November 16, 2010

Black and White: What Raises Your Risk of Stroke?

(Ivanhoe Newswire) "“ Vitamin D deficiency is associated with fatal stroke among whites, but according to this study, it is not linked to more stroke deaths among blacks.   Stroke is the third highest cause of death in the U.S.

Analyzing the health records of 7,981 black and white adults, researchers found that whites with deficient vitamin D levels had a doubled risk of dying from a stroke compared to whites with higher vitamin D levels. In contrast, researchers found no relationship between fatal strokes and vitamin D deficiency among blacks, even though blacks in the study generally had a 60 percent higher risk of dying from stroke compared to whites.

These results remained even after researchers accounted for various socioeconomic and stroke risk factors in both groups. Nearly 7 percent of whites in the study were vitamin D deficient, compared to slightly over 32 percent of blacks.

"We thought maybe the lower vitamin D levels might actually explain why blacks have higher risks for stroke," Erin Michos, M.D., M.H.S., the study's lead researcher and an assistant professor of medicine at Johns Hopkins University School of Medicine in Baltimore, Md was quoted as saying. "But we did not find the same relationship between vitamin D and stroke in blacks."

The adds to research about the potential health benefits of Vitamin D, a fat soluble vitamin involved in bone health that helps prevent rickets in children, protects against severe bone loss in adults, and potentially lowers the risks of heart disease, cancer, multiple sclerosis, diabetes and other medical conditions. Sources of vitamin D include exposure to ultraviolet B rays in sunlight, and eating fatty fish, egg yolks and fortified foods such as milk products and breakfast cereals.

Researchers used data from the Third National Health and Nutrition Examination Survey of Americans (NHANES-III) conducted between 1988 and1994. They followed the study participants for a median of 14 years. They measured vitamin D amounts based on blood levels of 25-hydroxyvitamin D, a form that represents vitamin D stored in the body.

Average levels of vitamin D were significantly lower in blacks compared to whites. By 2006, according to the National Death Index, there were a total 176 deaths from fatal stroke (116 among whites and 60 among blacks).

Blacks may be maturally resistant to the negative effects of low vitamin D levels, which might also explain the lower frequency of bone fractures despite the higher prevalence of vitamin D deficiency among blacks, Michos said.

 "Since stroke is the No. 3 cause of death in the United States, it's important for us to consider low vitamin D as a possible risk factor for stroke at least among whites," Michos said.

SOURCE: Annual American Heart Association's Scientific Sessions held in Chicago, IL on November 15, 2010