An abstract presented at the American Heart Association’s 2025 Scientific Sessions suggests that personalized supplementation with vitamin D cuts the risk of a heart attack in half among adults with heart disease. While these abstracts present preliminary findings that have not yet been published or peer-reviewed, if validated, this research would be of significant clinical importance.
The study, known as the TARGET-D trial, included 630 adults (with an average age of 63) who were treated for acute coronary syndrome at Intermountain Medical Center in Utah and were randomized to either a vitamin D group or a standard of care group. Rather than a fixed dose of vitamin D, a personalized dose was administered to achieve serum 25-OH vitamin D levels of at least 40 ng/mL (but not exceeding 80 ng/mL), necessitating monitoring every 3 months with dosage adjustments. Notably, 85% of study participants had blood levels below this threshold at baseline, and roughly 52% required doses of more than 5,000 IU to achieve the desired blood levels. Blood calcium levels were also monitored, and once 40 ng/mL was achieved, blood levels were only checked annually.
With an average follow-up of 4.2 years, participants assigned to the vitamin D group had a 52% lower risk of heart attack than those receiving standard of care. Although not yet peer-reviewed and with several limitations, including a small sample size and a lack of diversity among participants, the magnitude of the reduction is substantial. For context, a 2022 meta-analysis published in JAMA Internal Medicine indicates statins reduce the relative risk for myocardial infarction by 29%. Key to the TARGET-D trial appears to be the personalized dosing of vitamin D, necessitating large doses in most participants.