Omega-3s, Vitamin D Fail to Prevent Incident Atrial Fibrillation

Dietary supplementation with marine omega-3 fatty acids (EPA/DHA) and/or vitamin D does not reduce incident atrial fibrillation (AF), according to results of the first AF primary prevention study.

But neither does supplementation with either or both increase the incidence of AF.

The findings, from the VITAL Rhythm study, were presented during a late-breaking science session today at the virtual American Heart Associations Scientific Sessions 2020. The meeting runs from Friday, November 13 – Tuesday, November 17, 2020.

The commonly used supplements marine omega-3s and vitamin D have been implicated in upstream biologic processes that lead to the development of AF, study authors explain in the abstract. Results of observational studies on the effects of both on development of AF have been conflicting. Also questioned have been the risks and benefits of each for individuals with comorbid illness.

Researchers led by Christine M Albert, MD, PhD, founding chair of the department of cardiology in the Smidt Heart Institute at Cedars-Sinai Medical Center in Los Angeles and lead author of this study, hypothesized that long-term administration of the supplements might be effective in primary prevention.

“Current treatment options have limited long-term success and significant risks," said Albert in an AHA news release, "and there is a pressing need for preventive strategies.”

AF is the most common cardiac arrhythmia and affects approximately 33 million individuals globally.

The VITAL Rhythm Trial is the first, double-blind, placebo-controlled, randomized clinical trial investigating preventive therapies for AF and is an ancillary trial of the primary prevention VITAL trial of cardiovascular disease (CVD) and cancer.

The 2x2 factorial design tested daily supplementation with 2000 IU of vitamin D3/day and/or 840 mg omega-3 fatty acids (EPA:DHA in 1.2:1 ratio) vs placebo in reducing the risk of incident AF.

The study population included 25 119 adults, aged ≥50 years who had no history of AF, CVD, or cancer; mean age was 67 years, approximately 50% were women, and 21% were black. Incident AF diagnoses were prospectively ascertained both by participant self-report and claims data from the Centers for Medicare and Medicaid Services. Electrocardiogram evidence and/or a physician’s report documenting a new diagnosis of AF were required for confirmation.

During the 5.3-year study follow-up (2012-2017), there were 900 incident AF events (3.6% of the study population). There was no difference in AF between omega-3 fatty acid vs placebo (469 vs. 431, HR 1.09, 95% CI 0.96-1.24, p = 0.19) or vitamin D3 vs placebo (HR 1.09, 95% CI 0.96-1.25, p = 0.19).

“With regards to clinical care, these results do not support using marine omega-3 fatty acids or vitamin D to prevent atrial fibrillation," noted Albert in the AHA press release. "However, the results do provide reassurance that these supplements do not increase the overall risk of atrial fibrillation and appear to be generally safe for patients who are taking these supplements for other reasons.”

Abstract: The Vital Rhythm Trial: Omega-3 Fatty Acid and Vitamin D Supplementation in the Primary Prevention of Atrial Fibrillation​