Body Mass Index Distributions and Sociodemographic Factors Affecting BMI of Children Living in Anyang, Korean

Body mass index(BMI) is recognized as one of the most useful indexes for adiposity in children and adults. This study was conducted to provide information on BMI distribution by age and sex in Korean children, and to identify sociodemographic factors that affected BMI among children. The study was conducted on 2376 children(boys 1184, girls 1192) living in a middle-size city in Korea. Subjects were selected from the primary schoolchildren in grades 1-6 using the two-stage sampling method. Their mean age was 9.4 years. The percentile of BMI tended to increase as age increased in both sexes. The 85th percentile for boys, aged 6-12 years, was 19.8kg/㎡, and the 95th percentile was 22.5kg/㎡. The 85th percentile for girls, aged 6-12 years, was 18.9kg/㎡, and the 95th percentile was 21.5kg/㎡. Multiple regression analysis was carried out to predict BMI from percent ideal body weight (PIBW), age and sex. After adjusting PIBW and age, BMI for boys was 0.062kg/㎡ lower than that for girls. One year of age increased BIM by 0.55kg/㎡. The prevalence rate of overweight and obesity based on PIBW was 15.8% and 15.0% for boys, and 14.0% and 11.0% for girls, respectively. Demographic factors such as sex, age, and parents' obesity influenced children's BMI. After adjusting for sex, age and parents' BMI, the presence of another children in family, and mother's employment status showed a strong effect on children's BMI. The results suggest an age-sex specific BMI distribution of Korean children. The present study also provides direct evidence of a correlation between early life environmental factors, such as presence of siblings or mother's employment, and BMI level in Korean children.