Abstract

Introduction: Since the prevalence and severity of childhood obesity is increasing, understanding the effective factors for prevention of this disorder is important. Material and Methods: A total of 513 students of both sexes in the first year of primary schools, were recruited in this cross-sectional study. They were chosen randomly from 19 regions (of the ministry of education) from Tehran city. Their weight and height were measured, and information on infant birth and feeding characteristics (birth order, birth weight, the type of feeding in infancy, the duration of exclusive breast feeding, the duration of breast feeding and formula feeding) activity levels, the timing of the introduction of complementary foods were obtained. Descriptive statistical methods such as frequency distribution table, c2 test and central and dispersion parameters were used to describe samples. Results: Eight percent of the children were overweight and 11.7% were obese. There was no significant relation between the type of feeding (breast or formula feeding) and children's BMI. The duration of breast feeding was not significantly associated with children's BMI,. Children's BMI had a negative linear association with the duration of exclusive breast feeding (r=-0.151, P=0.0001). The duration of formula feeding was associated with children's BMI (r=0.108, P=0.007). Children's BMI had an inverse linear relation with the time of introduction of complementary foods (r=-0.128, P=0.002). Conclusion: This study shows the importance of duration of breast feeding in reducing the risk of childhood obesity.