The study compared body mass index (BMI) - a measure of body fat based on height and weight - against three generally accepted risk factors for cardiovascular disease among people with diabetes: high blood pressure, low-density lipoprotein (LDL) cholesterol (the "bad" cholesterol), high blood sugar and a combination of all three, according to Alain Bertoni, M.D., M.P.H., of Wake Forest University Baptist Medical Center.
Bertoni presented his findings today (Nov. 8) at the American Heart Association Scientific Sessions in New Orleans.
The results showed that, in general, the higher the BMI, the worse the control of these risk factors that lead to heart disease. "Among persons with diabetes, the degree of obesity may be an important barrier to optimal control of cardiovascular disease risk factors," Bertoni said. "Weight loss programs may be an important component of prevention of cardiovascular disease."
The study, called Look AHEAD, involves 5,145 participants at 16 medical centers and is funded by the National Institutes of Health. The study's main objective is to determine whether cardiovascular disease can be reduced by intensive lifestyle changes aimed at long-term weight loss and increasing exercise.
"Few studies have investigated degree of obesity and control of risk factors for cardiovascular disease," he said.
Bertoni, assistant professor of public health sciences - epidemiology, said the study showed that 41 percent of people who were only mildly overweight, with a BMI between 25 and 30, had blood pressure over the target of 130/80, compared to nearly 56 percent of those with a BMI over 40, considered morbidly obese. About 44 percent of those with a BMI between 30 and 35 and about 52 percent of those with a BMI between 35 and 40 had blood pressures above 130/80.
According to new national guidelines, systolic blood pressure in the 130-139 range or diastolic blood pressure in the 80-89 range is considered "pre-hypertension," which doubles the risk of developing high blood pressure, and requires action, especially in people with diabetes.
In the Look AHEAD study, control of blood sugar followed a similar pattern to blood pressure, but an increase in BMI did not appear to affect the levels of LDL cholesterol...
Control of all three risk factors followed a consistent pattern depending on BMI -- 13.9 percent of those with BMIs under 30, compared to 7.9 percent of those over 40.
On a different issue not involving BMI, researchers highlighted significant racial and ethnicity differences in control of risk factors. Results showed that 12.2 percent of Asian-Pacific Island participants met all three risk factor goals, compared to only 5 percent of blacks. Among whites, 11.9 percent met all three goals; among Native Americans, 11.3 percent; and 9.0 per cent among Hispanics.
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About Wake Forest University Baptist Medical Center: Wake Forest Baptist is an academic health system comprised of North Carolina Baptist Hospital and Wake Forest University Health Sciences, which operates the university's School of Medicine. The system comprises 1,298 acute care, psychiatric, rehabilitation and long-term care beds and is consistently ranked as one of "America's Best Hospitals" by U.S. News & World Report.