Association between social engagement frequency and depression among the older people in China: evidence from the 2011-2018 China Health and Retirement Longitudinal Study.

Background: Depression in older people is a major concern in China. Despite being known as a protective factor, it is unclear the extent to which social engagement mitigates depression or mediates socioeconomic mental health inequalities among Chinese older people. Methods: We conducted a survival analysis on 2891 respondents aged 55-77 without depression in 2011 from the Chinese Health and Retirement Longitudinal Study to estimate the relative risk of developing depression between 2011 and 2018 with different social engagement frequencies, having adjusted for age, sex, education, marriage, employment, household income, self-reported physical health and urban/rural residency. We then assessed the potential mediation effect of social engagement on the association between social class (measured by education) and depression. Results: Respondents who engaged in social activities almost daily were 15% less likely to develop depression (HR 0.85, 95% CI 0.74 to 0.98) than those who never. Respondents with secondary education and above were 20% less likely to develop depression (HR 0.80, 95% CI 0.69 to 0.94) and 60% more likely to engage in social activities (HR 1.60, 95% CI 1.48 to 1.74) than those with elementary education and below. After controlling social engagement frequencies, the effect of education on depression changed very little (HR 0.82, 95% CI 0.70 to 0.96). Conclusion: As an important modifiable protective factor, we however found no clear evidence of social engagement mediating between social class and depression. Future social policies should aim to improve well-being by promoting social engagement to prevent depression among Chinese older people.