Lower BMI cutoffs to define overweight and obesity in China.

OBJECTIVE:To investigate ethnic difference in the associations of BMI with comorbidity, mortality, and body composition between mainland Chinese and U.S. whites. METHODS:Ethnic-comparison study using data from China Health and Nutrition Survey, U.S. National Health and Nutrition Examination Survey, and data from Zhejiang University (China) and Columbia University (U.S.). RESULTS:Chinese people experienced greater odds of comorbidities than whites for a given BMI after standardizing for age and sex: 43% for diabetes, 30% for dyslipidemia, 28% for hypertension, 38% for metabolic syndrome, and 48% for hyperuricemia. Comparisons of BMI-mortality associations found that the U-shaped BMI-mortality curve shifted 1-2 kg m(-2) to the left in Chinese compared to whites. Compared to whites at BMIs of 25 and 30 kg m(-2), corresponding cutoffs in Chinese were 22.5 and 25.9 kg m(-2) in men, and 22.8 and 26.6 kg m(-2) in women after both fat and fat distribution were taken into account. CONCLUSIONS:Comorbidity, mortality, and body composition data consistently support the use of lower BMI cutoffs in Chinese than those in whites.