Is There a Link Between Appendectomies and Development of Parkinson Disease?

A person's chances of developing Parkinson disease (PD) may increase if the individual previously received an appendectomy, according to findings presented today during the 2019 annual meeting of Digestive Disease Week, which is taking place in San Diego, California through tomorrow.

According to the abstract in Gastroenterology, the study by researchers at Case Western Reserve was conducted to resolve whether appendectomies increased the risk for PD, since previous findings on this association were in conflict. A 2016 study in Movement Disorders that examined nearly 1.5 million people in Denmark found that individuals who had undergone appendectomies had a marginally higher risk of later developing PD. However, a 2018 Science Translational Medicine study of more than 1.6 million people in Sweden found that appendectomies were linked to delayed development of and lower overall risk for developing PD. The inconsistencies prompted a team of researchers to further examine the link between the conditions using large scale epidemiological data from the United States.

“Recent research into the cause of Parkinson’s has centered around alpha synuclein, a protein found in the gastrointestinal tract early in the onset of Parkinson’s,” said Mohammed Sheriff, MD, the study’s lead researcher, in a statement. “This is why scientists around the world have been looking into the gastrointestinal tract, including the appendix, for evidence about the development of Parkinson’s.”

The study by Sheriff's team is the largest to evaluate the relationship between the 2 conditions. Researchers examined electronic health records from Explorys Inc, an Ohio-based company that drew data from 26 major integrated health systems and represented over 62.2 million patients. Researchers identified patients who underwent appendectomies and were diagnosed with PD at least 6 months later.

Of the 488,190 patients who had undergone appendectomies, 4470, or 0.92%, eventually developed PD. Of the 61.7 million patients who didn’t have the procedure, only 177,230, or 0.29%, developed PD. Analysis determined that patients who underwent an appendectomy were over 3 times as likely to develop PD than those who hadn’t received the procedure.

Risk levels for PD were found to be the same regardless of differences in age, gender, or race. In addition to 6-month washout period programmed into their initial query, researchers said an additional limitation was their inability to tell the exact amount of time between appendectomies and PD diagnosis.

While researchers recognized that they had exposed a potential link between the conditions, they suggested further studies were required to confirm the association.

“This research shows a clear relationship between the appendix, or appendix removal, and Parkinson’s disease, but it is only an association,” Sheriff said. “Additional research is needed to confirm this connection and to better understand the mechanisms involved.”

Reference

Sheriff MZ, Mansoor E, Cooper GS. Parkinson’s disease is more prevalent in patients with appendectomies: a national population-based study. Presented at: 2019 Digestive Disease Week Annual Meeting; May 18-21, 2019; San Diego, CA. Abstract 739. gastrojournal.org/article/S0016-5085(19)40573-8/pdf.