Gender differences in the relative risk factors in children with simple obesity

Objective To analyze gender differences in the relative risk factors in children with simple obesity. Methods The cross-sectional survey included 2 852 children from 5 schools between 6 and 16 years old as the investigation subjects.Their height and weight were measured and self-administered questionnaires were delivered, including age, gender, birth weight, education of the guardians, feeding way in the first 6 months, history of parent's obesity and chronic disease, and diet and exercise factors were also investigated.Two thousand three hundred and ninety-six students who had completed the questionnaire contents were included in the study.According to body mass index(BMI), they were divided into normal weight group and overweight and obesity group, respectively.For both boys and girls, firstly single factor statistical analysis was carried out, then further multi factor Logistic regression analysis for those statistically significant risk factors. Results High birth weight was only boys' risk factor and the risk of obesity was 1.78 times the normal birth weight groups(95%CI 1.18-2.67, P=0.006); the risks of obesity for the boys and girls whose fathers were obese or overweight were 1.70 times and 1.91 times the normal weight fathers respectively(P=0.000). Accordingly, the risks of obesity for the boys and girls whose mothers were obese or overweight were1.86 times and 2.32 times, respectively(P=0.000). The fathers had at least 1 kind of chronic disease affecting boys(OR=1.45, 95%CI 1.05-2.01, P=0.024). In terms of diet, the girls who liked meat but not vegetables were prone to be obese (OR=1.85, 95%CI 1.06-3.21, P=0.030). At the same time, the risks of obesity for the boys and girls whose eating duration lasted less than 10 minutes were 3.93 times and 2.82 times those whose eating duration lasted 25 minutes (P<0.05). In terms of exercise, the findings showed that the risk for overweight or obesity in girls whose outdoor sports exercise lasted for at least 30 minutes but less than two times per week in summer and winter vacation was 2.32 times the girls whose outdoor sports exercise was more than 8 times per week (95%CI 1.15-4.67, P=0.018); the findings also showed that the risks for overweight or obesity in boys who almost didn't do exercise in the average school day was 2.56 times the boys who exercised for at least 60 minutes each day (95%CI 1.65-3.97, P=0.000). Conclusions The common risk factors for simple obesity in both girls and boys include the history of parents' obesity and eating speed and mothers' genetic effect which are more obvious.Risk factors for simple obesity in boys only include high birth weight, history of fathers chronic diseases(at least one disease among hypertension, diabetes, fatty liver, metabolic disorder of serum lipids), and they almost have no sports from Monday to Friday after school; otherwise, risk factors for simple obesity in girls only include lower consumption of vegetables than meat, outdoor sports no more than half an hour, less than 5 times weekly in winter and summer vacation. Key words: Child; Sex; Obesity; Risk factors