OBJECTIVES: To determine whether positive affect, defined as emotional contentment and happiness, remains stable in late life and to identify predictors of longitudinal change in positive affect.
DESIGN: Longitudinal observational study.
PARTICIPANTS: Six hundred sixty-three individuals aged 70 and older without disability at baseline and free of chronically depressed mood.
MEASUREMENTS: Positive affect, social network, social activity, chronic health conditions, activities of daily living, instrumental activities of daily living (IADLs), cognitive functioning, and negative affect measured over 54 months, at 18-month intervals, up to four times.
RESULTS: Positive affect remained relatively stable over 4.5 years of follow-up. Higher average levels of social activity and lower levels of negative affect were associated with higher positive affect. An increase of 1 point in negative affect (on a 7-point scale) was associated with a 0.23-point concurrent decrease in positive affect (on a 5-point scale). Needing help in an additional IADL was associated with a decrease in positive affect of 0.04 points. A greater number of chronic conditions at enrollment was associated with lower positive affect.
CONCLUSION: Positive affect is directly correlated with social involvement and inversely correlated with negative affect, IADL functioning, and comorbidity. Positive affect was mostly related to factors that do not change over time, although it showed some sensitivity to short- and long-term changes in physical health and functioning.