Epidemiology of type 1 diabetes in Asturias: 2002-2011

Type 1 diabetes mellitus (T1DM) is one of the most common chronic diseases in childhood. An increased incidence of T1DM has recently been noted in children under 15 years of age, and especially in the younger group. The purpose of this study was to know the incidence of T1DM in Asturias and its characteristics.

Children and young adults under 40 years of age living in Asturias and diagnosed with T1DM in public and private centers from January 1, 2002 to December 31, 2011, were included in the study. Information collected included age, sex, date of diagnosis, initial symptoms, and biochemical parameters of the disease.

A total of 436 patients were diagnosed, of whom 59.63% were males; 169 were younger than 15 years, 56.8% of them males. The age-adjusted overall incidence rate (IR) in Asturias of people diagnosed with diabetes before 40 years of age during this period was 9.45/100.000 population/year (95% CI: 8.58-10.38), 11.07 in males (95% CI: 9.77-12.50) and 7.77 in females (95% CI: 6,66-9,00). In subjects under 30 years of age, IR rate was 10.82 (95% CI: 9.67-12.07), 11.91 in males (95% CI: 10.23-13.78) and 7.61 in females (95% CI: 6,25-9.17). The IR in subjects younger than 15 years of age was 15.60 (95% CI: 13.33-18.13), 17.24/100,000 population/year (95% CI: 13.97-21.06) in males and 13, 86 (95% CI: 10.86-17.42) in females. Estimated IR adjusted by age group in children under 15 years of age was 9.58 (95% CI: 6.64-13.39) in those aged 0-4 years, 18.25 in those aged 5-9 years (95% CI: 14.06-23.31), and 18.78 (95% CI: 14.67-23.69) between 10 and 14 years of age. IR remained stable in virtually all age groups and in both sexes, except in girls under 4 years of age, who showed a significant upward trend. There were significant differences in incidence between the central area of Asturias, predominantly urban, and the peripheral areas, mainly devoted to farming and livestock breeding. Thus, while IR in Mieres was 8/100,000/year, in Jarrio reached 25.6/100,000/year.

In Asturias, incidence of T1DM in children and young adults is similar to that of the surrounding communities, but lower than the average in Spain. It has remained stable in recent years, except in the younger girls (in whom it has increased), and shows a great geographical variability between the center of the region and the periphery.