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Thurston SW, Harrington D, Mruzek DW, Shamlaye C, Myers GJ, van Wijngaarden E. Development of a long-term time-weighted exposure metric that accounts for missing data in the Seychelles Child Development Study. Neurotoxicology 2022; 92:49-60. [PMID: 35868427 PMCID: PMC9749919 DOI: 10.1016/j.neuro.2022.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 07/09/2022] [Accepted: 07/11/2022] [Indexed: 10/17/2022]
Abstract
In many studies of the health effects of toxicants, exposure is measured once even though exposure may be continuous. However, some studies collect repeated measurements on participants over an extended time with the goal of determining a long-term metric that captures the average or cumulative exposure. This can be challenging, especially when exposure is measured at irregular intervals and has some missing values. Here we describe a method for determining a measure of long-term exposure using data on postnatal mercury (Hg) from the Seychelles Child Development Study (SCDS) Main Cohort as a model. In this cohort (n = 779), we incorporate postnatal Hg values that were measured on most study participants at seven ages, three between 6 months and 5.5 years ("childhood"), and an additional four between 17 and 24 years ("early adulthood"). We develop time-weighted measures of average exposure during the childhood and the early adulthood periods and compare the strengths and weaknesses of our metric to two standard measures: overall average and cumulative exposure. We account for missing values through an imputation method that uses information about age- and sex-specific Hg means and the participant's Hg values at similar ages to estimate subject-specific missing Hg values. We compare our method to the implicit imputation assumed by these two standard methods, and to Fully Conditional Specification (FCS), an alternative method of imputing missing data. To determine the accuracy of our imputation method we use data from participants with no missing Hg values in the relevant time window. The imputed values from our proposed method are substantially closer to the observed values on average than the average or cumulative exposure, while also performing slightly better than FCS. In conclusion, time-weighted long-term exposure appears to offer advantages over cumulative exposure in longitudinal studies with repeated measures where the follow-up period for a toxicant is similar for all participants. Additionally, our method to impute missing values maximizes the number of participants for whom the overall exposure metric can be calculated and should provide a more accurate long-term exposure metric than standard methods when exposure has missing values. Our method is applicable to any study of long-term toxicant effects when longitudinal exposure measurements are available but have missing values.
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Affiliation(s)
- Sally W Thurston
- Department of Biostatistics and Computational Biology, University of Rochester Medical Center, Box 630, Rochester, NY 14642, United States; Department of Environmental Medicine, University of Rochester Medical Center, Rochester, NY, United States.
| | - Donald Harrington
- Department of Biostatistics and Computational Biology, University of Rochester Medical Center, Box 630, Rochester, NY 14642, United States
| | - Daniel W Mruzek
- Department of Pediatrics, University of Rochester Medical Center, Rochester, NY, United States
| | | | - Gary J Myers
- Department of Environmental Medicine, University of Rochester Medical Center, Rochester, NY, United States; Department of Pediatrics, University of Rochester Medical Center, Rochester, NY, United States; Department of Neurology, University of Rochester Medical Center, Rochester, NY, United States
| | - Edwin van Wijngaarden
- Department of Environmental Medicine, University of Rochester Medical Center, Rochester, NY, United States; Department of Public Health Sciences, University of Rochester Medical Center, Rochester, NY, United States
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De Silva AP, De Livera AM, Lee KJ, Moreno-Betancur M, Simpson JA. Multiple imputation methods for handling missing values in longitudinal studies with sampling weights: Comparison of methods implemented in Stata. Biom J 2020; 63:354-371. [PMID: 33103307 DOI: 10.1002/bimj.201900360] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 07/16/2020] [Accepted: 07/17/2020] [Indexed: 12/18/2022]
Abstract
Many analyses of longitudinal cohorts require incorporating sampling weights to account for unequal sampling probabilities of participants, as well as the use of multiple imputation (MI) for dealing with missing data. However, there is no guidance on how MI and sampling weights should be implemented together. We simulated a target population based on the Australian Bureau of Statistics Estimated Resident Population and drew 1000 random samples dependent on three design variables to mimic the Longitudinal Study of Australian Children. The target analysis was the weighted prevalence of overweight/obesity over childhood. We evaluated the performance of several MI approaches available in Stata, based on multivariate normal imputation (MVNI), fully conditional specification (FCS) and twofold FCS: a weighted imputation model, imputing missing data separately for each quintile sampling weight grouping, including the design stratum indicator in the imputation model, and using sampling weights as a covariate in the imputation model. Approaches based on available cases and inverse probability weighting (IPW), with time-varying weights, were also compared. We observed severe issues of convergence with FCS and twofold FCS. All MVNI-based approaches performed similarly, producing minimal bias and nominal coverage, except for when imputation was conducted separately for each quintile sampling weight group. IPW performed equally as well as MVNI-based approaches in terms of bias, however, was less precise. In similar longitudinal studies, we recommend using MVNI with the design stratum as a covariate in the imputation model. If this is unknown, including the sampling weight as a covariate is an appropriate alternative.
