The Metabolic Syndrome and Its Traits as Risk Factors for Subclinical Atherosclerosis

Context and objective: The metabolic syndrome (MetS) indicates an increased cardiovascular risk. The objective of the present study was to determine the impact of the MetS and its individual traits on subclinical atherosclerosis, as measured with six noninvasive measurements of atherosclerosis (NIMA) in a 50- to 70-yr-old Dutch population-based cohort. Furthermore, we determined the impact of three different definitions of the MetS. Design: We performed NIMA in 1517 participants of the Nijmegen Biomedical Study. The MetS was defined by definitions of the National Cholesterol Education Program, International Diabetes Federation, and the World Health Organization. Results: Participants with the MetS (National Cholesterol Education Program) were characterized by increased subclinical atherosclerosis compared with participants without any trait of the MetS, as reflected by lower ankle-brachial index at rest [percent change (95% confidence interval), M: - 5.2% (- 9; - 1), F: - 3.1% (- 6; - 1)] and after exercise [M: - 7.7% (- 17; + 2), F: - 6.6% (- 11; - 2)], higher augmentation index [M: + 4.8% (+ 3; + 7), F: + 1.9% (+ 4; + 18)], increased pulse wave velocity [M: + 22.8% (+ 15; + 32), F: + 20.5% (+ 14; + 28)], increased intima-media thickness [M: + 9.3% (+ 5; + 13), F: + 6.9% (+ 3; + 11)], and thicker plaques [M: + 17.6% (- 2; + 41), F: + 26.6% (+ 5; + 53)]. Most intriguingly, the number of traits was strongly associated with the severity of subclinical atherosclerosis because all NIMA gradually deteriorated with increasing number of traits present; NIMA were already deteriorated when one or two traits were present and further deteriorated when four or five traits of the MetS were present. Similar result were found when International Diabetes Federation and World Health Organization definitions of the MetS were used. Conclusions: For cardiovascular risk prediction, it is more important to take into account the presence of each individual trait and the number of traits of the MetS than to diagnose the presence of the MetS. (J Clin Endocrinol Metab 94: 2893-2899, 2009)