Parity, socioeconomic status, and depression in women's mid-to-late life: Evidence from two prospective cohorts.

Existing evidence on the relationship between parity and women's later-life depression was inconsistent. We aimed to examine the association of parity with depression in women's mid-late life, and to evaluate whether such association differs by socioeconomic status (SES). We used data of 9508 women from two nationally representative cohort studies: China Health and Retirement Longitudinal Study and US Health and Retirement Study. Participants were followed up from 2011 or 2012 (baseline) to 2018. Parity was the number of biological children; depression symptoms were measured using Center for Epidemiologic Studies Depression Scale. Logistic regression models were used to assess the association between parity status and depression. A total of 4291 women had depression at baseline, and 1804 women developed depression during follow-up. Compared to women with one child, those with no children had higher odds of baseline depression (odds ratio [OR] = 1.25, 95 % confidence interval [CI] = 1.00-1.56) and developing depression (OR = 1.98, 95 % CI = 1.41-2.79) during follow-up. For multiparous women, a higher parity was associated with higher prevalence and incidence of depression, with the odds of incident depression ranging from 1.49 (95 % CI = 1.22-1.82) to 1.86 (95 % CI = 1.47-2.34) for having two children to ≥4 children. Such associations were more evident among women with high and upper-middle SES, with the odds of incident depression increasing from 1.91 (95 % CI = 1.45-2.51) for women with two children to 2.65 (95 % CI = 1.87-3.78) for women with ≥4 children. However, these associations were not observed among women in low and lower-middle SES group. Our findings underscore that healthcare practice should consider reproductive histories and social context when addressing women's mental health issues.