Background: Dementia is a major public health problem because of its high prevalence in elderly individuals, particularly in the growing category of subjects aged 80 years or more. There is accumulating evidence that cholesterol may be implicated in the pathogenesis of dementia, and this has led us to assess the relationship between time spent with statins available and the risk of hospitalization for dementia.
Methods: A population-based, nested case-control study was carried out by including the cohort of 152,729 patients from Lombardy (Italy) aged 40 years or older who were newly treated with statins between 2003 and 2004. Cases were the 1380 patients who experienced hospitalization for dementia disease from initial prescription until 2010. Up to twenty controls were randomly selected for each case. Logistic regression was used to model the risk of dementia associated with the cumulative time during which statins were available. Monte-Carlo and rule-out sensitivity analyses were performed to account for unmeasured confounders.
Results: Compared with patients who had very short statins coverage (less than 6 months), those on 7-24, 25-48, and >48 months of coverage respectively had risk reductions of 15% (OR: 0.85; 95% CI: 0.74 to 0.98), 28% (OR: 0.72; 95% CI: 0.61 to 0.85), and 25% (OR: 0.75; 95% CI: 0.61 to 0.94). Simvastatin and atorvastatin were both associated with a reduced risk of dementia, while no similar evidence was observed for fluvastatin and pravastatin.
Conclusions: Long-term use of statins seems effective for the prevention of dementia.
Keywords: Alzheimer's disease; Dementia; Healthcare Utilization Database; Lipid-lowering agents; Monte-Carlo sensitivity analysis; Record linkage; Rule-out sensitivity analysis; Statins; Unmeasured confounders.
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