Association between age at first birth and depressive symptoms: the mediation effects of HDL-cholesterol

The objective of this study was to examine the potential association between age at first birth (AFB) and the risk of depressive symptoms in women, as well as to investigate the mediating role of HDL-cholesterol.

This study included 6821 women from the National Health and Nutrition Examination Survey (NHANES) in the United States (2007-2020). The relationship between AFB and depression was examined using multivariate logistic regression, smooth curve fitting, and generalized additive models. A mediational analysis was conducted to detect the mediating effects of HDL-cholesterol in the association between AFB and the depression. Finally, subgroup analyses were conducted to validate the robustness of our study results.

Among the 6821 women included in this study, 831 (12.18 %) were diagnosed with depression. Compared with the reference group of AFB patients aged 21-34 years (reference group), the odds ratio (OR) for AFB < 20 years was 1.95 with a 95 % confidence interval (1.68-2.26, p < 0.001). Nevertheless, there was no statistically significant difference among those with AFB > 30 years compared to the reference group (p = 0.2768). After multivariate adjustment, the OR for AFB < 20 years was OR = 1.33 with a 95 % confidence interval (1.13-1.56, p < 0.001). Moreover, there was a nonlinear correlation between HDL-cholesterol, BMI and the risk of AFB-induced depression (p < 0.05). Through a parallel mediator analysis, it was discovered that HDL-cholesterol significantly modulated the association between AFB and depression.

AFB may be associated with an increased risk of depression in women, and HDL-cholesterol plays a significant mediating role in the relationship.