; persons with an eGFRcys of less than 60 mL/minute/1.73 m(2) had a 0.64 (95% confidence interval: 0.51, 0.77) points/year faster decline in Modified Mini-Mental State Examination score and a 0.42 (95% confidence interval: 0.28, 0.56) points/year faster decline in Digit Symbol Substitution Test score compared with persons with an eGFRcys of 90 or more mL/minute/1.73 m(2). Additional adjustment for intermediate cardiovascular events modestly affected these associations. Participants with an eGFRcys of less than 60 mL/minute/1.73 m(2) had fewer cognitive impairment-free life-years on average compared with those with eGFRcys of 90 or more mL/minute/1.73 m(2), independent of confounders and mediating cardiovascular events (mean difference = -0.44, 95% confidence interval: -0.62, -0.26). Older adults with lower kidney function are at higher risk of worsening cognitive function.
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339
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Durazzo TC, Mattsson N, Weiner MW. Smoking and increased Alzheimer's disease risk: a review of potential mechanisms. Alzheimers Dement 2014; 10:S122-45. [PMID: 24924665 PMCID: PMC4098701 DOI: 10.1016/j.jalz.2014.04.009] [Citation(s) in RCA: 251] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND Cigarette smoking has been linked with both increased and decreased risk for Alzheimer's disease (AD). This is relevant for the US military because the prevalence of smoking in the military is approximately 11% higher than in civilians. METHODS A systematic review of published studies on the association between smoking and increased risk for AD and preclinical and human literature on the relationships between smoking, nicotine exposure, and AD-related neuropathology was conducted. Original data from comparisons of smoking and never-smoking cognitively normal elders on in vivo amyloid imaging are also presented. RESULTS Overall, literature indicates that former/active smoking is related to a significantly increased risk for AD. Cigarette smoke/smoking is associated with AD neuropathology in preclinical models and humans. Smoking-related cerebral oxidative stress is a potential mechanism promoting AD pathology and increased risk for AD. CONCLUSIONS A reduction in the incidence of smoking will likely reduce the future prevalence of AD.
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Affiliation(s)
- Timothy C Durazzo
- Center for Imaging of Neurodegenerative Diseases (CIND), San Francisco VA Medical Center, San Francisco, CA, USA; Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA.
| | - Niklas Mattsson
- Center for Imaging of Neurodegenerative Diseases (CIND), San Francisco VA Medical Center, San Francisco, CA, USA; Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA; Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
| | - Michael W Weiner
- Center for Imaging of Neurodegenerative Diseases (CIND), San Francisco VA Medical Center, San Francisco, CA, USA; Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA; Department of Psychiatry, University of California, San Francisco, San Francisco, CA, USA; Department of Medicine, University of California, San Francisco, San Francisco, CA, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
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340
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Tchetgen Tchetgen EJ. Identification and estimation of survivor average causal effects. Stat Med 2014; 33:3601-28. [PMID: 24889022 PMCID: PMC4131726 DOI: 10.1002/sim.6181] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 03/24/2014] [Accepted: 03/26/2014] [Indexed: 11/23/2022]
Abstract
In longitudinal studies, outcomes ascertained at follow-up are typically undefined for individuals who die prior to the follow-up visit. In such settings, outcomes are said to be truncated by death and inference about the effects of a point treatment or exposure, restricted to individuals alive at the follow-up visit, could be biased even if as in experimental studies, treatment assignment were randomized. To account for truncation by death, the survivor average causal effect (SACE) defines the effect of treatment on the outcome for the subset of individuals who would have survived regardless of exposure status. In this paper, the author nonparametrically identifies SACE by leveraging post-exposure longitudinal correlates of survival and outcome that may also mediate the exposure effects on survival and outcome. Nonparametric identification is achieved by supposing that the longitudinal data arise from a certain nonparametric structural equations model and by making the monotonicity assumption that the effect of exposure on survival agrees in its direction across individuals. A novel weighted analysis involving a consistent estimate of the survival process is shown to produce consistent estimates of SACE. A data illustration is given, and the methods are extended to the context of time-varying exposures. We discuss a sensitivity analysis framework that relaxes assumptions about independent errors in the nonparametric structural equations model and may be used to assess the extent to which inference may be altered by a violation of key identifying assumptions. © 2014 The Authors. Statistics in Medicine published by John Wiley & Sons, Ltd.
