The Association Between Cancer and Spousal Rate of Memory Decline: A Negative Control Study to Evaluate (Unmeasured) Social Confounding of the Cancer-memory Relationship

Cancer diagnoses are associated with better long-term memory in older adults, possibly reflecting a range of social confounders that increase cancer risk but improve memory. We used spouse's memory as a negative control outcome to evaluate this possible confounding, since spouses share social characteristics and environments, and individuals' cancers are unlikely to cause better memory among their spouses. We estimated the association of an individual's incident cancer diagnosis (exposure) with their own (primary outcome) and their spouse's (negative control outcome) memory decline in 3601 couples from 1998 to 2014 in the Health and Retirement Study, using linear mixed-effects models. Incident cancer predicted better long-term memory for the diagnosed individual. We observed no association between an individual's cancer diagnosis and rate of spousal memory decline. This negative control study suggests that the inverse association between incident cancer and rate of memory decline is unlikely to be attributable to social/behavioral factors shared between spouses.

Racial/Ethnic Disparities in Young Adulthood and Midlife Cardiovascular Risk Factors and Late-life Cognitive Domains: The Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) Study

BACKGROUND

Midlife cardiovascular risk factors (CVRF) increase dementia risk. Less is known about whether CVRF identified before midlife impact late-life cognition in diverse populations.

METHODS

Linear regression models examined hypertension, hyperlipidemia, and overweight/obesity at ages 30 to 59 with late-life executive function, semantic memory, verbal episodic memory, and global cognition in a cohort of Asians, blacks, Latinos, and whites (n=1127; mean age=75.8, range=65 to 98). Models adjusted for age at CVRF, age at cognitive assessment, sex, race/ethnicity, participant education, and parental education.

RESULTS

Overall, 34% had 1 CVRF at ages 30 to 59; 19% had 2+. Blacks (26%) and Latinos (23%) were more likely to have 2+ CVRF than Asians (14%) or whites (13%). Having 2+ CVRF was associated with lower global cognition [β=-0.33; 95% confidence interval (CI)=-0.45, -0.21], executive function (β=-0.26; 95% CI=-0.39, -0.13), verbal episodic memory (β=-0.34; 95% CI=-0.48, -0.20), and semantic memory (β=-0.20; 95% CI=-0.33, -0.07). Interaction by age (P=0.06) indicated overweight/obesity was negatively associated with executive function at ages 30 to 39 but not at ages 40 to 59. Race/ethnic-specific effects showed disparities in CVRF prevalence impact population disparities in late-life cognition.

CONCLUSION

Being overweight/obese in early adulthood and having 2+ CVRF in early adulthood/midlife are modifiable targets to redress racial/ethnic disparities in cognitive impairment and dementia.

Temporal Trends in Stroke-Related Memory Change: Results From a US National Cohort 1998-2016

BACKGROUND AND PURPOSE

Findings from the Framingham Heart Study suggest that declines in dementia incidence rates over recent decades are partially due to decreases in stroke incidence and mortality; however, whether trends of declining dementia rates extend to survivors of incident stroke remains unclear. We investigated evidence for temporal trends in memory change related to incident stroke in a nationally representative cohort.

METHODS

Adults age 50+ in the HRS (Health and Retirement Study) were followed across three successive 6-year epochs (epoch 1: 1998-2004, n=16 781; epoch 2: 2004-2010, n=15 345; and epoch 3: 2010-2016; n=15 949). Participants were included in an epoch if they were stroke-free at the start of that epoch. Annual rates of change in a composite z-standardized memory score were compared using demographic-adjusted linear regression models for stroke-free participants, those who survived after stroke, and those who died after stroke, considering memory change before stroke, at the time of stroke, and for years following stroke.

RESULTS

Crude stroke incidence rates decreased from 8.5 per 1000 person-years in epoch 1 to 6.8 per 1000 person-years in epoch 3. Rates of memory change before and following stroke onset were similar across epochs. Memory decrement immediately after stroke onset attenuated from -0.37 points (95% CI, -0.44 to -0.29) in epoch 1 to -0.26 (95% CI, -0.33 to -0.18) points in epoch 2 and -0.25 (95% CI, -0.33 to -0.17) points in epoch 3 (P value for linear trend=0.02).

