Effects of antimicrobial exposure on the risk of Parkinson's disease

We aimed to assess how antimicrobial exposure affects Parkinson's disease (PD) risk.

A nested case-control study was performed to examine the association between antimicrobial exposure and newly diagnosed PD using the Clinical Practice Research Datalink (CPRD). Each PD case was matched by age, sex, and year of diagnosis (index date) to up to 15 controls. Number of prescribed antimicrobial courses was assessed 1-5, 6-10, and 11-15 years prior to the index date. Logistic regression with generalized estimating equations (GEE) was used to estimate odds ratios (ORs) and false discovery rate-adjusted p-values between antimicrobial exposure and risk of PD.

We compared 12,557 PD cases with 80,804 matched controls. We found an inverse dose-response relationship between number of penicillin courses and PD risk across multiple time periods (5+ courses, 1-5 years prior: OR 0.85, 95 % CI 0.76-0.95, p = 0.043; 6-10 years prior: OR 0.84, 95 % CI: 0.73-0.95, p = 0.059; 11-15 years prior: OR 0.87, 95 % CI 0.74-1.02, p = 0.291). The number of macrolide courses was inversely but not significantly associated with PD risk 1-5 years prior to the index date (OR 0.89-0.91, 95 % CI: 0.79-0.99, adjusted p = 0.140-0.167). Exposure to ≥2 courses of antifungals 1-5 years prior was associated with an increased risk of PD (OR 1.16, 95 % CI: 1.06-1.27, p = 0.020).

In a large UK-representative population, the risk of PD was modestly lower among adults who had previously received multiple courses of penicillins in the last 15 years and modestly higher among those exposed to antifungal medicines in recent years.