The Karolinska Institutet study compared 7,200 children: some with obesity and risk markers such as abnormal blood and liver values and high blood pressure; some with obesity without such risk markers; and a control group of randomly selected children from the population.
By the age of 30, 17 percent of the children in the first group had developed type 2 diabetes, compared with nine percent of those without risk markers. In the control group, the figure was 0.5 percent.
A similar pattern was seen for high blood pressure and high blood lipids.
"Our results suggest that all children with obesity need treatment, even if they appear completely healthy on examination," says Claude Marcus, a professor at Karolinska Institutet.
Previously, the view was that children with normal blood and liver values and normal blood pressure probably did not need treatment for their obesity.
