Gastrointestinal inflammation has been implicated in PD. The aim of this study was to examine whether individuals with a history of CDI are at elevated risk of PD.

We performed a population‐based cohort study using Swedish national register data. Diagnoses of CDI and PD were extracted from the National Patient Register. Associations of CDI history with PD risk were estimated using Cox proportional hazards regression. We also explored whether the association differed by the source of CDI diagnosis, presence of recurrent infections, and pre‐infection use of antibiotics.

Amongst the study population of 4 670 423, 0.75% had a history of CDI. 165 in total and 47 035 incident PD cases were identified from individuals with and without CDI history, respectively. Across the entire follow‐up, a 16% elevation of PD risk was observed among the CDI group, which was mainly driven by increased PD risk within the first 24 months after CDI diagnosis. In a longer follow‐up, CDI was not associated with subsequent PD occurrence. This temporal pattern of CDI–PD associations was generally observed across all CDI subgroups.

The study concluded that the clostridium difficile may be associated with an increased short‐term PD risk, but this might be explained by reverse causation and/or surveillance bias. The findings of this research do not imply that CDI history affects long‐term PD risk.