Effects of Vitamin D Supplementation on Semen Quality, Reproductive Hormones, and Live Birth Rate: A Randomized Clinical Trial

Study answer

What this study found

Vitamin D plus calcium did not improve the main fertility outcomes in infertile vitamin D-insufficient men. At day 150, 25-OHD increased to 89 nmol/L versus 51 nmol/L with placebo, and inhibin B was higher (169 vs 154 pg/mL), but total sperm count, sperm concentration, motility, morphology, and overall live-birth outcomes were not improved. A subgroup signal suggested higher live-birth rates in men with oligozoospermia (35.6% vs 18.3%), but this finding was exploratory and not definitive.

Study & population

Randomized 1:1, placebo-controlled clinical trial conducted at a single center in Copenhagen, Denmark.

Intervention

Participants received an initial oral dose of 300,000 IU cholecalciferol, followed by cholecalciferol 1400 IU plus calcium 500 mg once daily for 150 days.

Key limitation

Single-center trial with a modest sample size and a 150-day follow-up limits power to detect clinical fertility effects.

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Original abstract