Infections have been suggested to play a role in the aetiology of type 1 diabetes. The presence of space-time clustering is consistent with the notion of an environmental component in disease aetiology, possibly linked to infections. We tested for evidence of space-time clustering among children and young adults under 30 years of age using data from a population-based register in Yorkshire, UK.Subjects and methods
Two data sets of children and young people diagnosed with type 1 diabetes were analysed: (1) children aged 0-14 years and resident in Yorkshire during 1978-2002; (2) those aged 15-29 years and resident in West Yorkshire during 1991-2002. Tests for space-time interactions between cases were applied. Addresses at diagnosis were geo-coded and used as the basis for the analyses.Results
The study analysed 3,019 type 1 diabetic patients in the 0-14 years age group and 989 patients in the 15-29 years group. Statistically significant space-time clustering based on place and time of diagnosis was detected both for the 10-14-year-olds (p=0.04) and for the 15-19-year-olds (p=0.01).Conclusions/interpretation
Previous studies of clustering of type 1 diabetes have generally been restricted to childhood. Our results from a data set that includes teenagers and young adults show that space-time clustering was limited to young people aged 10-19 years. This finding is consistent with an aetiology involving late exposure to infection. However, the question of whether this is directly diabetogenic or unmasks latent diabetes cannot be addressed by this methodology.