A study of the health system records of more than 60 million people has found a link between appendectomy and increased risk of developing Parkinson’s disease.
The scientists of the study compared data on individuals who had experienced an appendectomy, or appendix removal, to those who had not.
The study showed that those who had undergone an appendectomy were more than 3 times more probable to develop Parkinson’s disease later. The outcomes are a further signal of a link between the brain and gut in Parkinson’s disease.
Preceding studies have drawn different inferences about whether having an appendectomy might increase or lower an individual’s risk of developing Parkinson’s disease.
For instance, a 2016 Movement Disorders study of around 1.5 million people was conducted in Denmark. It found that people who had had an appendix removed were at considerably higher risk of developing Parkinson’s disease in the near future.
In contrast, a 2018 Science Translational Medicine study of around 1.6 million people in Sweden tied appendectomy to lower risk and delay in Parkinson’s disease development. This disagreement urged the investigators of a new study to embark on a much more broad analysis. It drew on the electronic health data of 62.2 million persons in 26 health systems in the U.S.
In a Gastroenterology abstract, the scientists propose that what is missing from the study on appendectomy and Parkinson’s disease risk is “large-scale epidemiological records.”
Parkinson’s, alpha-synuclein, and the gut
Parkinson’s disease gradually destroys cells in a part of the brain which helps control movement. Its symptoms include tremor, movement stiffness, slowness, and balance problems.
The number and proportion of people living with Parkinson’s disease are growing in aging populations. This is because it most often attacks older people. As so far, there is no cure and treatment which slows down Parkinson’s disease.
An avenue which scientists are following concerns alpha-synuclein, that is a protein which features in the development of Parkinson’s.
Though it is unclear what task it serves in those without the disease, alpha-synuclein forms toxic masses named Lewy bodies in the brains of those with Parkinson’s disease. Researchers also found that more recent research has found masses of alpha-synuclein in the digestive tract of individuals in the early phases of Parkinson’s.
This is the reason that scientists have been looking into the gastrointestinal tract, comprising the appendix, for an indication about the development of Parkinson’s disease.
Appendectomy and higher Parkinson’s risk
From the data of 62.2 million patient, the research team identified 488,190 people who had undergone an appendix removal. Of these, 4,470 individuals went on to get a diagnosis of Parkinson’s.
Of the remaining 61.7 million individuals, only 177,230 received a diagnosis of Parkinson’s disease. The research team also found that the more than 3 times higher probability of developing Parkinson’s disease following an appendix removal was not dependent on sex, age, or race.
This study shows a strong relationship between the appendix and Parkinson’s disease, but it is only a link. Further research is required to confirm this association and to better comprehend the mechanisms involved.