• TARGET-D Study: Presented at the American College of Cardiology conference, it showed that patients maintaining vitamin D levels between 40-80 ng/mL (100-200 nmol/L) had half the risk of heart attack, especially post-heart attack patients.
• Expert Opinions: Cardiologist Dr. B. Keith Ellis notes long-observed links between low vitamin D and cardiovascular risks; Prof. Markus Herrmann praises it as the first study specifying target blood levels for clearer conclusions.
• Vitamin D Roles: Supports bone metabolism with calcium, immune system, brain/muscle cells; potential anti-inflammatory effects, blood pressure/sugar regulation may protect the heart.
• Causation Debate: Low vitamin D might be a confounding factor reflecting outdoor activity and healthier lifestyles rather than direct cause.
• Sources and Deficiency: Found in fatty fish (salmon, sardines), fortified foods; body produces via sunlight; up to 1 billion people worldwide deficient, worse in northern countries during winter.
• Prior Trials: D-Health and VITAL trials showed no clear benefits; D-Health had borderline results for reducing heart attack risk.

Topol, Eric J. ‘COVID-19 Can Affect the Heart’. Science 370, no. 6515 (23 October 2020): 408–9. https://doi.org/10.1126/science.abe2813.

Dr. Tara C. Smith. (2021, January 23). A reminder: Especially among the elderly, some individuals will die shortly after receipt of the vaccine. What we need to understand is the background rate of such deaths. Are they higher then in the vaccinated population? We didn’t see that in the trials. Some data from @RtAVM. https://t.co/LJe9k1WJQC [Tweet]. @aetiology. https://twitter.com/aetiology/status/1352810672359428097