Appendectomy and Parkinson's Disease Risk: A Meta-Analysis

The emergence of alternative methods of treating appendicitis and the fact that the gut lymphoid tissue is active (in terms of immune modulation and gut microbiota replenishment) increased the concern about the association of appendectomy with systemic diseases. The literature on the association between appendectomy and Parkinson's disease (PD) lacks the current meta-analysis aimed to assess the association between appendectomy and PD. We systematically searched PubMed, Cochrane Library, and Google Scholar for relevant articles published in the English language, the searching engine was limited to the period from January 2010 to January 2021. Studies on humans were eligible, while animal and experimental studies were excluded, the keywords used were Parkinson's disease, appendicitis, Parkinsonism, appendectomy, gut lymphoid tissue, and movement disorders with protean ^"AND^" or ^"OR^".  Out of the 263 references found, 39 full texts were screened, and only five studies fulfilled the inclusion and exclusion criteria, the studies included 8210081 patients and showed that no association between appendectomy and PD, odd ratio, 1.16, 95% CI, 0.92-1.46, and P-value, 0.20. Significant heterogeneity was observed between the studies included (three from the United States of America and two from Europe) and no relationship was evident between appendectomy and PD, further studies controlling for the causes of appendectomy and temporal profile of both PD and appendectomy are recommended.