Positive affect and disability among older Mexican Americans with arthritis

OBJECTIVE: To examine the relationship between positive affect and subsequent functional disability in older Mexican Americans with self-reported physician-diagnosed arthritis. METHODS: We conducted a 2-year prospective cohort study using a population-based sample of 1,084 noninstitutionalized Mexican American subjects aged > or =65 years residing in 5 southwestern states. Measures included self-reported diagnoses of various medical conditions, functional ability, body mass index, and ratings of positive and negative affect. RESULTS: For 937 subjects with arthritis who reported no limitations in activities of daily living (ADLs) at baseline, 697 remained ADL independent, 84 became ADL dependent, 41 died, and 115 were lost to followup 2 years later. There was a significant association between high positive affect (score = 12) and reduced risk of ADL disability 2 years later, controlling for baseline sociodemographic variables, medical conditions, and negative affect (odds ratio 0.46, 95% confidence interval 0.22-0.94). There was an interaction effect between positive affect and sex, with positive affect having a larger effect in reducing risk of ADL dependence in men than in women. CONCLUSION: High positive affect was associated with lower incidence of ADL disability in older Mexican Americans with self-reported physician-diagnosed arthritis. The strength of the positive affect is stronger in men than in women.