BACKGROUND AND PURPOSE:

• Manson et al. (NEJM, 2018) assessed whether vitamin D reduces risk for cardiovascular disease and cancer in the general population

METHODS:

• Randomized, double-blind placebo-controlled trial (RCT)
  • VITAL trial (VITamin D and OmegA-3 TriaL)
  • Two-by-two factorial design
    • Vitamin D₃: 2000 IU per day
    • Marine n-3 fatty acids: 1 g per day
  • Participants
    • Men: ≥50 years
    • Women: ≥55 years
  • Primary outcomes
    • Major cardiovascular events
    • Invasive cancer (any)
  • Secondary outcomes
    • Site-specific cancers | Death from cancer | Additional cardiovascular events

RESULTS:

• 25,871 participants underwent randomization
  • There was a median follow-up of 5.3 years
  • 51% women
  • Mean age 67.1 years
  • Racially diverse cohort

Vitamin D intake did not impact either primary outcome

• Cancer
  • Vit D: 793
  • Placebo group: 824
  • Hazard ratio (HR) 0.96 (95% CI, 0.88 to 1.06; P=0.47)
• Major cardiovascular event
  • Vit D: 396
  • Placebo: 409
  • HR: 0.97 (95% CI, 0.85 to 1.12; P=0.69)

Vitamin D intake did not impact secondary outcomes

• Death from cancer: HR 0.83 (95% CI, 0.67 to 1.02)
• Breast cancer: 1.02 (95% CI, 0.79 to 1.31)
• Prostate cancer: 0.88 (95% CI, 0.72 to 1.07)
• Colorectal cancer: 1.09 (95% CI, 0.73 to 1.62)
• Myocardial infarction: 0.96 (95% CI, 0.78 to 1.19)
• Stroke: 0.95 (95% CI, 0.76 to 1.20)
• Death from cardiovascular causes: 1.11 (95% CI, 0.88 to 1.40)
• There was no difference in death from any cause
  • HR 0.99 (95% CI, 0.87 to 1.12)
• No excess risks of hypercalcemia or other adverse events were identified
• Effects did not vary according to baseline serum 25-hydroxyvitamin D levels

CONCLUSION:

• Supplementation with vitamin D does not reduce risk for cardiovascular disease or invasive cancer in an otherwise healthy population
• Authors acknowledge that while the study was appropriately powered for the primary endpoints, longer follow-up would be necessary to truly determine risk for cancer development and would need greater ‘n’ for site specific cancers

Learn More – Primary Sources:

Vitamin D Supplements and Prevention of Cancer and Cardiovascular Disease

Marine n−3 Fatty Acids and Prevention of Cardiovascular Disease and Cancer

Related ObG Topics:

Does Vitamin D Intake Decrease the Risk for Gestational Diabetes Mellitus?

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Is there a Causal Link between Vitamin D and Gestational Hypertension / Preeclampsia?