Objectives: The study describes the temporal trend of type 1 diabetes (IDDM) in the 0-29 year’s age range in the province of Trento between 1.1.1998 and 31.12.2017, as well as the seasonal and geographical distribution. Study Design: The source of the cases is represented by the provincial registry of IDDM which is part of the national RIDI (Italian register of insulin-dependent diabetes) network. We retrospectively calculated the distribution of total cases by sex, age class and by year. The trend of the annual incidence rate by age group was represented by a three-year moving average of the rate, to contain the annual fluctuations, considering the relative consistency of the cases. The values of the rates are provided with the relative 95% confidence intervals. The seasonal case trend and geographical distribution are also provided, considering, in particular, the incidence for the urban and the rural area and the altitude levels. The significance of the time trend was analysed using the Cochrane-Armitage criterion and the significance of the differences in proportions was analysed using the chi-squared test. Any seasonal differences were analysed using West & Harrison’s dynamic linear model. Results: Between 1998 and 2017, 421 cases of IDDM have been recorded amongst residents aged 0-29 years (21 cases per year). Males were 53% and the prevalent age range is 0-14 years, which constitutes 67.4% of cases. Rates fluctuate in the first 15 years; they appear stable over the last five years. The average annual incidence rate is higher in the 0-14 age group. Its mean value, considering males and females together, is 18/100,000/year (95% CI: 16.0-20.3) and it increase from 13.0 in 1998 to 17.8/100,000 in 2017. In paediatric age groups, the mean annual incidence rate is higher in 10-14 years. Its value is 20.8/100,000/year (95% CI: 17.2-25.10) and goes from 18.1 in 1998 to 14.6/100,000 in 2017. The number of new cases is higher in the months inciNovember- January but does not appear to be statistically significant. The mean annual incidence rate for the entire 0-29 years age range is slightly higher in rural than in urban areas (16.20 vs 14.0/100,000/year). Excess in rural areas is more evident for the 0-14 age group. The average annual incidence rate is higher among individuals residing in mountainous areas, both overall and for individual age groups. The increase in the incidence rate with the increase in altitude is at the limits of statistical significance. Conclusion: The incidence of IDDM in the age of 0-29 years seems to have stabilized over the last 5 years. The rate remains always higher in the age of 0-14 y, but decreases over time in the age of 0-4y. The growth of cases in foreign residents may have importance on the trend of the incidence. Excesses emerge in the winter months, in residents in rural and mountain areas. These excesses are not statistically significant.

Paediatric and juvenile type 1 diabetes in the province of Trento. Twenty years of observations, from 1998 to 2017

Pertile Riccardo;
2020-01-01

Abstract

Objectives: The study describes the temporal trend of type 1 diabetes (IDDM) in the 0-29 year’s age range in the province of Trento between 1.1.1998 and 31.12.2017, as well as the seasonal and geographical distribution. Study Design: The source of the cases is represented by the provincial registry of IDDM which is part of the national RIDI (Italian register of insulin-dependent diabetes) network. We retrospectively calculated the distribution of total cases by sex, age class and by year. The trend of the annual incidence rate by age group was represented by a three-year moving average of the rate, to contain the annual fluctuations, considering the relative consistency of the cases. The values of the rates are provided with the relative 95% confidence intervals. The seasonal case trend and geographical distribution are also provided, considering, in particular, the incidence for the urban and the rural area and the altitude levels. The significance of the time trend was analysed using the Cochrane-Armitage criterion and the significance of the differences in proportions was analysed using the chi-squared test. Any seasonal differences were analysed using West & Harrison’s dynamic linear model. Results: Between 1998 and 2017, 421 cases of IDDM have been recorded amongst residents aged 0-29 years (21 cases per year). Males were 53% and the prevalent age range is 0-14 years, which constitutes 67.4% of cases. Rates fluctuate in the first 15 years; they appear stable over the last five years. The average annual incidence rate is higher in the 0-14 age group. Its mean value, considering males and females together, is 18/100,000/year (95% CI: 16.0-20.3) and it increase from 13.0 in 1998 to 17.8/100,000 in 2017. In paediatric age groups, the mean annual incidence rate is higher in 10-14 years. Its value is 20.8/100,000/year (95% CI: 17.2-25.10) and goes from 18.1 in 1998 to 14.6/100,000 in 2017. The number of new cases is higher in the months inciNovember- January but does not appear to be statistically significant. The mean annual incidence rate for the entire 0-29 years age range is slightly higher in rural than in urban areas (16.20 vs 14.0/100,000/year). Excess in rural areas is more evident for the 0-14 age group. The average annual incidence rate is higher among individuals residing in mountainous areas, both overall and for individual age groups. The increase in the incidence rate with the increase in altitude is at the limits of statistical significance. Conclusion: The incidence of IDDM in the age of 0-29 years seems to have stabilized over the last 5 years. The rate remains always higher in the age of 0-14 y, but decreases over time in the age of 0-4y. The growth of cases in foreign residents may have importance on the trend of the incidence. Excesses emerge in the winter months, in residents in rural and mountain areas. These excesses are not statistically significant.
2020
Type 1 diabetes
Childhood and young adults
Temporal trend
Seasonal and territorial incidence
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11562/1128779
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