The rate of type 1 diabetes in Finland is accelerating, according to a new study, which used data from 11,000 children who developed type 1 diabetes between the years 1980 and 2005. Over this time, the incidence rate doubled.

Finland already has the highest incidence rate of type 1 diabetes worldwide. Diabetes rates differ significantly between countries, for reasons not entirely understood, with places like China and Venezuela having the lowest incidence of type 1 and Finland and Sardinia having the highest. The United States lies somewhere in between.

Although a steady increase in type 1 has been reported worldwide, it’s unclear whether this indicates that there are a higher total number of cases of type 1 diabetes or if it only appears that there are more cases because the disease usually begins in childhood. The current study indicates that, although the greatest acceleration in rate was observed in the youngest children, this trend could not explain the entire increase in incidence. So, it does appear that the overall number of people with type 1 diabetes is increasing, at least in Finland.

The researchers predict the emergence of 10,000 new cases of type 1 in Finland between 2006 and 2020. Valma Harjutsalo, PhD, researcher at the National Public Health Institute in Helsinki and lead author of the study, says, “We really hope that the predictions will not come true and the incidence ... will reach a plateau.” The authors also warn that “the steep increase in incidence noted in the last half of the 1990s might represent a serious signal about unhealthy changes in our everyday environment.”

This article was published in the May 24, 2008, issue of The Lancet.