Rationale Diagnostic Criteria of the Metabolic Syndrome

Abstract

Metabolic syndrome is a preceding risk of diabetes, hypertension and/or dyslipidemia, so the diagnosis of metabolic syndrome is important for further treatment. In 2005, the international diabetes foundation (IDF) reported a new diagnostic criterion of metabolic
syndrome, making abdominal obesity an essential factor required in the diagnosis. Waist circumference (WC) is used as a surrogate
marker of abdominal obesity, but it is defined based on the national cutoff point of each country. This study examined the validity
of diagnostic criteria ofmetabolic syndrome, especially focusing on the different criteria of WC, for international standardization.
Method We compared the efficacy of our previous weight-loss intervention by Japanese and IDF criteria by reanalyzing Saku control obesity program (SCOP). In IDF, the cutoff point of WC for men is 90 cm and 80 cm for women. On the contrary, the cutoff point of WC
is 85 cm for men and 90 cm for women in Japan. Factors for diagnosis was evaluated, and the prevalence of metabolic syndrome at
baseline and 1 year later was compared by the different diagnostic criteria. Result and Discussion In Japanese criteria, the rate of metabolic syndrome among men decreased from 100% to 97.3%, and among women 96.6% to 88.6%. However, when we applied the IDF criteria, the rate of metabolic syndrome among men decreased from 97.4% to 88.5%, and among women 100% to 100%. These results suggested that the prevalence of metabolic syndrome by IDF criteria is underdiagnosis in men and over-diagnosis in women compared to the Japanese criteria. Japanese cutoff point is calculated by the computed tomography (CT) scan data in which 100 cm2 abdominal fat area corresponds to nearly 100 cm WC. The standardization of diagnostic criteria is important to compare the efficacy of intervention and prevention of diseases between countries.