CONCLUSIONS

Decreases in stroke-related dementia in recent years may be partially attributable to smaller memory decrements immediately after stroke onset. Findings suggest reductions in stroke incidence and improvements in stroke care may also reduce population burden of dementia. Further investigations into whether temporal trends are attributable to improvements in stroke care are needed.

Cognitive Reserve, Incident Cancer, and Rate of Memory Decline in Later Life

Cognitive reserve (cognitive skills and abilities acquired before onset of brain pathology) helps maintain cognitive function during aging. Cognitive decline after cancer treatment, known as “chemobrain,” is a prevalent outcome among older cancer survivors. It is unknown whether cognitive reserve buffers against acute neuropathological events such as cancer-related cognitive decline. We examined acute and long-term rate of memory decline associated with incident cancer diagnosis by education levels as proxy for cognitive reserve (low: <12 years; intermediate: 12 to <16 years; high: ≥16 years) in 14,449 adults aged 50+ in the US Health and Retirement Study from 1998-2016. Memory (z-scored) was assessed biennially as immediate and delayed word recall combined with proxy assessments. We used adjusted linear mixed models to determine long-term rates of memory decline before and after cancer diagnosis, and acute memory decline immediately after diagnosis (3,248 incident cases), and compared them with corresponding memory trajectories in cancer-free participants. Acute memory decline immediately after diagnosis was larger in those with low (-0.098 SD units, 95% CI: -0.150, -0.045) versus high (-0.038 SD units, 95% CI: -0.084, -0.008) education. Long-term memory decline after cancer was faster in those with low (-1.16 SD units/decade, 95% CI: -1.25, -1.07) versus high (-0.89 SD units/decade, 95% CI: -0.96, -0.82) education. Consistent with previous research showing an inverse cancer-dementia relationship, individuals with cancer had more favorable memory trajectories than cancer-free individuals with similar age and education. Among those with cancer, lower cognitive reserve was associated with greater acute and long-term memory decline after diagnosis.

Mediation of the Associations of Physical Activity With Cardiovascular Events and Mortality by Diabetes in Older Mexican Americans

Low physical activity (PA) among older adults increases the risk of cardiovascular disease (CVD) and mortality through metabolic disorders such as type 2 diabetes. We aimed to elucidate the extent to which diabetes mediates the effect of nonoccupational PA levels on CVD and mortality among older Mexican Americans. This study included 1,676 adults from the Sacramento Area Latino Study on Aging (1998-2007). We employed Cox proportional hazards regression models to investigate associations of PA level with all-cause mortality, fatal CVD, and nonfatal CVD events. Utilizing causal mediation analysis within a counterfactual framework, we decomposed the total effect of PA into natural indirect and direct effects. Over a median of 8 years of follow-up, low PA (<25th percentile) was associated with increased risks of all-cause mortality (hazard ratio (HR) = 1.36, 95% confidence interval (CI): 1.06, 1.75), fatal CVD (HR = 2.05, 95% CI: 1.42, 2.97), and nonfatal CVD events (HR = 1.67, 95% CI: 1.18, 2.37) in comparison with high PA (>75th percentile). Diabetes mediated 11.0%, 7.4%, and 5.2% of the total effect of PA on all-cause mortality, fatal CVD, and nonfatal CVD events, respectively. Our findings indicate that public health interventions targeting diabetes prevention and management would be a worthwhile strategy for preventing CVD and mortality among older Mexican Americans with insufficient PA levels.

Rate of Memory Change Before and After Cancer Diagnosis

IMPORTANCE

Patients with a history of cancer, even nonfatal cancers, have lower subsequent Alzheimer disease incidence. An inverse biological link between carcinogenesis and neurodegeneration has been hypothesized, although survival and detection biases are possible explanations.

OBJECTIVE

To compare long-term memory trajectories before and after incident cancer with memory trajectories of similarly aged individuals not diagnosed with cancer.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study included 14 583 US adults born before 1949 with no cancer history from the Health and Retirement Study. Biennial assessments were performed for up to 16 years from 1998 to 2014. Data analysis was performed from January 8 to October 5, 2018.

