Ethnic and Sex Differences in the Association Between Organochlorine Exposure and Cognitive Function in Late Life

Abstract

Background Organochlorine pesticides persist in the environment and body for extended periods. However, little is known about their long-term impact on cognition in older adults and if their influence differs by race/ethnicity (hereinafter ethnicity) and sex. Methods We evaluated cognitive function and organochlorine levels by ethnicity and sex in 979 adults, age 60+ from the National Health and Nutrition Examination Surveys (2011-2014). We utilized weighted linear generalized estimating equations to measure differences between seven log-transformed lipid-adjusted organochlorines (ng/g) and cognitive function. A composite cognitive function score was created using the mean of the z-scores from immediate and delayed of a word-list memory test, verbal fluency, and digit substitution test. Covariates included age, education, marital status, sex, and ethnicity. Exploratory sensitivity analyses included BMI, Ratio of Income-to-Poverty (IPR), and occupation, which were added to the models individually. Weighted sample included: 55.4% females; 79.8% NH-White; 9.2% NH-Black; 3.4% Mexican-American; 4.0% Other-Hispanic; 3.5% NH-Asian. Results We found significant differences in cognitive outcomes and organochlorine levels across ethnic and sex groups. The variability in cognitive performance and organochlorine exposure both within and between these groups, suggests that organochlorines may play a role in cognitive disparities, despite limited significant interaction effects. Sensitivity analyses adjusting for BMI, IPR, and longest occupation held indicated that most specific-organochlorine associations remained significant. Conclusion Our findings emphasize the importance of examining both the distributions of organochlorines and cognition by ethnicity and sex and their interactions to understand how each may contribute to cognitive health disparities in older adults.