Lower body mass index cutoff is required for Chinese as a risk factor for coronary artery disease and other obesity-related metabolic disorders

Department of Medicine
The George Washington University Medical Center
2150 Pennsylvania Avenue, NW
Washington, DC 20037
tcheng{at}mfa.gwu.edu

Dear Sir:

I agree with Pan et al (1) that there is a need to set a lower body mass index (BMI; in kg/m²) cutoff for Chinese in Taiwan as a risk factor for various obesity-related metabolic disorders. They proposed a BMI of slightly below 24 for Taiwan Chinese (1). This is very similar to that suggested for Hong Kong Chinese in 1999 by Ko et al (2), who used a BMI of 23 to define overweight in screening for diabetes, hypertension, dyslipidemia, or albuminuria in that population.

The BMI cutoff for Chinese is indeed much lower than that for other populations: the normal mean for mainland Chinese is 18.5–23.9 (3). Because Chinese have a lower baseline BMI to begin with, fewer increments are needed to reach obesity, so that BMIs of 24–27.9 are considered to indicate overweight and BMIs 28 are considered to indicate obesity (3). Risk factors increase with BMIs higher than the baseline value of 21.0: at BMIs of 23.0–24.9, the risk of hypertension, hypertriglyceridemia, and coronary artery disease is doubled, and at BMIs of 25.0–26.9, the risk is tripled (4).

Therefore, whether Taiwan, Hong Kong, or mainland Chinese, all Chinese have a lower BMI as a risk factor for coronary heart disease and other obesity-related metabolic disorders than do people in the West (5, 6). This fact has immense clinical and public health implications, because 1 of every 4 persons living today is Chinese (7).

REFERENCES

1. Pan W-H, Flegal KM, Chang H-Y, Yeh W-T, Yeh C-J, Lee W-C. Body mass index and obesity-related metabolic disorders in Taiwanese and US whites and blacks: implications for definitions of overweight and obesity for Asians. Am J Clin Nutr 2004;79:31–9.
2. Ko GT, Chan JC, Cockram CS, Woo J. Prediction of hypertension, diabetes, dyslipidemia or albuminuria using simple anthropometric indexes in Hong Kong Chinese. Int J Obes Relat Metab Disord 1999;23:1136–42.
3. Chinese Medical Association Subsection of Cardiovascular Disease, Chinese Journal of Cardiology Editorial Board. Highlights of the Second National Conference on Dyslipidemia. Chin J Cardiol 2002;30:643–6.
4. Li G, Chen X, Jang J, Wang J, Xing X, Yang W, Hu Y. Obesity, coronary heart disease risk factors and diabetes in Chinese: an approach to the criteria of obesity in the Chinese population. Obes Rev 2002;3:167–72.
5. Cheng TO. Chinese's body mass index is much lower as a risk factor for coronary artery disease. Circulation 2004;109:e184.
6. Cheng TO. The current state of cardiology in China. Int J Cardiol (in press).
7. Population world: population of China. Internet: http://www.populationworld.com/China.php (Accessed 4 February 2004).