Background
: Waist circumference and BMI have been known as an independent predictor for cardiovascular diseases. But some people with a normal BMI or normal waist circumference may have cardiovascular risk factors. Therefore, the purpose of this study was to investigate the simplicity and the usefulness of waist/height ratio as an index of obesity and to investigate the waist/height ratio as a predictor for metabolic risks in individuals with normal weight and/or normal waist circumference.

Methods : The subjects were 1,157 individuals (635 men, 522 women). The morbidity index for metabolic risk factors was calculated by the sum of the risk factors scores (one point per item, if present). We set the criteria of obesity as BMI≥25 kg/m², waist circumference of ≥90 cm in males and ≥80 cm in females, waist/hip ratio of ≥0.9 in males and ≥0.8 in females, and waist/height ratio of ≥50 cm/cm*100.

Results : There was a significant correlation among waist/ height ratio, waist/hip ratio, BMI, and waist circumference (P=0.000). The odds ratios for morbidity index (≥3) in normal BMI, waist circumference, and waist/hip ratio subjects with waist/height over 50 were significantly higher with 4.60, 3.83, and 2.79, respectively, and also higher in normal BMI with normal waist circumference subjects with 3.90 (P=0.000).

Conclusion : Waist/height ratio may be used a simple and practical index of obesity. Especially, it may be useful in subjects with normal BMI or normal waist circumference when predicting their metabolic risks.