Reduced Maternal Serum Total, Free and Bioavailable Vitamin D Levels and its Association with the Risk for Postpartum Depressive Symptoms

Abstract

Background: Low vitamin D levels have been implicated in postpartum depressive disorders. However, studies on bioavailable vitamin D levels in postpartum depression are limited. Our study aimed to assess the serum concentrations of total, free and bioavailable 25-hydroxyvitamin D (25(OH)D) levels in women with postpartum depressive symptoms (PPD) and the association between 25(OH)D levels and PPD at 6 week post-delivery.

Methods: In this cross-sectional study, a total of 330 cases and 330 age and BMI matched controls were recruited from the tertiary care hospital in South India. Women with depressive symptoms were assessed using the validated Edinburg Postnatal Depression Scale (EPDS) and cut-off score ≥10 was used. Serum 25(OH)D and VDBP levels were measured using commercially available ELISA kits.

Results: Serum total, free and bioavailable 25(OH)D levels were significantly lower in postpartum depressive women compared to non-depressive women (p <0.001, p = 0.01). A significant negative correlation was observed between 25(OH)D, free 25(OH)D and bioavailable 25(OH)D with EPDS score in total study subjects (p <0.001, r = -0.19; p <0.001, r = -0.14 and p <0.001, r = -0.14). Multivariate linear regression analysis further confirmed a significant association between serum total, free and bioavailable 25(OH)D levels and EPDS score (p <0.001∗).

Conclusions: Our study demonstrated that lower serum total, free and bioavailable 25(OH)D levels were associated with postpartum depressive symptoms. Hypovitaminosis D after delivery may be a risk factor for postpartum depression.

Keywords: 25(OH)D; Bioavailable vitamin D; Free vitamin D; Postpartum depression; Vitamin D; Vitamin D Binding Protein.