- Vitamin D is a fat-soluble vitamin that is important for bone health and immune system support
- Australian researchers followed a group of older people to see whether vitamin D supplements could reduce the risk of major heart disease events.
- The researchers gave the test group a monthly vitamin D supplement which they took for five years.
- While the risk reduction was not as great as the researchers had hoped, they did learn that the people who took vitamin D supplements had a small risk reduction for certain major cardiovascular events.
A study recently published byThe BMJdetails a clinical trial led by a group of Australian researchers who wanted to learn what impact vitamin D may have on reducing major heart disease events such as heart attacks and strokes.
The researchers followed a group of older adults who were between ages 60 and 84. This particular age group is known to be at a higher risk for developing heart disease.
While the scientists did not find that vitamin D had any impact on strokes when comparing the control and test groups, they did learn that the rate of major cardiovascular events was 9% lower in the group that took the vitamin D supplement.
A more in-depth vitamin D study
Cardiovascular disease (CVD) is the top cause of death in the U.S. While CVD can affect adults of all ages, the highest rates of disease are among older people ages 65 and older.
Considering how deadly CVD can be, as well as the burden it may have on the healthcare system, scientists have been looking for ways to improve treatments for such diseases as well as prevent them.
According to the study authors, prior studies did not show a connection between vitamin D and reducing CVD risk, but the authors thought those studies had limitations. The authors noted that “vitamin D has biological effects which suggest it could influence cardiovascular disease,” which prompted them to do a more in-depth study focusing on older adults.
The researchers recruited 21,315 people ages 60 to 84. They excluded participants who were already taking vitamin D supplements or had a history of certain conditions, such as sarcoidosis and hypercalcemia.
The test group took vitamin D once per month for five years in the form of a 60,000 IU vitamin D-3 pill. The control group took a placebo.
The researchers collected baseline information to learn about the socioeconomic status, lifestyle, and dietary habits of the participants. They monitored the participants throughout the study for adverse events and took surveys, and checked blood samples to make sure the participants adhered to taking their supplements.
Additionally, the participants provided access to their medical records so the researchers could obtain information about cardiovascular events, medications prescribed, and any mortality data.
Does Vitamin D have heart benefits?
Some past observational studies have suggested a possible association of higher blood levels of vitamin D with lower rates of CVD.
While clinical studies have not confirmed that vitamin D supplementation positively impacts heart health, this new study shows that it may provide some benefits.
Of the participants taking vitamin D, heart attack incidents were 19% lower compared to the placebo group.
The vitamin D group also had lower rates of coronary revascularization, which can include procedures such as a coronary artery bypass graft (more commonly referred to as a heart bypass).
While the overall rate of major cardiovascular events was 9% lower in the groups taking vitamin D, the study findings did not show a lower rate among stroke events.
The authors noted a caveat to the 9% reduction – they say it is possible that people taking statins or other cardiovascular drugs could have contributed to this reduction.
“For total major cardiovascular events, there was some indication of a stronger effect in those who were using statins or other cardiovascular drugs at baseline,” write the authors.
For this reason, the authors say more testing is needed before they can definitively say that vitamin D alone helps with CVD.
“In conclusion, these findings indicate that vitamin D supplementation might reduce the incidence of major cardiovascular events, particularly myocardial infarction, and coronary revascularization,” write the authors.
“This protective effect could be more marked in those taking statins or other cardiovascular drugs at baseline. Subgroup analyses in other large trials might help to clarify this issue,” the authors continue.
Is vitamin D enough to reduce CVD risk?
Dr. Yu-Ming Ni, a cardiologist at MemorialCare Heart and Vascular Institute at Orange Coast Medical Center in Fountain Valley, California, spoke with Medical News Today about the study. Dr. Ni did not consider the study results significant enough at this point to show that vitamin D supplements help reduce CVD rates.
“In reviewing this study, it is tempting to conclude that there may be a trend toward a benefit for vitamin D supplementation for cardiovascular disease prevention, particularly as it relates to preventing heart attacks (myocardial infarction),” he said.
Dr. Ni said that compared to existing research on vitamin D and CVD, the current study “did not demonstrate a significant benefit of Vitamin D supplementation, even if there was a trend toward one.”
While Dr. Ni did not think the study showed promise for using vitamin D to reduce CVD risk, the doctor said it is still a vital supplement for bone health.
Dr. Dmitriy Nevelev, an associate director of cardiology at Staten Island University Hospital in New York, had a slightly different take on the study when discussing it with MNT.
After pointing out that other large studies have researched vitamin D and CVD and shown no “significant effect,” Dr. Nevelev said “many of these studies had limitations such as suboptimal adherence with daily therapy, insufficient dose of vitamin D, or an overall lower risk population.”
“This study overcame some of these limitations by providing a once-monthly treatment with high adherence and enrolling a large, clinically diverse population. The findings overall supported the notion that vitamin D supplementation may reduce the risk of heart disease, albeit mildly,” Dr. Nevelev continued.
Like the study authors, Dr. Nevelev believes further research is needed on vitamin D supplements and CVD.
“Even if the findings do not immediately impact our approach to supplementation, they provide a reason to continue research to determine if there is a particular population that stands to benefit,” said Dr. Nevelev.
“Of particular interest was the finding that patients who took statins saw a more pronounced reduction of heart disease with supplementation, possibly because vitamin D allows the liver to more efficiently process these medications.”
— Dr. Dimitriy Nevelev
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