The risk of atrial fibrillation (A-fib), the most common type of heart arrhythmia, increases with age and it could pose a serious threat to a person’s health. New research from the University of Eastern Finland found taking higher-than-recommended doses of vitamin D was able to reduce the risk of A-fib in older men and women in their study.
A-fib is an irregular and often rapid heartbeat that can lead to blood clots and increase the risk of stroke and heart failure. Scientists at the UEF were looking at the impact of vitamin D on the condition and published their findings in the American Heart Journal.
These findings were part of a larger study conducted by University of Eastern Finland researchers between the years 2012 and 2018 designed to see what impact vitamin D supplementation had on cardiovascular diseases and cancers. The Finnish Vitamin D Trial (FIND) involved nearly 2,500 participants. The men were 60 years and older and the women were 65 years and older.
They were divided randomly between three groups: a placebo group and two vitamin D supplement groups. The placebo group was given no extra vitamin D. One supplement group was asked to take 40 micrograms (1600 IU) per day, while the other supplement group was asked to take 80 micrograms (3200 IU) per day.
All study participants were allowed to take their own personal vitamin D supplement of 20 micrograms (800 IU), which was the recommended dose for the study participants according to their age.
No one in the study had been diagnosed with cardiovascular disease or cancer prior to the start. All were asked to complete comprehensive questionnaires at the outset and throughout. The questions pertained to lifestyle, nutrition and risk factors for disease, as well an incidence of disease during the five-year-trial.
Data was also pulled from Finland’s national health register to track the occurrence of disease and death. And 20 percent of the participants were randomly selected for more detailed screenings and testing.
A total of 190 participants were diagnosed with atrial fibrillation during the trial. Seventy-six came from the placebo group, while 59 were in the 40 microgram group and 55 in the 80 microgram group. That meant the risk of A-fib was 27 percent lower than the placebo in the 40 microgram group and 32 percent lower in the 80 microgram group.
The group selected for extra screening at the start of the trial had a vitamin D concentration of 75 nmol/L. At the one-year mark that number was unchanged in the placebo group but rose to 100 nmol/L in the 40 microgram cohort and 120nmol/L in the 80 microgram cohort.
Researchers say further study is needed before recommendations that exceed the current suggested dose of daily vitamin D can be made. Previous reports from the FIND trial did not show any change in the rates of other heart conditions or cancers as a result of vitamin D supplementation.