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Affiliation(s)
- Anurika P De Silva
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Victoria, Australia
| | - Alysha M De Livera
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Victoria, Australia
| | - Katherine J Lee
- Clinical Epidemiology and Biostatistics Unit, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - Margarita Moreno-Betancur
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Victoria, Australia.,Clinical Epidemiology and Biostatistics Unit, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - Julie A Simpson
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Victoria, Australia
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De Silva AP, Moreno-Betancur M, De Livera AM, Lee KJ, Simpson JA. Multiple imputation methods for handling missing values in a longitudinal categorical variable with restrictions on transitions over time: a simulation study. BMC Med Res Methodol 2019; 19:14. [PMID: 30630434 PMCID: PMC6329074 DOI: 10.1186/s12874-018-0653-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 12/27/2018] [Indexed: 12/17/2022] Open
Abstract
Background Longitudinal categorical variables are sometimes restricted in terms of how individuals transition between categories over time. For example, with a time-dependent measure of smoking categorised as never-smoker, ex-smoker, and current-smoker, current-smokers or ex-smokers cannot transition to a never-smoker at a subsequent wave. These longitudinal variables often contain missing values, however, there is little guidance on whether these restrictions need to be accommodated when using multiple imputation methods. Multiply imputing such missing values, ignoring the restrictions, could lead to implausible transitions. Methods We designed a simulation study based on the Longitudinal Study of Australian Children, where the target analysis was the association between (incomplete) maternal smoking and childhood obesity. We set varying proportions of data on maternal smoking to missing completely at random or missing at random. We compared the performance of fully conditional specification with multinomial and ordinal logistic imputation, and predictive mean matching, two-fold fully conditional specification, indicator based imputation under multivariate normal imputation with projected distance-based rounding, and continuous imputation under multivariate normal imputation with calibration, where each of these multiple imputation methods were applied, accounting for the restrictions using a semi-deterministic imputation procedure. Results Overall, we observed reduced bias when applying multiple imputation methods with restrictions, and fully conditional specification with predictive mean matching performed the best. Applying fully conditional specification and two-fold fully conditional specification for imputing nominal variables based on multinomial logistic regression had severe convergence issues. Both imputation methods under multivariate normal imputation produced biased estimates when restrictions were not accommodated, however, we observed substantial reductions in bias when restrictions were applied with continuous imputation under multivariate normal imputation with calibration. Conclusion In a similar longitudinal setting we recommend the use of fully conditional specification with predictive mean matching, with restrictions applied during the imputation stage. Electronic supplementary material The online version of this article (10.1186/s12874-018-0653-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Anurika Priyanjali De Silva
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Victoria, Australia.
| | - Margarita Moreno-Betancur
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Victoria, Australia.,Clinical Epidemiology and Biostatistics Unit, Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.,Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia
| | - Alysha Madhu De Livera
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Victoria, Australia
| | - Katherine Jane Lee
- Clinical Epidemiology and Biostatistics Unit, Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - Julie Anne Simpson
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Victoria, Australia
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4
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De Silva AP, Moreno-Betancur M, De Livera AM, Lee KJ, Simpson JA. A comparison of multiple imputation methods for handling missing values in longitudinal data in the presence of a time-varying covariate with a non-linear association with time: a simulation study. BMC Med Res Methodol 2017; 17:114. [PMID: 28743256 PMCID: PMC5526258 DOI: 10.1186/s12874-017-0372-y] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 06/26/2017] [Indexed: 02/06/2023] Open
Abstract
Background Missing data is a common problem in epidemiological studies, and is particularly prominent in longitudinal data, which involve multiple waves of data collection. Traditional multiple imputation (MI) methods (fully conditional specification (FCS) and multivariate normal imputation (MVNI)) treat repeated measurements of the same time-dependent variable as just another ‘distinct’ variable for imputation and therefore do not make the most of the longitudinal structure of the data. Only a few studies have explored extensions to the standard approaches to account for the temporal structure of longitudinal data. One suggestion is the two-fold fully conditional specification (two-fold FCS) algorithm, which restricts the imputation of a time-dependent variable to time blocks where the imputation model includes measurements taken at the specified and adjacent times. To date, no study has investigated the performance of two-fold FCS and standard MI methods for handling missing data in a time-varying covariate with a non-linear trajectory over time – a commonly encountered scenario in epidemiological studies. Methods We simulated 1000 datasets of 5000 individuals based on the Longitudinal Study of Australian Children (LSAC). Three missing data mechanisms: missing completely at random (MCAR), and a weak and a strong missing at random (MAR) scenarios were used to impose missingness on body mass index (BMI) for age z-scores; a continuous time-varying exposure variable with a non-linear trajectory over time. We evaluated the performance of FCS, MVNI, and two-fold FCS for handling up to 50% of missing data when assessing the association between childhood obesity and sleep problems. Results The standard two-fold FCS produced slightly more biased and less precise estimates than FCS and MVNI. We observed slight improvements in bias and precision when using a time window width of two for the two-fold FCS algorithm compared to the standard width of one. Conclusion We recommend the use of FCS or MVNI in a similar longitudinal setting, and when encountering convergence issues due to a large number of time points or variables with missing values, the two-fold FCS with exploration of a suitable time window. Electronic supplementary material The online version of this article (doi:10.1186/s12874-017-0372-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Anurika Priyanjali De Silva
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, VIC, Australia
| | - Margarita Moreno-Betancur
- Clinical Epidemiology and Biostatistics Unit, Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, VIC, Australia.,Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, VIC, Australia
| | - Alysha Madhu De Livera
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, VIC, Australia
| | - Katherine Jane Lee
- Clinical Epidemiology and Biostatistics Unit, Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, VIC, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
| | - Julie Anne Simpson
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, VIC, Australia.
