Hayashi et al. (1) reported from cross-sectional data that the optimal cut points of intra-abdominal fat area, waist circumference, and BMI were 96 cm2, 90 cm, and 25 kg/m2, respectively, for Japanese men and 75 cm2, 84 cm, and 23 kg/m2, respectively, for Japanese women, identifying subjects with two or more nonadipose components of the metabolic syndrome (1). They criticized the arbitrary and inconsistent methodology used by the Examination Committee of Criteria for Obesity Disease in Japan to derive the peculiar cut points of waist circumference (85 cm for men and 90 cm for women) (2). We already criticized this arbitrary and inconsistent methodology used by the Examination Committee of Criteria for Obesity Disease in Japan (3,4), and the International Diabetes Federation (IDF) changed their attitude and added a footnote to their table of ethnic-specific cut points of waist circumference indicating that the Japanese cut points of waist circumference proposed by the Examination Committee of Criteria for Obesity Disease in Japan were not recommended as criteria of abdominal obesity for Japanese and Asian cut points of waist circumference (90 cm for men and 80 cm for women) should be used for Japanese patients as a temporary measure (5–7).
More importantly, Kiyohara et al. (8) reported from longitudinal data (Hisayama Study) that metabolic syndrome diagnosed using the waist circumference cut point of 85 cm was not a significant risk factor for incidence of cardiovascular disease in Japanese men but that the metabolic syndrome diagnosed using the waist circumference cut point of 90 cm was a significant risk factor for incidence of cardiovascular disease in Japanese men. Sone et al. (9) reported from longitudinal data (Japan Diabetes Complications Study) that the metabolic syndrome diagnosed using the waist circumference cut point of 90 cm was not a significant risk factor for incidence of cardiovascular disease in Japanese diabetic women but that the metabolic syndrome diagnosed using the waist circumference cut point of 80 cm was a significant risk factor for incidence of cardiovascular disease in Japanese diabetic women (4). Therefore, Asian cut points of waist circumference (90 cm for men and 80 cm for women) should be used for Japanese patients as a temporary measure of abdominal obesity as suggested by the IDF.
Obesity has recently become regarded as an endocrine disease related to inflammation rather than merely as an anthropometric disorder, and C-reactive protein (CRP) has been established as an independent risk factor for cardiovascular disease and is significantly positively related to insulin resistance and leptin and significantly negatively related to adiponectin even in individuals with a normal BMI. Therefore, I proposed a new criteria of metabolic syndrome (10,11) in which controversial waist circumference is replaced by CRP (0.7 mg/l as the cut point for Japanese patients) for future studies of metabolic syndrome but not for the clinical diagnosis at present (12). Anthropometric markers of obesity such as BMI, waist circumference, and waist-to-height ratio should be used as screening tools toward more proximal risk factors for diabetes and cardiovascular disease.
