RESUMO
Objective To investigate the accuracy of body mass index (BMI) as the evaluation standard for obesity in Miao adults in Guangxi, to find out the BMI cutoff value suitable for the evaluation standard of adult obesity, and to provide an accurate and reliable reference value for the prevention and treatment of obesity in Miao nationality adults. Methods Using a cross-sectional design, residents aged 18 years or older in the Miao villages in Rongshui Miao Autonomous County, Guangxi, were selected as the research subjects, and their body composition was measured. The percent body fat (PBF) standard was used as the “gold standard” for obesity, and the BMI standard for obesity in Chinese adults was used as the positive screening standard. The accuracy of the BMI standard was evaluated, and the ROC curve analysis was used to determine the optimal BMI cutoff value for obesity in Miao adults. Results The detection rate of obesity of Miao adults in Guangxi by BMI method was lower than that by PBF method (10.3% vs 19.0%, χ2=426.62, P“gold standard”, BMI had a good diagnostic performance for obesity in Miao adults (AUC=0.959, P2 and 25.55 kg/m2 for men and women, respectively. Conclusion BMI is of great value for the diagnosis of obesity in Miao adults, but it should not be used as an exclusion criterion for obesity. Especially in the case of a small sample size, the risk of misclassification bias is relatively high.