RECENT research has demonstrated that there may be a connection between various gastrointestinal problems and Parkinson’s disease (PD). Studies have shown that dysphasia, gastroparesis, and irritable bowel syndrome (IBS) without diarrhoea may come with an increased risk of later developing the neurological disease, with evidence to suggest that “the pathological molecule associated with [PD] can indeed travel from the gut to the brain,” according to chair of the department of medicine at Mayo Clinic Arizona, Phoenix, USA, Pankaj Jay Pasricha.
Pasricha and colleagues carried out a combined case-control and cohort study involving 24,624 individuals with new onset idiopathic PD, with matched negative controls (NC), and patients who had been diagnosed with Alzheimer’s disease and cerebrovascular disease. Cohorts were also compared for development of PD, Alzheimer’s disease, and cardiovascular disease within the last 5 years.
Both case-control and cohort analyses revealed that gastroparesis (odds ratio [OR]: 4.64; relative risk [RR]: 2.43), dysphagia (OR: 3.58; RR: 2.27), IBS (OR: 3.53; RR: 1.17), and constipation (OR: 3.32; RR: 2.38) all show associations with later development of PD versus negative controls. However, functional dyspepsia, IBS with diarrhoea, diarrhoea, and faecal incontinence did not show any specific link with PD, while IBS with constipation and intestinal pseudo-obstruction showed specificity to PD in the case-control (OR: 4.11) and in the cohort analysis (RR: 1.84).
Further analysis demonstrated that undergoing an appendectomy decreased the risk of developing PD in the cohort analysis (RR: 0.48). Moreover, conditions and interventions such as inflammatory bowel disease and vagotomy were not proven to have any association with PD.
Despite evidence to suggest a connection between certain gastrointestinal problems and PD, this research does not prove a causal relationship. While these conditions may be used to predict PD, Pasricha concluded that there is “no need for alarm” when it comes to cause or effect, adding that “the overall risk for developing PD is low, so even a two to four increase still translates to a very low absolute risk. The overwhelming majority of patients with these gastrointestinal conditions will never develop PD.”
