Boys may be especially prone to excess weight gain, the findings indicate.
The researchers base their findings on a nationally representative sample of more than 3000 pupils attending 127 schools across Norway. All the children were part of the national 2010 Norwegian Child Growth Study.
School nurses measured the height, weight, and waist circumference of the children whose average age was 8, to gauge general overweight, as defined by the International Obesity Task Force (IOTF), and (abdominal) obesity, as defined by a waist to height ratio of 0.5 or more.