Association between body mass index (BMI) and height from birth to 5 years in Chilean preschool children Asociación entre el índice de masa corporal y la talla desde el nacimiento hasta los 5 años en preescolares Chilenos

Background: It has been shown that excess weight gain during childhood is associated with a greater risk of obesity; this relationship may be mediated by growth in height. Aim: To quantify the associations between z scores for body mass index (BMIZ) and height for age (HAZ) from birth to 5 years of age and to assess how this association varies according to age and adiposity. Material and Methods: Weight and height were recorded at 11 occasions from birth on a cohort of 1089 Chilean five year-old children with a birth weight > 2500 g. BMI, BMIZ, HAZ and prevalence of obesity were calculated. We determined the cross-sectional association between BMIZ and HAZ for the total sample and by 3 BMI Z categories, using Pearson correlation. We determined the probability of obesity according to four HAZ categories. Results: Obesity increased continuously reaching approximately 16% at 5 years. Stunting was virtually nonexistent. No association between BMIZ and HAZ was observed at birth, while at