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Jamsen KM, Gnjidic D, Hilmer SN, Ilomäki J, Le Couteur DG, Blyth FM, Handelsman DJ, Naganathan V, Waite LM, Cumming RG, Bell JS. Drug Burden Index and change in cognition over time in community-dwelling older men: the CHAMP study. Ann Med 2017; 49:157-164. [PMID: 27763767 DOI: 10.1080/07853890.2016.1252053] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
OBJECTIVE Anticholinergic and sedative medications are associated with acute cognitive impairment, but the long-term impact on change in cognition is unclear. This study investigated the effect of anticholinergic and sedative medications, quantified using the Drug Burden Index (DBI), on change in cognition over time in community-dwelling older men. METHODS This was a prospective cohort study of men aged ≥70 years in Sydney, Australia. DBI was assessed at baseline, 2, and 5 years. Cognitive performance was assessed using the Mini-Mental State Exam (MMSE) at each wave. Logistic quantile mixed-effects modelling was used to assess the adjusted effect of DBI on the median MMSE-time profile. Analyses were restricted to men with English-speaking backgrounds (n = 1059, 862, and 611 at baseline, 2, and 5 years). RESULTS Overall, 292 (27.7%), 258 (29.9%), and 189 (31.3%) men used anticholinergic or sedative medications at baseline, 2, and 5 years. There was a concave relationship between MMSE and time, where higher DBI corresponded to lower MMSE scores (coefficient: -0.161; 95% CI: -0.250 to -0.071) but not acceleration of declining MMSE over time. CONCLUSIONS Exposure to anticholinergic and sedative medications is associated with a small impairment in cognitive performance but not decline in cognition over time. KEY MESSAGES Exposure to anticholinergic and sedative medications, quantified using the Drug Burden Index, is associated with small cross-sectional impairments in cognitive performance. There was no evidence that exposure to anticholinergic and sedative medications is associated with accelerating decline in cognitive performance over a 5-year follow-up. Older people taking anticholinergic and sedative medications may derive immediate but small benefits in cognitive performance from clinical medication reviews to minimize or cease prescribing of these medications.
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Affiliation(s)
- Kris M Jamsen
- a Centre for Medicine Use and Safety, Faculty of Pharmacy and Pharmaceutical Sciences , Monash University , Parkville , VIC , Australia.,b National Health and Medical Research Council Cognitive Decline Partnership Centre , Hornsby Ku-ring-gai Hospital , Hornsby , NSW , Australia
| | - Danijela Gnjidic
- c Centre for Education and Research on Ageing and Ageing and Alzheimer's Institute , Concord Hospital , Concord , NSW , Australia.,d Faculty of Pharmacy , University of Sydney , Sydney , NSW , Australia
| | - Sarah N Hilmer
- b National Health and Medical Research Council Cognitive Decline Partnership Centre , Hornsby Ku-ring-gai Hospital , Hornsby , NSW , Australia.,e Kolling Institute of Medical Research , Sydney Medical School, University of Sydney , Sydney , NSW , Australia
| | - Jenni Ilomäki
- a Centre for Medicine Use and Safety, Faculty of Pharmacy and Pharmaceutical Sciences , Monash University , Parkville , VIC , Australia
| | - David G Le Couteur
- c Centre for Education and Research on Ageing and Ageing and Alzheimer's Institute , Concord Hospital , Concord , NSW , Australia.,f Sydney Medical School , University of Sydney , Sydney , NSW , Australia.,g ANZAC Research Institute , University of Sydney, Concord Hospital , Concord , NSW , Australia
| | - Fiona M Blyth
- c Centre for Education and Research on Ageing and Ageing and Alzheimer's Institute , Concord Hospital , Concord , NSW , Australia.,f Sydney Medical School , University of Sydney , Sydney , NSW , Australia
| | - David J Handelsman
- f Sydney Medical School , University of Sydney , Sydney , NSW , Australia.,g ANZAC Research Institute , University of Sydney, Concord Hospital , Concord , NSW , Australia
| | - Vasi Naganathan
- c Centre for Education and Research on Ageing and Ageing and Alzheimer's Institute , Concord Hospital , Concord , NSW , Australia.,f Sydney Medical School , University of Sydney , Sydney , NSW , Australia
| | - Louise M Waite
- c Centre for Education and Research on Ageing and Ageing and Alzheimer's Institute , Concord Hospital , Concord , NSW , Australia.,f Sydney Medical School , University of Sydney , Sydney , NSW , Australia
| | - Robert G Cumming
- c Centre for Education and Research on Ageing and Ageing and Alzheimer's Institute , Concord Hospital , Concord , NSW , Australia.,h Sydney School of Public Health , University of Sydney , Sydney , NSW , Australia
| | - J Simon Bell
- a Centre for Medicine Use and Safety, Faculty of Pharmacy and Pharmaceutical Sciences , Monash University , Parkville , VIC , Australia.,b National Health and Medical Research Council Cognitive Decline Partnership Centre , Hornsby Ku-ring-gai Hospital , Hornsby , NSW , Australia
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6
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Becaria Coquet J, Tumas N, Osella AR, Tanzi M, Franco I, Diaz MDP. Breast Cancer and Modifiable Lifestyle Factors in Argentinean Women: Addressing Missing Data in a Case-Control Study. Asian Pac J Cancer Prev 2016; 17:4567-4575. [PMID: 27892664 PMCID: PMC5454599 DOI: 10.22034/apjcp.2016.17.10.4567] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
A number of studies have evidenced the effect of modifiable lifestyle factors such as diet, breastfeeding and nutritional status on breast cancer risk. However, none have addressed the missing data problem in nutritional epidemiologic research in South America. Missing data is a frequent problem in breast cancer studies and epidemiological settings in general. Estimates of effect obtained from these studies may be biased, if no appropriate method for handling missing data is applied. We performed Multiple Imputation for missing values on covariates in a breast cancer case-control study of Córdoba (Argentina) to optimize risk estimates. Data was obtained from a breast cancer case control study from 2008 to 2015 (318 cases, 526 controls). Complete case analysis and multiple imputation using chained equations were the methods applied to estimate the effects of a Traditional dietary pattern and other recognized factors associated with breast cancer. Physical activity and socioeconomic status were imputed. Logistic regression models were performed. When complete case analysis was performed only 31% of women were considered. Although a positive association of Traditional dietary pattern and breast cancer was observed from both approaches (complete case analysis OR=1.3, 95%CI=1.0-1.7; multiple imputation OR=1.4, 95%CI=1.2-1.7), effects of other covariates, like BMI and breastfeeding, were only identified when multiple imputation was considered. A Traditional dietary pattern, BMI and breastfeeding are associated with the occurrence of breast cancer in this Argentinean population when multiple imputation is appropriately performed. Multiple Imputation is suggested in Latin America’s epidemiologic studies to optimize effect estimates in the future.
