Gender Difference and Changes in the Prevalence of Obesity Over Time in Children Under 12 Years Old: A Meta-analysis.

Objective: Evaluating changes over time in the odds of obesity according to sex.

Methods: PubMed, Embase, Cochrane Library, and China National Knowledge Database were searched for relevant studies. Full-text studies evaluating the influence of sex on obesity were analyzed. We used R 3.4.3 to assess the impact of results in the selected studies, calculated pooled prevalence and odds ratio (OR) with their respective 95% confidence intervals (CIs). P<0.10 and I2>50% indicated high heterogeneity, and the random-effects model was used, otherwise, the fixed-effects model was used.

Results: The included studies reported the prevalence of obesity in children covering 1987-2017 intervals. The pooled prevalence of obesity in boy and girl groups were 0.13 (95% CI: 0.08, 0.20) and 0.10 (95% CI: 0.07, 0.13). In the analysis of the boy group, the pooled OR in earlier time (1987-2013) vs. recent time (2011-2017) was 0.98 (95% CI: 0.76, 1.26). The estimated OR for girls in earlier vs. recent time was 1.01 (95% CI: 0.80, 1.28). In the analysis of studies with follow-up period ≥ 10 years, the pooled OR for obesity in earlier vs. recent time period was 0.99 (95% CI: 0.76, 1.30). For those with follow-up period < 10 years, the pooled OR in earlier vs. recent time period was 0.94 (95% CI: 0.57, 1.54).

Conclusions: Comprehensive measurements are required to control obesity among children albeit with nonsignificant gender difference and time trend for obesity rates in children.