Women’s Health
Vitamin D deficiency and the odds of bacterial vaginosis among US women: Results from NHANES 2001-2004 Yinglin Dai* Yinglin Dai Dai Dai Department of Epidemiology and Biostatistics, College of Human Medicine, Michigan State University, East Lansing, MI, USA
Bacterial Vaginosis (BV), a vaginal microbiome dysbiosis marked by depletion of protective Lactobacillus species and overgrowth of anerobic bacteria, affects about 30% of US premenopausal women. Vitamin D may support a healthy vaginal microbiome through glycogen synthesis used by Lactobacillus species to produce lactic acid, lower vaginal pH, and reduce BV risk. Thus, vitamin D deficiency could plausibly increase BV risk. However, studies among non-pregnant women have yielded discrepant results. We conducted a cross-sectional analysis using data from the National Health and Nutrition Examination Survey cycles 2001-2004. The study population comprised premenopausal, non-pregnant, non-breastfeeding women ages 20-49 years (unweighted N=1380). Serum 25-hydroxyvitamin D (25(OH)D) levels were categorized as <20, 20-30, and ≥30 ng/ml to define deficient, insufficient, and sufficient vitamin D status, respectively. Gram-stained slides of vaginal samples were examined by microscopy and scored using Nugent’s criteria for negative, intermediate, and positive BV. We conducted multinomial logistic regression to estimate the adjusted (aOR) and 95%CIs for the associations between vitamin D status and intermediate and positive BV. The weighted prevalence of intermediate and positive BV was 29% and 28%, respectively. Our data suggested that deficient (vs. sufficient) vitamin D was associated with increased odds of intermediate BV (aOR 1.31, 95%CI: 0.84-2.04) and positive BV (aOR 2.36 95%CI: 1.53-3.64). No association was observed with insufficient vitamin D. To explore the mechanism, we evaluated the outcome of higher vaginal pH (>4.5) using log-binomial regression. Deficient vitamin D was associated with higher vaginal pH (adjusted prevalence ratio 1.42, 95%CI: 1.39-1.45). In this US non-pregnant population, our results suggest that deficient vitamin D status is associated with BV. Further research is warranted in a prospective setting to understand the underlying mechanisms.