The study was conducted in an effort to understand the association on an East Asian population, since most investigations aiming to look at this link have been conducted in Western populations.
A great amount of evidence, more than 25 epidemiological studies, has been collected during the last 50 years looking at the association between PD and cancer. Most of these studies have found that patients with PD are at a lower risk of developing cancer when compared with individuals without the condition. However, most studies have been conducted in Western populations, with evidence showing that genetic background plays an important role in disease development.
The researcher team from the National Taiwan University College of Medicine, led by Pan-Chyr Yang, M.D., Ph.D., used the Taiwan National Health Insurance Research Database and included a total of 62,023 patients with a recent diagnosis of PD, who were diagnosed between 2004 and 2010. A total of 124,046 individuals without PD were used as controls.
The results showed there was not an association between a diagnosis of PD and increased risk of ovarian, breast, or thyroid cancers. However, the researchers found that PD was associated with 16 other types cancers such as gastrointestinal tracts cancers, lung cancers, lymphoma/leukemia, malignant brain tumors, some hormone-related cancers, urinary tract cancers, melanoma and other skin cancers.
According to the team their study has some limitations such as underestimation of PD incidence, smoking status (which was not included in their analysis), speculation about pesticide exposure and remaining questions on genetic correlations.
“Based on this nationwide study on the association between PD [Parkinson disease] and cancer risk, we conclude that PD is a risk factor for most cancer in Taiwan. In our cohort, only breast, ovarian and thyroid cancers show no association with PD. Further studies are needed to clarify whether our findings can be applied to other East Asian populations. The striking differences between our study and the previous studies in Western cohorts suggest the importance of ethnicity and environmental exposures in disease pathogenesis,” the authors stated in a recent news release.