The study compared how four different growth references determined the prevalence of thinness and overweight, based on height and weight measurements from a nationally representative sample of Swedish children from seven to nine years of age.
The height and weight measurements of 4518 Swedish schoolchildren aged seven to nine years were carried out in 2008 using a standardised protocol. The prevalence of different degrees of thinness and overweight was calculated using international growth references from the World Health Organization, the International Obesity Task Force and two Swedish growth references from Werner and Karlberg.
Depending on which growth reference we used, the prevalence of different degrees of thinness varied from 7.5% to 16.9% for the boys and 6.9% to 13.7% for the girls, while the prevalence of overweight, including obesity and severe obesity, varied from 16.5% to 25.7% for the boys and 18.2 to 25.2% for the girls. There were also significant gender differences depending on the growth reference we used.
Using four different growth references, two international and two Swedish, produced wide variations in the prevalence of thinness and overweight, together with significant gender differences. In the absence of a global definition, we need both national and international growth references.