Gender differences in the relationships between elementary-school students' weight status and measures of screen time, physical activity, fitness, and diet

Understanding which health behaviors increase children's risk for obesity is an increasingly important public health goal. Our study examined gender-specific associations between several health behaviors and obesity in school-aged children. Data were from 387 third-grade students from rural Midwestern schools. Health behaviors included passive (television/video viewing) and active forms (video/computer game playing) of screen time, physical activities and cardiovascular fitness, and several measures of diet. Body mass index was used to identify those children who were of a healthy weight, overweight, and obese. Multinomial logistic regression analyses were conducted separately for girls and boys. Results showed that the multinomial models were statistically significant for girls [Χ²(18)=42.2, p<.01; R²=35%] and for boys [Χ²(18)=47.0, p<.001; R²=38%]. In girls, the odds ratios (OR) for the specific health behaviors showed no significant predictors of overweight status, but obese girls did spend significantly more time watching television/videos (OR=1.65) and showed poorer cardiovascular fitness (OR=0.82) than girls of a healthy weight. Overweight boys were significantly more likely than healthy weight boys to watch more television/videos (OR=2.08) and play fewer video/computer games (OR=0.57). Obese boys were significantly more likely to watch more television/videos than healthy weight boys (OR=1.99), and they also showed significantly poorer cardiovascular fitness (OR=0.84). Our results show a clear relationship between obesity and passive, but not active, forms of screen time. Furthermore, because physical activity and fitness were controlled by our models, the relationship between obesity and passive screen time is not simply a function of lower activity levels in obese children.