OBJECTIVES: The role of different body fat indicators and age in assessing the prevalence of obesity is unclear. We aimed to examine to what extent different body fat indicators including BMI, waist circumference (WC) and waist-to-hip ratio (WHR) affect the prevalence of overweight and obesity among Chinese adults taking age into account.

METHODS: This population-based cross-sectional study included a random sample of 7,603 adults aged 20-79 years across entire Tianjin, China. BMI, WC, and WHR were used to define overweight and obesity following standard criteria. Prevalence rates were calculated and standardized using local age- and gender-specific census data. Logistic regression was used in data analysis.

RESULTS: Using the combination of BMI, WC, and WHR, the prevalence of overweight and obesity was 69.8%, and increased with age till the age of 60 and a decline thereafter. The prevalence of overweight assessed by BMI was higher than that assessed by WC and WHR, while the prevalence of obesity defined by BMI was much lower than that defined by WC or WHR.

CONCLUSION: The prevalence of overweight and obesity is about 70% among Chinese adults. Adiposity indicators and age play an important role in the prevalence of overweight and obesity.