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Rabideau DJ, Nierenberg AA, Sylvia LG, Friedman ES, Bowden CL, Thase ME, Ketter TA, Ostacher MJ, Reilly-Harrington N, Iosifescu DV, Calabrese JR, Leon AC, Schoenfeld DA. A novel application of the Intent to Attend assessment to reduce bias due to missing data in a randomized controlled clinical trial. Clin Trials 2014; 11:494-502. [PMID: 24872362 DOI: 10.1177/1740774514531096] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Missing data are unavoidable in most randomized controlled clinical trials, especially when measurements are taken repeatedly. If strong assumptions about the missing data are not accurate, crude statistical analyses are biased and can lead to false inferences. Furthermore, if we fail to measure all predictors of missing data, we may not be able to model the missing data process sufficiently. In longitudinal randomized trials, measuring a patient's intent to attend future study visits may help to address both of these problems. Leon et al. developed and included the Intent to Attend assessment in the Lithium Treatment - Moderate dose Use Study (LiTMUS), aiming to remove bias due to missing data from the primary study hypothesis. PURPOSE The purpose of this study is to assess the performance of the Intent to Attend assessment with regard to its use in a sensitivity analysis of missing data. METHODS We fit marginal models to assess whether a patient's self-rated intent predicted actual study adherence. We applied inverse probability of attrition weighting (IPAW) coupled with patient intent to assess whether there existed treatment group differences in response over time. We compared the IPAW results to those obtained using other methods. RESULTS Patient-rated intent predicted missed study visits, even when adjusting for other predictors of missing data. On average, the hazard of retention increased by 19% for every one-point increase in intent. We also found that more severe mania, male gender, and a previously missed visit predicted subsequent absence. Although we found no difference in response between the randomized treatment groups, IPAW increased the estimated group difference over time. LIMITATIONS LiTMUS was designed to limit missed study visits, which may have attenuated the effects of adjusting for missing data. Additionally, IPAW can be less efficient and less powerful than maximum likelihood or Bayesian estimators, given that the parametric model is well specified. CONCLUSIONS In LiTMUS, the Intent to Attend assessment predicted missed study visits. This item was incorporated into our IPAW models and helped reduce bias due to informative missing data. This analysis should both encourage and facilitate future use of the Intent to Attend assessment along with IPAW to address missing data in a randomized trial.
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Affiliation(s)
- Dustin J Rabideau
- Biostatistics Center, Massachusetts General Hospital, Boston, MA, USA
| | - Andrew A Nierenberg
- Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA Harvard Medical School, Boston, MA, USA
| | - Louisa G Sylvia
- Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA Harvard Medical School, Boston, MA, USA
| | - Edward S Friedman
- Department of Psychiatry, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Charles L Bowden
- Department of Psychiatry, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Michael E Thase
- Department of Psychiatry, School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Terence A Ketter
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
| | - Michael J Ostacher
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
| | - Noreen Reilly-Harrington
- Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA Harvard Medical School, Boston, MA, USA
| | - Dan V Iosifescu
- Department of Psychiatry, Mount Sinai School of Medicine, New York, USA
| | - Joseph R Calabrese
- Department of Psychiatry, Case Western Reserve University, School of Medicine, Cleveland, OH, USA
| | - Andrew C Leon
- Psychiatry and Public Health, Weill Cornell Medical College, New York, USA
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Gottesman RF, Rawlings AM, Sharrett AR, Albert M, Alonso A, Bandeen-Roche K, Coker LH, Coresh J, Couper DJ, Griswold ME, Heiss G, Knopman DS, Patel MD, Penman AD, Power MC, Selnes OA, Schneider ALC, Wagenknecht LE, Windham BG, Wruck LM, Mosley TH. Impact of differential attrition on the association of education with cognitive change over 20 years of follow-up: the ARIC neurocognitive study. Am J Epidemiol 2014; 179:956-66. [PMID: 24627572 DOI: 10.1093/aje/kwu020] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Studies of long-term cognitive change should account for the potential effects of education on the outcome, since some studies have demonstrated an association of education with dementia risk. Evaluating cognitive change is more ideal than evaluating cognitive performance at a single time point, because it should be less susceptible to confounding. In this analysis of 14,020 persons from a US cohort study, the Atherosclerosis Risk in Communities (ARIC) Study, we measured change in performance on 3 cognitive tests over a 20-year period, from ages 