The association of vascular dementia with T2D is stronger than that of nonvascular or Alzheimer dementia, according to a study presented at EASD.
The increased risk for dementia associated with type 2 diabetes (T2D) is strongest for vascular dementia, according to research presented this week at the virtual European Association for the Study of Diabetes Meeting.
A link between T2D and elevated risk for dementia has been observed for some time but the association with different subtypes of dementia has been unclear. Study authors, led by Carlos Celis-Morales, DrPH, of the Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, examined to what extent T2D is associated with Alzheimer, vascular and nonvascular dementia and whether the associations differed by level of glycemic control.
Participants were from the Swedish National Diabetes Register study and included 378 299 patients with T2D and 1 886 022 age- and sex-matched controls. At follow-up (median 6.8 years) 5.7% (21 651) patients with T2D and 5.2% (98,723) of controls had developed dementia.
The strongest association was observed for vascular dementia
Hazard ratio (HR) for patients with T2D, 1.36 [95% CI 1.03, 1.09] vs matched controls. For nonvascular dementia, the association with T2D was somewhat lower: HR, 1.08 [95% CI 1.04, 1.12]). The risk of Alzheimer dementia for patients with T2D was lower than for controls: HR, 0.92 [95% CI 0.87, 0.98]).
A dose-response association was observed after stratifying analyses by A1c level. When T2D patients with A1c <7%(52 mmol/mol)were compared to those with A1c >10% (87 mmol/mol) , risk was higher for Alzheimer (HR: 1.34 [95% IC 1.03, 1.75]), vascular dementia (HR: 1.93 [95% IC 1.53, 2.42]) and non-vascular dementia (HR: 1.67 [95% IC 1.45, 1.91]).
A landmark analysis conducted at 3 years found that the associations remained similar for vascular and non-vascular dementia but disappeared for Alzheimer.
The authors conclude that the association of T2D with neurodegenerative diseases differs by dementia type with the largest effect seen for vascular dementia. Based on analyses stratified by level of A1c, poor glycemic control is associated with an increased risk of developing vascular and non-vascular dementia.