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Original article
Inflammatory bowel disease increases the risk of Parkinson’s disease: a Danish nationwide cohort study 1977–2014
  1. Marie Villumsen1,
  2. Susana Aznar2,
  3. Bente Pakkenberg2,3,
  4. Tine Jess1,
  5. Tomasz Brudek2
  1. 1 Center for Clinical Research and Disease Prevention, Bispebjerg and Frederiksberg Hospital, Copenhagen, Denmark
  2. 2 Research Laboratory for Stereology and Neuroscience, Bispebjerg and Frederiksberg Hospital, Copenhagen, Denmark
  3. 3 Faculty of Health, Institute of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
  1. Correspondence to Dr Tomasz Brudek, Research Laboratory for Stereology and Neuroscience, Bispebjerg and Frederiksberg Hospital, Copenhagen DK-2400, Denmark; tomasz.brudek{at}


Objective Intestinal inflammation has been suggested to play a role in development of Parkinson’s disease (PD) and multiple system atrophy (MSA). To test the hypothesis that IBD is associated with risk of PD and MSA, we performed a nationwide population-based cohort study.

Design The cohort consisted of all individuals diagnosed with IBD in Denmark during 1977–2014 (n=76 477) and non-IBD individuals from the general population, who were comparable in terms of gender, age and vital status (n=7 548 259). All cohort members were followed from IBD diagnosis/index date to occurrence of PD and MSA (according to the Danish National Patient Register).

Results Patients with IBD had a 22% increased risk of PD as compared with non-IBD individuals (HR=1.22; 95% CI 1.09 to 1.35). The increased risk was present independently of age at IBD diagnosis, gender or length of follow-up. The overall incidence of MSA was low in our study, and the regression analysis suggested a tendency towards higher risk of developing MSA in patients with IBD as compared with non-IBD individuals (HR=1.41; 95% CI 0.82 to 2.44). Estimates were similar for women and men. The increased risk of parkinsonism was significantly higher among patients with UC (HR=1.35; 95% CI 1.20 to 1.52) and not significantly different among patients with Crohn’s disease (HR=1.12; 95% CI 0.89 to 1.40).

Conclusions This nationwide, unselected, cohort study shows a significant association between IBD and later occurrence of PD, which is consistent with recent basic scientific findings of a potential role of GI inflammation in development of parkinsonian disorders.

  • Parkinson’s disease
  • parkinsonism
  • inflammatory bowel disease
  • hazard ratio
  • inflammation
  • enteric nervous system

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  • Contributors BP, TB, SA and TJ designed the study. TB and MV drafted the first version of the manuscript. All authors contributed substantially to the manuscript. TB and SA did the literature search. MV analysed the data. MV, TJ and TB interpreted the analyses. All authors approved the final manuscript. All authors, external and internal, had full access to all of the data (including statistical reports and tables) in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

  • Funding This study was supported by grants from Parkinsonforeningen, Landsforeningen Multipel System Atrofi, and Aage og Johanne Louis-Hansens Fond.

  • Disclaimer The funding agencies had no role in the design and conduct of the study; the collection, management, analysis and interpretation of the data; the preparation, review or approval of the manuscript; or the decision to submit the manuscript for publication.

  • Competing interests None declared.

  • Patient consent Not required.

  • Ethics approval The study was register based and complied with the regulations and registrations set up by the Danish Data Protection Agency and the Danish Health Data Authority (FSEID-00001565).

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement No additional data available.

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