Anthropometric measurement

Children’s weight and height were measured in duplicate following standards described by Cogill [20] The average of two measurements was recorded. A SECA digital weighing scale (calibrated at the beginning of each day and after every 10th child) was used to measure weight to the nearest 0.1 kg. Standing height was measured to the nearest 0.1 cm using a microtoise. Body mass index (BMI) was computed as weigh/height² (kg/m²) and converted to BMI for age z-scores using the 2007 WHO Growth reference for school-aged children and adolescents [21]. Thinness and overweight were defined as a BMI for age below and above 2SDs from the WHO growth reference median, respectively [22].