There has been long-running controversy regarding the association between statins and PD risk. Two studies with conflicting results are examined here.
Studies going back at least a decade have had conflicting results about statin use and PD risk. Animal studies suggest benefits of statins on dopaminergic neurons; however, observational studies in humans link statin use to both increased and decreased PD risk. Higher cholesterol levels have been linked to decreased PD risk. A recent meta-analysis found statins had no association on PD risk when studies adjusted for hyperlipidemia.1
Researchers at Penn State investigated the controversy around the role of statins and their effects on PD. In June 2017, a report of the claims-based study linking statins to increased PD risk made headlines.2-5 The study comprised 2322 patients with PD matched and 2311 controls. Study participants were matched by age, gender, and duration of follow up. Data were adjusted for hyperlipidemia. Of the statins linked to increased PD risk, the strongest risk was for lipophilics (OR 1.58, P < .0001) vs hydrophilics (OR 1.19, P = .25). Lipophilics included atorvastatin, lovastatin, and simvastatin-all can cross the blood-brain barrier. Findings suggest that initiating statins may speed the onset of PD (< 1 year OR = 1.82; 1-2.5 years OR = 1.75; ≥ 2.5 years OR = 1.37; P < .0001).
In April 2017 an Israeli-based study was published without much fanfare. Rozani and colleagues reported that no link had been found between statins and PD. The population-based cohort study looked at new statin users aged 49 to 79 years: N = 232,877; n = 2550 patients with PD. Researchers evaluated changes in statin use over time and PD risk. Data from a large health services organization that insures 25% of Israeli population were used; and adjusted for LDL levels. Mean follow up was 7.6 years.
The study showed no link between statins and PD risk regardless of age, LDL, statin type or potency in patients with at least 1 year of statin adherence. Moreover, no association was found in patients with 5 years of statin adherence and no association by baseline LDL (age-pooled results): LDL ≤ 160mg/dL: women HR 1.01 (1.00-1.02); men HR 0.99 (0.99-1.01); LDL > 160 mg/dL: women HR 0.97 (0.98-1.01); men HR 0.99 (0.98-1.01).
“[O]ur large-scale population-based study involving high-quality registry data on refined statin adherence does not support the hypothesis that long-term statin adherence confers protection against PD. Our study exemplified the importance of a refined assessment of statin adherence patterns and the applications of time-dependent modeling techniques to assess whether statins actually affect PD risk. Additional large-scale observational studies employing long-term follow-up periods are needed to further elucidate this point.”3
There has been long-running controversy regarding the association between statins and PD risk. Animal studies suggest a protective effect, whereas observational studies in humans suggest both increased and decreased risks. A recent Penn State study suggests increased risk for PD with statin use, especially for lipophilic statins and during the period when statins are initiated. On the other hand, a recent study from Tel Aviv University suggests that there is no association between statins and PD risk, regardless of age, statin type, statin potency, baseline LDL, and statin duration (up to 5 years). Both studies suggest no protective effect of statin use on PD risk, but larger, longer-term studies are needed to clear up the controversy.
1. Bykov K, Yoshida K, Weisskopf MG, et al. Confounding of the association between statins and Parkinson disease: systematic review and meta-analysis. Pharmacoepidemiol Drug Saf. 2017;26:294-300.
2. Liu G, Sterling NW, Kong L, et al. Statins may facilitate Parkinson's disease: Insight gained from a large, national claims database. Mov Disord. 2017;32:913-917.
3. Sandoiu A. Statins may raise the risk of Parkinson disease. Medical News Today. June 15, 2017. Accessed November 30, 2017.
4. Penn State. Statins may not be used for protection against Parkinson disease. Science News. June 14, 2017. Accessed November 30, 2017.
5. Melville NA. Statin use linked to increased Parkinson risk. Medscape. October 26,2016. Accessed November 30, 2017.
6. Rozani V, Giladi N, El-Ad B, et al. Statin adherence and the risk of Parkinson's disease: a population-based cohort study. PLoS One. 2017;12:e0175054.