Patients with inflammatory bowel disease (IBD) have a 22% higher risk of developing Parkinson’s disease, a large-scale observational study suggests.
The study, “Inflammatory bowel disease increases the risk of Parkinson’s disease: a Danish nationwide cohort study 1977–2014,” was published in the journal Gut.
Previous studies have shown that Parkinson’s patients have both motor and non-motor clinical features, which can include gastrointestinal dysfunctions. In fact, gastrointestinal issues tend to appear quite early in the Parkinson’s development course and can significantly contribute to Parkinson’s-related complications.
IBD is characterized by chronic inflammatory immune activity — which is a fundamental element of neurodegenerative disorders such as Parkinson’s and multiple system atrophy (MSA).
While there is significant biological evidence supporting a link between gut inflammation and the development of Parkinson’s and MSA, real-life evidence from population studies is lacking.
Danish researchers set out to conduct a nationwide study of all patients diagnosed with IBD in Denmark between 1977 and 2014 — 76,477 patients — to assess the proportion of patients who would later develop either Parkinson’s or MSA. Individuals without IBD — 7,548,259 — were used as comparative controls.
Over a 37-year period, 335 patients with IBD and 39,784 patients without IBD developed Parkinson’s. Additionally, 13 patients with IBD and 866 patients without IBD were diagnosed with MSA.
Researchers found that IBD patients had a 22% higher risk of developing Parkinson’s than non-IBD individuals. Statistical analysis showed that this higher risk was present even after accounting for age at IBD diagnosis, gender, or length of follow-up.
While no meaningful conclusions can be drawn regarding the link between MSA and IBD since the overall incidence of MSA was low in the study, statistical analysis did indicate there was a tendency toward a higher risk of MSA development in patients with IBD compared with patients without IBD.
Therefore, the authors conclude, “in this nationwide Danish cohort study of all patients with IBD followed for more than 8 million person-years, we found a significantly increased risk of [Parkinson’s disease] when comparing patients with IBD with non-IBD individuals from the general Danish population.”