Increasing Prevalence of Metabolic Syndrome Among U.S. Adults
Objective: The prevalence of the metabolic syndrome is high among U.S. adults. Our purpose was to determine whether the prevalence of this syndrome has changed since 1988-1994.
Research Design and Methods: A total of 6,436 men and women aged ≥20 years from the National Health and Nutrition Examination Survey (NHANES) III (1988-1994) and 1,677 participants from NHANES 1999-2000 were included in the analyses. We used the definition of the metabolic syndrome developed by the Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults.
Results: The unadjusted prevalence of the metabolic syndrome was 23.1% in NHANES III and 26.7% in NHANES 1999-2000 (P = 0.043), and the age-adjusted prevalences were 24.1 and 27.0% (P = 0.088), respectively. The age-adjusted prevalence increased by 23.5% among women (P = 0.021) and 2.2% among men (P = 0.831). Increases in high blood pressure, waist circumference, and hypertriglyceridemia accounted for much of the increase in the prevalence of the metabolic syndrome, particularly among women.
Conclusions: The increased prevalence of the metabolic syndrome is likely to lead to future increases in diabetes and cardiovascular disease.

In 2001, the Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (NCEP/ATP III) provided a working definition of the metabolic syndrome based on five commonly measured clinical criteria that clinicians could implement in their practices. Using these criteria, we estimated that the unadjusted prevalence of the metabolic syndrome among U.S. adults was 21.7% during 1988-1994. Since then, the prevalence of the metabolic syndrome using NCEP/ATP III criteria has been described for other study populations. The prevalence of the metabolic syndrome among participants of the Framingham Offspring Study and San Antonio Heart Study ranged from 21.3 to 32.8% during the early to mid-1990s. High prevalences have been noted among patients infected with the human immunodeficiency virus, Filipina women, and Native Americans. In addition, the NCEP/ATP III criteria have been applied in other countries. Recent work has shown that people with the metabolic syndrome based on the NCEP/ATP III criteria are at increased risk for diabetes and cardiovascular disease.

Obesity and physical activity are two important determinants of the metabolic syndrome. Because the prevalence of obesity has continued to increase in the U.S. during the 1990s, we theorized that the prevalence of the metabolic syndrome among adults had increased as well. To test this hypothesis, we used data from two national surveys: the National Health and Nutrition Examination Survey (NHANES) III and NHANES 1999-2000.