Can vitamin D reduce recurrence of BV?

High doses of vitamin D may not help prevent recurrence of bacterial vaginosis (BV), according to results of a randomized controlled trial by researchers from Ohio State University.

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In the double-blind trial, 118 women with symptomatic BV who had visited an urban sexually transmitted disease clinic received 500 mg of oral metronidazole for 7 days. Half were randomized to receive 9 doses of 50,000 IU of cholecalciferol (vitamin D₃) over the course of 24 weeks and half received placebo. Nugent scoring after 4, 12, and 24 weeks was used to assess recurrent BV.

The majority of participants (74%) were black and the median age was 26 years. Median pre-supplementation serum levels of vitamin D were similar across both arms of the study: 16.6 ng/mL in the vitamin D arm and 15.8 ng/mL in the control arm. After the study ended, serum levels were 30.5 ng/mL in those receiving vitamin D, versus 17.8 ng/mL in controls. Of women in the vitamin D arm, 16% were vitamin D deficient (<20 ng/mL) versus 57% in the placebo arm.

Prevalence of BV was similar among women who received vitamin D and those on placebo at the 4- and 12-weeks visits. At the 24-week visit, prevalence of BV was 65% in the vitamin D group versus 48% in the control group. Median time to BV recurrence was 13.7 weeks in the vitamin D group and 14.3 weeks in the control group. Overall, recurrence of BV was not reduced with supplementation (intention-to-treat hazard ratio, 1.11; 95% confidence interval, 0.68–1.81).

Study limitations noted by the authors included its small size, lack of test of cure, and higher-than-expected loss to follow up at 24 weeks. A strength was the demonstrated rise in 25(OH)D in women randomized to vitamin D versus controls, which showed strong evidence of compliance. Their findings, the authors concluded, “suggest that short-term, high-dose vitamin D supplement does not reduce BV recurrence in nonpregnant women. Given the established associations between BV and negative health outcomes, effective interventions to reduce BV’s impact continue to be urgently needed.”

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