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Affiliation(s)
- Julia Becaria Coquet
- Instituto de Investigaciones en Ciencias de la Salud (INICSA-UNC-CONICET), Universidad Nacional de Cordoba (UNC), Cordoba Capital, Cordoba, Argentina.
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Jamsen KM, Bell JS, Hilmer SN, Kirkpatrick CMJ, Ilomäki J, Le Couteur D, Blyth FM, Handelsman DJ, Waite L, Naganathan V, Cumming RG, Gnjidic D. Effects of Changes in Number of Medications and Drug Burden Index Exposure on Transitions Between Frailty States and Death: The Concord Health and Ageing in Men Project Cohort Study. J Am Geriatr Soc 2016; 64:89-95. [PMID: 26782856 DOI: 10.1111/jgs.13877] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVES To investigate the effects of number of medications and Drug Burden Index (DBI) on transitions between frailty stages and death in community-dwelling older men. DESIGN Cohort study. SETTING Sydney, Australia. PARTICIPANTS Community-dwelling men aged 70 and older (N=1,705). MEASUREMENTS Self-reported questionnaires and clinic visits were conducted at baseline and 2 and 5 years. Frailty was assessed at all three waves according to the modified Fried frailty phenotype. The total number of regular prescription medications and DBI (a measure of exposure to sedative and anticholinergic medications) were calculated over the three waves. Data on mortality over 9 years were obtained. Multistate modeling was used to characterize the transitions across three frailty states (robust, prefrail, frail) and death. RESULTS Each additional medication was associated with a 22% greater risk of transitioning from the robust state to death (adjusted 95% confidence interval (CI)=1.06-1.41). Every unit increase in DBI was associated with a 73% greater risk of transitioning from the robust state to the prefrail state (adjusted 95% CI=1.30-2.31) and a 2.75 times greater risk of transitioning from the robust state to death (adjusted 95% CI=1.60-4.75). There was no evidence of an adjusted association between total number of medications or DBI and the other transitions. CONCLUSION Although the possibility of confounding by indication cannot be excluded, additional medications were associated with greater risk of mortality in robust community-dwelling older men. Greater DBI was also associated with greater risk of death and transitioning from the robust state to the prefrail state.
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Affiliation(s)
- Kris M Jamsen
- Centre for Medicine Use and Safety, Faculty of Pharmacy and Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia.,Cognitive Decline Partnership Centre, Hornsby Ku-ring-gai Hospital, Hornsby, New South Wales, Australia
| | - J Simon Bell
- Centre for Medicine Use and Safety, Faculty of Pharmacy and Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia.,Cognitive Decline Partnership Centre, Hornsby Ku-ring-gai Hospital, Hornsby, New South Wales, Australia.,Sansom Institute, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Sarah N Hilmer
- Cognitive Decline Partnership Centre, Hornsby Ku-ring-gai Hospital, Hornsby, New South Wales, Australia.,Kolling Institute of Medical Research, University of Sydney, Sydney, New South Wales, Australia
| | - Carl M J Kirkpatrick
- Centre for Medicine Use and Safety, Faculty of Pharmacy and Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Jenni Ilomäki
- Centre for Medicine Use and Safety, Faculty of Pharmacy and Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - David Le Couteur
- Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia.,Centre for Education and Research on Ageing, Concord, New South Wales, Australia.,ANZAC Institute, Concord Hospital, Concord, New South Wales, Australia
| | - Fiona M Blyth
- Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia.,Centre for Education and Research on Ageing, Concord, New South Wales, Australia
| | - David J Handelsman
- Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia.,ANZAC Institute, Concord Hospital, Concord, New South Wales, Australia
| | - Louise Waite
- ANZAC Institute, Concord Hospital, Concord, New South Wales, Australia
| | - Vasi Naganathan
- Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia.,Centre for Education and Research on Ageing, Concord, New South Wales, Australia
| | - Robert G Cumming
- Centre for Education and Research on Ageing, Concord, New South Wales, Australia.,Sydney School of Public Health, University of Sydney, Sydney, New South Wales, Australia
| | - Danijela Gnjidic
- Centre for Education and Research on Ageing, Concord, New South Wales, Australia.,Faculty of Pharmacy, University of Sydney, Sydney, New South Wales, Australia
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8
