High Prevalence of Obesity but Low Physical Activity in Children Aged 9-11 Years in Beijing

Objective: To investigate the prevalence and associated factors of childhood overweight/obesity in the Shunyi district of Beijing, China. Methods: This study adopted a cross-sectional survey and included 10,855 children aged 6-18 years in the Shunyi district of Beijing, China. Analyses were stratified by age group (6-8, 9-11, 12-14, and 15-18 years). Results: The prevalence of overweight and obesity among children aged 6-18 years was high with 17.62% and 29.05% in boys, 17.57% and 18.04% in girls, respectively. Both boys and girls aged 9-11 years had the highest rate of obesity in comparison with the other age groups, though the differences in children aged 9-11 years and 12-14 years were not statistically significant. Compared with age 6-8 years, age 9-11 years (OR=1.59, 95% CI 1.41-1.79, P<0.01) and 12-14 years (OR=1.26, 95% CI 1.48-1.73, P<0.01) were independently positively associated with obesity. Importantly, in all subjects, the percentages of being physically active (exercise time >= 120 minutes/week) were lower in children aged 9-11 years in comparison to children in other age groups. This phenomenon remained when this comparison was performed respectively in the normal-weight, overweight, and obesity groups. Even after adjustment for other potential confounders, the probability of being physically active (exercise time >120 minutes/week) was lower in children aged 9-11 years (OR=0.86, 95% CI 0.78-0.94, P<0.01), but higher in children aged 12-14 years (OR=1.91, 95% CI 1.69-2.17, P<0.01) and aged 15-18 years (OR=2.22, 95% CI 1.85- 2.66, P<0.01), when compared with children aged 6-8 years. Conclusion: Children aged 9-11 years had a higher prevalence of obesity, but a lower percentage of being physically active. Targeted intervention programs in this key group are needed to address this problem in China.