Determinants of depressive symptoms among persons 80 years and older: longitudinal national evidence from the health, aging, and retirement study in Thailand, 2015–2022

Background: Few studies have longitudinally assessed the determinants of depressive symptoms among persons 80 years and older. The aim of this study was to estimate the determinants of depressive symptoms among persons 80 years and older based on 4-wave national longitudinal data from Thailand. Methods: Data from the Health, Aging, and Retirement in Thailand study from 2015, 2017, 2020 and 2022 were utilized. The sample was restricted to community-dwelling persons 80 years and older (analytic sample: n = 2763 observations). For the pooled sample, average age was 85.0 years (range 80–117 years). Established measurements were used to assess depressive symptoms. Linear fixed effects regression was applied to assess the time-variant determinants and outcomes. Results: Regressions found that higher functional disability and an increase in the number of chronic conditions worsened depressive symptoms. More favourable self-rated physical health, and higher exercise frequency improved depressive symptoms. In addition, among women higher subjective economic status decreased depressive symptoms. Conclusions: This longitudinal study enhances our understanding of the determinants of depressive symptoms among persons 80 years and older. Strategies to delay or decrease functional disability, chronic conditions, increase physical activity, and improve subjective economic status may help in reducing depressive symptoms.