VITAL: Omega-3 and Vitamin D Supplements Did Not Reduce Major CVD Events, Invasive Cancers

Vitamin D supplementation, as well as omega-3 fatty acid supplementation, were not associated with a significant reduction in major cardiovascular disease (CVD) events and total invasive cancer, with a caveat, according to new data presented at the American Heart Association 2018 Scientific Sessions in Chicago.

The double-blind, placebo-controlled study, 2X2 factorial study, presented by JoAnne E. Manson, MD, of Harvard Medical School, was designed to examine the primary prevention role that daily supplements had in reducing the risk for developing cancer, heart disease, and stroke in people with no history of the conditions. The study population included 25,871 adults who were randomized to either vitamin D₃ (cholecalciferol; 2000 IU daily) and marine omega-3 fatty acids (fish oil, eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA], 1 gram daily); (2) vitamin D and omega-3 placebo; (3) vitamin D placebo and omega-3 fatty acids; or (4) both placebos. Primary study endpoints were major cardiovascular events, (a composite of myocardial infarction, stroke, and CVD mortality) and total invasive cancer, with a secondary endpoint Median follow-up was 5.3 years.

The results suggested that while neither omega-3s nor vitamin D significantly reduced the primary endpoints of major CVD events or total invasive cancer, omega-3 fatty acid supplements were associated with a 28% reduction (nominal p-value=0.003; Bonferroni-adjusted p-value=0.015). Additionally, the greatest reductions were seen in African Americans and in those with low dietary fish intake. There were also observed reductions in percutaneous coronary intervention, fatal MI, a composite endpoint of total coronary heart disease. A reduction in total cancer mortality was reported in analyses excluding early follow-up.

Discussant Jane Armitage, MD, of the University of Oxford, noted that the VITAL was a large, well-done study, and that the study results were a good test of the study hypothesis that produced a robust null result. The reductions in total MI seen with omega-3s, she noted, were less robust and required follow-up.

Read the full study manuscript in the New England Journal of Medicine.

Read more DocWire News coverage of AHA 2018 here.