Trends in the distribution of body mass index among Chinese adults, aged 20–45 years (1989–2000)

Abstract

Objective: To describe body mass index (BMI, in kg/m²) distribution patterns and trends among Chinese adults, aged 20–45 years (1989–2000). Design: A descriptive, population-based study of BMI change. Setting: Chinese provinces (eight in 1989 and 1997; nine in 2000), representative of the household-based surveys (the China Health and Nutrition Survey, 1989–2000) using multistage, random cluster sampling, supplemented with annual household consumption survey data of the State Statistical Bureau (SSB). Subjects: A total of 4527, 4507 and 4046 adults, aged 20–45 years, in 1989, 1997 and 2000, respectively. Measurements: BMI (underweight: BMI2 and overweight: BMI⩾25 kg/m²). Percentile curves for BMI in 1989 and 2000 were constructed by gender and age using the LMS (lambda, mu, sigma) method. Results: Compared with 1989, the 2000 BMI distribution curves flattened at higher levels of BMI (men and women). There was a 13.7% increase in the proportion of men and a 7.9% increase of women who were overweight or obese with a resulting greater change in the annualized prevalence rate for men. This increase in the prevalence of overweight and obesity was far greater than the decrease (2.1% for men; 2.2% for women) in that of underweight. Age–gender-specific percentile curves showed BMI increases mainly among women, aged 35–45 years, and among men at all age groups. Conclusions: Chinese BMI dynamics show much greater rates of change among men, aged 20–45 years, than among women, with the increase among women concentrated between ages 35 and 45 years. These changes portend large shifts in other diet-related non-communicable diseases in China over the following decades. Controlling the increasing trends of BMI, especially in men, is an important public health problem facing China.