According to clinical research in The BMJ, vitamin D supplementation may lower the incidence of serious cardiovascular events like heart attacks in persons over 60. Even though this is the largest trial to date, the researchers emphasize that the absolute risk difference was minor and that more research is necessary, especially for those using statins or other medications for cardiovascular disease.
Heart and blood vessel disorders are collectively called cardiovascular disease (CVD), one of the leading causes of death worldwide. As the population ages and chronic diseases increase, CVD events, including heart attacks and strokes, are expected to rise. Although randomized controlled trials have not found evidence that vitamin D supplements reduce the incidence of cardiovascular events, observational studies have consistently demonstrated a relationship between low vitamin D levels and CVD risk. Different trial designs can have an impact on the outcomes.
Australian researchers set out to determine whether giving older persons monthly vitamin D supplements will affect the frequency of major cardiovascular events to resolve this issue. Their D-Health Trial recruited 21,315 Australians between the ages of 60 and 84 who were randomly assigned to receive one capsule of either 60,000 IU vitamin D (10,662 participants) or a placebo (10,653 participants) administered orally at the start of each month for up to five years. The study took place from 2014 to 2020.
Participants who had previously had hypercalcemia (high calcium levels), hyperparathyroidism (overactive thyroid), kidney stones, osteomalacia (soft bones), sarcoidosis, an inflammatory condition, or who were already taking more than 500 IU/day of vitamin D were excluded from the study. Then, serious cardiovascular events such as heart attacks, strokes, and coronary revascularization (therapy to return regular blood flow to the heart) were identified using hospital admissions and mortality data.
Five years on average, were spent in treatment, and more than 80% of individuals said they took at least 80% of the study tablets. 1,336 trial participants (6.6% in the placebo group and 6% in the vitamin D group) had severe cardiovascular events.
Compared to the placebo group, the rate of major cardiovascular events was 9% lower in the vitamin D group (5.8 fewer incidents per 1,000 participants). There was no change in stroke rates between the two groups, but the risk of heart attack was 19% lower, and the rate of coronary revascularization was 11% lower in the vitamin D group.
Those taking statins or other cardiovascular medications at the beginning of the experiment appeared to experience a more significant effect, but the researchers claim these findings were not statistically significant. The researchers estimate that 172 individuals would need to take vitamin D supplements every month to avoid one severe cardiovascular incident.
According to the researchers, the findings may only apply to some communities, particularly those where a higher percentage of people are vitamin D deficient, who agree there may have been a little underestimation of incidents. However, it should be noted that this was a sizable trial with excellent retention and adherence rates and nearly complete data on cardiovascular events and death outcomes.
Therefore, they claim that their research indicates vitamin D intake may lower the risk of serious cardiovascular events. They continue by stating that “this protective effect may be more pronounced in those taking statins or other cardiovascular medications at baseline,” they advise further investigation to clarify this matter.