Socioeconomic Status and Physical Functioning: A Longitudinal Study of Older Chinese People.

Objectives: We aimed to assess the longitudinal associations of socioeconomic status and physical functioning using a large population-based survey data in China.

Method: We used four waves of the Chinese Longitudinal Healthy Longevity Survey (2002-2011). Physical functioning was assessed by activities of daily living (ADL) and instrumental activities of daily living (IADL) measures. Socioeconomic status was assessed using educational attainment, occupational status, household income, financial resources, and access to health services. Latent growth curve model combined with selection model was utilized.

Results: High education was not associated with the baseline level or the rate of change in ADL score but predicted better baseline IADL functioning. High income was related to better IADL functioning but had no effect on the rate of change in IADL. Inadequate financial resources and unavailability of health services were mainly associated with poorer ADL and IADL functioning at baseline. White-collar occupation was unrelated to the trajectory of physical functioning.

Discussion: This study provides no support either for the cumulative disadvantage or age-as-leveler theory. Improving financial status and accessibility of health care services, especially in lower social classes, may help to improve the overall level of physical functioning of the older adults.