Lower BMI Cutoffs to Define Overweight and Obesity in China

ObjectiveTo investigate ethnic difference in the associations of BMI with comorbidity, mortality, and body composition between mainland Chinese and U.S. whites. MethodsEthnic-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.). ResultsChinese 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. ConclusionsComorbidity, mortality, and body composition data consistently support the use of lower BMI cutoffs in Chinese than those in whites.