The modifying effect of positive emotion on the relationship between cognitive impairment and disability among older Mexican Americans: a cohort study

Objective: To determine if positive emotion modifies the relationship between cognitive impairment and activities of daily living disability status over 10 years in Mexican American adults aged 75 years and older. Methods: A retrospective cohort design using data from the Hispanic established populations for the epidemiologic studies of the elderly. About 2674 participants aged 75 years and older were included and followed over 10 years. Cognition was measured using the mini-mental state examination, positive emotion was measured using four questions from the Center for Epidemiologic Studies Depression Scale, and disability was measured using seven activities of daily living items. A series of generalized estimating equations models were used, with the initial analysis including those with disability at baseline and subsequent analyses excluding disability at baseline. Results: Positive emotion and cognitive impairment consistently decreased and increased risk for activities of daily living disability, respectively. Positive emotion was a significant modifier in the cross-sectional analysis, and was not a statistically significant modifier in the longitudinal or predictive series analysis. Conclusions: Positive emotion and cognitive impairment differentially affect the risk of developing activities of daily living disability. Further research is needed to explore the interaction of positive emotion and cognitive impairment, and to identify appropriate interventions that address the specific cognitive and emotional needs of older Mexican Americans.Implications for rehabilitation Promoting emotional well-being may be protective against incident disability for older adults. Cognitive impairment significantly predicts incident disability in activities of daily living and should be considered an early indicator of impending disability for older adults.