High-dose vitamin D may reduce risk of new atrial fibrillation

TOP LINE:

High dose Vitamin D supplementation can prevent atrial fibrillation (AF) in healthy elderly men and women, suggests a post-hoc analysis of a randomized trial conducted in Finland.

METHODOLOGY:

• Observational studies have suggested that vitamin D deficiency is associated with an increased risk of AF, but few randomized trials have examined the effect of vitamin D supplementation on the incidence of AF in healthy people. .

• The study, a post-hoc analysis of a trial that explored the effects of vitamin D3 supplementation on the incidence of cardiovascular disease and cancer, included 2,495 healthy, vitamin D-sufficient elderly people, elderly an average of 68.2 years, of which 43% were women.

TO TAKE WITH:

• During a follow-up of an average of 4.1 years, the risk of incident AF was reduced by 27% for participants who received the 1600 IU/day dose compared to placebo; relative risk (HR), 0.73 (95% confidence interval [CI]0.52 – 1.02; P = 0.07), and 32% for those in the 3,200 IU/day arm; RR, 0.68 (95% CI, 0.48, 0.96; P = .03).

• The risk of incident AF was reduced by 30% in a comparison of the two vitamin D groups combined versus the placebo group; RR, 0.70 (95% CI, 0.53, 0.94; P = .02).

• After excluding 122 participants who reported taking antiarrhythmic drugs at baseline, the 1600 IU/day group showed a significant 27% reduction in the risk of AF (95% CI, 4% – 58%; P = 0.03) and the 3200 IU/day group, a non-significant percentage of 30% (95% CI, 5% – 53%; P = 0.08) risk reduction.

IN PRACTICE:

According to the authors, high-dose vitamin D3 supplementation may reduce the incidence of AF in a generally healthy older population with ample vitamin D sufficiency. Further controlled trials are needed, particularly in diverse populations, note- they.

STUDY DETAILS:

The study was conducted by Jyrki K. Virtanen, PhD, University of Eastern Finland, Institute of Public Health and Clinical Nutrition, Kuopio, and colleagues. It was published in the American Journal of the Heart.

BOUNDARIES:

Atrial fibrillation was not prespecified as the primary outcome, and the results differ from those of other randomized controlled trials. No information on the type of AF (whether paroxysmal or non-paroxysmal, for example) was available, nor was the participants’ history of AF. All participants were white and from Finland, which limits the generalizability of the results.

DISCLOSURES:

The study was supported by the Academy of Finland, University of Eastern Finland, Juho Vainio Foundation, Medicinska Understödsföreningen Liv och Hälsa, Finnish Foundation for Cardiovascular Research, Finnish Diabetes Research Foundation and Foundation Finnish culture. Co-author JoAnn E. Manson MD, MPH, DrPH, revealed she received grants from the National Institutes of Health and Mars Edge. Co-author Matti Uusitupa, MD, PhD, revealed he received a grant from Orion Corp. The other authors disclosed no relevant financial relationship.

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