"Vitamin D, Omega-3 Trial (VITAL)". The New England Journal of Medicine. 2018. DOI:10.1056/NEJMoa1811403.
### Clinical Question
Does supplementation with Vitamin D (2000 IU/day) reduce the risk of cancer or cardiovascular disease among older adults?
### Bottom Line
Supplementation with Vitamin D did not result in a lower incidence of invasive cancer or cardiovascular events compared to a placebo.
### Major Points
VITAL was a large-scale, randomized, placebo-controlled trial that tested the effects of daily Vitamin D (2000 IU) and Omega-3 fatty acids (1 g) on the primary prevention of cancer and cardiovascular disease in older adults. With a median 5.3 years follow-up, neither the incidence of invasive cancer nor major cardiovascular events was reduced by Vitamin D supplementation.
### Guidelines
Current guidelines from the U.S. Preventive Services Task Force report insufficient data to evaluate the effectiveness of Vitamin D supplementation for cancer or cardiovascular disease prevention.
### Design
- Nationwide, randomized, double-blind, placebo-controlled trial with two-by-two factorial design
- N=25,871 men (aged ≥50) and women (aged ≥55)
- Intervention: Vitamin D3 (cholecalciferol) 2000 IU/day
- Comparators: Placebo
- Primary endpoints: invasive cancer of any type, major cardiovascular events (myocardial infarction, stroke, or death from cardiovascular causes)
- Secondary endpoints: site-specific cancers, death from cancer, and additional cardiovascular events
- Median follow-up: 5.3 years
### Population
- Inclusion criteria: Men ≥50 years old and women ≥55 years old, no history of cancer (except nonmelanoma skin cancer) or cardiovascular disease at trial entry
- Exclusion criteria: History of various serious conditions, including hypercalcemia and renal failure
- Baseline characteristics: Mean age 67.1 years, 51% women, racially diverse (20% black participants)
### Interventions
- Vitamin D3 (cholecalciferol) 2000 IU per day
### Outcomes
- Primary outcomes: Invasive cancer (HR 0.96, 95% CI 0.88-1.06), major cardiovascular events (HR 0.97, 95% CI 0.85-1.12)
- Secondary outcomes: No significant differences in site-specific cancers or cardiovascular events
- Death from cancer: Non-significant reduction (HR 0.83, 95% CI 0.67-1.02)
- Adverse events: Hypercalcemia, kidney stones, and gastrointestinal symptoms were not significantly different between the Vitamin D and placebo groups
### Criticisms
- The lack of significant results may be due to the study design, including the duration of follow-up and the selected Vitamin D dose.
- Subgroup analyses should be interpreted with caution, as they were not adjusted for multiple comparisons.
### Funding
- Funded by the National Institutes of Health and others
- Trial agents donated by Pharmavite (Vitamin D) and Pronova BioPharma/BASF (fish oil)
### Further Reading
- VITAL research group's full list of members and supplementary material are available at NEJM.org.