Does aspirin protect against Alzheimer's dementia? A study in a Swedish population-based sample aged > or =80 years.

Objective: It has been reported that aspirin and other non-steroidal anti-inflammatory drugs (NSAID) may protect against dementia of Alzheimer's type and/or vascular dementia. However, co-morbidity and the dose of aspirin may be critical. A major indication for low-dose aspirin is prophylaxis after stroke and transient ischaemic attacks, conditions that may obscure an anti-dementia effect by the drug. Alternatively, low-dose aspirin may be insufficient if the protective effect is due to an anti-inflammatory mechanism. The aim of this study was to assess whether high-dose or low-dose aspirin may protect against Alzheimer's dementia in subjects aged > or =80 years. For comparison, effects of (other) NSAID, paracetamol and D-propoxyphene were studied.

Methods: Global, cross-sectional, and longitudinal (1991-2000) epidemiological analyses of clinical, cognitive and drug treatment data on 702 individuals 80 years old or more (351 twin pairs of same sex), all alive at inclusion: mean age 83.9 years (80-99 years). Calculations were made with logistic regression of associations between use of various analgesics and cognitive function, after adjustment for age, gender, and cardiovascular and cerebrovascular diseases.

Results: Users of high-dose aspirin had significantly lower prevalence of Alzheimer's dementia and better-maintained cognitive function than non-users. There were numerically similar but not significant associations with use of low-dose aspirin and other NSAID. There were no such associations with use of either paracetamol or D-propoxyphene.

Conclusion: Aspirin might protect against Alzheimer's disease, but controlled trials are warranted.