Ethnic differences in body mass index, weight and height among school children in the north of iran.

OBJECTIVE Overweight and obesity are common health problems among adolescents. This study was set up to evaluate these problems and certain socio-demographic-related factors among three ethnic groups as represented by primary school children in northern Iran in 2010. MATERIALS AND METHODS This was a descriptive and cross-sectional study performed on 7433 students (Fars-native=3268, Turkman=2852, Sisstani=1313) from 112 schools in urban and rural areas. The schools and students were chosen by cluster and stratified sampling. The data were collected by interviewers for all samples throughout the study. Overweight and obesity were identified on the basis of the BMI cut-off Centers for Disease Control and Prevention (CDC) values (in excess of the 85(th) and 95(th) percentiles, respectively). SPSS 16.0 software for Windows was used for the analysis. RESULTS Linear regression analyses revealed that weight, height and BMI increased by 2.70 kg, 4.62 cm and 0.42 kgm(-2), respectively, in boys (p=0.001) and 3.12 kg, 5.19 cm and 0.52 kgm(-2), respectively, in girls (p=0.001) for each year increase in age. In total, overweight was identified in 8.4% of those studied, while obesity was common in 14.1% of students. The rates of overweight and obesity were significantly different among all three ethnic groups (p=0.001). These rates were higher among the Fars-native individuals and lower among the Sisstani individuals as compared with the other groups. Logistic regression analyses showed that the risk of overweight and obesity was 2.104 (1.769-2.502, CI: 95%)-fold greater in the Fars-native as compared with the Sisstanish ethnic group and 2.297 (1.911-2.761, CI 95)-fold greater in the good economic group as compared with the poor economic group. CONCLUSION One out of seven primary school children in northern Iran suffers from obesity and overweight, although the rates differed among the three ethnic groups examined. This study emphasizes the importance of public health training about obesity for children, especially those living in urban areas and those from high-income families.