Potential of four definitions of metabolic syndrome to discriminate individuals with different 10-year cardiovascular disease risk scores: a cross-sectional analysis of an Iranian cohort

OBJECTIVE: We aimed to reveal the potential of four different metabolic syndrome (Mets) definitions to differentiate subjects according to 10-year risk of cardiovascular disease. DESIGN: A cross-sectional analysis of a prospective cohort. SETTING: This study used baseline data from the Shiraz Heart Study, a prospective cohort study in Shiraz, Iran. Participants were screened against Mets definitions including modified WHO, National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III), American Heart Association (AHA) and International Diabetes Federation (IDF). Also, Framingham risk score (FRS) and atherosclerotic cardiovascular disease (ASCVD) risk score were determined for each participant. PARTICIPANTS: A total number of 7225 participants of both genders entered the study. They were selected through defined family physician centres in different geographical areas. Urban residents with no migration plan were included. Those who were far from study centres or with disabilities that made them incapable to cooperate were excluded. RESULTS: Participants were 47.68% (N=3445) male with the mean age of 52.13±8.00 years. The number of subjects with Mets identified by WHO was the lowest (N=1676), while the percentage of subjects with high risk score was the highest, 17.1% (N=282) in FRS and 9.8% (N=162) in ASCVD risk score. There were statistically significant differences in the mean risk scores between participants with and without Mets according to AHA, WHO and NCEP ATP III definitions (p<0.001). In IDF definition, the risk scores of subjects with Mets were not statistically different compared with peers without Mets, neither based on FRS (p=0.247) nor ASCVD risk score (p=0.193). CONCLUSIONS: IDF was not the appropriate definition for discrimination of subjects with Mets and/or those at high risk of future cardiovascular events. AHA, WHO and NCEP ATP III definitions were effective to discriminate subjects with Mets from peers without Mets.