The First Nationwide Study of the Prevalence of the Metabolic Syndrome and Optimal Cut-off Points of Waist Circumference in the Middle East: The National Survey of Risk Factors for Non-Communicable Diseases of Iran

Abstract

Objective: To provide the first national estimate on the prevalence of the metabolic syndrome (MetS) and its components, as well as the first ethnic-specific cut-off point for waist circumference (WC) in the Eastern Mediterranean Region.

Research Design and Methods: This national survey was conducted in 2007 on 3024 Iranians aged 25-64 years living in urban and rural areas of all 30 provinces in Iran. The MetS was defined by different criteria, namely the definition of the National Cholesterol Education Program-Adult Treatment Panel III (ATP III), the International Diabetes Federation (IDF) criteria, and the modified definition of the NCEP/ATP III (ATPIII/AHA/NHLBI).

Results: The age-standardised prevalence of the MetS was about 34.7% (95% CI 33.1, 36.2) based on the ATP III criteria, 37.4% (35.9-39.0%) based on the IDF definition, and 41.6% (40.1-43.2%) based on the ATPIII//AHA/NHLBI criteria. By all definitions, the prevalence of the MetS was higher in women, in urban areas, and in the 55-64-year age group compared to men, rural areas and other age groups, respectively. The burden of the MetS was estimated to affect more than 11 million Iranians. The optimal cut-off point of WC for predicting at least two other components of the MetS as defined by IDF was 89 cm for men and 91 cm for women.

Conclusions: The high prevalence of the MetS with considerable burden on the middle-aged population mandates the implementation of national policies for its prevention, notably by tackling obesity. The obtained WC cut-off points can be used in the region.