Cardiovascular disease (CVD) is a common preventable disease that afflicts millions. In this recent study published in JAMA, it was found that taking high-dose vitamin D supplements does not prevent heart problems like CVD.
Recent meta-analyses of individuals with low vitamin D have confirmed an increased risk of cardiovascular disease (CVD). However, taking additional vitamin D supplements has yielded mixed results across various other studies. Previously, the Women’s Health Initiative found no benefit of taking supplemental low-dose vitamin D to reduce risk of CVD. Based on current data, the benefits of taking vitamin D for the explicit purpose of reducing the likelihood of CVD appears inconclusive. In order to further confirm whether or not vitamin D really has any effect at all, the authors of a recently published study in the Journal of the American Medical Association (JAMA) ran clinical trials where a monthly high-dose of vitamin D was administered.
The individuals of interest for this study were mainly people in the age group of 50 to 84 years, living in New Zealand. Participants were excluded if they had underlying medical conditions or retracted their consent to the study. Eligible participants consisted of a large sample of 5110 volunteers, out of which 2558 were randomly selected to take vitamin D supplements and 2552 were also randomly selected to take a placebo pill instead. These subjects were then mailed a soft-gel oral capsule (containing vitamin D or placebo) every month for a range of 2.5 to 4.2 years. Levels of vitamin D in the blood were periodically measured. Using New Zealand’s National Health Index Number to track each participant, data on death and hospital discharges were collected for each and every individual. Categorically, hospitalizations caused directly by cardiovascular disease (as determined by the CVD code developed by researchers) were taken as notable results. These included diagnoses such as chronic ischemic heart disease, pulmonary embolism, cardiac arrest and many more. In the end, the results showed that there was no reduction in CVD risk with a monthly high dose of vitamin D.
The effects of taking vitamin D even more regularly than in the current study— such as weekly or even daily —is yet to be known to be effective at lowering CVD risk. However, based on the rigorous testing by this clinical trial, where subjects were randomized, tested double blind and included placebos, it can be said that vitamin D does not prevent CVD. Despite previous studies yielding mixed results, this particular study appears to heavily support the idea that taking supplemental vitamin D to prevent CVD has no effect at all.
Written By: Harin Lee, BSc