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Ordóñez-Mena JM, Schöttker B, Mons U, Jenab M, Freisling H, Bueno-de-Mesquita B, O’Doherty MG, Scott A, Kee F, Stricker BH, Hofman A, de Keyser CE, Ruiter R, Söderberg S, Jousilahti P, Kuulasmaa K, Freedman ND, Wilsgaard T, de Groot LCPGM, Kampman E, Håkansson N, Orsini N, Wolk A, Nilsson LM, Tjønneland A, Pająk A, Malyutina S, Kubínová R, Tamosiunas A, Bobak M, Katsoulis M, Orfanos P, Boffetta P, Trichopoulou A, Brenner H. Quantification of the smoking-associated cancer risk with rate advancement periods: meta-analysis of individual participant data from cohorts of the CHANCES consortium. BMC Med 2016; 14:62. [PMID: 27044418 PMCID: PMC4820956 DOI: 10.1186/s12916-016-0607-5] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Accepted: 03/18/2016] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Smoking is the most important individual risk factor for many cancer sites but its association with breast and prostate cancer is not entirely clear. Rate advancement periods (RAPs) may enhance communication of smoking related risk to the general population. Thus, we estimated RAPs for the association of smoking exposure (smoking status, time since smoking cessation, smoking intensity, and duration) with total and site-specific (lung, breast, colorectal, prostate, gastric, head and neck, and pancreatic) cancer incidence and mortality. METHODS This is a meta-analysis of 19 population-based prospective cohort studies with individual participant data for 897,021 European and American adults. For each cohort we calculated hazard ratios (HRs) for the association of smoking exposure with cancer outcomes using Cox regression adjusted for a common set of the most important potential confounding variables. RAPs (in years) were calculated as the ratio of the logarithms of the HRs for a given smoking exposure variable and age. Meta-analyses were employed to summarize cohort-specific HRs and RAPs. RESULTS Overall, 140,205 subjects had a first incident cancer, and 53,164 died from cancer, during an average follow-up of 12 years. Current smoking advanced the overall risk of developing and dying from cancer by eight and ten years, respectively, compared with never smokers. The greatest advancements in cancer risk and mortality were seen for lung cancer and the least for breast cancer. Smoking cessation was statistically significantly associated with delays in the risk of cancer development and mortality compared with continued smoking. CONCLUSIONS This investigation shows that smoking, even among older adults, considerably advances, and cessation delays, the risk of developing and dying from cancer. These findings may be helpful in more effectively communicating the harmful effects of smoking and the beneficial effect of smoking cessation.
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Affiliation(s)
- José Manuel Ordóñez-Mena
- />Network Aging Research (NAR), Heidelberg University, Heidelberg, Germany
- />Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, D-69120 Heidelberg, Germany
| | - Ben Schöttker
- />Network Aging Research (NAR), Heidelberg University, Heidelberg, Germany
- />Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, D-69120 Heidelberg, Germany
| | - Ute Mons
- />Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, D-69120 Heidelberg, Germany
| | - Mazda Jenab
- />International Agency for Research on Cancer (IARC), Lyon, France
| | - Heinz Freisling
- />International Agency for Research on Cancer (IARC), Lyon, France
| | - Bas Bueno-de-Mesquita
- />Department of Chronic Diseases, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
- />Department of Gastroenterology and Hepatology, University Medical Centre, Utrecht, The Netherlands
- />Division of Epidemiology and Biostatistics, the School of Public Health, Imperial College London, London, United Kingdom
- />Department of Social & Preventive Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Mark G. O’Doherty
- />UKCRC Centre of Excellence for Public Health, Queens University of Belfast, Belfast, UK
| | - Angela Scott
- />UKCRC Centre of Excellence for Public Health, Queens University of Belfast, Belfast, UK
| | - Frank Kee
- />UKCRC Centre of Excellence for Public Health, Queens University of Belfast, Belfast, UK
| | - Bruno H. Stricker
- />Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Albert Hofman
- />Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | | | - Rikje Ruiter
- />Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Stefan Söderberg
- />Department of Public Health and Clinical Medicine, Cardiology, and Heart Center, Umeå University, Umeå, Sweden
| | - Pekka Jousilahti
- />National Institute for Health and Welfare (THL), Helsinki, Finland
| | - Kari Kuulasmaa
- />National Institute for Health and Welfare (THL), Helsinki, Finland
| | - Neal D. Freedman
- />Nutritional Epidemiology Branch, Division of Cancer Epidemiology & Genetics, National Cancer Institute, Rockville, MD USA
| | - Tom Wilsgaard
- />Department of Community Medicine, UiT The Arctic University of Norway, Tromsø, Norway
| | | | - Ellen Kampman
- />Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands
| | - Niclas Håkansson
- />Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Nicola Orsini
- />Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Alicja Wolk
- />Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Lena Maria Nilsson
- />Nutritional Research, Department of Public Health and Clinical Medicine, and Arcum, Arctic Research Centre at Umeå University, Umeå, Sweden
| | - Anne Tjønneland
- />Diet, Genes and Environment, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Andrzej Pająk
- />Jagiellonian University Medical College, Faculty of Health Sciences, Krakow, Poland
| | - Sofia Malyutina
- />Institute of Internal and Preventive Medicine, Novosibirsk, Russia
| | - Růžena Kubínová
- />National Institute of Public Health, Prague, Czech Republic
| | - Abdonas Tamosiunas
- />Institute of Cardiology of Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Martin Bobak
