Objective: To assess the magnitude of overweight and obesity and its associated sociodemographic factors in adolescents attending junior high schools in Xi'an, Shanxi province.
Methods: A total of 1 804 adolescents attending junior high schools in Xi'an (age: 11-17 years) were enrolled randomly from 30 schools in 6 districts in Xi'an. Overweight and obesity was categorized with body mass index (BMI) cutoffs from Working Group of Obesity in China (WGOC). Underweight was defined by BMI-Z < or = -2 s. Sociodemographic information was collected from the parents of the survey participants using self-administered, structured and precoded questionnaires.
Results: Overall 17.4% of adolescents were overweight or obese (overweight 11.2%; obesity 6.2%), but there was a marked gender difference in the prevalence with 20.2% of boys versus 14.4% of the girls being overweight or obese. The prevalence of underweight was 2.7%. In a multivariate model, age, residence, household wealth, and parents' BMI were significantly associated with overweight and obesity (P < 0.05). After having been adjusted for age and gender, the odds ratio of an adolescent being overweight and obese was 2.7 (95% CI: 1.8-4.0) folds higher in urban areas than in rural areas, and was 1.6 (95% CI: 1.04-2.5) folds higher for adolescents from rich families than those from poor families. An adolescent with one or both parents overweight was 1.8 (95% CI: 1.3-2.5) more likely to be overweight themselves compared to those with normal weight parents.
Conclusions: Overweight and obesity is a major public health problem in adolescents in Xi'an. Overweight and obesity is more prevalent in younger boys from richer families living in urban districts and those whose parents were either overweight or obese.