Parkinson’s disease and risk of colorectal cancer: A population-based case-control study in Taiwan

Objective: The aim of this study was to evaluate whether there is an association between Parkinson’s disease (PD) and colorectal cancer in Taiwan. Methods: This was a case-control study using claim data of the Taiwan National Health Insurance Program. There were 64,619 subjects aged 20-84 with newly diagnosed colorectal cancer as cases and 64,619 randomly selected subjects without colorectal cancer as controls from 2005 to 2011. Both cases and controls were matched by sex, age, comorbidities, and index year of diagnosing colorectal cancer. Subjects who were diagnosed with PD within 5 years of diagnosing colorectal cancer were excluded. The multivariable logistic regression model was used to estimate the adjusted odds ratio (OR) and 95% confidence interval (95% CI) for risk of colorectal cancer associated with PD. Results: After adjusting for confounding factors, the multivariable logistic regression analysis revealed that the adjusted OR of colorectal cancer was 0.69 for subjects with PD more than 5 years before index date (95% CI 0.59, 0.81), as compared with subjects without PD. Conclusion: PD is associated with reduced odds of colorectal cancer. Further research is needed to elucidate the mechanisms underlying our findings.