48-67 years (1990-1992) through ages 70-89 years (2011-2013). Generalized estimating equations were used to evaluate the association between education and cognitive change in unweighted adjusted models, in models incorporating inverse probability of attrition weighting, and in models using cognitive scores imputed from the Telephone Interview for Cognitive Status for participants not examined in person. Education did not have a strong relationship with change in cognitive test performance, although the rate of decline was somewhat slower among persons with lower levels of education. Methods used to account for selective dropout only marginally changed these observed associations. Future studies of risk factors for cognitive impairment should focus on cognitive change, when possible, to allow for reduction of confounding by social or cultural factors.
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Aguirre-Acevedo DC, Henao E, Tirado V, Muñoz C, Giraldo Arango D, Lopera Restrepo F, Jaimes Barragán F. [Factors Associated with Cognitive Decline in a Population Less than 65 Years Old. A Systematic Review]. REVISTA COLOMBIANA DE PSIQUIATRIA 2014; 43:113-122. [PMID: 26574966 DOI: 10.1016/j.rcp.2014.02.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 02/10/2014] [Accepted: 02/24/2014] [Indexed: 06/05/2023]
Abstract
INTRODUCTION Cognitive decline could begin 20 years before the diagnosis of dementia. Besides age, several factors related to medical, socioeconomic, and behavioral and genetic condition may be associated with cognitive decline. The aim of this systematic review was to summarize evidence on the risk and protective factors for cognitive decline in people under 65 years old. METHODS A systematic review was conducted using a search strategy in MEDLINE and Embase, including longitudinal studies to analyze the effect of protective or risk factors on cognitive decline in a population under 65 years old. RESULTS A total of 22 studies were included in this review. Factors such as diabetes, hyperinsulinemia, overweight or obesity, metabolic syndrome, education, physical activity, cognitive stimulation, marital status and diet, could be related to cognitive decline before 65 years of age. CONCLUSIONS Cardiovascular risk factors and lifestyle conditions may be associated with cognitive decline before 65 years of age. However, the quality of the evidence was low.
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Affiliation(s)
| | - Eliana Henao
- Grupo de Neurociencias de Antioquia, Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
| | - Victoria Tirado
- Grupo de Neurociencias de Antioquia, Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
| | - Claudia Muñoz
- Grupo de Neurociencias de Antioquia, Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia
| | | | - Francisco Lopera Restrepo
- Grupo de Neurociencias de Antioquia, Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia; Grupo Académico de Epidemiología Clínica y Departamento de Medicina Interna, Facultad de Medicina, Universidad de Antioquia; Unidad de Investigaciones, Hospital Pablo Tobón Uribe, Medellín, Colombia
| | - Fabián Jaimes Barragán
- Grupo Académico de Epidemiología Clínica y Departamento de Medicina Interna, Facultad de Medicina, Universidad de Antioquia; Unidad de Investigaciones, Hospital Pablo Tobón Uribe, Medellín, Colombia
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Abstract
BACKGROUND Studies of hypertension and cognition variously report adverse, null, and protective associations. We evaluated evidence supporting three potential explanations for this variation: an effect of hypertension duration, an effect of age at hypertension initiation, and selection bias due to dependent censoring. METHODS The Normative Aging Study is a prospective cohort study of men in the greater Boston area. Participants completed study visits, including hypertension assessment, every 3-5 years starting in 1961. Seven hundred fifty-eight of 1,284 men eligible at baseline completed cognitive assessment between 1992 and 2005; we used the mean age-adjusted cognitive test Z score from their first assessment to quantify cognition. We estimated how becoming hypertensive and increasing age at onset and duration since hypertension initiation affect cognition. We used inverse probability of censoring weights to reduce and quantify selection bias. RESULTS A history of hypertension diagnosis predicted lower cognition. Increasing duration since hypertension initiation predicted lower mean cognitive Z score (-0.02 standard units per year increase [95% confidence interval= -0.04 to -0.001]), independent of age at onset. Comparing participants with and without hypertension, we observed noteworthy differences in mean cognitive score only for those with a long duration since hypertension initiation, regardless of age at onset. Age at onset was not associated with cognition independent of duration. Analyses designed to quantify selection bias suggested upward bias. CONCLUSIONS Previous findings of null or protective associations between hypertension and cognition likely reflect the study of persons with short duration since hypertension initiation. Selection bias may also contribute to cross-study heterogeneity.
