Objective Low serum vitamin D levels have been associated with increased prevalence of the reproductive tract condition bacterial vaginosis (BV). The objective of this trial was to evaluate the effect of high-dose vitamin D supplementation on BV recurrence. Study design This randomized, placebo-controlled, double-blinded trial enrolled 118 women with symptomatic BV from an urban STD clinic (clinicaltrials.gov registration NCT01450462). All participants received 500mg oral metronidazole twice daily for seven days. Intervention participants (n=59) also received nine doses of 50,000 international units of cholecalciferol (vitamin D3) over 24 weeks; control women (n=59) received matching placebo. Recurrent BV was assessed via Nugent scoring after 4, 12 and 24 weeks. We assessed the effect of the intervention using an intention-to-treat approach, fitting Cox proportional hazards models to evaluate recurrent BV over the follow-up period. Results Most participants (74%) were black, with a median age of 26 years. Median presupplementation serum 25-hydroxyvitamin D [25(OH)D] was similar across randomization arms: 16.6 ng/mL in the vitamin D arm and 15.8 ng/mL in the control arm. At trial completion, median 25(OH)D among women receiving vitamin D was 30.5 ng/mL, vs 17.8 ng/mL in control women; 16% of women receiving vitamin D and 57% receiving placebo remained vitamin D deficient (<20 ng/mL). BV prevalence among women randomized to vitamin D was very similar to those randomized to placebo at the 4- and 12-week visits, but by the 24-week visit, BV prevalence was 65% among women in the vitamin D arm and 48% among control women. BV recurrence was not reduced by vitamin D supplementation (intention-to-treat hazard ratio, 1.11; 95% confidence interval, 0.68-1.81). Among women experiencing recurrent BV, median time to recurrence was 13.7 weeks in the vitamin D arm and 14.3 weeks in the control arm. Conclusions Women receiving vitamin D experienced significant increases in serum 25(OH)D, but this increase was not associated with decreased BV recurrence in this high-risk STD clinic population.

No abstract

No abstract