- />Department Epidemiology and Public Health, University College London, London, UK
| | | | - Philippos Orfanos
- />University of Athens, Medical School, Department of Hygiene, Epidemiology and Medical Statistics, Athens, Greece
| | - Paolo Boffetta
- />Hellenic Health Foundation, Athens, Greece
- />Institute for Translational Epidemiology and Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY USA
| | - Antonia Trichopoulou
- />Hellenic Health Foundation, Athens, Greece
- />University of Athens, Medical School, Department of Hygiene, Epidemiology and Medical Statistics, Athens, Greece
| | - Hermann Brenner
- />Network Aging Research (NAR), Heidelberg University, Heidelberg, Germany
- />Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, D-69120 Heidelberg, Germany
- />German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany
- />Division of Preventive Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - on behalf of the Consortium on Health and Ageing: Network of Cohorts in Europe and the United States (CHANCES)
- />Network Aging Research (NAR), Heidelberg University, Heidelberg, Germany
- />Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, D-69120 Heidelberg, Germany
- />International Agency for Research on Cancer (IARC), Lyon, France
- />Department of Chronic Diseases, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
- />Department of Gastroenterology and Hepatology, University Medical Centre, Utrecht, The Netherlands
- />Division of Epidemiology and Biostatistics, the School of Public Health, Imperial College London, London, United Kingdom
- />Department of Social & Preventive Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
- />UKCRC Centre of Excellence for Public Health, Queens University of Belfast, Belfast, UK
- />Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
- />Department of Public Health and Clinical Medicine, Cardiology, and Heart Center, Umeå University, Umeå, Sweden
- />National Institute for Health and Welfare (THL), Helsinki, Finland
- />Nutritional Epidemiology Branch, Division of Cancer Epidemiology & Genetics, National Cancer Institute, Rockville, MD USA
- />Department of Community Medicine, UiT The Arctic University of Norway, Tromsø, Norway
- />Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands
- />Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
- />Nutritional Research, Department of Public Health and Clinical Medicine, and Arcum, Arctic Research Centre at Umeå University, Umeå, Sweden
- />Diet, Genes and Environment, Danish Cancer Society Research Center, Copenhagen, Denmark
- />Jagiellonian University Medical College, Faculty of Health Sciences, Krakow, Poland
- />Institute of Internal and Preventive Medicine, Novosibirsk, Russia
- />National Institute of Public Health, Prague, Czech Republic
- />Institute of Cardiology of Lithuanian University of Health Sciences, Kaunas, Lithuania
- />Department Epidemiology and Public Health, University College London, London, UK
- />Hellenic Health Foundation, Athens, Greece
- />University of Athens, Medical School, Department of Hygiene, Epidemiology and Medical Statistics, Athens, Greece
- />Institute for Translational Epidemiology and Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY USA
- />German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany
- />Division of Preventive Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
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9
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Karahalios A, Simpson JA, Baglietto L, MacInnis RJ, Hodge AM, Giles GG, English DR. Change in weight and waist circumference and risk of colorectal cancer: results from the Melbourne Collaborative Cohort Study. BMC Cancer 2016; 16:157. [PMID: 26917541 PMCID: PMC4768408 DOI: 10.1186/s12885-016-2144-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 02/08/2016] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Studies reporting the association between change in weight or body mass index during midlife and risk of colorectal cancer have found inconsistent results, and only one study to date has reported the association between change in waist circumference (a measure of central adiposity) and risk of colorectal cancer. METHODS We investigated the association between risk of colorectal cancer and changes in directly measured waist circumference and weight from baseline (1990-1994) to wave 2 (2003-2007). Cox regression, with age as the time metric and follow-up starting at wave 2, adjusted for covariates selected from a causal model, was used to estimate the Hazard Ratios (HRs) and 95 % Confidence Intervals (CIs) for the change in waist circumference and weight in relation to risk of colorectal cancer. RESULTS A total of 373 cases of colorectal cancer were diagnosed during an average 9 years of follow-up of 20,605 participants. Increases in waist circumference and weight were not associated with the risk of colorectal cancer (HR per 5 cm increase in waist circumference = 1.02; 95 % CI: 0.95, 1.10; HR per 5 kg increase in weight = 0.93; 0.85, 1.02). For individuals with a waist circumference at baseline that was less than the sex-specific mean value there was a slight increased risk of colorectal cancer associated with a 5 cm increase in waist circumference at wave 2 (HR = 1.08; 0.97, 1.21). CONCLUSION Increases in waist circumference and weight during midlife do not appear to be associated with the risk of colorectal cancer.
