Objective: To evaluate the prevalence of overweight and obesity among Iranian adolescents and their relationship with modifiable environmental factors.
Methods: The subjects of the present study were 1000 girls and 1000 boys, aged between 11 and 18 years selected by multistage random sampling, their parents (n = 2000) and their school staff (n = 500 subjects) in urban and rural areas of two provinces in Iran. Data concerning body mass index (BMI), nutrition and the physical activity of the subjects were analyzed by SPSSV10/Win software.
Results: The prevalence of 85th percentile </= body mass index (BMI) < 95th percentile and BMI > 95th percentile in girls was significantly higher than boys (10.7 +/- 1.1 and 2.9 +/- 0.1%vs 7.4 +/- 0.9 and 1.9 +/- 0.1%, respectively; P < 0.05). The mean BMI value was significantly different between urban and rural areas (25.4 +/- 5.2 vs 23.2 +/- 7.1 kg/m2, respectively; P < 0.05). A BMI> 85th percentile was more prevalent in families with an average income than in high-income families (9.3 +/- 1.7 vs 7.2 +/- 1.4%, respectively; P < 0.05) and in those with lower-educated mothers (9.2 +/- 2.1 vs 11.5 +/- 2.4 years of mothers education, respectively). The mean total energy intake was not different between overweight or obese and normal-weight subjects (1825 +/- 90 vs 1815 +/- 85 kCal, respectively; P > 0.05), but the percentage of energy derived from carbo-hydrates was significantly higher in the former group compared with the latter (69.4 vs 63.2%, respectively; P < 0.05). Regular extracurricular sports activities were significantly lower and the time spent watching tele-vision was significantly higher in overweight or obese than non-obese subjects (time spent watching telelvision: 300 +/- 20 vs 240 +/- 30 min/day, P < 0.05). A significant linear association was shown between the frequency of consumption of rice, bread, pasta, fast foods and fat/salty snacks and BMI (beta = 0.05-0.06; P < 0.05). A significant correlation was shown between BMI percentiles and serum triglyceride, high-density lipoprotein-cholesterol and systolic blood pressure (Pearson's r = 0.38, -0.32 and 0.47, respectively).
Conclusions: Enhanced efforts to prevent and control overweight from childhood is a critical national priority, even in developing countries. To be successful, social, cultural and economic influences should be considered.