Determination of the Critical Age for Onset Overweight of Preschool and School Population of the Region of Leiria

Introduction: The objectives of this study were to determine the prevalence of overweight among children aged 2 to 10 years of an institution in the region of Leiria, to assess whether birth weight is a risk factor and to determine the critical period for the onset of excess weight in this population. Methods: This study was performed in a sample of 294 children attending a private educational institution in Leiria, between 2009 and 2013 based on anthropometric measurements routinely performed in the institution. Measurement of weight and height was performed at two different times in each school year to all children aged between 2 and 10 years old. Each child did one to eight evaluations for 4 years of this study. Weight, height and body mass index (BMI) were evaluated according to the Center of Disease Control and Prevention cut-off points. Results: This study demonstrated that from 2 to 10 years the prevalence of overweight varies between 4.6 % (at two years of age) and 34.5 % (at seven years of age). It was also observed a trend to higher prevalence of overweight in females. The age of adiposity rebound was lower in children with overweight compared to children with normal BMI. In the population studied there was no relation between overweight and weiht at birth and ages of 3 and 5 years were critical periods for the onset of overweight. Discussion/Conclusion: In our study, the prevalence of overweight among children is lower than the values obtained in similar Portuguese studies and birth weight is not a good predictor of overweight. Children aged 3 and 5 years should be targeted for preventive measures against overweight.