Increased prevalence of Down’s syndrome in individuals with type 1 diabetes in Denmark: a nationwide population-based study

Abstract

Aims/hypothesis: In patients with Down's syndrome, dogma has long held that the prevalence of diabetes is increased. The aim of the present study was to determine the actual prevalence of Down's syndrome among type 1 diabetic patients. Subjects, materials and methods: The background population included all children born in Denmark between 1981 and 2000. Registryvalidated and clinical data on type 1 diabetes and Down's syndrome diagnoses were obtained from the National Disease Register and Danish Cytogenetic Central Register, respectively. Results: The prevalence of Down's syndrome in the background population was 0.09%, whereas we identified a prevalence of Down's syndrome in type 1 diabetes patients of 0.38% (95% CI 0.17-0.75), corresponding to a 4.2-fold increased prevalence compared with the background population (p=7.3×10 −5). Conclusions/interpretation: To the best of our knowledge this is the first population-based study addressing the prevalence of Down's syndrome among verified type 1 diabetes patients. A more than fourfold increased prevalence of Down's syndrome among type 1 diabetes patients supports the notion that genes on chromosome 21 may confer risk for type 1 diabetes, probably also in the general population.

Down’s syndrome in diabetic patients aged <20 years: an analysis of metabolic status, glycaemic control and autoimmunity in comparison with type 1 diabetes

“…This is very close to the prevalence of 0.38% reported in a study of the Danish population [2] that suggested an association with HLA genotypes and the possibility of genetic risk loci on chromosome 21. The 0.38% prevalence of Down's syndrome in our population of diabetic patients was much higher than the Down's syndrome prevalence in other general populations.…”

“…The Danish study [2] found that the onset of type 1 diabetes occurred at an earlier age of 6 years in Down's syndrome patients compared with 8.2 years in the background population. In our study, we found a smaller difference of 8.2 vs 8.4 years.…”

“…Dutch researchers reported a threefold increase in the prevalence of type 1 and type 2 diabetes in patients with Down's syndrome compared with the general population [1]. In Denmark the prevalence of Down's syndrome among patients with diabetes is 4.2 times higher than in the general population [2].…”

Islet Autoimmunity in Children With Down’s Syndrome

“…In a questionnaire-based study of 20,362 patients with Down's syndrome in the U.K. and U.S., the prevalence of diabetes diagnosed before age 20 years in the Down's syndrome population was some six times higher than expected (5), and other studies suggest an approximate fourfold increase in childhood diabetes (3,6). A more recent population-based study of the prevalence of type 1 diabetes in Down's syndrome in Denmark demonstrated a fourfold increased risk of type 1 diabetes in children with Down's syndrome (7). Although classification was generally made on clinical grounds alone, most appear to have type 1 diabetes.…”

Transcriptional profiling of type 1 diabetes genes on chromosome 21 in a rat beta-cell line and human pancreatic islets

“…We have recently demonstrated the prevalence of Down's syndrome in T1D to be four times increased, supporting genes on chromosome 21 to be responsible for this higher prevalence. 20 Such genes might also be important in T1D in general.…”