EXPOSURES

Self-reported physician diagnosis of any cancer (excluding nonmelanoma skin cancer) during follow-up.

MAIN OUTCOMES AND MEASURES

A composite memory score standardized to a mean (SD) of 0 (1) at baseline was based on immediate and delayed word-list recall and proxy assessments. The rate of memory change among people diagnosed with cancer during follow-up before and after diagnosis was compared with rate of memory change in individuals who remained cancer free during follow-up using linear mixed-effect models with random intercepts and slopes.

RESULTS

A total of 14 583 participants were included in the sample (mean [SD] age, 66.4 [10.4] years; 8453 [58.0%] female). The mean (SD) follow-up was 11.5 (5.1) years; 2250 had a cancer diagnosis during follow-up, and 12 333 had no cancer diagnosis during follow-up. The rate of memory decline in the decade before a cancer diagnosis was 10.5% (95% CI, 6.2%-14.9%), which was slower than memory decline in similarly aged cancer-free individuals. For individuals diagnosed at 75 years of age, mean memory function immediately before diagnosis was 0.096 SD units (95% CI, 0.060-0.133 SD units) higher compared with that among similarly aged cancer-free individuals. A new cancer diagnosis was associated with a short-term decline in memory of -0.058 (95% CI, -0.084 to -0.032) SD units compared with memory before diagnosis. After diagnosis, the rate of memory decline was 3.9% (95% CI, 0.9%-6.9%) slower in individuals with cancer than in those without a cancer diagnosis.

CONCLUSIONS AND RELEVANCE

In this study, older individuals who developed cancer had better memory and slower memory decline than did similarly aged individuals who remained cancer free. These findings support the possibility of a common pathologic process working in opposite directions in cancer and Alzheimer disease.

Associations of Income Volatility With Incident Cardiovascular Disease and All-Cause Mortality in a US Cohort

BACKGROUND

Income volatility is on the rise and presents a growing public health problem. Because in many epidemiological studies income is measured at a single point in time, the association of long-term income volatility with incident cardiovascular disease (CVD) and mortality has not been adequately explored. The goal of this study was to examine associations of income volatility from 1990 to 2005 with incident CVD and all-cause mortality in the subsequent 10 years.

METHODS

The Coronary Artery Risk Development in Young Adults Study is an ongoing prospective cohort study conducted within urban field centers in Birmingham, AL; Chicago, IL; Minneapolis, MN; and Oakland, CA. We studied 3937 black and white participants 23 to 35 years of age in 1990 (our study baseline). Income volatility was defined as the intraindividual SD of the percent change in income across 5 assessments from 1990 to 2005. An income drop was defined as a decrease of ≥25% from the previous visit and less than the participant's average income from 1990 to 2005. CVD events (fatal and nonfatal) and all-cause mortality between 2005 and 2015 were adjudicated with the use of medical records and death certificates. CVD included primarily acute events related to heart disease and stroke.

RESULTS

A total of 106 CVD events and 164 deaths occurred between 2005 and 2015 (incident rate, 2.76 and 3.66 per 1000 person-years, respectively). From Cox models adjusted for sociodemographic, behavioral, and CVD risk factors, higher income volatility and more income drops were associated with greater CVD risk (high versus low volatility: hazard ratio, 2.07; 95% CI, 1.10-3.90; ≥2 versus 0 income drops: hazard ratio, 2.54; 95% CI, 1.24-5.19) and all-cause mortality (high versus low volatility: hazard ratio, 1.78; 95% CI,1.03-3.09; ≥2 versus 0 income drops: hazard ratio, 1.92; 95% CI, 1.07-3.44).

CONCLUSIONS

In a cohort of relatively young adults, income volatility and drops during a 15-year period of formative earning years were independently associated with a nearly 2-fold risk of CVD and all-cause mortality.

