Reproductive history and risk of depressive symptoms in postmenopausal women: A cross-sectional study in eastern China

Background: Although there are potential mechanisms of female hormones in depression, conflicting results still exist in epidemiological studies. This study aimed to determine whether reproductive history, an important indicator of estrogen exposure across the lifetime, is associated with risk of depressive symptoms in postmenopausal women. Methods: We analyzed the baseline data from Zhejiang Ageing and Health Cohort Study including 5537 postmenopausal women. Depressive symptoms were assessed through the application of Patient Health Questionnaire-9 scale (PHQ-9). Logistic regression models, controlling for an extensive range of potential con-founders, were generated to examine the association between reproductive history and risk of depressive symptoms in later life. Results: Longer reproductive period (Odds Ratio (OR) = 0.972, 95% Confidence Interval (CI) 0.955-0.989), regular menstrual cycle (OR = 0.723, 95% CI 0.525-0.995), later age at first gave birth (OR = 0.953, 95% CI 0.919-0.988) were significantly associated with a reduced risk of late-life depressive symptoms. Among women with regular menstrual cycle, longer cycle length increased the risk (OR = 1.050, 95% CI 1.016-1.085). Meanwhile, more full-term pregnancies and more incomplete pregnancies were related to higher prevalence of depressive symptoms. Women who underwent tubal sterilization as only type of contraceptive surgery were found less likely to suffer depressive symptoms in later life (OR = 0.433, 95% CI 0.348-0.538). Limitations: Cross-sectional data could not make a causation conclusion. Conclusions: Our results indicated that reproductive factors were significantly associated with risk of depressive symptoms in postmenopausal women. Further longitudinal studies are needed.