Several studies have shown that vitamin D deficiency is associated with depression. A recent study has assessed the relationship between vitamin D levels and risk for antenatal depression in a cohort of African-American women. Vitamin D deficiency is more common among African-American women than in Caucasians. The active form of vitamin D is produced as a byproduct of natural sun exposure. Because women with darker skin have more melanin, which blocks the sun’s rays and affects the skin’s ability to produce the active form of vitamin D, they typically have lower vitamin D levels.
In this study, a group of African-American women (n=178) were recruited from obstetrics clinics of a large health system. Serum 25-hydroxyvitamin D (25-OHD) levels were assessed. Depression symptoms were measured using the Center for Epidemiological Studies Depression (CES-D) scale where a CES-D ? 16 was used as a measure clinical depression.
The mean serum 25-OHD level was 13.4 ± 8.4?ng/mL; most women (82.6%, n=147) were vitamin D inadequate or deficient (25-OHD < 20?ng/mL). The mean CES-D score was 15.2 ± 10.7. 74 of the women (41.6%) had a CES-D ? 16, suggestive of clinical depression. A significant inverse relationship was found between log (25-OHD) and CES-D ? 16 (odds ratio [OR] 0.54, 95% confidence interval [CI] 0.29-0.99, p=0.046). For every 1-unit increase in log (25-OHD) (corresponding to 2.72?ng/mL increase in 25-OHD), the odds of having a CES-D ? 16 decreased by 46%.
This is the first study to show an association between low vitamin D levels and increased risk for antenatal depression. In this population, the rates of depression were very high (41.6%). Typically studies show depression in between 10% and 20% of pregnant women.
In a previous study carried out in Pittsburgh, the researchers did not observe a correlation between vitamin D levels and risk for antenatal depression. However, in that study, only 19% of the participants were African-American, and the mean serum 25-OHD level was significantly higher (32.8?ng/mL). It may be that the link between vitamin D deficiency and antenatal depression in more of an issue in women who are vitamin D deficient.
Ruta Nonacs, MD PhD
Bodnar LM, Wisner KL, Luther JF, et al. An exploratory factor analysis of nutritional biomarkers associated with major depression in pregnancy. Public Health Nutr. 2011 Dec 8:1-9.
Cassidy-Bushrow AE, Peters RM, Johnson DA, Li J, Rao DS. Vitamin D Nutritional Status and Antenatal Depressive Symptoms in African American Women. J Womens Health (Larchmt). 2012 Jul 23. [Epub ahead of print]