African Americans at Greater Risk of Type 2 Diabetes
May 2, 2000 -- Middle-aged African Americans are far more likely to develop
adult-onset, or type 2, diabetes than middle-aged whites, with women much more
likely than men to develop the disease, a study in this week's issue of the
Journal of the American Medical Association reports.
The study also indicated that much of the extra risk in women may be due to
controllable factors, particularly excess weight.
"One of the most important findings of our study is that the excess risk
of developing diabetes in African American women is almost 50% due to adiposity
[excess fat]," researcher Linda Kao, PhD, tells WebMD. "Clearly, this
suggests that if that population could be targeted for prevention, we could
reduce the incidence of type 2 diabetes substantially." Kao is a
postdoctoral fellow in the department of epidemiology at Johns Hopkins
University in Baltimore.
Type 2 diabetes, which is by far the most common type, typically begins
after age 40. It occurs when the body can't make enough or properly use
insulin, the hormone that maintains blood sugar levels. Often, it can be
controlled by weight loss, improved nutrition, and exercise, though medications
must sometimes be used. If not successfully managed, diabetes can lead to heart
disease; stroke, eye and kidney problems; and problems involving the blood
vessels, nerves, and feet.
Kao and colleagues used questionnaire and test results from about 12,000
participants in the Atherosclerosis Risk in Communities study, which has
gathered data from more than 15,000 people living in four U.S. communities
beginning in 1986.
"The profile of established risk factors for diabetes was clearly worse
in African American women than in their white counterparts," the
researchers write. "In particular, African American women had fewer years
of formal education, were more likely to report a family history of diabetes,
had greater measures of adiposity ... and reported less physical activity
during leisure time." The racial difference in these risk factors, except
for the difference in weight, was also seen in African American vs. white
According to the study, the risk of developing diabetes was about 2.4 times
greater for African American women and about 1.5 times greater for African
American men than for their white counterparts. The risk drops by almost half
in African American women after the figures are adjusted to account for excess
weight, but, Kao says, "the increased risk among African Americans still
persists, indicating that some other factor, perhaps a genetic or environmental
factor, or both, remains unidentified."
Helaine Resnick, PhD, a research fellow in the epidemiology, demography and
biometry program at the National Institute on Aging of the National Institutes
of Health, reviewed the study for WebMD. "I absolutely agree with this
paper's conclusion that a lot of the risk of developing type 2 diabetes in this
population is modifiable," she says.