Overweight and obesity risk factors in children aged 3-7 years: a prospective study in the city of Kraków.

BACKGROUND: Early identified factors determining overweight and obesity in childhood may be important for preventive purposes.

AIM: To evaluate the influence of the commonly accepted and hypothetical risk factors for overweight/obesity and their mutual relations, using the method of classification trees.

SUBJECTS AND METHODS: The data were collected during anthropometric surveys carried out in 2010 in Kraków, Poland. The study involved 1042 pre-school children aged 3-7 years. BMI was calculated for all subjects classified as underweight, normal body weight and overweight, according to the IOTF cut-offs. In order to determine the correlation between genetic, environmental and lifestyle factors and the child's BMI, this study used information from a questionnaire filled in by the mothers.

RESULTS: Relatively high birth weights, relatively long times of breastfeeding and father's obesity were conducive to the appearance of overweight and obesity in boys. Other overweight risk factors included alcohol consumption by the mother, her low education level and a relatively low mother's age at birth. Among girls, factors leading to overweight included high birth weight, high father's BMI and family situation reported as below very good by their mothers. It was found that a moderate duration of breastfeeding is conducive to a normal weight of children at pre-school age, although in boys this regularity is better documented.

CONCLUSIONS: The biological, social and lifestyle factors related to the child's mother significantly determined the child's BMI.