Socioeconomic position and physical and mental health among middle-aged and older adults: Cross-sectional and longitudinal results from a national community sample in Thailand

The aim of this study was to assess the physical and mental health status of middle-aged and older adults in relation to socioeconomic status in Thailand, both in a cross-sectional and longitudinal study. We analyze national cross-sectional and longitudinal data from the Health, Aging, and Retirement in Thailand (HART) study in 2015 and 2017. Health outcome measures included 1) physical chronic disease, 2) probable depression, 3) self-rated physical health, and 4) self-rated mental health.The cross-sectional sample included 5,616 participants and the longitudinal sample included 3,708 participants. The oldest group (>= 75 years) had a lower prevalence of high income 7.9%, compared to the middle-aged group (45-59 years) 43.2%, had a higher prevalence of no education (14.8%) compared to the middle-aged group (2.0%), and had a lower prevalence of employed (11.9%) compared to the middle-aged group (80.6%). In cross-sectional analysis, we found that higher income, employed and higher education was associated with better self-reported physical health among two or all three age groups, and with better self-reported mental status among one, two or three age groups. Lower income, not employed, and lower education were associated with physical comorbidity among one or two of the younger age groups. Lower income, but not employment status and education, were associated with probable depression among two of the younger age groups. Furthermore, in longitudinal analysis of the health outcomes, we found that higher income, employed and higher education were associated with better self-reported physical and mental health among two or all three age groups, and lower income, and not employed but not lower education were associated with physical comorbidity counts and depression scores among two or all three age groups. The results show that a significant gap in physical and mental health status between middle-aged and older adults in Thailand can be attributed to a lower socioeconomic status. To address the effects of both aging and lower socioeconomic status, interventions that improve economic and health status are indicated.