Measures of SES for Electronic Health Record-based Research

INTRODUCTION

Although infrequently recorded in electronic health records (EHRs), measures of SES are essential to describe health inequalities and account for confounding in epidemiologic research. Medical Assistance (i.e., Medicaid) is often used as a surrogate for SES, but correspondence between conventional SES and Medical Assistance has been insufficiently studied.

METHODS

Geisinger Clinic EHR data from 2001 to 2014 and a 2014 questionnaire were used to create six SES measures: EHR-derived Medical Assistance and proportion of time under observation on Medical Assistance; educational attainment, income, and marital status; and area-level poverty. Analyzed in 2016-2017, associations of SES measures with obesity, hypertension, type 2 diabetes, chronic rhinosinusitis, fatigue, and migraine headache were assessed using weighted age- and sex-adjusted logistic regression.

RESULTS

Among 5,550 participants (interquartile range, 39.6-57.5 years, 65.9% female), 83% never used Medical Assistance. All SES measures were correlated (Spearman's p≤0.4). Medical Assistance was significantly associated with all six health outcomes in adjusted models. For example, the OR for prevalent type 2 diabetes associated with Medical Assistance was 1.7 (95% CI=1.3, 2.2); the OR for high school versus college graduates was 1.7 (95% CI=1.2, 2.5). Medical Assistance was an imperfect proxy for SES: associations between conventional SES measures and health were attenuated <20% after adjustment for Medical Assistance.

CONCLUSIONS

Because systematically collected SES measures are rarely available in EHRs and are unlikely to appear soon, researchers can use EHR-based Medical Assistance to describe inequalities. As SES has many domains, researchers who use Medical Assistance to evaluate the association of SES with health should expect substantial unmeasured confounding.

Compartmental Model Diagrams as Causal Representations in Relation to DAGs

Compartmental model diagrams have been used for nearly a century to depict causal relationships in infectious disease epidemiology. Causal directed acyclic graphs (DAGs) have been used more broadly in epidemiology since the 1990s to guide analyses of a variety of public health problems. Using an example from chronic disease epidemiology, the effect of type 2 diabetes on dementia incidence, we illustrate how compartmental model diagrams can represent the same concepts as causal DAGs, including causation, mediation, confounding, and collider bias. We show how to use compartmental model diagrams to explicitly depict interaction and feedback cycles. While DAGs imply a set of conditional independencies, they do not define conditional distributions parametrically. Compartmental model diagrams parametrically (or semiparametrically) describe state changes based on known biological processes or mechanisms. Compartmental model diagrams are part of a long-term tradition of causal thinking in epidemiology and can parametrically express the same concepts as DAGs, as well as explicitly depict feedback cycles and interactions. As causal inference efforts in epidemiology increasingly draw on simulations and quantitative sensitivity analyses, compartmental model diagrams may be of use to a wider audience. Recognizing simple links between these two common approaches to representing causal processes may facilitate communication between researchers from different traditions.

Survival after dementia diagnosis in five racial/ethnic groups

INTRODUCTION

Information on anticipated survival time after dementia diagnosis among racially/ethnically diverse patients is needed to plan for care and evaluate disparities.

METHODS

Dementia-free health care members aged ≥64 years were followed (1/1/2000-12/31/2013) for dementia diagnosis and subsequent survival (n = 23,032 Asian American; n = 18,778 African American; n = 21,000 Latino; n = 4543 American Indian/Alaska Native; n = 206,490 white). Kaplan-Meier curves were estimated for survival after dementia diagnosis by race/ethnicity. We contrasted mortality patterns among people with versus without dementia using Cox proportional hazards models.

RESULTS

After dementia diagnosis (n = 59,494), whites had shortest median survival (3.1 years), followed by American Indian/Alaska Natives (3.4 years), African Americans (3.7 years), Latinos (4.1 years), and Asian Americans (4.4 years). Longer postdiagnosis survival among racial/ethnic minorities compared with whites persisted after adjustment for comorbidities. Racial/ethnic mortality inequalities among dementia patients mostly paralleled mortality inequalities among people without dementia.

DISCUSSION

Survival after dementia diagnosis differs by race/ethnicity, with shortest survival among whites and longest among Asian Americans.

