Omega-3 fatty acids and/or vitamin D3 supplementation do not reduce incident AF

The VITAL-Rhythm trial: Omega-3 Fatty Acid and Vitamin D Supplementation in the Primary Prevention of Atrial Fibrillation

News - Nov. 14, 2020

Presented at the AHA Scientific Sessions 2020 by Christine M. Albert (Los Angeles, CA, USA)

Introduction and methods

Atrial fibrillation (AF) is the most common heart rhythm disturbance and results in symptoms that impair quality of life and confers risks to a multitude of factors such as stroke, heart failure and CV death.

Current treatment options for AF are employed relatively late in the disease process and are associated with significant risks and limited long-term success. Despite the need for primary prevention strategies, large randomized controlled trials examining the prevention of AF have not been initiated due to feasibility concerns.

Low levels of omega-3 fatty acids and vitamin D have been associated with increased risks of incident AF, which suggest that supplementation of these factors might prevent AF. However, the current available data are somewhat conflicting. This study evaluated whether daily supplementation with omega-3 fatty acids and/or vitamin D3 was a beneficiary strategy in the primary prevention of incident AF.

The VITAL-Rhythm Study, an ancillary trial of the VITAL trial, is a double-blind, placebo-controlled, randomized trial, in a 2x2 factorial design, that tested daily supplementation of 840 mg omega-3 fatty acids (1 gram/day, comprised of 460 mg EPA and 380 mg of DHA) and/or 2000 IU vitamin D3. Men (≥50 years) and women (≥55 years) in the United States without a prior history of CVD, cancer, or AF were included in the study. Participants (n=25,119) received mail-based questionnaires to report their health outcome. New diagnoses of AF were reported via follow-up questionnaires, and were verified by medical billing and hospitalization records. AF events were confirmed by medical record review or ECG data. Median follow-up was 5.3 years.

Main results

  • 900 Participants (3.6%) experienced an AF events. 72.9% Of these AF events were confirmed via ECG data, the remaining 27.1% via medical record reports.
  • Of all confirmed AF events, 58.4% were paroxysmal and 38.4% persistent. The type of AF event could not be classified in 3.1% of cases.
  • The majority of participants (61.9%) had symptoms prior to their AF diagnosis compared to 27.4% who were symptom-free before diagnosis.
  • There was no difference in incident AF between participants using EPA/DHA supplements or placebo (HR 1.09, 95% CI: 0.96-1.24, P=0.19).
  • No differences in incident AF were detected in participants on vitamin D3 supplements compared to those on placebo (HR 1.09, 95% CI: 0.96-1.25, P=0.19).


The VITAL-Rhythm trial found no association between daily supplementation with omega-3 fatty acids and/or vitamin D3 and lower risk of AF.


Renate Schnabel (Hamburg, Germany) started by showing that daily use of omega-3 fatty acids and/or vitamin D3 supplement intake had, compared to placebo, no effect on MACE outcomes in the mother trial VITAL. So, it is not surprising to see a lack of benefit of these two supplements on AF outcomes in the ancillary VITAL-Rhythm trial, she said.

Schnabel continued by highlighting the importance of the design of the study. Pragmatic trials, compared to the traditional randomized clinical trial (RCT), can perhaps be a better option for AF studies. RCTs are often costly and inefficient due to regulatory issues. Pragmatic trials on the other hand, are less costly, can enroll large numbers of participants, have fewer regulatory restrictions, are embedded in clinical routine care, and have a simple design. The trials do require infrastructure that can facilitate easy and quick enrollment.

This is the largest and longest randomized trial of daily high-dose vitamin D and omega-3 fatty acid supplementation and the largest AF primary prevention trial, said Schnabel. It has set the stage for AF primary prevention trials and upcoming substudies in subcohorts.

- Our reporting is based on the information provided during AHA Scientific Sessions 2020 –

Watch a video on the VITAL-Rhythm trial

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