Vitamin D treatment for five years decreased the risk of atrial fibrillation

Atrial fibrillation is a frequent cardiac arrhythmia associated with a substantial morbidity risk. It is a frequent arrhythmia that worsens with age and has been associated with stroke, heart failure, and death. Although observational studies imply that vitamin D insufficiency is related to an increased risk of atrial fibrillation, there is limited evidence that vitamin D treatment can reduce the risk.

From 2012 to 2018, the University of Eastern Finland hosted the Finnish Vitamin D Trial (FIND), which enrolled 2,495 people aged 60 to 65. The individuals were divided into one placebo group and two vitamin D3 supplementation groups. 

Participants were also allowed to take their vitamin D supplement, up to 20 micrograms per day, which was the recommended dose for this age group at the start of the trial. Participants in the trial had not been diagnosed with cardiovascular disease or cancer at the start of the study. 

They completed detailed questionnaires on their lifestyles and nutrition and risk factors for diseases and disease occurrence, both at the start and during the study. Data on disease occurrence and death rates were also acquired.

During the five-year study, 190 patients were diagnosed with atrial fibrillation. Compared to the placebo group, the risk of atrial fibrillation was 27% lower in the 40 micrograms group and 32% lower in the 80 micrograms group. After one year, the mean baseline serum calcidiol concentration was 100 nmol/l in the 40 micrograms group and 120 nmol/l in the 80 micrograms group. The placebo group showed no significant change in calcidiol levels.

The FIND trial is the first to show that vitamin D supplementation lowers the risk of atrial fibrillation in otherwise healthy men and women. Previous research has only revealed an effect at 10 or 50 micrograms per day. Further confirmation of the FIND study results is required before vitamin D dosages far exceeding existing recommendations may be suggested for avoiding atrial fibrillation. 

The FIND project previously reported findings indicating no link between the occurrence of other cardiovascular events or malignancies.

The result shows that These posthoc analyses indicate that high-dose vitamin D3 supplementation may lower the incidence of AF in an elderly population that is otherwise healthy and vitamin D adequate.

The FIND study was funded by the Research Council of Finland, the University of Eastern Finland, and the Juho Vainio Foundation.

Journal Reference:

1. Jyrki K. Virtanen, Sari Hantunen, etal. The effect of vitamin D3 supplementation on atrial fibrillation in generally healthy men and women: The Finnish Vitamin D Trial. American Heart Journal. DOI: 10.1016/j.ahj.2023.05.024