Search

Background— In addition to predicting cardiovascular disease (CVD) morbidity and mortality, the metabolic syndrome is strongly associated with the development of type 2 diabetes mellitus (DM), itself an important risk factor for CVD. Our objective was to compare the ability of various metabolic syndrome criteria (including those recently proposed by the International Diabetes Federation), markers of insulin resistance (IR) and inflammation, and impaired glucose tolerance (IGT) in the prediction of DM and to determine whether various proposed modifications to the National Cholesterol Education program (NCEP) metabolic syndrome definition improved predictive ability. Methods and Results— We examined 822 subjects in the Insulin Resistance Atherosclerosis Study aged 40 to 69 years who were nondiabetic at baseline. After 5.2 years, 148 individuals had developed DM. IGT, metabolic syndrome definitions, and IR markers all significantly predicted DM, with odds ratios ranging from 3.4 to 5.4 (all P P >0.05). Similarly, although IR and inflammation variables were significantly associated with incident DM when included in multivariate models with NCEP-defined metabolic syndrome (all P P >0.05). Conclusions— The International Diabetes Federation and NCEP metabolic syndrome definitions predicted DM at least as well as the World Health Organization definition, despite not requiring the use of oral glucose tolerance testing or measures of IR or microalbuminuria. Modifications or additions to the NCEP metabolic syndrome definition had limited impact on the prediction of DM.

Type 2 diabetes is associated with a marked increase in the risk of coronary heart disease (CHD).1 In addition, small increases in glucose concentrations in the nondiabetic range also may be associated with an increased risk of CHD (see the Diabetes Epidemiology: Collaborative Analysis of Diagnostic Criteria in Europe [DECODE] study2). However, the increase in CHD in diabetic subjects may not be entirely due to increases in glucose levels per se, because in many studies, including the United Kingdom Prospective Diabetes Study (UKPDS),3 although glucose levels were significantly related to CHD, the magnitude of the association is only modest. One explanation for the increased risk of CHD in diabetics may be the insulin resistance syndrome.4 A related possibility may be the atherogenicity of the prediabetic state.4 Indeed, insulin resistance, rather than decreased insulin secretion, seems to be most responsible for the increased cardiovascular risk factors in the prediabetic state (ie, increased triglyceride and blood pressure and decreased high-density lipoprotein cholesterol [HDL-C] even before the onset of diabetes).5 In some studies, insulin concentrations (as a surrogate for insulin resistance) have been strongly related to CHD6; however, in other studies that include meta-analysis, insulin concentrations have been only modestly associated with CHD.7 See Circulation . 2002;105:1311–1316 Until recently, most insulin immunoassays cross-reacted …