Association between blood folate concentrations and depression in reproductive aged U.S. women, NHANES (2011-2012).

Background: Blood folate concentrations have been linked to an increased risk of depression in adults. Depression is particularly pronounced among women; however, the association between folate concentration and depression is not well-examined among women of reproductive age. The purpose of our study was to assess the association between low serum and red blood cell folate concentration and the risk of moderate to severe depression among non-pregnant women of reproductive age in the United States (U.S.).

Methods: We used data from nationally representative, population-based U.S. National Health and Nutrition Examination Survey (NHANES) (2011-2012) examining non-pregnant women of reproductive age (20-44 years). We compared serum and red blood cell (RBC) folate concentrations between women with and without self-reported depression based on Patient Health Questionnaire-9 (PHQ-9) scores, and examined the association between folate concentrations and depression using linear and logistic regression analysis.

Results: A total of 16.7% of eligible women in our study reported to have moderate to severe depression. The median serum folate concentrations for women with and without depression were 17.8ng/ml and 17.2ng/ml, respectively (P = <0.01). There was no statistical difference in median RBC folate concentrations between women with and without depression (P = 0.2). Serum folate concentration was weakly associated with an increased risk of moderate to severe depression among non-pregnant women of reproductive age, after adjusting for important demographic and life-style factors (aOR: 1.11; 95% CI: 1.01, 1.22). There was no interaction with race and ethnicity.

Limitations: Cross-sectional design.

Conclusions: Folate concentrations in the blood may partly explain the increased risk of moderate to severe depression among non-pregnant women of reproductive age in the U.S. Robust prospective studies are needed to confirm our findings.