With one study ruling out lack of exercise as a leading cause of obesity among African-Americans, new research from Dartmouth's Institute for Quantitative Biomedical Sciences (iQBS) and the Center for Genomic Medicine may off some clues as to why obesity rates in the black community continue to soar.
According to a study of more than 30,000 people with African heritage -- the largest genetic search for "obesity genes" -- genetics is a likely cause. Here's how:
People from different populations share similar genetic traits that impact body size, authors and professors Jason Moore, Christopher Amos and Scott Williams explain in their research, which was published online in the April 2013 edition of Nature Genetics. 32 gene variants previously associated with BMI in European and Asian populations were discovered in people with African ancestry, to be exact.
One key distinction prevailed, however: That people with African ancestry possess three genetic variations that work in concert with environmental factors to impact BMI -- genes unique to the African-American set.
"A person who carries these variants may be predisposed to having higher BMI or becoming obese," said University of Louisville researcher Kira Taylor, whose team was also involved in the study. "But it is important to note these genes only account for a small percentage of higher BMI in the population," Taylor added, noting that environmental and behavioral factors like poor diet and lack of physical activity also play a major role.
"While some genetic variants are likely to increase or decrease weight in all people, most are likely to influence weight in specific people depending on their genetic background and their unique environmental history including diet, toxic metal exposure, exercise, etc," Moore said in a release highlighting his findings.
And while Moore and his colleagues agree that their findings may help scientists to understand and clinicians to better prevent or treat, obesity in this population, he cautions that his paper is just a start to understanding the role of genetic variation in obesity.
In a study published in the same journal earlier this month, an international team of researchers made a similar discovery, identifying four new genetic markers that they say could contribute to the most extreme cases of obesity in childhood. The findings suggest that childhood obesity may be driven by different genetic factors than adult obesity, and that the two conditions may be treated in different ways.