Loyola to study vitamin D deficiency in people of African descent

Loyola University Chicago Stritch School of MedicineDec 1 2011

Loyola University Chicago Stritch School of Medicine researchers have received a five-year, $2.8 million grant from the National Institutes of Health to study vitamin D deficiency in people of African descent.

Researchers will evaluate the relation between low vitamin D levels and risks for certain chronic diseases, including osteoporosis and heart disease.

Evidence from numerous previous studies is "inconclusive and needs to be studied further," said Ramon Durazo, PhD, principal investigator and assistant professor in the Department of Preventive Medicine and Epidemiology. "This grant will allow us to take a more in-depth look at the role this nutrient plays in a specific group of people who are at risk for these conditions."

The study will include about 2,500 people, ages 25 - 45, from Ghana, South Africa, Seychelles, Jamaica and metropolitan Chicago. Researchers will determine whether lower vitamin D levels in African populations compared with whites should be considered abnormal, or whether this disparity represents an ethnic-specific trait. The study also will evaluate whether vitamin D deficiency is related to bone density and factors that contribute to heart disease, including obesity, high blood pressure and blood sugar levels.

In the United States, African Americans have been reported to have much lower vitamin D levels. "This is currently thought to be due to their darker skin color, which impairs the ability to utilize the sun for the production of the nutrient," said Pauline Camacho, MD, director of Loyola University Health System's Osteoporosis and Metabolic Bone Disease Center. "Also, this group often has a higher body mass index. This could play a role in the deficiency, as vitamin D is a fat-soluble vitamin."

Only about 3 percent of African Americans have optimal levels of vitamin D. Some researchers believe low levels may contribute to obesity, high blood pressure and cardiovascular disease.

Sampling African-origin populations across a range of latitudes, calcium intakes, diet patterns and lifestyles will enable researchers help define the optimal level of Vitamin D in the multi-ethnic U.S. population.