Vitamin D deficiency does not increase stroke risk among blacks

Editor's note: The data showed blacks have low levels of vitamin D and high risk of death from stroke.  No association between the two was found maybe because the vitamin D levels in most blacks were too low to result in any difference in the risk of stroke. But that does not mean that vitamin D has nothing to do with stroke.  In any case, blacks need to take vitamin D supplements because it is harder for them to make vitamin D through the sun exposure, compared to whites.

A new study presented at the American Heart Association's Scientific Sessions 2010 found vitamin D deficiency was linked to a higher risk of death from stroke among whites, but not among blacks. 

Vitamin D deficiency is known to be associated with high risk of cardiovascular disease.  Blacks are at higher risk of insufficient or deficient vitamin D because the pigments in the skin of blacks prevent bio-synsthesis of this vitamin. 

Erin Michos, M.D., M.H.S., at Johns Hopkins University School of Medicine in Baltimore, Md and colleagues anayzed health data from a group of 7,981 black and white adults and found whites with deficient vitamin D levels were twice as likely to die from a stroke as those with higher vitamin D levels. 

For blacks, the association did not exist, even though blacks in the study were 60 percent more likely to die from stroke compared to whites.   

The results held true after adjustments for confounders like socioeconomic factors including age, sex, income and education level, along with stroke risk factors including diabetes, high blood pressure, cholesterol, body mass index, smoking, physical activity and alcohol use. 

Vitamin D deficiency was found more commonly among blacks than whites, 32 percent versus 7 percent. 

Previous studies found blacks are both more likely to have insufficient vitamin D and more likely to have strokes, compared to whites. 

The study did not take stroke survivors into account. Because of this, the results do not apply to stroke survivors.

Jimmy Downs and editing by Rachel Stockton