By CAROL HENDERSON
UNC-CH News Services
CHAPEL HILL-- Obese blacks face a 30 percent greater risk of experiencing physical disabilities because of their weight than whites, according to researchers at the Thurston Arthritis Research Center at the University of North Carolina at Chapel Hill School of Medicine.
"In other words, the same 20 pounds seem to be more of a problem for African-Americans than for Caucasians," said Dr. Joanne Jordan, research assistant professor of medicine.
In seven of 20 simple household activities, such as getting out of chairs and running errands, obesity was strongly linked to difficulty in performing the tasks, but only for the blacks.
"We're wondering why," Jordan said.
Differences in fat distribution may offer an explanation, she said. U.S. blacks also tend to be more obese than U.S. whites.
An article on Jordan's research appears in the December issue of Arthritis Care and Research, an American College of Rheumatology journal. Other UNC-CH researchers working on the project are Gheorghe Luta, Anca Dragomir and Dr. John Fryer of the School of Public Health, and Dr. Jordan Renner at the School of Medicine.
The research is the first racially balanced, population-based study examining functional differences between blacks and whites and is part of the Johnston County Osteoarthritis Project. In all, 3,600 people will be evaluated.
"Previous studies have been limited to Caucasians," Jordan said. "If African-Americans were included at all, there were too few of them to be able to draw valid statistical conclusions."
Subjects for the study were recruited by local interviewers who made house calls and questioned residents, age 45 and older, in rural Johnston County, N.C. Using the Health Assessment Questionnaire, subjects evaluated their own functional status, based on their perceived ability to perform simple household tasks. Later, participants' body mass index was measured, blood samples were drawn and subjects were given knee x-rays to check for osteoarthritis. Participants' condition will be tracked for five years.
Another finding was that in every case where knee pain was reported, regardless of ethnicity, participants had trouble performing all tasks, even such activities as reaching high for objects that didn't involve using the legs.
"We've known from national studies that rural dwellers might have more difficulty with arthritis than urban dwellers and that even with the same amount of arthritis rural dwellers are more likely to be disabled by it," Jordan said. "What's different about this project is that it's the first study to examine these issues in detail, including the ethnic differences in obesity and disability."
Obesity has not gotten the attention it deserves, Jordan said.
"Above and beyond other risk factors for disability, like knee pain, obesity all by itself can cause disability."
The U.S. Centers for Disease Control and Prevention and the National Institutes of Health support the project through the Thurston Arthritis Research Center.
Anyone living in Johnston County interested in more information about osteoarthritis projects can call the Rural Health Research Center in Smithfield, N.C. at (919) 934-1295.
- 30 -
Note: Jordan can be reached at (919) 966-4191.
Contacts: David Williamson, Juliet Dickey