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.

Background
: The waist/hip ratio is an useful index of abdominal obesity, but it includes two variables which may result in a false interpretation. The purpose of this study is to evaluate the usefulness of waist/height ratio as a predictor for the risk factors of coronary artery disease(CAD).

Methods : 1395 persons(818 men & 577 women) were selected as subjects who visited the Health Examination Center at Ewha Mokdong Hospital from October 1996 to March 1997. Waist circumference was measured at the level of umbilicus with standing position. Hip circumference was measured at the level of the largest circumference of the hip. We set the criteria of the risk factors as hypertension(systolic BP≥140mmHg and/or diastolic BP≥90mmHg), glucose intolerance(fasting blood glucose≥115mg/dl), hypertriglyceridemia(>160mg/dl), hypercholesterolemia(≥200mg/dl), and low HDL-cholesterol level(<35mg/dl). The morbidity index of CAD was calculated by the sum of the risk factor scores(one point per item if present).

Results : There was significant correlation between waist/height ratio, waist/hip ratio and body mass index(BMI)(p=0.0001). BMI had more strong correlation with waist/height ratio(r=0.81) than waist/hip ratio(r=0.48). According to the simple regression analysis, BMI, waist/hip ratio and waist/height ratio had significant correlation with all of the risk factors and the morbidity index. According to the multiple regression analysis, waist/height ratio had significant correlation with age, weight, height, systolic BP, triglyceride, cholesterol and HDL-cholesterol. The risk factor morbidity index of the groups with waist/height ratio over 0.45 was significantly more higher than the group of the lowest risk factor morbidity index(waist/height ratio under 0.4) in men(p=0.01). For women, 0.46 was the level which the risk factor morbidity index increased significantly(p<0.01).

Conclusion : Waist/height ratio can be a useful index of abdominal obesity. And it may be used as a more easier and better predictor of multiple CAD risk factors than waist/hip ratio. We can predict that waist/height ratio over 0.45 in men and over 0.46 in women may have more higher coronary artery disease risk.