Jump, Hop, or Skip: Modeling Practice Effects in Studies of Determinants of Cognitive Change in Older Adults

Improvements in cognitive test scores upon repeated assessment due to practice effects (PEs) are well documented, but there is no empirical evidence on whether alternative specifications of PEs result in different estimated associations between exposure and rate of cognitive change. If alternative PE specifications produce different estimates of association between an exposure and rate of cognitive change, this would be a challenge for nearly all longitudinal research on determinants of cognitive aging. Using data from 3 cohort studies-the Three-City Study-Dijon (Dijon, France, 1999-2010), the Normative Aging Study (Greater Boston, Massachusetts, 1993-2007), and the Washington Heights-Inwood Community Aging Project (New York, New York, 1999-2012)-for 2 exposures (diabetes and depression) and 3 cognitive outcomes, we compared results from longitudinal models using alternative PE specifications: no PEs; use of an indicator for the first cognitive visit; number of prior testing occasions; and square root of the number of prior testing occasions. Alternative specifications led to large differences in the estimated rates of cognitive change but minimal differences in estimated associations of exposure with cognitive level or change. Based on model fit, using an indicator for the first visit was often (but not always) the preferred model. PE specification can lead to substantial differences in estimated rates of cognitive change, but in these diverse examples and study samples it did not substantively affect estimated associations of risk factors with change.

Body mass index and cognitive function: the potential for reverse causation

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.

Abstract T P147: Estimating the Effect of Antidepressant Use on Stroke Risk in the Presence of Competing Risks: A Simulation Study

Introduction: Research on determinants of stroke must account for competing risks (events, such as death, that preclude subsequent stroke). Fine and Gray competing risk regression models are increasingly used in place of traditional Cox proportional hazards models to account for competing risks, but may not always provide clinically relevant estimates.

Hypothesis: Even when antidepressant use has no effect on stroke risk, both Fine and Gray and Cox models can yield spurious associations if antidepressants affect mortality.

Methods: We simulated data (50 simulations) on 3000 individuals followed for up to ten years with biennial assessments of stroke status. We considered two scenarios. In both scenarios, we set antidepressant use to have no effect on stroke risk. In Scenario 1, we set antidepressant use to increase mortality (HR (hazard ratio)=2.00). In Scenario 2, we set antidepressant use to decrease mortality (HR=0.50).

Results: In Scenario 1, the average stroke incidence rate was 16.5/1,000 person years and the average mortality rate was 33.9/1,000 person years. Even though antidepressants had no effect on stroke in the simulations, both Fine and Gray (average HR=0.69) and Cox (average HR=0.83) models estimated protective effects of antidepressants on stroke. Fine and Gray models incorrectly rejected the null hypothesis in 22% of simulations and Cox models incorrectly rejected the null hypothesis in 10% of simulations. In Scenario 2, the average incidence rate was 16.9/1,000 person years and the average mortality rate was 31.3/1,000 person years. Even though antidepressants had no effect on stroke in the simulations, both Fine and Gray (average HR=1.22) and Cox (average HR=1.09) models estimated protective effects of antidepressants on stroke. Fine and Gray models incorrectly rejected the null hypothesis in 20% of simulations and Cox models incorrectly rejected the null hypothesis in 8% of simulations.

Conclusions: For exposures that affect mortality, both Cox models and Fine and Gray corrections can yield misleading results regarding effects on stroke risk. This is important for interpreting findings on controversial topics, such as the effect of antidepressants on stroke.

Type 2 diabetes and cognitive decline over 14 years in middle-aged African Americans and whites: the ARIC Brain MRI Study

BACKGROUND

Diabetes predicts late-life dementia, but the association with rate of cognitive decline is inconsistent and has rarely been examined in non-white populations, despite the high prevalence of diabetes in African Americans. We evaluated the effect of diabetes on cognitive decline in middle-aged African Americans and whites.

METHODS

Atherosclerosis Risk in Communities (ARIC) Brain MRI Study participants (n = 1,886, mean age = 60, 49% African American) underwent assessments of verbal memory, processing speed, and verbal fluency four times over 14 years. Using race-stratified mixed linear effects models, we examined cognitive change for participants with prevalent (baseline) diabetes and incident (diagnosed after baseline) diabetes versus those without diabetes.

