Platelet function a potential biomarker of Alzheimer’s disease

A higher platelet response in middle-aged individuals who are free of antiplatelet therapy carries an increased risk of dementia in late life, according to a cohort study with 20 years of follow up.

Researchers examined associations between baseline platelet function and incident dementia risk in the community‐based FHS (Framingham Heart Study) longitudinal cohorts. They used the cumulative incidence function and applied inverse probability weighted Cox proportional cause‐specific hazards regression models, with adjustment for demographic and clinical covariates. Platelet aggregation response was assessed using light transmission aggregometry.

The analysis included 1,847 FHS participants (average age 53 years, 57.5 percent female). The median platelet aggregation response to 1.0 µmol/L adenosine diphosphate (ADP) was 11.0. Participants with a higher response to ADP (above median) were older, predominantly women, and more likely to have a higher high‐density lipoprotein cholesterol and total cholesterol.

A total of 154 participants developed dementia over a median follow-up of 20.5 years, of which 121 had Alzheimer’s. Platelet aggregation response to ADP 1.0 µmol/L showed an independent and positive association with dementia risk. In the fully adjusted regression models, each 10‐unit increase in the response to 1.0 µmol/L ADP conferred a 7-percent increase in dementia risk.

Results of sensitivity analyses were consistent, with associations showing the same directionality for participants defined as adenosine diphosphate hyper‐responders and for the platelet response to 0.1 µmol/L epinephrine.

The findings suggest that platelet phenotypes may be associated with the rates of incident dementia and thus have a potential prognostic value. Additional studies with methodological innovations for large‐scale exploration of platelet function in at risk populations are warranted.