Bidirectional Association Between Probable Depression and Multimorbidity Among Middle-Aged and Older Adults in Thailand.

Introduction: The purpose of this study was to assess the bidirectional association between multimorbidity (MM) and probable depression in a longitudinal study in Thailand. Methods: We analyzed longitudinal data of participants 45 years and older from two consecutive waves (in 2015 and 2017) of Health, Aging, and Retirement in Thailand (HART). Probable depression was assessed using the Center for Epidemiological Studies Depression scale. Logistic regression analysis was conducted to assess the association between baseline probable depression and incident physical MM, and baseline physical MM and incident probable depression. Results: In all, 2712 participants without MM at baseline and 2684 without probable depression at baseline were included. At follow-up 15.6% of probable depression cases and 11.4% of nonprobable depression cases developed physical MM, and at follow-up 13.3% of physical MM cases and 8.9% of nonphysical MM cases developed probable depression. In the final logistic regression analysis, adjusted for age, sex, marital status, income, education, body mass index, physical activity, smoking tobacco, alcohol use, and social engagement, probable depression at baseline was positively associated with incident physical MM (aOR: 1.50, 95% CI: 1.09 to 2.06), and physical MM at baseline was positively associated with incident probable depression (aOR: 1.47, 95% CI: 1.07 to 2.02). Discussion: Baseline physical MM increases the risk of incident probable depression and baseline probable depression increases the risk of incident physical MM among middle-aged and older adults in Thailand.