Study leader Maciej Buchowski of Vanderbilt University in Nashville said the odds of severe obesity were nearly 4.5 times higher in white women, among those in the highest quartile of sedentary behavior.
Buchowski and colleagues analyzed data from 22,948 African-American women and 7,830 white women living in 12 southeastern U.S. states. The study participants -- mostly in their fifth decade -- were enrolled in the ongoing Southern Community Cohort Study from 2002 to 2006.
"The key take-home message here is that reducing time in sedentary behavior is important," Buchowski said in statement. "Our population was economically disadvantaged, so it is unlikely that they could join a club to participate in structured physical activity."
Buchowski said researchers did not do a controlled trial and the reasons for the racial disparities remain unclear. He suspects a cultural explanation, a difference in metabolism between the two groups or another difference.