title: Dementia onset, incidence and risk in type 2 diabetes: a matched cohort study with the Fremantle Diabetes Study Phase I.
abstract: The study aimed to assess the incidence, age of onset, survival and relative hazard of dementia in well-categorised community-based patients with type 2 diabetes compared with a matched cohort of individuals without diabetes.
  
  
  
  A longitudinal observational study was undertaken involving 1291 participants with type 2 diabetes from the Fremantle Diabetes Study and 5159 matched residents without documented diabetes. Linkage with health-related databases was used to detect incident dementia. Relative hazards were assessed using both cause-specific and subdistribution proportional hazards models.
  
  
  
  During 13.8 ± 5.8 years of follow-up, incident dementia occurred in 13.9% and 12.4% of the groups of participants with and without diabetes, respectively (p = 0.15). With type 2 diabetes, the incidence of dementia was higher (incidence rate ratio [IRR] 1.28, 95% CI 1.08, 1.51), as was the competing risk of death (IRR 1.50, 95% CI 1.38, 1.64). The ages when dementia was first recorded and when death with dementia occurred were both earlier with diabetes, by 1.7 (95% CI 0.6, 2.9) and 2.3 (95% CI 1.1, 3.6) years, respectively (both p ≤ 0.004). Type 2 diabetes was associated with an adjusted subdistribution HR of 1.18 (95% CI 1.00, 1.39), and a cause-specific HR of 1.51 (95% CI 1.27, 1.78) for all-cause dementia.
  
  
  
  Type 2 diabetes is associated with an increased incidence of dementia, and dementia onset occurs at a younger age. The relative hazards of both dementia and premature mortality are increased and, as a consequence, the increased risk of dementia in type 2 diabetes is not as marked as suggested by cause-specific HRs.
authors.affiliation: School of Medicine and Pharmacology, The University of Western Australia, PO Box 480, Fremantle, WA, 6959, Australia.
authors.forename: Wendy A
authors.initials: WA
authors.lastname: Davis
authors.affiliation: Centre for Population Health Research, School of Public Health, Curtin University of Technology, Perth, WA, Australia.
authors.forename: Renate R
authors.initials: RR
authors.lastname: Zilkens
authors.affiliation: School of Psychiatry and Clinical Neurosciences, The University of Western Australia, Fremantle Hospital, Fremantle, WA, Australia.
authors.forename: Sergio E
authors.initials: SE
authors.lastname: Starkstein
authors.affiliation: School of Medicine and Pharmacology, The University of Western Australia, PO Box 480, Fremantle, WA, 6959, Australia.
authors.forename: Timothy M E
authors.initials: TM
authors.lastname: Davis
authors.affiliation: School of Medicine and Pharmacology, The University of Western Australia, PO Box 480, Fremantle, WA, 6959, Australia. David.Bruce@uwa.edu.au.|School of Medicine and Pharmacology, Fremantle Hospital, PO Box 480, Fremantle, Western Australia, 6959, Australia. David.Bruce@uwa.edu.au.
authors.forename: David G
authors.initials: DG
authors.lastname: Bruce
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D003704:Dementia / Q000453:epidemiology* / Q000209:etiology*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D012307:Risk Factors
keywords: Case cohort study; Dementia; Longitudinal study; Type 2 diabetes