Heart Dangers of Low Vitamin D Levels May Vary
Study found whites, Asians more affected than blacks, Hispanics
By Denise Mann
TUESDAY, July 9 (HealthDay News) -- The heart risks of having low levels of vitamin D may hinge on what race or ethnicity you are, new research suggests.
Specifically, the team of scientists found it might increase heart disease risk among white or Chinese individuals, but it does not seem to pose any cardiovascular danger to black or Hispanic adults.
"We think that the differences are mainly due to biologic differences in vitamin D metabolism between race [and] ethnicity groups. However, future studies are needed to more carefully examine these potential differences," said study author Cassianne Robinson-Cohen, of the University of Washington, in Seattle. "Our results suggest that we should use caution in extrapolating results from studies conducted in European Americans to all race [and] ethnicity groups."
Vitamin D is known as the sunshine vitamin because the human body produces it when exposed to the sun's rays. In recent years, vitamin D deficiency has been linked to a host of illnesses, including heart disease, certain cancers, osteoporosis, diabetes, Alzheimer's disease, schizophrenia and some autoimmune disorders. The Institute of Medicine recommends 600 international units (IU) per day for everyone aged 1 to 70 and 800 IU a day for adults older than 70.
In the study, researchers measured vitamin D levels among more than 6,400 people of different ethnic backgrounds. None had evidence of heart disease when the study began.
After more than eight years of follow-up, 361 participants had had a heart attack or another heart-related event. White people were 26 percent more likely to experience a heart-related event for every drop in vitamin D levels of 10 nanograms per milliliter of blood (ng/mL), and Chinese people showed a 67 percent higher risk for the same drop. However, the same relationship was not seen among black and Hispanic people in the study.
Dr. Keith Norris, an associate professor of medicine at the David Geffen School of Medicine at University of California, Los Angeles, co-wrote an editorial accompanying the new study.
"This study brings up some interesting ideas about vitamin D and heart disease, and how it may differ in different populations," he said.
Ironically, blacks and Hispanics are known to have lower levels of vitamin D than their white or Asian counterparts, Norris said.
"We would think that the populations with lower vitamin D levels would be at greater risk for heart disease," but these findings suggest the complete opposite, he said.
In the study, black participants had the lowest vitamin D levels at 19.2 ng/mL. Hispanic participants had vitamin D levels of 24.6 ng/mL. By contrast, Chinese individuals had mean vitamin D levels of 26.7 ng/mL and white participants had a mean levels of 30.1 ng/ml.