RESULTS

African Americans had more advanced diabetes, as indicated by fasting blood glucose levels, anti-diabetes medication use, and cardiovascular risk profiles. African Americans with prevalent diabetes experienced 41% greater annual decline in processing speed scores (p = 0.048) and 50% greater annual decline in verbal fluency scores (p = 0.042) than those without diabetes; incident diabetes was not associated with cognitive decline. Among whites, diabetes was not associated with cognitive decline.

CONCLUSIONS

Prevalent diabetes was associated with greater cognitive decline in middle-aged African Americans, possibly reflecting adverse effects of longer duration and more advanced diabetes.

Racial/ethnic differences in dementia risk among older type 2 diabetic patients: the diabetes and aging study

OBJECTIVE Although patients with type 2 diabetes have double the risk of dementia, potential racial/ethnic differences in dementia risk have not been explored in this population. We evaluated racial/ethnic differences in dementia and potential explanatory factors among older diabetic patients. RESEARCH DESIGN AND METHODS We identified 22,171 diabetic patients without preexisting dementia aged ≥60 years (14,546 non-Hispanic whites, 2,484 African Americans, 2,363 Latinos, 2,262 Asians, 516 Native Americans) from the Kaiser Permanente Northern California Diabetes Registry. We abstracted prevalent medical history (1 January 1996 to 31 December 1997) and dementia incidence (1 January 1998 to 31 December 2007) from medical records and calculated age-adjusted incidence densities. We fit Cox proportional hazards models adjusted for age, sex, education, diabetes duration, and markers of clinical control. RESULTS Dementia was diagnosed in 3,796 (17.1%) patients. Age-adjusted dementia incidence densities were highest among Native Americans (34/1,000 person-years) and African Americans (27/1,000 person-years) and lowest among Asians (19/1,000 person-years). In the fully adjusted model, hazard ratios (95% CIs) (relative to Asians) were 1.64 (1.30-2.06) for Native Americans, 1.44 (1.24-1.67) for African Americans, 1.30 (1.15-1.47) for non-Hispanic whites, and 1.19 (1.02-1.40) for Latinos. Adjustment for diabetes-related complications and neighborhood deprivation index did not change the results. CONCLUSIONS Among type 2 diabetic patients followed for 10 years, African Americans and Native Americans had a 40-60% greater risk of dementia compared with Asians, and risk was intermediate for non-Hispanic whites and Latinos. Adjustment for sociodemographics, diabetes-related complications, and markers of clinical control did not explain observed differences. Future studies should investigate why these differences exist and ways to reduce them.

Weight and body composition changes during oral contraceptive use in obese and normal weight women

BACKGROUND

Oral contraceptive (OC) use seems to have little effect on weight change in normal weight women. Most previous studies have excluded obese women, so the effect of OC use on weight change in obese women is unknown.

METHODS

This analysis evaluates weight and body composition change with OC use among obese (body mass index [BMI] 30.0-39.9) and normal weight (BMI 19.0-24.9) women who were randomly assigned to two OC doses: 20 μg ethinyl estradiol (EE) and 100 μg levonorgestrel (LNG) OCs or 30 μg EE and 150 μg LNG OCs. Follow-up occurred after three to four OC cycles. Weight and body composition were measured at baseline and at follow-up using a bioelectrical impedance analyzer.

RESULTS

Among 150 women (54 obese and 96 normal weight) who used OCs for 3 to 4 months, there were no clinically or statistically significant weight or body composition changes in the overall group or by BMI or OC formulation group.

CONCLUSIONS

These findings add to evidence that EE/LNG OCs are not associated with short term weight or body composition change for normal weight women and suggest that OCs are also are not associated with short term weight or body composition change in obese women.

