SUNDAY, Nov. 13, 2005 (HealthDay News) -- The largest study of its kind has found that 37 percent of blacks in Jackson, Miss., have metabolic syndrome, a collection of conditions that puts them at a much higher risk for coronary heart disease.
This data, to be presented Monday at the annual American Heart Association (AHA) meeting in Dallas, contrasts with previous information indicating that blacks, especially men, had a lower incidence of the syndrome than whites.
"The available information suggests that 24 percent of the U.S. population has metabolic syndrome. But, if anything, the data that's been out there is that African-American men have less of this. They have lots of risk factors, primarily hypertension, but not this metabolic stew," said Dr. Robert Bonow, chief of cardiology at Northwestern University in Chicago and past president of the AHA. Black women had been thought to have the same prevalence of the syndrome as white women.
The study should point to new directions for preventing heart disease in black men and women, particularly in Mississippi, which has the highest mortality rate from cardiovascular disease in the nation.
"This study is somewhat of a biopsy on some of the underlying causes for that extraordinarily high rate of cardiovascular morbidity and mortality in the state," said Dr. Herman Taylor Jr., director of the Jackson Heart Study and Shirley professor for the study of health disparities at the University of Mississippi Medical Center in Jackson.
"Although the cardiovascular disease epidemic seems to be trailing off, Mississippi has not seen a decline in mortality. These findings may be a bellwether telling us that unless we get aggressive about obesity and related risk factors, we may see a total flattening of the improvement and maybe even a reversal," Taylor added at an AHA news conference Sunday.
Most of the data currently available on metabolic syndrome is for white, middle-aged people, said Dr. Robert Eckel, the AHA president.
Now scientists are starting to do research on ethnic minorities and older adults.
Metabolic syndrome is generally diagnosed when a person has at least three of these conditions: elevated waist circumference, elevated triglycerides, reduced HDL or "good" cholesterol, elevated blood pressure and elevated fasting glucose.
The Jackson Heart Study, the largest-ever population-based study of the determinants of cardiovascular disease among blacks, tracked 5,000 adults living in the Jackson metropolitan area.
There was an "extraordinarily high prevalence" of metabolic syndrome, with 37.2 percent of those aged 21 to 89 and over meeting the criteria, Taylor said. More than 40 percent of the women met the criteria.
The rates of metabolic syndrome ranged from 15.9 percent among those aged 20 to 34 to a peak of 47.2 percent in those aged 65 and over.
"Profiles were different for different age groups," Taylor added. "Central obesity is the most frequently occurring risk factor for all age groups, except the most elderly. Hypertension and elevated fasting blood glucose increased in frequency among the older age groups in particular, and low HDL appears to be less frequently a risk among older African-Americans, while triglycerides do not change substantially."
Of the five factors that comprise metabolic syndrome, participants were most likely to have overly large waistlines (65.3 percent), elevated blood pressure (63.7 percent) and low HDL (44 percent). Only one in 10 did not suffer from any of the five risk factors.
The high blood pressure was expected, Bonow said, but the waistline information is new and is probably driving the HDL levels.
All study participants and their physicians were told of any abnormalities found as part of the study, Taylor said. "They were all made aware of the importance of getting attention for it," he said. "We have several community-based outreach programs. We're not going to let this information sit on a medical library shelf."
The information should eventually have implications beyond Jackson, Mississippi, although it's not yet clear if other populations have the same rate of problems. Jackson is located in the so-called "stroke belt."
"It's further evidence that the obesity problem is creeping in even in segments of the population where there used to be less of this. The newer information is that African-American men are not immune to this, and, in the wrong environment, they're going to have some problems," Bonow said. "At least in some areas of the country, this may be a real bad signal."
The American Heart Association has more on metabolic syndrome.