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Affiliation(s)
- Amalia Karahalios
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Bouverie Street, Melbourne, 3010, Australia.
| | - Julie A Simpson
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Bouverie Street, Melbourne, 3010, Australia. .,Cancer Epidemiology Centre, Cancer Council Victoria, 615 St Kilda Road, Melbourne, 3004, Australia.
| | - Laura Baglietto
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Bouverie Street, Melbourne, 3010, Australia. .,Cancer Epidemiology Centre, Cancer Council Victoria, 615 St Kilda Road, Melbourne, 3004, Australia. .,Team 9, Lifestyle, Genes and health: integrative trans-generational epidemiology, Inserm U1018, Centre for Research in Epidemiology and Population Health, Gustave Roussy Institute, 114 rue Edouard Vaillant, Villejuif Cedex, 94805, France. .,Paris-South University, Villejuif, France.
| | - Robert J MacInnis
- Cancer Epidemiology Centre, Cancer Council Victoria, 615 St Kilda Road, Melbourne, 3004, Australia.
| | - Allison M Hodge
- Cancer Epidemiology Centre, Cancer Council Victoria, 615 St Kilda Road, Melbourne, 3004, Australia.
| | - Graham G Giles
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Bouverie Street, Melbourne, 3010, Australia. .,Cancer Epidemiology Centre, Cancer Council Victoria, 615 St Kilda Road, Melbourne, 3004, Australia.
| | - Dallas R English
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Bouverie Street, Melbourne, 3010, Australia. .,Cancer Epidemiology Centre, Cancer Council Victoria, 615 St Kilda Road, Melbourne, 3004, Australia.
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10
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Sawyer ACP, Chittleborough CR, Mittinty MN, Miller-Lewis LR, Sawyer MG, Sullivan T, Lynch JW. Are trajectories of self-regulation abilities from ages 2-3 to 6-7 associated with academic achievement in the early school years? Child Care Health Dev 2015; 41:744-54. [PMID: 25332070 DOI: 10.1111/cch.12208] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/18/2014] [Indexed: 11/24/2022]
Abstract
BACKGROUND The aim of this study was to estimate the association between two key aspects of self-regulation, 'task attentiveness' and 'emotional regulation' assessed from ages 2-3 to 6-7 years, and academic achievement when children were aged 6-7 years. METHODS Participants (n = 3410) were children in the Longitudinal Study of Australian Children. Parents rated children's task attentiveness and emotional regulation abilities when children were aged 2-3, 4-5 and 6-7. Academic achievement was assessed using the Academic Rating Scale completed by teachers. Linear regression models were used to estimate the association between developmental trajectories (i.e. rate of change per year) of task attentiveness and emotional regulation, and academic achievement at 6-7 years. RESULTS Improvements in task attentiveness between 2-3 and 6-7 years, adjusted for baseline levels of task attentiveness, child and family confounders, and children's receptive vocabulary and non-verbal reasoning skills at age 6-7 were associated with greater teacher-rated literacy [B = 0.05, 95% confidence interval (CI) = 0.04-0.06] and maths achievement (B = 0.04, 95% CI = 0.03-0.06) at 6-7 years. Improvements in emotional regulation, adjusting for baseline levels and covariates, were also associated with better teacher-rated literacy (B = 0.02, 95% CI = 0.01-0.04) but not with maths achievement (B = 0.01, 95% CI = -0.01-0.02) at 6-7 years. For literacy, improvements in task attentiveness had a stronger association with achievement at 6-7 years than improvements in emotional regulation. CONCLUSIONS Our study shows that improved trajectories of task attentiveness from ages 2-3 to 6-7 years are associated with improved literacy and maths achievement during the early school years. Trajectories of improving emotional regulation showed smaller effects on academic outcomes. Results suggest that interventions that improve task attentiveness when children are aged 2-3 to 6-7 years have the potential to improve literacy and maths achievement during the early school years.
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Affiliation(s)
- A C P Sawyer
- Discipline of Public Health, School of Population Health, University of Adelaide, Adelaide, SA, Australia
| | - C R Chittleborough
- Discipline of Public Health, School of Population Health, University of Adelaide, Adelaide, SA, Australia
| | - M N Mittinty
- Discipline of Public Health, School of Population Health, University of Adelaide, Adelaide, SA, Australia
| | - L R Miller-Lewis
- Research and Evaluation Unit, Women's and Children's Health Network, Adelaide, SA, Australia.,Discipline of Paediatrics, University of Adelaide, Adelaide, SA, Australia
| | - M G Sawyer
- Research and Evaluation Unit, Women's and Children's Health Network, Adelaide, SA, Australia.,Discipline of Paediatrics, University of Adelaide, Adelaide, SA, Australia
| | - T Sullivan
- Discipline of Public Health, School of Population Health, University of Adelaide, Adelaide, SA, Australia
| | - J W Lynch
- Discipline of Public Health, School of Population Health, University of Adelaide, Adelaide, SA, Australia.,School of Social and Community Medicine, University of Bristol, Bristol, UK
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11
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Abstract
OBJECTIVES Demonstrate the application of decision trees--classification and regression trees (CARTs), and their cousins, boosted regression trees (BRTs)--to understand structure in missing data. SETTING Data taken from employees at 3 different industrial sites in Australia. PARTICIPANTS 7915 observations were included. MATERIALS AND METHODS The approach was evaluated using an occupational health data set comprising results of questionnaires, medical tests and environmental monitoring. Statistical methods included standard statistical tests and the 'rpart' and 'gbm' packages for CART and BRT analyses, respectively, from the statistical software 'R'. A simulation study was conducted to explore the capability of decision tree models in describing data with missingness artificially introduced. RESULTS CART and BRT models were effective in highlighting a missingness structure in the data, related to the type of data (medical or environmental), the site in which it was collected, the number of visits, and the presence of extreme values. The simulation study revealed that CART models were able to identify variables and values responsible for inducing missingness. There was greater variation in variable importance for unstructured as compared to structured missingness. DISCUSSION Both CART and BRT models were effective in describing structural missingness in data. CART models may be preferred over BRT models for exploratory analysis of missing data, and selecting variables important for predicting missingness. BRT models can show how values of other variables influence missingness, which may prove useful for researchers. CONCLUSIONS Researchers are encouraged to use CART and BRT models to explore and understand missing data.
