Objective: To evaluate the effect of discontinuing statin therapy on incidence of Parkinson disease (PD) in statin users.
Methods: Participants who were free of PD and initiated statin therapy were recruited between 2001 and 2008. We examined the association between discontinuing use of statins with different lipophilicity and the incidence of PD using the Cox regression model with time-varying statin use.
Results: Among the 43,810 statin initiators, the incidence rate for PD was 1.68 and 3.52 per 1,000,000 person-days for lipophilic and hydrophilic statins, respectively. Continuation of lipophilic statins was associated with a decreased risk of PD (hazard ratio [HR] 0.42 [95% confidence interval 0.27-0.64]) as compared with statin discontinuation, which was not modified by comorbidities or medications. There was no association between hydrophilic statins and occurrence of PD. Among lipophilic statins, a significant association was observed for simvastatin (HR 0.23 [0.07-0.73]) and atorvastatin (HR 0.33 [0.17-0.65]), especially in female users (HR 0.11 [0.02-0.80] for simvastatin; HR 0.24 [0.09-0.64] for atorvastatin). As for atorvastatin users, the beneficial effect was seen in the elderly subgroup (HR 0.42 [0.21-0.87]). However, long-term use of statins, either lipophilic or hydrophilic, was not significantly associated with PD in a dose/duration-response relation.
Conclusions: Continuation of lipophilic statin therapy was associated with a decreased incidence of PD as compared to discontinuation in statin users, especially in subgroups of women and elderly. Long-term follow-up study is needed to clarify the potential beneficial role of lipophilic statins in PD.