Table 2. Comprehension and Test re-test study: description of the anthropometric variables, expressed as mean (±standard deviation), according to the different age groups in the sample of 324 children and adolescents (Comprehension study) and121 children and adolescents (Test re-Test study) randomly selected from the population-based cohort provided by the Secretaría de Educación de Bogotá (Bogotá's Education Secretary), 2001-2002. Comprehension Study Test re-test Study Comprehension Study Test re-test Study Comprehension Study Test re-test Study (8-10 yr) (8-10 yr) (11-13 yr) (11-13 yr) (14-16 yr) (14-16 yr) N 108 41 108 40 108 40 Age (yr) 9.1 (.8) 9.1 (.8) 12.1 (.8) 12.1 (.8) 15.0 (.8) 15.0 (.8) Height (m) 1.36 (.08) 1.35 (.07) 1.53 (.07) 1.52 (.07) 1.61 (.07) 1.61 (.08) Weight (kg) 29.8 (5.1) 29.4 (4.8) 41.5 (7.5) 40.7 (8.0) 53.2 (7.6) 52.7 (7.9) BMI (kg·m-2) 16.2 (2.0) 16.0 (2.0) 17.7 (3.0) 17.5 (2.8) 20.4 (2.9) 20.5 (2.8)