['To examine mortality rates and causes of death among subjects diagnosed with type 1 diabetes aged <or=29 years.', 'Subjects with type 1 diabetes from a population-based register in Yorkshire, U.K., diagnosed between 1978 and 2004 were linked to the U.K. National Health Service Central Register for death notifications. Deaths were coded using ICD-9 (1979-2000) and ICD-10 (2001-2005). Standardized mortality ratios (SMRs) were calculated using expected numbers of deaths from U.K. mortality rates by cause of death and age at diagnosis.', 'A total of 4,246 individuals were followed up, providing 50,471 person-years of follow-up. Mean follow-up length was 12.8 years for individuals aged 0-14 years and 8.3 for those aged 15-29 years. Overall, 108 patients died, of whom 77 (71%) were male. A total of 74 (1.7/1,000 person-years) deaths occurred in inidividuals aged 0-14 years and 34 (4.6/1,000 person-years) in those aged 15-29 years. The SMR was 4.7 (95% CI 3.8-5.6) overall, similar for males and females, but higher for individuals aged 15-29 years (SMR 6.2 [95% CI 4.3-8.6]) compared with those aged 0-14 years (4.2 [3.3-5.3]). The SMR rose with increasing disease duration. A total of 47 of 108 deaths (44%) occurred from diabetes complications, 32 of which were acute and 15 chronic. Twenty-two percent (n = 24) of deaths were attributed to accidents or violence (SMR 2.1 [95% CI 1.4-3.2]), including six suicides. Sixteen percent of all deaths were related to drug misuse (including insulin but excluding tobacco and alcohol) (SMR 6.4 [95% CI 3.7-10.2]).'] Are acute complications and drug misuse important causes of death for children and young adults with type 1 diabetes : results from the Yorkshire Register of diabetes in children and young adults?