A recent study from the University of Eastern Finland found that taking higher-than-recommended vitamin D dosages for five years lowered the incidence of atrial fibrillation in older men and women.

Atrial fibrillation is the most prevalent arrhythmia, with an increased risk with age and an increased risk of stroke, heart failure, and death. Vitamin D has been demonstrated to have an influence on the atrial shape and electrical activity of the heart, implying that it might prevent atrial fibrillation.

The Finnish Vitamin D Trial, FIND, was conducted at the University of Eastern Finland from 2012 to 2018. Its major goal was to investigate the correlations of vitamin D supplementation with the prevalence of cardiovascular illnesses and malignancies. The five-year study included 2,495 participants, 60-year-old or older men and 65-year-old or older women, who were randomly assigned to one of three groups: one placebo group and two vitamin D3 supplementation groups, with one group taking a supplement of 40 micrograms (1600 IU) per day and the other taking an 80 microgram (3200 IU) per day. All participants were also permitted to take their own vitamin D supplement, up to 20 micrograms (800 IU) per day, which was the recommended level at the start of the trial.

At baseline, study participants had not been diagnosed with cardiovascular disease or cancer, and they completed comprehensive questionnaires, both at the beginning and throughout the study, on their lifestyles and nutrition, as well as on risk factors of diseases and disease occurrence. Data on the occurrence of diseases and deaths were also obtained from Finnish nationwide health registers. Approximately 20 pc of participants were randomly selected for more detailed examinations and blood samples.

During the five-year study, 190 participants were diagnosed with atrial fibrillation: 76 in the placebo group, 59 in the 40 micrograms group, and 55 in the 80 micrograms group. The risk of atrial fibrillation was 27 pc lower in the 40 micrograms group, and 32 pc lower in the 80 micrograms group, when compared to the placebo group. In the sub-cohort selected for more detailed examinations, the mean baseline serum calcidiol concentration, which is a marker of the body’s vitamin D concentration, was relatively high, 75 nmol/l. After one year, the mean calcidiol concentration was 100 nmol/l in the 40 micrograms group, and 120 nmol/l in the 80 micrograms group. No significant change in the calcidiol concentration was observed in the placebo group.

FIND is the first randomized controlled trial to observe that vitamin D supplementation reduces the risk of atrial fibrillation in generally healthy men and women. Previous research is limited to only two randomized trials, which did not observe an effect when using doses of 10 micrograms (400 IU) or 50 micrograms (2000 IU) per day. Further confirmation of the present results from the FIND study is therefore needed before doses of vitamin D that significantly exceed current recommendations can be recommended for preventing atrial fibrillation. The FIND study has previously published findings showing no association with the incidence of other cardiovascular events or cancers. (ANI)