Life course socioeconomic position and incidence of mid-late life depression in China and England: a comparative analysis of CHARLS and ELSA.

Background: Despite the growing prevalence of depression in the Chinese elderly, there is conflicting evidence of life course socioeconomic position (SEP) and depression onset in China, and whether this association is akin to that observed in Western societies. We compared incident risk of mid-late life depression by childhood and adulthood SEP in China and England, a country where mental health inequality is firmly established.

Methods: Depression-free participants from the China Health and Retirement Longitudinal Study (N=8508) and the English Longitudinal Study of Ageing (N=6184) were studied over 4 years. Depressive symptoms were classified as incident cases using the Center for Epidemiologic Studies Depression Scale criteria. Associations between SEP (education, wealth, residence ownership and childhood/adolescent deprivation) and depression symptom onset were assessed using Cox proportional hazards models. In China, we also investigated children's government employment status as a SEP marker.

Results: Higher education and wealth predicted lower incidence of depression in both countries. The association with non-ownership of residence appeared stronger in England (HR 1.61, 95% CI 1.41 to 1.86) than in China (HR 1.11, 95% CI 0.95 to 1.29), while that with childhood/adolescent deprivation was stronger in China (HR 1.43, 95% CI 1.29 - 1.60) than in England (HR 1.33, 95% CI 0.92 to 1.92). Chinese adults whose children were employed in high-status government jobs, had lower rates of depression onset.

Conclusions: Consistent findings from China and England demonstrate that SEP is a pervasive determinant of mid-late life depression in very diverse social contexts. Together with conventional measures of SEP, the SEP of children also affects the mental health of older Chinese.