Use of statins and risk of hospitalization with dementia: a Danish population-based case-control study

Several epidemiologic studies have indicated reduced risk of dementia among users of statins. We assessed the risk of hospitalization with dementia associated with use of statins in a population-based case-control study in 4 Northern Danish counties in the period 1991 to 2005. We identified 11,039 cases with dementia and 110,340 age- matched and sex-matched population controls using data from the National Patient Registry, the Danish Psychiatric Central Register, and the Civil Registration System. Prescriptions for statins filled before the admission for dementia were identified using population-based prescription databases. We used conditional logistic regression analysis to compute relative risk of hospitalization with dementia associated with use of statins using nonusers as reference group. We found an overall reduced risk of hospitalization with dementia among statin users (adjusted odds ratio: 0.67, 95% confidence intervals: 0.60-0.75). The reduced risk associated with statin use remained robust in various subanalyses, however, we found no clear dose-response pattern between the number of filled prescriptions for statin and the risk of hospitalization with dementia. In conclusion, we found a reduced risk of hospitalization with dementia among users of statins, however, whether this association is causal remains to be clarified.