Prevalence and correlates of metabolic syndrome based on a harmonious definition among adults in the US

Background: Recently, a Joint Scientific Statement bridged differences between previous definitions of metabolic syndrome. Our objective was to estimate the prevalence of metabolic syndrome in a representative sample of US adults and to examine its correlates. Methods: We analyzed data for up to 3461 participants aged >= 20 years of the 2003-2006 National Health and Nutrition Examination Survey. Results: Using waist circumference thresholds of 102 cm for men and >= 88 cm for women, the age-adjusted prevalence of metabolic syndrome was 34.3% among all adults, 36.1% among men, and 32.4% among women. Using racial- or ethnic-specific International Diabetes Federation criteria for waist circumference, the age-adjusted prevalence of metabolic syndrome was 38.5% for all participants, 41.9% for men, and 35.0% for women. Prevalence increased with age, peaking among those aged 60-69 years. Prevalence was lower among African American men than White or Mexican American men, and lower among White women than among African American or Mexican American women. In a multivariate regression model, significant independent associations were noted for age (positive), gender (men higher than women), race or ethnicity (African Americans and participants of another race lower than Whites), educational status (inverse), hypercholesterolemia (positive), concentrations of C-reactive protein (positive), leisure time physical activity (inverse), microalbuminuria (positive), and hyperinsulinemia (positive). Additional adjustment for body mass index weakened many of the associations, with educational status and microalbuminuria no longer significant contributors to the model. Conclusion: Metabolic syndrome continues to be highly prevalent among adults in the US.