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Mendes de Leon CF, Rajan KB. Psychosocial influences in onset and progression of late life disability. J Gerontol B Psychol Sci Soc Sci 2014; 69:287-302. [PMID: 24389123 DOI: 10.1093/geronb/gbt130] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
OBJECTIVES Disability in older age has been related to several psychosocial characteristics, including social networks, social engagement, and depression. However, the exact role of these characteristics in the disablement process remains uncertain. METHOD Data come from a population-based study of black and white adults aged ≥65 years (N = 5,306), with up to 9 yearly data on the primary outcome measure, activities of daily living (ADL) disability. We use a two-part regression model to simultaneously test the association between each psychosocial characteristic and both onset and progression of ADL disability, while controlling for demographic variables, education, and mode of interview in the first model and health status variables in the second model. RESULTS Social networks were negatively associated with onset of ADL disability but not associated with progression. The association became non-significant after adjustment for health status. Social engagement was negatively associated with both onset and progression of disability, even after adjustment for health status. Depression was significantly associated with onset of disability after adjustment for health status but not with progression of disability. DISCUSSION The results suggest a differential role for psychosocial characteristics in the disablement process, with generally stronger associations for transitions to onset of ADL disability than progression of ADL disability.
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Affiliation(s)
- Carlos F Mendes de Leon
- Correspondence should be addressed to Carlos F. Mendes de Leon, Department of Epidemiology, University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI 48109. E-mail:
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Köhler S, Baars MAE, Spauwen P, Schievink S, Verhey FRJ, van Boxtel MJP. Temporal evolution of cognitive changes in incident hypertension: prospective cohort study across the adult age span. Hypertension 2013; 63:245-51. [PMID: 24296281 DOI: 10.1161/hypertensionaha.113.02096] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Midlife hypertension is a risk factor for dementia, but little is known about the cognitive trajectories of individuals with incident hypertension. This study follows the cognitive functioning in prevalent and incident hypertension for 12 years and in relation to age and treatment status. Cognitively intact adults aged 25 to 84 years (n=1805) were serially assessed at baseline, 6 years, and 12 years. Hypertension was defined by sphygmomanometry or antihypertensive medication use, and its association with cognitive decline was tested in random-effects models. At baseline, 638 (35.3%) participants had hypertension. They showed faster decline in memory (χ(2) test for homogeneity=35.75; df=2; P<0.001), executive functions (χ(2)=21.68; df=2; P<0.001), and information processing speed (χ(2)=81.96; df= 2; P<0.001) than baseline normotensive participants. At follow-up, 352 individuals (30.2%) developed incident hypertension. They showed faster decline in memory (χ(2)=7.88; df=2; P=0.019) and information processing speed (χ(2)= 18.06; df=2; P<0.001), especially from 6- to 12-year follow-up. Effects were most pronounced and widespread in midlife for both prevalent and incident hypertension and in those with untreated and uncontrolled hypertension. This study shows that incident hypertension predicts cognitive decline in middle-aged individuals, and those with poorly controlled blood pressure are most at risk. In newly diagnosed individuals, decline evolves gradually, possibly opening a window for early intervention.
