Appendectomy and the Risk of Parkinson's Disease: A Korean Nationwide Study

Background: The vermiform appendix is considered a potential reservoir for the abnormal alpha-synuclein aggregate in Parkinson's disease (PD). Previous epidemiologic evidence on the association between appendectomy and PD risk remains inconclusive, especially outside the Western world. Objectives: To investigate the association between appendectomy and PD risk in Korea. Methods: Among 703,831 eligible adult subjects in the National Health Insurance Service sample cohort, we identified 16,122 patients who underwent appendectomy. The rest formed the control group. PD risk was assessed using time-dependent Cox regression analyses. Results: The appendectomy group did not have altered risk of PD compared with the control group in either unadjusted [hazard ratio (HR) 1.32, 95% confidence interval (CI) 0.97-1.80, P = 0.08] or adjusted model (HR 1.42, CI 0.88-2.30, P = 0.15). No further statistical difference appeared when stratified by sex. Conclusions: Appendectomy is not associated with altered risk of PD in the Korean population.