In April 2005, the International Diabetes Federation (IDF) has formulated a new worldwide definition of the metabolic syndrome in a global consensus statement built on earlier WHO, the ATPIII definitions. The aim of this study was to estimate the prevalence of this syndrome using the IDF definition among Iranian adults and to compare it with the prevalence estimated using the two other definitions. 

Methods: The prevalence of the MES was determined according to the three different definitions in 10368 men and women aged≥20 years participated in the cross-sectional phase of the Tehran Lipid and Glucose Study (TLGS). To assess the degree of agreement between different MES definitions, the k test was used. 

Results: The prevalence of MES (95% confidence interval) was 32.1% (31.2-33.0) by the IDF definition, 33.2% (32.3-34.1) by the ATPIII and 18.4% (17.6-19.2) according to the WHO definition. The sensitivity, specificity and concordance of the IDF definition for detecting MES were 91%, 89% for the ATPIII definitions and 73%, 77% for the WHO definition, respectively. The k statistics for the agreement of the IDF definition was 66.3±0.01 with the ATPIII and 39.5±0 with the WHO definition.

Conclusion: In the Iranian population, the IDF definition for MES has a good concordance with the ATP III definition and a low concordance with the WHO definition.