Factors associated with adolescents' overweight and obesity at community, school and household levels in Xi'an City, China: results of hierarchical analysis.

Objective: To identify personal and environmental factors associated with adolescent overweight and obesity in Xi'an city, China.

Subjects/methods: A total of 1804 adolescents from 30 junior high schools in six districts in Xi'an City. Community, school, household and individual characteristics were self reported by parents, school doctors and students. Factors associated with adolescent overweight and obesity were identified using a hierarchical logistic regression.

Results: In all adolescents, after adjustment for age and gender, factors significantly associated with overweight and obesity were: living in urban districts (odds ratio (OR): 4.0, 95% confidence interval (CI): 2.7-6.0); limited use of school sports facilities (OR: 1.7, 95% CI: 1.1-2.6); wealthy households (OR: 1.7, 95% CI: 1.1-2.6); parental restrictions on purchasing snacks (OR: 1.5, 95% CI: 1.03-2.0); having an overweight/obese parent (OR: 1.8, 95% CI: 1.3-2.5); having soft drinks more than four times per week (OR: 1.6, 95% CI: 1.02-2.5) and not fussy about foods (OR: 1.7, 95% CI: 1.2-2.2). Eating sweets was negatively associated with overweight/obesity (OR: 0.6, 95% CI: 0.4-0.9). Separate gender analyses revealed that in boys, low physical activity (OR: 2.0, 95% CI: 1.1-3.8) and higher energy intake (OR: 1.8, 95% CI: 1.1-2.9) were also associated with overweight/obesity. In girls, less school sports meetings (OR: 2.3, 95% CI: 1.3-4.0); parental decisions about eating fast foods (OR: 1.8, 95% CI: 1.1-2.9) and availability of home video games (OR: 1.7, 95% CI: 1.1-2.5) were also significant.

Conclusions: Preventive strategies for adolescent overweight and obesity in Xi'an should address the community and school environments to reinforce behavioral change. Gender differences also need to be considered when planning interventions.