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Affiliation(s)
- Nicholas J Tierney
- Department of Statistical Science, Mathematical Sciences, Science & Engineering Faculty, Queensland University of Technology, Brisbane, Queensland, Australia
- ARC Centre of Excellence for Mathematical and Statistical Frontiers (ACEMS), Brisbane, Queensland, Australia
| | - Fiona A Harden
- Faculty of Health, Clinical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
- Institute of Health and Biomedical Innovation, Brisbane, Queensland, Australia
| | - Maurice J Harden
- Hunter Industrial Medicine, Newcastle, New South Wales, Australia
| | - Kerrie L Mengersen
- Department of Statistical Science, Mathematical Sciences, Science & Engineering Faculty, Queensland University of Technology, Brisbane, Queensland, Australia
- ARC Centre of Excellence for Mathematical and Statistical Frontiers (ACEMS), Brisbane, Queensland, Australia
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12
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Karahalios A, Simpson JA, Baglietto L, MacInnis RJ, Hodge AM, Giles GG, English DR. Change in body size and mortality: results from the Melbourne collaborative cohort study. PLoS One 2014; 9:e99672. [PMID: 24988430 PMCID: PMC4079561 DOI: 10.1371/journal.pone.0099672] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 05/17/2014] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND The association between change in weight or body mass index, and mortality is widely reported, however, both measures fail to account for fat distribution. Change in waist circumference, a measure of central adiposity, in relation to mortality has not been studied extensively. METHODS We investigated the association between mortality and changes in directly measured waist circumference, hips circumference and weight from baseline (1990-1994) to wave 2 (2003-2007) in a prospective cohort study of people aged 40-69 years at baseline. Cox regression, with age as the time metric and follow-up starting at wave 2, adjusted for confounding variables, was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for change in body size in relation to mortality from all causes, cardiovascular disease and cancer. RESULTS There were 1465 deaths (109 cancer, 242 cardiovascular disease) identified during an average 7.7 years of follow-up from 21 298 participants. Compared to minimal increase in body size, loss of waist circumference (HR: 1.26; 95% CI: 1.09-1.47), weight (1.80; 1.54-2.11), or hips circumference (1.35; 1.15-1.57) were associated with an increased risk of all-cause mortality, particularly for older adults. Weight loss was associated with cardiovascular disease mortality (2.40; 1.57-3.65) but change in body size was not associated with obesity-related cancer mortality. CONCLUSION This study confirms the association between weight loss and increased mortality from all-causes for older adults. Based on evidence from observational cohort studies, weight stability may be the recommended option for most adults, especially older adults.
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Affiliation(s)
- Amalia Karahalios
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Victoria, Australia
- Cancer Epidemiology Centre, Cancer Council Victoria, Melbourne, Victoria, Australia
- * E-mail:
| | - Julie A. Simpson
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Victoria, Australia
- Cancer Epidemiology Centre, Cancer Council Victoria, Melbourne, Victoria, Australia
| | - Laura Baglietto
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Victoria, Australia
- Cancer Epidemiology Centre, Cancer Council Victoria, Melbourne, Victoria, Australia
| | - Robert J. MacInnis
- Cancer Epidemiology Centre, Cancer Council Victoria, Melbourne, Victoria, Australia
| | - Allison M. Hodge
- Cancer Epidemiology Centre, Cancer Council Victoria, Melbourne, Victoria, Australia
| | - Graham G. Giles
- Cancer Epidemiology Centre, Cancer Council Victoria, Melbourne, Victoria, Australia
| | - Dallas R. English
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Victoria, Australia
- Cancer Epidemiology Centre, Cancer Council Victoria, Melbourne, Victoria, Australia
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13
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Lee KJ, Simpson JA. Introduction to multiple imputation for dealing with missing data. Respirology 2013; 19:162-167. [PMID: 24372814 DOI: 10.1111/resp.12226] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2013] [Accepted: 10/13/2013] [Indexed: 11/26/2022]
Abstract
Missing data are common in both observational and experimental studies. Multiple imputation (MI) is a two-stage approach where missing values are imputed a number of times using a statistical model based on the available data and then inference is combined across the completed datasets. This approach is becoming increasingly popular for handling missing data. In this paper, we introduce the method of MI, as well as a discussion surrounding when MI can be a useful method for handling missing data and the drawbacks of this approach. We illustrate MI when exploring the association between current asthma status and forced expiratory volume in 1 s after adjustment for potential confounders using data from a population-based longitudinal cohort study.
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Affiliation(s)
- Katherine J Lee
- Clinical Epidemiology and Biostatistics Unit, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia.,Department of Paediatrics, The University of Melbourne, Melbourne, Victoria, Australia
| | - Julie A Simpson
- Centre for Molecular, Environmental, Genetic & Analytic Epidemiology, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Victoria, Australia
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