Dementia onset, incidence and risk in type 2 diabetes: a matched cohort study with the Fremantle Diabetes Study Phase I

Abstract

Aims/hypothesis The study aimed to assess the incidence, age of onset, survival and relative hazard of dementia in wellcategorised community-based patients with type 2 diabetes compared with a matched cohort of individuals without diabetes. Methods 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. Results 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 causespecific HR of 1.51 (95% CI 1.27, 1.78) for all-cause dementia. Conclusions/interpretation 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.

Cognitive Function Deficits Associated With Long-Duration Type 1 Diabetes and Vascular Complications

“…Longitudinal studies show that cognition is negatively affected in type 1 diabetes (17). The mechanisms proposed include insulin resistance, inflammation, oxidative stress (18), and neurovascular dysfunction (19).…”

Mild cognitive impairment and progression to dementia in people with diabetes, prediabetes and metabolic syndrome: a systematic review and meta-analysis

“…Diabetes has been identified as a key risk factor for dementia and MCI [ 4 , 8 , 9 ], so the growing prevalence of glycaemic disorders [ 10 ] has the potential to further increase the burden of MCI and dementia on healthcare systems. Understanding the links between cognitive impairment and diabetes, and the risk factors that might predict progression to dementia in people with diabetes is important in trying to mitigate such risks [ 11 ].…”

Investigating the Relationship Between Type 2 Diabetes and Dementia Using Electronic Medical Records in the GoDARTS Bioresource

“…While links between type 2 diabetes and vascular dementia have been largely consistent and compatible with established understanding of micro-and macrovascular complications of type 2 diabetes, for Alzheimer disease, such links are more contentious. Although a number of molecular and cellular processes are shared between type 2 diabetes and Alzheimer pathology (10), the strength of the epidemiological association is overall weaker than it is for vascular dementia and not demonstrated in all studies (11)(12)(13). Furthermore, while clinicopathological studies consistently support an association of type 2 diabetes with neurovascular pathologies, this has not been the case for Alzheimer pathology (14)(15)(16)(17)(18).…”