Type 2 diabetes and 10-year risk of dementia and cognitive impairment among older Mexican Americans

OBJECTIVE

Type 2 diabetes has been linked with increased risk of dementia and cognitive impairment among older adults and with premature mortality in young and middle-aged adults. No studies have evaluated the association between diabetes and dementia among Mexican Americans, a population with a high burden of diabetes. We evaluated the association of diabetes with incidence of dementia and cognitive impairment without dementia (CIND) among older Mexican Americans while accounting for competing risk from death.

RESEARCH DESIGN AND METHODS

This study included 1,617 participants 60-98 years of age from the Sacramento Area Latino Study on Aging followed up to 10 years from 1998. We evaluated the association between diabetes and dementia/CIND with competing risk regression models.

RESULTS

Participants free of dementia/CIND at baseline (n = 1,617) were followed annually up to 10 years. There were 677 (41.9%) participants with diabetes, 159 (9.8%) incident dementia/CIND cases, and 361 (22.3%) deaths. Treated and untreated diabetes (hazard ratio 2.12 [95% CI 1.65-2.73] and 2.15 [1.58-2.95]) and dementia/CIND (2.48 [1.75-3.51]) were associated with an increased risk of death. In models adjusted for competing risk of death, those with treated and untreated diabetes had an increased risk of dementia/CIND (2.05 [1.41-2.97] and 1.55 [0.93-2.58]) compared with those without diabetes.

CONCLUSIONS

These findings provide evidence that the association between type 2 diabetes and dementia/CIND among Mexican Americans remains strong after accounting for competing risk of mortality. Treatments that modify risk of death among those with diabetes may change future dementia risk.

Abstract 175: Stroke and 10-year Risk of Dementia and Cognitive Impairment Among Older Mexican Americans

Background: Stroke is a leading cause of death in the United States and has been linked to an increased risk of dementia and cognitive impairment. The prevalence of stroke and vascular risk factors are higher among Mexican Americans than non-Hispanic whites, but the literature on stroke and dementia and cognitive impairment among this growing ethnic group remains largely unexplored.

Objective: We evaluated the association between non-fatal stroke and incidence of dementia/cognitive impairment without dementia (CIND) in a cohort of older Mexican Americans, accounting for the competing risk of mortality.

Methods: The present study included 1,617 participants from the Sacramento Area Latino Study on Aging (SALSA), a population-based study of Mexican Americans aged 60-98 years, who were free of dementia/CIND at baseline in 1998-1999 and followed through 2007. At annual study visits, stroke events were identified by self-report of a physician diagnosis or hospitalization and dementia and CIND cases were identified with a three-phase clinical assessment protocol. We evaluated the association between baseline and time dependent stroke and incidence of dementia/CIND with Fine and Gray competing risk regression models to account for the competing risk of mortality.

Results: There were 221 participants with a history of stroke at baseline or who experienced a non-fatal stroke during the study. Over a mean follow-up of 6.5 years, there were 159 incident dementia/CIND cases and 298 deaths (n=61 deaths due to stroke). After accounting for the competing risk of mortality and adjusting for sex, education, waist circumference, diabetes, and systolic blood pressure, individuals with a stroke event had a three-fold increased risk of dementia/CIND compared to those with no stroke event (hazard ratio=2.97, 95% CI: 2.05-4.30).

Conclusions: These results suggest that among older Mexican Americans, stroke is strongly associated with incidence of dementia/CIND, even after accounting for traditional vascular risk factors and the competing risk of mortality.

The association of blood pressure and mortality differs by self-reported walking speed in older Latinos

BACKGROUND

In some older adults, higher blood pressure (BP) is associated with a lower risk of mortality. We hypothesized that higher BP would be associated with greater mortality in high-functioning elders and lower mortality in elders with lower functional status.

METHODS

Participants were 1,562 Latino adults aged 60-101 years in the Sacramento Area Latino Study on Aging. Functional status was measured by self-reported walking speed, and BP was measured by automatic sphygmomanometer. Death information was determined from vital statistics records.

