A University of Pittsburgh study indicates genetic variants may be more prevalent in African-Americans, which may explain why they may be more likely than whites to develop certain potentially life-threatening illnesses.

African-Americans are more likely than whites to suffer from kidney disease, stroke, and premature birth labor.  Inflammation is common to these and other autoimmune disorders. 

In attempting to find out why blacks are stricken more often than whites, researchers, led by Roberta Ness of the University of Pittsburgh in Pennsylvania, examined a host of gene variants that increase inflammation.  

Genes contain hereditary information in the form of DNA in a cell's nucleus and control the production of proteins.

The study involved 180 African-American women and 400 white women who came to the University of Pittsburgh to give birth between 1997 and 2001.

The researchers found that African-Americans had many more variants in regulatory proteins than white Americans.  Even though African-American women were more likely than white women to carry some of these variants, the variants were present in fewer than half of the black women.

Dr. Ness says not all African-Americans have a genetic predisposition to an autoimmune disease, nor will all those with a predisposition develop a disease. 

Dr. Ness says a person with a predisposition to autoimmune disease has to be exposed to an environmental trigger.  She says there are many conditions that might trigger autoimmune disorders, such as heart disease and diabetes.

"We know absolutely for certain that a huge determinant of racial disparities are socio-economic status, living conditions, behaviors," said Dr. Ness.  "I mean these are very different in our country between African-Americans and whites.  And they are probably a very big part of the picture." 

Earlier studies, including a report by researchers at the National Institute of Diabetes and Digestive and Kidney Diseases, have noted that African-Americans are more likely to have genetic mutations associated with inflammation.

The University of Pittsburgh study connecting genetic variants and immune system disorders was published in the American Journal of Epidemiology.