title: Excess mortality in Type 1 diabetes diagnosed in childhood and adolescence: a systematic review of population-based cohorts.
abstract: OBJECTIVE
  Systematic review of mortality in childhood-/adolescent-diagnosed Type 1 diabetes and examination of factors explaining the mortality variation between studies.
  
  
  METHODS
  Relevant studies were identified from systematic searches of MEDLINE and EMBASE. Observed and expected numbers of deaths were extracted, and standardised mortality ratios (SMRs) and 95 % confidence intervals (CIs) were calculated. Negative binomial regression was used to investigate association between mortality and study/country characteristics.
  
  
  RESULTS
  Thirteen relevant publications with mortality data were identified describing 23 independent studies. SMRs varied markedly ranging from 0 to 854 (χ (2) = 70.68, df = 21, P < 0.0001). Significant associations were observed between SMR and mid-year of follow-up [incidence rate ratio (IRR) 0.95, 95 % CI 0.91-0.99 equivalent to a 5 % decrease per year], between SMR and infant mortality rate (IRR 1.07, 95 % CI 1.02-1.12, a 7 % increase for each death per 1,000 live births) and, after omitting an outlier, between SMR and health expenditure as a percentage of gross domestic product (GDP) (IRR 0.79, 95 % CI 0.68-0.93, a 21 % decrease for each one percent increase in GDP). No relationship was detected between SMR and a country's childhood diabetes incidence rate or GDP.
  
  
  CONCLUSIONS
  Excess mortality in childhood-/adolescent-diagnosed Type 1 diabetes is apparent across countries worldwide. Excesses were less marked in more recent studies and in countries with lower infant mortality and higher health expenditure.
authors.affiliation: Institute of Clinical Sciences B, Centre for Public Health, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Grosvenor Road, Belfast, BT12 6BJ, Northern Ireland, UK.
authors.forename: Eileen
authors.initials: E
authors.lastname: Morgan
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Cardwell
authors.forename: Catherine J
authors.initials: CJ
authors.lastname: Black
authors.forename: David R
authors.initials: DR
authors.lastname: McCance
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Patterson
mesh_terms: D000293:Adolescent; D017668:Age of Onset; D002423:Cause of Death; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003922:Diabetes Mellitus, Type 1 / Q000453:epidemiology / Q000401:mortality*; D005260:Female; D006801:Humans; D007223:Infant; D009026:Mortality