Factors in Association Between Parkinson Disease and Risk of Cancer in Taiwan

To the Editor In their article, Lin et al¹ analyzed the association between Parkinson disease (PD) and subsequent risk of cancer in data obtained from the Taiwan National Health Insurance Research Database, using a cohort design. Although most studies show a lower risk of cancer after PD,² Lin et al found a nearly 60% elevated risk for all subsequent cancers and increased risks for 16 of 19 specific cancer types examined. The authors conclude, “the differences between our study and most previous cohorts suggest the importance of ethnicity and environmental exposures in disease pathogenesis.”