Waist circumference is a better predictor of Obesity-related health risk than body mass index in the Chinese including children.

To the Editor: Among the five anthropometric indices for diagnosing obesity--body mass index (BMI), percent body fat, waist circumference (WC), waist-to-hip ratio and waist-to-stature ratio--the most commonly used index around the world is BMI. (1) Recently, Ng and Lai (2) introduced another index, weight-length index, to be used together with BMI to define childhood obesity in Chinese in Taiwan. However, measurement of WC as a preferable determinant of cardiovascular and metabolic risks is increasingly gaining popularity in recent years. That WC is indeed a better index than BMI as a measure of obesity among the Chinese has been recently reported in both Chinese men, (3) women (3,4) and children. (5)

Another reason for the superiority of WC over BMI is that for Chinese individuals, who make up one quarter of the world's population, the cut-off points for BMI for detection of cardiovascular risk factors are lower than the criteria set by the World Health Organization. The Chinese have a lower baseline BMI to begin with (baseline value = 21; mean = 18.5-23.9). (6) Furthermore, it takes a smaller increment for them to reach an obese level, so that a BMI of 24 to 27.9 is considered to be overweight and a BMI greater than or equal to 28 is considered obese. (6)

References

1. Cheng TO. Waist circumference versus body mass index in risk prediction of coronary heart disease: comparing apples and oranges. J Int Med 2004;255:690-691.

2. Ng K-C, Lai S-W. Application of anthropometric indices in childhood obesity. South Med J 2004;97:566-570.

3. Jia WP, Lu JX, Xiang KS, et al. Prediction of abdominal visceral obesity from body mass index, waist circumference and waist-hip ratio in Chinese adults: receiver operating characteristic curves analysis. Biomed Environ Sci 2003;16:206-211.

4. Rosenthal AD, Jin F, Shu X-O, et al. Body fat distribution and risk of diabetes among Chinese women. Int J Obesity 2004;28:594-599.

5. Iwata F, Hara M, Okada T, et al. Body fat ratios in urban Chinese children. Pediatr Int 2003;45:190-192.

6. Cheng TO. The current state of cardiology in China. Int J Cardiol 2004;96:425-439.

Tsung O. Cheng, MD

Professor of Medicine, George Washington University Medical Center, Washington, D.C.

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