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Affiliation(s)
- Sebastian Köhler
- School for Mental Health and Neuroscience, Dr Tanslaan 10, PO Box 616 (DRT10), 6229 ET Maastricht, The Netherlands.
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Anderson JP, Tchetgen Tchetgen EJ, Lo Re V, Tate JP, Williams PL, Seage GR, Horsburgh CR, Lim JK, Goetz MB, Rimland D, Rodriguez-Barradas MC, Butt AA, Klein MB, Justice AC. Antiretroviral therapy reduces the rate of hepatic decompensation among HIV- and hepatitis C virus-coinfected veterans. Clin Infect Dis 2013; 58:719-27. [PMID: 24285848 DOI: 10.1093/cid/cit779] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Human immunodeficiency virus (HIV) coinfection accelerates the rate of liver disease outcomes in individuals chronically infected with hepatitis C virus (HCV). It remains unclear to what degree combination antiretroviral therapy (ART) protects against HCV-associated liver failure. METHODS We evaluated 10 090 HIV/HCV-coinfected males from the Veterans Aging Cohort Study Virtual Cohort, who had not initiated ART at entry, for incident hepatic decompensation between 1996 and 2010. We defined ART initiation as the first pharmacy fill date of a qualifying ART regimen of ≥3 drugs from ≥2 classes. Hepatic decompensation was defined as the first occurrence of 1 hospital discharge diagnosis or 2 outpatient diagnoses for ascites, spontaneous bacterial peritonitis, or esophageal variceal hemorrhage. To account for potential confounding by indication, marginal structural models were used to estimate hazard ratios (HRs) of hepatic decompensation, comparing initiation of ART to noninitiation. RESULTS We observed 645 hepatic decompensation events in 46 444 person-years of follow-up (incidence rate, 1.4/100 person-years). Coinfected patients who initiated ART had a significantly reduced rate of hepatic decompensation relative to noninitiators (HR = 0.72; 95% confidence interval [CI], .54-.94). When we removed individuals with HIV RNA ≤400 copies/mL at baseline from the analysis (assuming that they may have received undocumented ART at entry), the hazard ratio became more pronounced (HR = 0.59; 95% CI, .43-.82). CONCLUSIONS Initiation of ART significantly reduced the rate of hepatic decompensation by 28%-41% on average. These results suggest that ART should be administered to HIV/HCV-coinfected patients to lower the risk of end-stage liver disease.
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348
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Baeten S, Van Ourti T, van Doorslaer E. The socioeconomic health gradient across the life cycle: what role for selective mortality and institutionalization? Soc Sci Med 2013; 97:66-74. [PMID: 24161090 PMCID: PMC3831059 DOI: 10.1016/j.socscimed.2013.08.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 07/30/2013] [Accepted: 08/10/2013] [Indexed: 11/30/2022]
Abstract
Several studies have documented the now fairly stylized fact that health inequalities by income differ across the age distribution: in cross-sections the health gap between rich and poor tends to widen until about age 50 and then declines at higher ages. It has been suggested that selective mortality and institutionalization could be important factors driving the convergence at higher ages. We use eight waves of a health survey linked to four registries (on mortality, hospitalizations, (municipal) residence status and taxable incomes) to test this hypothesis. We construct life cycle profiles of health for birth year/gender/income groups from the health surveys (based on 128,689 observations) and exploit the registries to obtain precise estimates of individual probabilities of mortality and institutionalization using a seven year observation period for 2,521,122 individuals. We generate selection corrected health profiles using an inverse probability weighting procedure and find that attrition is indeed not random: older, poorer and unhealthier individuals are significantly more likely not to survive the next year and to be admitted to an institution. While these selection effects are very significant, they are not very large. We therefore reject the hypothesis that selective dropout is an important determinant of the differential health trajectories by income over the life course in the Netherlands.
