Weight changes and the incidence of depressive symptom in the middle-aged and older adults: findings from the Chinese nationwide cohort study

Previous studies, predominantly in Western individuals, have reported weight gain or weight loss are related to the increased depressive symptoms at all ages, but no study of depressive symptoms has examined its relation to actual (not just self-reported) weight changes in the middle-aged and older adults. Evidence of the relationship in older Asian individuals remains sparse. The study aimed to examine the relationship between weight changes and incidence of depressive symptoms in a nationally representative sample of community-dwelling older Asians.

Data were obtained from the China Health and Retirement Longitudinal Study (CHARLS), which included 17,284 adults aged 45 years. Participants were followed every two years using a face-to-face, computer-aided personal interview (CAPI) and structured questionnaire. We excluded participants with no follow-up data. The numbers of individuals who completed both the baseline and follow-up surveys were 3118 for the short-term (two years from 2011–2013) and the long-term (four years from 2011–2015). Additionally, to associate weight change with subsequent depressive symptoms, we also included 2472 participants without depressive symptom in 2013 and observed the incidence of depressive symptom in 2015 (subsequent term from 2013–2015). Finally, weight changes were classified as loss > -3%, stable-3–3%, gain3-6%, gain6-9%, and gain > 9%. Multivariable-adjusted cox regression in the study were used to assess the hazard ratios (HRs) of each weight change category.

The incidence of depressive symptoms was 20.72% in the 2011–2013, 27.04% in the 2011–2015, and 23.02% in 2013–2015. Weight loss > 3% for all intervals was associated with higher depressive symptoms than stable weight during the 2011–2013 [1.305(1.031,1.651)] among the total populations. When stratified by sex, the results in males and females were different from those in the total population [females:1.389(0.997, 1.935); males:1.263(0.902, 1.767)]. Weight loss > 3% for intervals was associated with higher depressive symptoms than stable weight during the 2013–2015[1.643(1.140, 2.368)] among the males and its effect was also stronger for the total in 2011–2013. Moreover, there was no significant association between weight gain and incident depressive symptom, and no significant interaction effect in terms of the sex*weight changes.

Our findings could inform health promotion interventions to body-weight management aimed at improving the health of the middle-aged and older adults, particularly in the total people with short-term weight loss and males with subsequent term weight loss.