Mertsalmi TH, et al. - Researchers undertook this nationwide, register-based, case-control investigation to examine the influence of antibiotic exposure on the risk of Parkinson disease (PD). All patients who received a diagnosis of PD from 1998 to 2014 in Finland were selected. They gathered data on individual purchases of orally delivered antibiotics during the years 1993 to 2014. They used conditional logistic regression to evaluate the link between previous antibiotic exposure and PD. Overall 13,976 PD cases and 40,697 controls were examined. For oral exposure to macrolides and lincosamides, the strongest link with PD risk was identified. Positive link with PD risk was reported for exposure to antianaerobics and tetracyclines 10 to 15 years prior to the index date, sulfonamides and trimethoprim 1 to 5 years prior to the index date, and antifungal medications 1 to 5 years prior to the index date, following correction for multiple comparisons. Further positive links for broad-spectrum antibiotics were revealed in post hoc analyses. Overall, in relation to exposure to certain types of oral antibiotics, there appeared a raised risk of PD with a delay that was consistent with the proposed duration of a prodromal period. Based on the observed pattern of links, the hypothesis that influences on gut microbiota could connect antibiotics to PD was supported, however, confirmation in further investigations is required.