RESUMEN
The increasing trend in recent years of overweight and obesity in children, known to be associated with adult obesity and other physical and mental diseases, makes them one of the most important health and social problems today. Lifestyle is an effective factor in the etiology of child overweight and obesity. The purpose of this study was to examine the relationship of overweight and obesity in primary schoolgirls in the 3[rd] -5[th] grades in the 6[th] district of Tehran with some lifestyle variables. This was a case-control study including 314 primary schoolgirls in the 3[rd] -5[th] grades, selected by simple cluster-sampling in the 6[th] district of Tehran. Data were collected on the following variables: body weight, height and body mass index [BMI]; pocket money; types of snacks usually consumed and the amount of money spent on them; duration of daily sedentary activities and snack consumption during these activities; sleeping hours; skipping main meals; type of snack taken in case of skipping breakfast; physical activity; and how the girls went to school [i.e., on foot, by bus, etc.]. The statistical tests used were Chi-square [or Fisher], Mann Whitney, one-way ANOVA, Turkey's HSD, and backward stepwise regression. The following variables were positively associated with overweight and obesity in the schoolgirls: media use [such as TV watching, electronic games, computer using] during weekdays and weekends, pocket money and the proportion of it spent on snacks, frequency and kinds of snacks during sedentary activities, meal skipping frequency and the kind of snack substituted for breakfast. Sleep duration, frequency of snacking, daily physical activity, and walking duration [between school and home] were inversely related to overweight and obesity. No associations were found between overweight and obesity on the one hand and after-dinner snack or homework duration on the other hand. Overweight and obesity among the 3[rd]-5[th] grade are related to schoolgirls' lifestyle variables, the most important of which are sleep duration, eating snacks when watching television or working with the computer, skipping breakfast or dinner, and pocket money and the proportion of it spent on snacks. Not all these associations are statistically significant