Low vitamin D blood levels are linked to greater risk of heart disease in whites and Chinese, but not in blacks and Hispanics, reveals a new study appearing this week in JAMA, a journal published by the American Medical Association.
Growing evidence has suggested that low blood levels of 25-hydroxyvitamin are associated with higher risk of developing coronary heart disease among whites. Few of these studies included substantial numbers of people from other races.
Vitamin D levels tend to be lower among people from other racial and ethnic minority groups, and some of these populations have higher rates of heart disease. However, after correcting for other risk factors for heart disease in their large, multi-ethnic study group, the researchers reporting in the JAMA
paper did not find an association between low vitamin D and cardiovascular events in their black and Hispanic study participants.
"Our study suggests that the results of ongoing vitamin D clinical trials conducted in white populations should be applied cautiously to people of other racial and ethnic backgrounds," said Cassianne Robinson-Cohen, the lead author for the JAMA
paper. The senior author is Ian deBoer, University of Washington assistant professor of medicine, Division of Nephrology.
Robinson-Cohen is an affiliate instructor in epidemiology at the UW School of Public Health and a researcher at the Kidney Research Institute, where her team explores the genetic, metabolic and epidemiological factors related to heart and kidney disease.
She noted that the findings in their recent JAMA
paper came from an observational study, not a randomized clinical trial, and could not guarantee cause and effect.
"Our future studies will examine the genetics affecting the levels and use of Vitamin D in the body to try to figure out why the link between low vitamin D blood levels and heart disease varies by race and ethnicity," she said. "We don't know for sure, but perhaps genes affecting the need for and use of vitamin D could have evolved to adapt to different levels of sun exposure in places where various ethnic subgroups of people originated."