Dementia–type 2 diabetes link driven mostly by vascular risk
medwireNews: The increased risk for dementia associated with type 2 diabetes is strongest for vascular dementia, researchers have reported at the virtual 56th EASD Annual Meeting.
And much of this association was explained by cardiovascular risk factors, said presenter Carlos Celis-Morales (University of Glasgow, UK).
The team drew on an average 7.03 years of follow-up of 378,299 people with type 2 diabetes and 1,886,022 age- and sex-matched controls identified in the Swedish National Diabetes Register. During this time, 10,143 people with diabetes and 46,479 control participants developed dementia, most commonly nonvascular dementia, followed by Alzheimer’s disease and vascular dementia.
After accounting for income, education, country of birth, and prevalent cardiovascular disease, people with type 2 diabetes had a small but significant 8% increased risk for developing nonvascular dementia and an 8% reduced risk for Alzheimer’s disease.
But they had a 35% increased risk for vascular dementia, Celis-Morales stressed.
When the team looked at glycated hemoglobin (HbA1c) level in the overall study population, they found a linear association between HbA1c and the risk for both vascular and nonvascular dementia, although the association was stronger for vascular dementia. For Alzheimer’s disease, only people in the two highest HbA1c categories (≥76 mmol/mol; 9.1%) had an increased risk, when compared with those in the lowest category (<53 mmol/mol; 7.0%).
Age was the factor with the largest individual impact on the association between type 2 diabetes and dementia; however, its influence was weakest for vascular dementia, accounting for 57% of the effect compared with around 70–80% of the effect on the risk for the other two subtypes.
And although no single cardiovascular risk factor accounted for more than 10% of the effect of diabetes on vascular dementia risk, these factors together accounted for 40% of the association, with blood pressure, existing cardiovascular disease, duration of type 2 diabetes, and BMI having the largest individual effects.
By contrast, these factors accounted for only around 10% of the effect of diabetes on Alzheimer’s disease risk and 20% of its association with nonvascular dementia risk, the presenter noted.
“These findings are important [and] of potential public health relevance, as body mass index and other [cardiovascular risk factors] are modifiable,” concluded Celis-Morales.
“Therefore, identification of high-risk individuals and tailored interventions or treatment could attenuate the dementia risk attributable to […] type 2 diabetes.”
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