Aim: To examine incidence and trends of Type 1 diabetes worldwide for the period 1990-1999.
Methods: The incidence of Type 1 diabetes (per 100 000/year) was analysed in children aged <or= 14 years from 114 populations in 112 centres in 57 countries. Trends in the incidence of Type 1 diabetes were analysed by fitting Poisson regression models to the dataset.
Results: A total of 43,013 cases were diagnosed in the study populations of 84 million children. The age-adjusted incidence of Type 1 diabetes among 112 centres (114 populations) varied from 0.1 per 100,000/year in China and Venezuela to 40.9 per 100,000/year in Finland. The average annual increase in incidence calculated from 103 centres was 2.8% (95% CI 2.4-3.2%). During the years 1990-1994, this increase was 2.4% (95% CI 1.3-3.4%) and during the second study period of 1995-1999 it was slightly higher at 3.4% (95% CI 2.7-4.3%). The trends estimated for continents showed statistically significant increases all over the world (4.0% in Asia, 3.2% in Europe and 5.3% in North America), except in Central America and the West Indies where the trend was a decrease of 3.6%. Only among the European populations did the trend in incidence diminish with age.
Conclusions: The rising incidence of Type 1 diabetes globally suggests the need for continuous monitoring of incidence by using standardized methods in order to plan or assess prevention strategies.