Prevalence of diabetes by BMI: China Nutrition and Health Surveillance (2015-2017) and US National Health and Nutrition Examination Survey (2015-2018)

Introduction The risk of diabetes begins at a lower body mass index (BMI) among Asian adults. This study compares the prevalence of diabetes in the United States and China by BMI. Methods Data from the 2015-2017 China Nutrition and Health Surveillance (n=176,223) and the 2015-2018 US National Health and Nutrition Examination Survey (n=4,464) were used. Diagnosed diabetes was self-reported. Undiagnosed diabetes was no report of diagnosed diabetes and fasting plasma glucose >=126 mg/dL or hemoglobin A1c>=6.5%. Predicted age-adjusted prevalence estimates by BMI were produced using sex- and country-specific logistic regression models. Results In China, the age-adjusted prevalence of total diabetes was 7.8% (95% CI 7.4-8.3%), lower than the 14.6% (95% CI 13.1-16.3%) in the US. The prevalence of diagnosed diabetes was also lower in China than the US. There were no statistically significant differences in the prevalence of undiagnosed diabetes between China and the US. The distribution of BMI in China is lower than in the US and the predicted prevalence of total diabetes is similar in China and the US when comparing adults with the same BMI. The predicted prevalence of undiagnosed diabetes was higher in China than in the US for both men and women and this disparity increased with BMI. When comparing adults at the same BMI there was little difference in prevalence of total diabetes, but diagnosed diabetes was lower in China than the US and undiagnosed was higher. Conclusion While differences in BMI appear to explain nearly all of the differences in total diabetes prevalence in the two countries, not all factors that are associated with diabetes risk have been investigated.