[Lifestyle and physical condition factors associated with gender-specific BMI in Spanish preadolescents].

Obesity has become one of the most serious health problems in our society and is associated with a multitude of conditions and complications at puberty. Through this descriptive, cross-sectional study we intended, first, to know the differences by gender in lifestyle and physical condition variables, and second, to know the determinants related to lifestyle and physical condition for a Spanish population aged 10 to 12 years with a medium socioeconomic status. The variables analyzed were BMI, physical condition variables (agility, flexibility, and cardiorespiratory capacity), and health habit variables (quality and frequency of food, physical activity, sedentary lifestyle, and sleep duration). We found significant differences between girls and boys in food quality and frequency, physical activity, sedentary lifestyle, flexibility, and maximum oxygen consumption variables. In the predictive analysis, the models significantly predicted the BMI for the total sample, the group of boys, and the group of girls. Explanatory variables include quality of breakfast, sedentary lifestyle, VO2 max and agility.