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Affiliation(s)
- Steef Baeten
- Institute for Health Policy and Management, Erasmus University Rotterdam
| | - Tom Van Ourti
- Erasmus School of Economics, Erasmus University Rotterdam, Tinbergen Institute, and NETSPAR
| | - Eddy van Doorslaer
- Institute for Health Policy and Management, Erasmus University Rotterdam
- Erasmus School of Economics, Erasmus University Rotterdam, Tinbergen Institute, and NETSPAR
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Winding TN, Andersen JH, Labriola M, Nohr EA. Initial non-participation and loss to follow-up in a Danish youth cohort: implications for relative risk estimates. J Epidemiol Community Health 2013; 68:137-44. [PMID: 24072742 DOI: 10.1136/jech-2013-202707] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND Initial non-participation and loss to follow-up in the Danish youth cohort Vestliv could introduce selection bias of the measured risk estimates. OBJECTIVE To investigate the impact of initial non-participation and loss to follow-up on the validity of descriptive measures and selected estimates of relative risk. METHODS Of the 3681 young people defining the source population, 83% answered a questionnaire at baseline in 2004. At follow-up waves in 2007 and 2010, the response rates were 71% and 64%, respectively. Relative ORs (RORs) were used to examine the impact of initial non-participation and loss to follow-up on the association between socioeconomic or personal risk factors at age 14/15 and educational attainment at age 20/21. RORs were calculated as OR (baseline population)/OR (source population) or OR (follow-up population)/OR (baseline population). RESULTS The participants had slightly better school abilities and came more often from homes with two adults, higher income or higher educational level. These differences increased at subsequent follow-ups. The effect of initial non-participation on the ORs was modest with most RORs being close to one. Loss to follow-up led to larger variations in the RORs ranging from 0.77 to 1.62 although for most estimates, the bias was minor. None of the measured RORs were statistically different from one indicating no significant bias. CONCLUSIONS Although certain characteristics were related to those who initially chose to participate and especially to those who participated at follow-ups, it did not have any large influence on the relative risk estimates measured in the study.
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Affiliation(s)
- Trine N Winding
- Department of Occupational Medicine, Danish Ramazzini Centre, Regional Hospital Herning, , Herning, Denmark
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Participation and retention of youth with perinatal HIV infection in mental health research studies: the IMPAACT P1055 psychiatric comorbidity study. J Acquir Immune Defic Syndr 2013; 63:401-9. [PMID: 23714737 DOI: 10.1097/qai.0b013e318293ad53] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
BACKGROUND Obtaining accurate estimates of mental health problems among youth perinatally infected with HIV (PHIV) helps clinicians develop targeted interventions but requires enrollment and retention of representative youth into research studies. METHODS The study design for IMPAACT P1055, a US-based, multisite prospective study of psychiatric symptoms among PHIV youth and uninfected controls aged 6 to 17 years old, is described. Participants were compared with nonparticipants by demographic characteristics and reasons were summarized for study refusal. Adjusted logistic regression models were used to evaluate the association of psychiatric symptoms and other factors with loss to follow-up (LTFU). RESULTS Among 2281 youth screened between 2005 and 2006 at 29 IMPAACT research sites, 580 (25%) refused to participate, primarily because of time constraints. Among 1162 eligible youth approached, 582 (50%) enrolled (323 PHIV and 259 Control), with higher participation rates for Hispanic youth. Retention at 2 years was significantly higher for PHIV than Controls (84% vs 77%, P = 0.03). In logistic regression models adjusting for sociodemographic characteristics and HIV status, youth with any self-assessed psychiatric condition had higher odds of LTFU compared with those with no disorder (adjusted odds ratio = 1.56, 95% confidence interval: 1.00 to 2.43). Among PHIV youth, those with any psychiatric condition had 3-fold higher odds of LTFU (adjusted odds ratio = 3.11, 95% confidence interval: 1.61 to 6.01). CONCLUSIONS Enrollment and retention of PHIV youth into mental health research studies is challenging for those with psychiatric conditions and may lead to underestimated risks for mental health problems. Creative approaches for engaging HIV-infected youth and their families are required for ensuring representative study populations.
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