Gastrointestinal symptoms have been thought to precede the development of cerebrovascular disease, and some research suggests that gut conditions may also precede the development of certain neurological conditions like Alzheimer’s and Parkinson’s disease. As such the researchers designed this study to test this hypothesis using data from a US nationwide medical record network called TriNetX.
This study involved comparing data from 24,624 people diagnosed with Parkinson’s Disease (PD) of unknown cause with those diagnosed with other neurological conditions: 19,046 with Alzheimer’s Disease (AD), 23,942 with cerebrovascular disease (CD), and 24,624 controls with none of these diseases. Those with PD were matched with those in the other groups to compare the frequency of gut conditions included in their electronic health records for an average of 6 years before being diagnosed with Parkinson’s Disease.
The researchers hypothesis was then tested in another way by dividing all the adults who had been diagnosed with any of 18 gut conditions into separate groups, then they were matched with those without that particular gut condition and followed for 5 years to see if any of them developed PD or any other neurological disorder.
According to the researchers both of their analyses indicated that 4 gut conditions were associated with a higher risk of being diagnosed with Parkinson’s Disease: gastroparesis, dysphagia, and constipation were all associated with more than double the increased risk of developing PD in the 5 years preceding diagnosis, and IBS without diarrhea was associated with a 17% higher risk.
Appendix removal appeared to have a protective effect, and neither inflammatory bowel disease nor vagotomy was associated with a heightened risk. Additionally, functional dyspepsia, IBS with diarrhea, and diarrhea plus fecal incontinence were found to be more prevalent among those who developed Parkinson’s Disease as well as Alzheimer’s Disease, and cerebrovascular disease.
This study had several limitations including relatively short follow-ups, and due to the nature of observational studies, the findings are not able to establish definitive cause, but despite these, the researchers are still confident that their findings give reason for additional research to verify their results.
“This study is the first to establish substantial observational evidence that the clinical diagnosis of not only constipation, but also dysphagia, gastroparesis and irritable bowel syndrome without diarrhoea might specifically predict the development of Parkinson’s disease,” write the authors who add that “These findings warrant alertness for [gastrointestinal] syndromes in patients at higher risk for Parkinson’s disease and highlight the need for further investigation of [gastrointestinal] precedents in Alzheimer’s disease and cerebrovascular disease.”
