Revisiting the Association Between Inflammatory Bowel Disease and Parkinson's Disease

Background Several studies have reported an association between inflammatory bowel disease (IBD) and Parkinson's disease (PD). The aim of this study is to re-evaluate for an association between IBD and PD while controlling for potential socioeconomic and environmental confounders. Methods We performed a retrospective cohort study using the Truven Health Marketscan database between January 1, 2005, and December 31, 2014. Individuals with IBD and household age-matched controls were identified. Adjusted hazard ratios (HRs) were calculated for the development of incident PD, adjusting for age, sex, residence type, US region, comorbidities, and behavior. Results In all, 154 051 subjects with IBD and an equal number of controls were identified. During a mean (SD) follow-up of 3.8 (2.2) years, 132 incident PD cases were identified. There was no significant association between IBD and PD (adjusted HR, 1.01; 0.72-1.42) when adjusting for the confounders previously mentioned. Conclusions We found no statistically significant association between these disorders. It is possible that previous associations identified between these disorders were confounded by environmental and socioeconomic factors.