Lipoprotein-associated phospholipase A2 and risk of dementia in the Cardiovascular Health Study

- LpPLA2 mass and activity were both related to an increased risk of dementia in the Cardiovascular Health Study.
- The risk of Alzheimer's dementia was increased two-fold in the highest compared to lowest quartile of Lp-PLA2 mass.
- Lp-PLA2 activity doubled the risk of mixed dementia (AD and vascular dementia) in the highest compared to lowest quartile.
- These associations were independent of demographics, cardiovascular disease and its risk factors.
- These data add to the literature reporting conflicting results of the association between LpPLA2 and dementia.

ObjectiveTo evaluate associations between Lipoprotein-associated phospholipase A2 (Lp-PLA2) mass and activity with risk of dementia and its subtypes.MethodsAnalysis were completed on 3320 participants of the Cardiovascular Health Study (CHS), a population-based longitudinal study of community-dwelling adults age ≥65 years followed for an average of 5.4 years. Baseline serum Lp-PLA2 mass was measured using a sandwich enzyme immunoassay and Lp-PLA2 activity utilized a tritiated-platelet activating factor activity assay. Cox proportional hazards regression assessed the relative risk of incident dementia with higher baseline Lp-PLA2 adjusting for demographics, cardiovascular disease (CVD) and risk factors, inflammation markers and apolipoprotein E (APOE) genotype.ResultsEach standard deviation higher Lp-PLA2 mass and activity were related to increased risk of dementia (fully adjusted HR: 1.11 per SD, 95% CI: 1.00-1.24 for mass; HR: 1.12 per SD, 95% CI: 1.00-1.26 for activity). Persons in the highest quartile of Lp-PLA2 mass were 50% more likely to develop dementia than those in the lowest quartile in adjusted models (HR: 1.49; 95% CI: 1.08-2.06). Among dementia subtypes, the risk of AD was increased two-fold in the highest compared to lowest quartile of Lp-PLA2 mass (adjusted HR: 1.98, 95% CI: 1.22-3.21). Results were attenuated in models of mixed dementia and VaD. Lp-PLA2 activity also doubled the risk of mixed dementia in the highest compared to lowest quartile (HR: 2.21, 95% CI: 1.12-4.373).InterpretationThese data support Lp-PLA2 as a risk factor for dementia independent of CVD and its risk factors. Further study is required to clarify the role of Lp-PLA2-related mechanisms in dementia subtypes.