What factors may contribute to sex differences in childhood obesity prevalence in China?

Abstract

AbstractObjectivePrevious studies in China showed large sex differences in childhood overweight and obesity (OW/OB) rates. However, limited research has examined the cause of these sex differences. The present study aimed to examine individual and parental/familial factors associated with sex differences in childhood OW/OB rates in China.DesignVariables associated with child weight status, beliefs and behaviours, and obesity-related parenting practices were selected to examine their sex differences and association with a sex difference in child OW/OB outcomes using logistic regression analysis.SettingCross-sectional data analysis using the 2011 China Health and Nutrition Survey.SubjectsChildren aged 6–17 years (n 1544) and their parents.ResultsOverall child OW/OB prevalence was 16·8 %. Adolescent boys (AB; 12–17 years) were about twice as likely to be overweight/obese as adolescent girls (AG; 15·5 v. 8·4 %, P<0·05). AB more likely had energy intake exceeding recommendations, self-perceived underweight, underestimated their body weight and were satisfied with their physical activity level than AG. AG more likely practised weight-loss management through diet and self-perceived overweight than AB. Mothers more likely identified AG’s weight accurately but underestimated AB’s weight. Stronger associations with risk of childhood OW/OB were found in boys than girls in dieting to lose weight (OR=6·7 in boys v. 2·6 in girls) and combined maternal and child perception of the child’s overweight (OR=35·4 in boys v. 14·2 in girls).ConclusionsLarge sex differences in childhood obesity may be related to the sex disparities in weight-related beliefs and behaviours among children and their parents in China.