Association between vitamin D supplementation and mortality: systematic review and meta-analysis

Study answer

What this study found

Vitamin D supplementation did not reduce all-cause mortality, cardiovascular mortality, or non-cancer, non-cardiovascular mortality. Pooled estimates were null for all-cause mortality (RR 0.98, 95% CI 0.95 to 1.02), cardiovascular mortality (RR 0.98, 0.88 to 1.08), and non-cancer, non-cardiovascular mortality (RR 1.05, 0.93 to 1.18). Cancer mortality was lower with vitamin D (RR 0.84, 95% CI 0.74 to 0.95), with the benefit seen in vitamin D3 rather than vitamin D2. Longer follow-up was associated with greater all-cause mortality benefit, and the authors called for additional large randomized…

Study & population

This was a systematic review and meta-analysis of 52 randomized controlled trials enrolling 75,454 adults aged 18 years and older with various health conditions.

Intervention

Vitamin D supplementation was evaluated across randomized trials using varying regimens, including daily, weekly, and monthly bolus dosing.

Key limitation

Most trials were relatively short, with a median follow-up of 1.2 years, which may limit detection of mortality effects.

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Original abstract