Childhood diabetes

The Yorkshire Register of Diabetes in Children and Young Adults is one of the key components of the Paediatric Epidemiology Group’s research program. This population based register contains demographic and clinical details on over 3000 children diagnosed with insulin dependent Type 1 diabetes since 1978 and information continues to be collected. The register covers the former Yorkshire Regional Health Authority and information is gathered from hospital clinicians, computerised hospital episode statistics and General Practitioners ensuring registration of the optimal number of children with diabetes. This clinical database is unique in the UK in terms of its size and the broad range of research which it has fostered.

The register is used
• as a research tool to facilitate investigations of the environmental aetiology of diabetes in children and young people
• to study molecular genetics
• to underpin health services research

Results (see below) have been published in peer review scientific journals and presented at conferences bringing national and international recognition to our ongoing research. Since 1996 contributions to 2 major collaborative European studies, EURODIAB (EUROpean childhood DIABetes project) and the IDA (Insulin dependent Diabetes in young Adults) study.

The causes of childhood diabetes remain unclear although it is acknowledged that for around 10% of children there is a genetic component. Thus for the majority of children exposures to environmental factors are key to the development of their condition and the underlying theme of our research has been to clarify these external influences. Investigations have focussed on describing patterns of childhood diabetes in the Yorkshire population and characterising areas of low and high risk using the register and descriptive epidemiological techniques. In addition a major case control study was performed to identify risk factors associated with pregnancy and early life exposures looking specifically at factors linked to infections. This study also collected blood samples from children with diabetes and their parents and siblings for a parallel study of genetic susceptibility to diabetes in collaboration with Professors John Todd at Cambridge University, and Steve Bains at Birmingham University.

The results of a series of studies describing the patterns of childhood diabetes in Yorkshire clearly show epidemiological features, which are consistent with an environmental aetiology and cannot be explained by genetic susceptibility.
• Over the last two decades the incidence of diabetes has risen steadily in children of all ages in both urban and rural areas whereas other populations in Europe and the UK have shown particular increases in those under 5 years.
• Childhood diabetes occurs more commonly in sparsely populated areas shown by a novel ecological analysis led by Dr Anthony Staines and a mapping exercise using the register and census data.
• Associations between childhood diabetes and high levels of nitrate in drinking water were observed in Yorkshire as part of an effort to explain the uneven distribution of the disease. This key finding was tested through collaboration with registers in Scotland, Leicester and Oxford where no links were found.
• Changing rates of occurrence of a disease when populations migrate indicates a likely influence of the environment. For south Asian children in Bradford low rates, reflecting those of the Indian subcontinent, have risen to match that of the indigenous population over the last 20 years.

In the first major case-control interview study of childhood diabetes in the UK, the focus was on the identification of pregnancy and early life risk factors. A new finding was the identification of higher risk linked to mothers experiencing hypertension in early pregnancy and delivering by caesarean section and further analysis identified a protective effect for breast feeding. A contribution has also been made to genetic studies of childhood diabetes through analysis of blood samples collected on the case control study which have contributed to the identification of the fact that fathers transmit susceptibility more strongly than mothers and new susceptibility genes for childhood diabetes.

Type 1 diabetes in 15-29 year olds

The diabetes register has recently been extended to those aged 15-29 years. Yorkshire are leading contributors both in terms of data and epidemiological expertise to an EU funded initiative which aims to identify patterns of clinical presentation and genetic susceptibility across Europe - the IDA (Insulin dependent Diabetes in young Adults) study. The first analysis of Yorkshire data has shown that although numbers of children (0-14 years) with diabetes are increasing there is no corresponding increase in young adults. This was presented at a European conference (September 2000).