4. Statistical Analysis

First, we compared the children’s BMI z-score and weight status between girls and boys stratified by child age, maternal education and weight status, household income, and urban/rural residence. Then, we examined sex differences in children’s weight-related behaviors, including energy intake, SSB consumption, diet control to manage weight, daily sleep duration, and daily TV viewing time. Next, we examined sex differences in children’s self-perceived weight, maternal perception of her child’s weight, and the comparison of the perceptions to the children’s actual body weight using weight status established by 2000 International Obesity Task Force (IOTF) BMI cutoff points. T-test and chi-square test were used to assess sex differences and displayed with means and standard deviation (SD) or percentage (%).

Finally, using separate logistic regression models, we estimated sex differences in the association between ow/ob and each of the risk factors found to vary by child sex in the earlier analyses of child weight-related behaviors and beliefs and maternal weight status and perception of child weight with marginally statistical significance (p < 0.1) after adjusting for obesity-related socio-demographics. Odds ratios (OR) and 95% confidence intervals (CIs) were reported.

Data management and analyses were conducted using Stata 15 (StataCorp. College Station, TX) and SAS 9.3 (SAS Institute, Cary, NC).