Is vitamin D deficiency actually a cardiovascular risk factor for Black men in northern cities?

Melanin reduces skin synthesis of vitamin D from ultraviolet B radiation. Black men living at northern US latitudes, Chicago, Detroit, New York, Minneapolis, have materially higher rates of vitamin D deficiency than white men at the same latitude. The association between vitamin D deficiency and hypertension, adverse cardiac remodeling, and increased cardiovascular mortality is documented in epidemiological studies, with a proposed mechanism involving vitamin D's role in the renin-angiotensin-aldosterone system regulation and its effects on vascular smooth muscle function.

This is not a case where I am recommending vitamin D as a cardiovascular panacea, the RCT evidence for vitamin D supplementation reducing hard cardiovascular outcomes is mixed, with the VITAL trial not showing a significant reduction in MACE in the overall population. What the evidence does support is that Black men in northern cities have a higher baseline prevalence of deficiency, and that maintaining 25-hydroxyvitamin D levels above 40 ng/mL is a reasonable target with no meaningful downside risk. The recommendation is measurement first, know your level, rather than universal supplementation without data. (Holick, NEJM, 2007)

Cardiologist's calibrated position, Promising (2) for vitamin D deficiency correction as a cardiovascular risk modification in deficient Black men. Unsupported (5) for vitamin D supplementation producing hard cardiovascular outcome benefits in replete individuals.

What to do: Ask for 25-hydroxyvitamin D on your next panel. If your level is below 30 ng/mL, supplement at 2,000–4,000 IU daily with vitamin K2 to target the 40–60 ng/mL range. Recheck at 3 months.

For the full picture, read The Cardiac Inheritance.