BackgroundThis study compared the association between the 3 definitions of metabolic syndrome (MetS) suggested by the World Health Organization (WHO), National Cholesterol Education Programme (NCEP ATP III), and International Diabetes Federation (IDF), and the risk of cardiovascular diseases (CVD) and shows the prevalence and characteristics of persons with MetS in continental vs. coastal regions and rural vs. urban residence in Croatia.Material/MethodsA prospective multicenter study was conducted on 3245 participants ≥40 years, who visited general practices from May to July 2008 for any reason. This was a cross-sectional study of the Cardiovascular Risk and Intervention Study in Croatia-family medicine project (ISRCTN31857696).ResultsAll analyzed MetS definitions showed an association with CVD, but the strongest was shown by NCEP ATP III; coronary disease OR 2.48 (95% CI 1.80–3.82), cerebrovascular disease OR 2.14 (1.19–3.86), and peripheral artery disease OR 1.55 (1.04–2.32), especially for age and male sex. According to the NCEP ATP III (IDF), the prevalence was 38.7% (45.9%) [15.9% (18.6%) in men, and 22.7% (27.3%) in women, and 28.4% (33.9%) in the continental region, 10.2% (10.9%) in the coastal region, 26.2% (31.5%) in urban areas, and 12.4% (14.4%) in rural areas. Older age, male sex, and residence in the continental area were positively associated with MetS diagnosis according to NCEP ATP III, and current smoking and Mediterranean diet adherence have protective effects.ConclusionsThe NCEP ATP III definition seems to provide the strongest association with CVD and should therefore be preferred for use in this population.