Vitamin D supplementation and major cardiovascular events: D-Health randomised controlled trial

Study answer

What this study found

Vitamin D3 60,000 IU/month for up to five years showed a possible reduction in major cardiovascular events versus placebo (HR 0.91; 95% CI 0.81–1.01). Absolute risk reduction: 5.8 fewer events per 1,000 participants over five years; number needed to treat: 172. Myocardial infarction risk reduced (HR 0.81; 95% CI 0.67–0.98); coronary revascularisation reduced (HR 0.89; 95% CI 0.78–1.01); stroke effect small and not significant (HR 0.99; 95% CI 0.80–1.23). Interactions with baseline statin or cardiovascular drug use were not statistically significant, though signals suggested larger benefits…

Study & population

Design: Randomised, double-blind, placebo-controlled trial (D-Health Trial) conducted in Australia (2014–2020).

Intervention

60,000 IU vitamin D3 monthly, orally, for up to five years.

Key limitation

Possible undercounting of events due to missing private-hospital data for some states; undercounting would be small and unlikely to differ between groups.

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Original abstract