Background and Objectives. The purpose of the study was to investigate the relationship between children's birth weight/length and a risk of overweight and obesity. Materials and Methods. The study involved 747 children from kindergartens, as well as primary and middle schools from southeastern Poland. All the subjects were examined on fasting status. Each child was examined for body mass and height, in order to calculate their body mass index (BMI), and BMI centile. The parents completed a questionnaire related to basic information about the child and the family. Results. In the study group, the male infants presented greater birth body weight and birth body length. A comparison of the distribution of birth weights and lengths between the children with normal BMI and with high BMI showed statistically significant differences only in the case of birth length of 12-15-year-old children and in the group of boys aged 12-15 years. In the case of the female children and the group of 7-11-year-olds a statistically significant difference was found in the BMI centile at a later age-a higher centile was found in the girls and in the children aged 7-11 years classified as adequate for gestational age (AGA). Conclusions. Birth body weight is positively related to BMI centile; however, no significant differences were found in birth weight between children with overweight/obesity and children with normal body weight. Birth length is associated with a lower BMI centile only in boys aged 12-15 years, and lower birth length is found in boys with overweight and obesity.
Keywords: body birth length; body birth weight; pediatric obesity; pediatric overweight.