RESULTS

There were 442 deaths from 1998 to 2010; 53% were cardiovascular. Mean BP levels (mmHg) varied across fast, medium, and slow walkers: 136, 139, and 140 mmHg (systolic), p = .02 and 75, 76, and 77 mmHg (diastolic), p = .08, respectively. The relationship between systolic BP and mortality varied by self-reported walking speed: The adjusted hazard ratio for mortality in slow walkers was 0.96 per 10 mmHg higher systolic BP (95% confidence interval: 0.89, 1.02) and 1.29 (95% confidence interval: 1.08, 1.55) in fast walkers (p value for interaction <.001). We found a similar pattern for diastolic BP, although the interaction did not reach statistical significance; the adjusted hazard ratio per 10 mmHg higher diastolic BP was 0.89 (95% confidence interval: 0.78, 1.02) in slow walkers and 1.20 (95% confidence interval: 0.82, 1.76) in fast walkers (p value for interaction = .06).

CONCLUSIONS

In high-functioning older adults, elevated systolic BP is a risk factor for all-cause mortality. If confirmed in other studies, the assessment of functional status may help to identify persons who are most at-risk for adverse outcomes related to high BP.

Helicobacter pylori infection is associated with an increased rate of diabetes

OBJECTIVE

Chronic infections could be contributing to the socioeconomic gradient in chronic diseases. Although chronic infections have been associated with increased levels of inflammatory cytokines and cardiovascular disease, there is limited evidence on how infections affect risk of diabetes.

RESEARCH DESIGN AND METHODS

We examined the association between serological evidence of chronic viral and bacterial infections and incident diabetes in a prospective cohort of Latino elderly. We analyzed data on 782 individuals aged >60 years and diabetes-free in 1998-1999, whose blood was tested for antibodies to herpes simplex virus 1, varicella virus, cytomegalovirus, Helicobacter pylori, and Toxoplasma gondii and who were followed until June 2008. We used Cox proportional hazards regression to estimate the relative incidence rate of diabetes by serostatus, with adjustment for age, sex, education, cardiovascular disease, smoking, and cholesterol levels.

RESULTS

Individuals seropositive for herpes simplex virus 1, varicella virus, cytomegalovirus, and T. gondii did not show an increased rate of diabetes, whereas those who were seropositive for H. pylori at enrollment were 2.7 times more likely at any given time to develop diabetes than seronegative individuals (hazard ratio 2.69 [95% CI 1.10-6.60]). Controlling for insulin resistance, C-reactive protein and interleukin-6 did not attenuate the effect of H. pylori infection.

CONCLUSIONS

We demonstrated for the first time that H. pylori infection leads to an increased rate of incident diabetes in a prospective cohort study. Our findings implicate a potential role for antibiotic and gastrointestinal treatment in preventing diabetes.

Pharmacokinetics of a combined oral contraceptive in obese and normal-weight women

BACKGROUND

This study was conducted to compare oral contraceptive (OC) pharmacokinetics (PK) in normal-weight [body mass index (BMI) 19.0-24.9] and obese (BMI 30.0-39.9) women.

STUDY DESIGN

During the third week of the third cycle of OC use, we admitted 15 normal-weight and 15 obese women for collection of 12 venous specimens over 24 h. Using radioimmunoassay techniques, we measured levels of ethinyl estradiol (EE) and levonorgestrel (LNG). During the same cycle, women underwent twice-weekly sonography to assess ovarian follicular development and blood draws to measure endogenous estradiol (E2) and progesterone levels.

RESULTS

Obese women had a lower area under the curve (AUC; 1077.2 vs. 1413.7 pg*h/mL) and lower maximum values (85.7 vs. 129.5 pg/mL) for EE than normal-weight women (p=.04 and <0.01, respectively); EE trough levels were similar between BMI groups. The similar, but smaller, differences in their LNG levels for AUC and maximum values (C(max)) were not statistically significant. While peak values differed somewhat, the LNG trough levels were similar for obese and normal-weight women (2.6 and 2.5 ng/mL, respectively). Women with greater EE AUC had smaller follicular diameters (p=.05) and lower E2 levels (p=.04). While follicular diameters tended to be larger among obese women, these differences were not statistically significant.

CONCLUSION

OC hormone peak levels are lower among obese women compared to normal-weight women, but their trough levels are similar. In this small study, the observed PK differences did not translate into more ovarian follicular activity among obese OC users.