Increasing incidence of childhood type 1 diabetes in Montenegro from 1997 to 2006

Objective: To determine and analyze the incidence of type 1 diabetes mellitus (T1DM) in 0- to 14-yr-old children in Montenegro from 1997 to 2006. Research design and methods: This was a prospective study. Primary case ascertainment came from a diabetes register and secondary independent data source was from prescription data. Age and sex-standardized incidence rates were calculated using direct method, assuming an equal distribution in each age/sex group. The 95% confidence interval (CI) were estimated assuming the Poisson distribution. The independent effects of calendar year, two 5-yr time periods, sex and age groups were estimated with Poisson regression modeling. Results: During the 10-yr period, 184 new cases of type 1 diabetes were identified. Case ascertainment was 100% complete using the capture-recapture method. The mean annual standardized incidence rate over the 10-yr period was 13.4/100 000/yr (95% CI: 11.5-15.5). It increased on average by 4.6% per year (95% CI: -0.4 to -9.6%, p = 0.07). The time-period specific incidence rate from year 1997 to 2001 was significantly lower (10.8; 8.5-13.5) compared with the second period from 2002 to 2006 (16.3; 13.3-19.7), (p < 0.0001). The age-specific incidence for the 0-4-yr age group was significantly lower (8.9; 6.3-12.3) than in 5- to 9-yr age group (14.1; 10.8-18.1); and in the 10-14 yr group (17.2; 13.7-21.3) per 100 000 children. Conclusions: The incidence rate in last 5 yr places Montenegro in the group of countries with moderate risk for development of type 1 diabetes in children. The average annual increase in incidence is 4.6%.