Increasing incidence of childhood-onset type 1 diabetes mellitus among Estonian children in 1999-2006. Time trend analysis 1983-2006.

BACKGROUND

The incidence of childhood-onset type 1 diabetes mellitus (T1DM) among Estonian children under 15 years of age was 10.1 per 100,000 per year in 1983-1990 and 12.2 per 100,000 per year in 1991-1998 with the highest incidence in age-group 10.0-14.9 years in both periods. From 1983 to 1998, the incidence increased most rapidly in age-group 0-4.9 years.

OBJECTIVE

To determine the incidence of T1DM among Estonian children in 1999-2006 and to compare the results with the data from 1983 to 1998.

SUBJECTS AND METHODS

In 1999-2006, population-based incidence data were collected from two centers where all children with T1DM are seen after the diagnosis. Data for earlier periods were obtained from previously published data. Subjects were divided into three age-groups: 0-4.9 years, 5.0-9.9 years and 10.0-14.9 years.

RESULTS

Between 1999 and 2006, 310 new cases of T1DM were diagnosed in Estonian children aged 0-14.9 years. The age-standardized incidence rate for that period was 17.2 [95% confidence interval (CI) 13.1-21.2]. The incidence was the highest, 21.2 (95% CI 17.7-25.3) in age-group 5.0-9.9 years. Over the time period 1983-2006, the incidence of childhood-onset T1DM in Estonian children under 15 years of age increased annually by an average 3.3% with the most rapid annual increase-9.3%-occurring in the youngest age-group.

CONCLUSIONS

The incidence of childhood-onset T1DM in Estonia continues to rise and the age of onset of the disease becomes younger.