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.