In a community-based cohort of 692 Japanese individuals, Hara et al. (1) investigated the relationship between cutoff values used for the waist circumference to define central obesity and rates of detection of subjects displaying multiple risk factors of metabolic syndrome. Using the receiver-operator characteristic (ROC) curve, they proposed an optimal cutoff point of waist circumference for the diagnosis of metabolic syndrome in the Japanese population to yield maximal sensitivity plus specificity, with cutoffs of 85 cm in men and 78 cm in women.
In the Ohasama study, another Japanese general-population study (2,3), we also attempted to determine the most suitable cutoff level for waist circumference in terms of associations with insulin resistance (IR). We investigated relationships between the cutoff values used for waist circumference measured at the umbilical level and rates of subjects with IR among 329 residents (235 women) in Ohasama aged ≥35 years (mean age 64 years, mean BMI 24 kg/m2) without antidiabetes medication. Subjects participated in the diabetes screening program conducted, in addition to the home blood pressure measurement program (2), from 2002 to 2004. The ROC curve for waist circumference to predict the presence of IR, as defined by a homeostasis model assessment of IR >1.73 (4), was plotted using SAS version 9.2 software (SAS Institute, Cary, NC).
According to the ROC curve, the cutoff level yielding maximal sensitivity plus specificity for predicting the presence of IR was 83 cm in men and 75 cm in women. Sensitivity and specificity using these cutoff values were 80 and 63%, respectively, in men and 85 and 58%, respectively, in women.
These results, together with those by Hara et al. (1), suggest that the cutoff point for waist circumstance in Japanese women, which is used to predict metabolic syndrome or IR, is lower than that proposed by the International Diabetes Federation (90 cm).
Footnotes
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