CHICAGO (AP) _ A syndrome linked to obesity, diabetes and heart disease is most common among Mexican-American women and least common among black men, a study found.
Metabolic syndrome affects about 22 percent of U.S. adults, or at least 47 million Americans. Symptoms often include high blood pressure, poor cholesterol levels, high blood sugar and a disproportionately large waist.
Researchers analyzed data from a 1988-94 national health survey and found that prevalence ranged from 27 percent of Mexican-American women to 14 percent of black men.
The percentage of black and white women affected was 21 percent and 23 percent respectively. Among men, the rates were 21 percent for Mexican-Americans and 24 percent for whites.
The disparities are probably due to genetics, though there may be some unknown environmental factors that the study did not measure, said Columbia University's Dr. Steven Heymsfield, a co-author.
The ethnic differences remained even after factors including body-mass index, socioeconomic status and physical inactivity _ all linked to the syndrome _ were considered.
The findings appear in Monday's Archives of Internal Medicine. The study was led by Dr. Yong-Woo Park of Sungkyunkwan University in Seoul, South Korea. Researchers from Stanford University also participated.
The numbers are ``staggering,'' but the data ``are now 8 to 14 years old, and the situation has likely worsened,'' James Hill and Dr. Daniel Bessesen of the University of Colorado Health Sciences Center said in an accompanying editorial.
The syndrome was present in at least half of obese people studied, more than 20 percent of overweight people and less than 6 percent of normal-weight people. It was most common among smokers and in people age 50 and up.
Those affected are prone to developing obesity, diabetes and heart disease, but diet, exercise and quitting smoking can reduce the risk.
Metabolic syndrome is also sometimes called syndrome X and the insulin resistance syndrome.
Affected people have at least three of the following symptoms: a waist measuring more than 40 inches for men and 35 inches for women; levels of triglycerides _ fats in the blood _ of at least 150 milligrams per deciliter; levels of high-density cholesterol _ the ``good cholesterol'' _ of less than 40 mgs in men and less than 50 mgs in women; blood pressure of at least 135 over 80; and blood sugar of at least 110 mgs per deciliter.