The risk of developing Parkinson's was 19 percent lower among those who had their appendix surgically removed decades earlier.
Using health registries in Sweden covering some 1.7 million people followed for 50 years, and a second USA dataset encompassing 849 people, researchers found that those who had their appendix removed in early adulthood generally saw their risk of developing Parkinson's disease cut by 19 per cent, said the study in the journal Science Translational Medicine. Parkinson's is often more common in rural areas, which may be due to exposure to pesticides that are thought to be linked to the disease, Labrie said.
Study coauthor Viviane Labrie, an assistant professor at the Van Andel Research Institute in MI, doesn't go quite as far, telling CNN the disease is a multisystem disorder, "so there's likely to be many sites of origin in terms of where Parkinson's disease starts, the [gastrointestinal tract] being one of them".
"Despite having a reputation as largely unnecessary, the appendix actually plays a major part in our immune systems, in regulating the makeup of our gut bacteria and now, as shown by our work, in Parkinson's disease", senior author Viviane Labrie from Van Andel Research Institute in MI told The Guardian.
Knowing that people with Parkinson's also suffer from gastrointestinal disorders like constipation at least 10 years before the disease's better known symptoms like tremors, stiffness, and poor balance appear, researchers made a decision to take a closer look at the appendix and its potential role.
Common among the complications of Parkinson's is the onset of gastrointestinal dysfunction - including constipation - which can actually precede mobility loss by as much as 20 years. However, in Parkinson's patients, this protein can build up into clumps, killing off cells in the parts of the brain responsible for movement and producing the tremors, stiffness, and slowness that characterize the illness.More news: `Man eater` tigress Avni killed in Maharashtra
For a while, researchers have suspected a type of protein called α-synuclein as one of the culprits behind the disease. "It's able to move from neuron to neuron and it has been shown that it can travel in experimental evidence - that it can travel up the nerve that connects the gastrointestinal [GI] tract to the brain", said Labrie.
What's more, after honing in on the specific experiences of about 850 Parkinson's patients, the researchers determined that appendix removal was also associated with a 3.6-year delay in the onset of Parkinson's among those who had the surgery and still developed the disease.
Conway, who was not involved in the research, added that "several previous studies have looked for relationships between appendix removal and various other diseases, including heart disease as well as various diseases of the gut".
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Parkinson's is a slow acting disease. She explained that drug therapies could target this finding to prevent Parkinson's disease.
An analysis of around 1.7 million people has revealed a curious link between the appendix and Parkinson's disease.More news: Kim vows to build strong country despite sanctions
For years, scientists have hypothesized about what might cause the gut-Parkinson's connection.
She described the link between Parkinson's and the appendix as "particularly interesting".
Researchers suggest that the appendix might also be the source for a protein called α-synuclein that has been implicated in Parkinson's, reports Aimee Cunningham at ScienceNews. "And if it were to enter the brain, it can seed and spread from there and have neurotoxic effects that could eventually lead to Parkinson's disease". But strangely, this is true regardless of whether a person suffers from Parkinson's or not - suggesting the proteins are just one of many factors contributing to the development of the disease.
That kind of study doesn't prove that removing the appendix is what reduces the risk, cautioned Dr. Andrew Feigin, executive director of the Parkinson's institute at NYU Langone Health, who wasn't involved in Wednesday's research.
The condition remains poorly understood and has no effective treatment. They imaged 48 appendixes taken from people without Parkinson's.
This field of research is asking as many new questions as it answers.More news: Air quality improves slightly, diesel curbs likely