Effect of sociodemographic and physical activity on cognitive function in older adults: A nationwide cross-sectional...

We aimed to assess the effect of socioeconomic status and physical activity on cognitive function using a large population-based survey data in China.

We took advantage of the Chinese Longitudinal Healthy Longevity Survey conducted in 2014 to examine the relationship between sociodemographic, physical activity, and cognitive function in older adults (OAs) for persons aged above 65 (N = 2848). Socioeconomic status was assessed by sex, age, co-residence situation, category of residence, years of schooling, and marital status. Multiple linear regression for predictors was utilized. Physical activity was assessed using activities of daily living (ADL) and instrumental activities of daily living (IADL) measures. Cognitive function was assessed by the Modified Mini-Mental State Examination.

The mean age of the OAs was 80.65 years (SD = 8.55). Their mean Mini-Mental State Examination score was 21.55 (SD = 2.38), mean ADL Total score was 6.24 (SD = 0.95), and mean IADL Total score was 10.21 (SD = 3.84). OAs' age at testing, co-residence and category of residence significantly predicted both ADL Total score and IADL Total score (P < 0.05), sex significantly predicted IADL Total score (R²  = 0.02, β = 0.13, P = 0.000) but not ADL Total score (R²  = 0.00, β = 0.02, P = 0.211). OAs' sex, age, co-residence, and years of schooling significantly predicted cognitive function (P < 0.05), IADL total score significantly predicted cognitive function (P < 0.01), while the relationship between ADL total score and cognitive function was not significant (P = 0.94).

OAs' sex, age, co-residence, years of schooling, and IADL were significantly associated with cognitive function. Improving OAs' IADL, especially in lower social classes, may help to improve the overall cognitive function of the OAs.