A nationwide study of metabolic syndrome prevalence in Iran; a comparative analysis of six definitions

INTRODUCTION: To integrate and execute a proper preventive plan and reduce the risk of non-communicable diseases (NCDs), policy makers need to have access to both reliable data and a unique definition of metabolic syndrome (MetS). This study was conducted on the data collected by cross-sectional studies of WHO’s STEPwise approach to surveillance of NCD risk factors (STEPs) to estimate the national and sub-national prevalence rates of MetS in Iran in 2016. MATERIALS AND METHODS: The prevalence of MetS was estimated among 18,414 individuals aged ≥25 years living in urban and rural areas of Iran using various definition criteria; National Cholesterol Education Program Adult Treatment Panel III 2004 (ATP III), International Diabetes Federation (IDF), American Heart Association/National Heart, Lung, and Blood Institute (AHA/NHLBI), Joint Interim Statement (JIS). Regional IDF (RIDF) and JIS (RJIS) were defined using ethnicity-specific values of waist circumference for the country. RESULTS: National prevalence rate of MetS based on ATP III, IDF, AHA/NHLBI, JIS, RIDF and RJIS criteria were 38.3% (95% CI 37.4–39.1), 43.5% (42.7–44.4), 40.9% (40.1–41.8), 47.6% (46.8–48.5), 32.0% (31.2–32.9), and 40.8% (40.0–41.7), respectively. The prevalence was higher among females, in urban residents, and those aged 65–69 years. MetS was expected to affect about 18.7, 21.3, 20.0, 23.3, 15.7, and 20.0 million Iranians, respectively, based on ATP III, IDF, AHA/NHLBI, JIS, RIDF and RJIS. The two most common components noted in this population were reduced high-density lipoprotein cholesterol (HDL-C) levels and central obesity. CONCLUSION: High prevalence rate of MetS among Iranian adults is alarming, especially among females, urban residents, and the elderly. The JIS definition criteria is more appropriate to determine higher number of Iranians at risk of NCDs. Proper management and prevention of MetS is required to adopt multiple national plans including lifestyle modifications, medical interventions, and public education on NCDs risk factors.