Baylor University Medical Center Proceedings April 2014, Volume 27, Number 2 | Page 18

Ethnic disparities in the prevalence of the metabolic syndrome in American adults: data from the Examination of National Health and Nutrition Examination Survey 1999–2010 Lilly Ramphal, MD, MPH, Jun Zhang, MPH, and Sumhiro Suzuki, PhD Data from the National Health and Nutrition Examination Survey were stratified by weight, gender, and ethnicity for six survey years from 1999 to 2010 for variables that satisfy the criteria for metabolic syndrome (MS). Results showed that 34% of the US adult population had MS. No significant gender disparities in MS prevalence were found. Black men had a significantly lower prevalence of MS than Black women and White men from 1999 to 2008 (P < 0.05). Women had a 60% higher abdominal adiposity than men in the US population (P = 0.00048; pregnant females were excluded). Although there seem to be ethnic differences in the prevalence of MS, the expression of MS is not a sufficient risk to culminate in cardiovascular disease; rather, nutritional, genetic, and environmental factors are necessary to finalize its expression into overt disease. ndividuals with the metabolic syndrome (MS) are at increased risk for cardiovascular disease. Multiple definitions based on different organizations’ guidelines are used to define MS. In 2007, the International Diabetes Federation (IDF) provided a definition of MS that differed from that of the National Cholesterol Education Program (NCEP) (Table 1). This study used the IDF’s definition of MS because it is more stringent (1). MS is a major health problem globally and can vary in some ethnic groups (2). Limited information is available regarding the prevalence of MS and its trend using IDF’s definition in the US. To date, most population-based studies using IDF’s criteria were conducted outside the US (3). Previous studies cite some ethnic disparity in the prevalence of MS and its various components. Papoutsakis et al found that non-Hispanic Black adolescent males had lower odds of having MS (4). Palaniappan et al showed that Asian Americans had a greater prevalence of MS despite having a low body mass index (BMI) and a lower prevalence of being overweight or obese (2). Fitzpatrick et al demonstrated that African American adolescents are less likely to have MS compared with non-Hispanic White groups (5). Cardiovascular risk factors that define MS are associated with weight status, and differences exist among African Americans and Hispanics when compared with White ethnic groups (5–11). Ford et al estimated the prevalence of MS in the US as defined by Adult Treatment Panel (ATP) reports based on National Health and Nutrition Examination Survey (NHANES) surveys from 1988 to 1994 (7). Ervin et al examined individual I 92 Table 1. Varying definitions of the metabolic syndrome Criteria NCEP NCEP revised IDF Waist circumference >102 in men (cm) >88 in women >102 in men >88 in women ≥94 in men ≥80 in women Triglyceride (mmol/L) ≥1.7 ≥1.7 ≥1.7 HDL cholesterol (mmol/L) <1.03 in men <1.03 in men <1.03 in men <1.29 in women <1.29 in women <1.29 in women Systolic cuff blood pressure (mm Hg) ≥130 ≥130 ≥130 Diastolic cuff blood pressure (mm Hg) ≥85 ≥85 ≥85 Fasting glycemia (mmol/L) ≥6.1 ≥5.6 ≥5.6 Definition Meet 3 or more Meet 3 or more Meet waist criteria criteria circumstance criterion and 2 or more other criteria NCEP indicates National Cholesterol Education Program; IDF, International Diabetes Foundation; HDL, high-density lipoprotein. risk factors for MS defined by NCEP criteria using NHANES data from 2003 to 2006 (8). No recent study has been done that examines MS as defined by the IDF among adult ethnic groups in the US. Obese individuals are more likely to have MS compared with normal-weight individuals. Vakil et al demonstrated that waist circumference is independently associated with an increased prevalence of coronary artery disease and thus is heavily weighted with risk factors for cardiovascular risk (9). Few studies have been done to show how weight status and MS are distributed among different ethnicities in the US adult population. The purpose of this study was to identify trends in the prevalence of MS in the US population as defined by the IDF From the Departments of Environmental Health (Ramphal) and Biostatistics (Zhang), the University of North Texas School of Public Health, Fort Worth, Texas. Corresponding author: Lilly Ramphal, MD, MPH, Department of Environmental Health, University of North Texas School of Public Health, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107-2699 (e-mail: [email protected]). Proc (Bayl Univ Med Cent) 2014;27(2):92–95