WASHINGTON, June 22 (UPI) -- A large study in Taiwan concluded that Parkinson's disease is associated with 16 different types of cancer among people there, despite many studies that have said having Parkinson's decreased the chances of cancer.
Both Parkinson's and cancer generally are disorders of aging, so a potential relationship between them would not be surprising, but scientists point to considering cultural genetic differences and information not available to researchers at the National Taiwan University College of Medicine.
"Our study concludes that PD is is associated with most cancers in Taiwan," researchers wrote in the study, which is published in JAMA Ocnology. "Further studies are needed to clarify whether our findings can be applied to other East Asian populations. The differences between our study and most previous cohorts suggest the importance of ethnicity and environmental exposures in disease pathogenesis."
Researchers reviewed the medical records of 62,023 newly diagnosed Parkinson's patients and 124,046 people who did not have Parkinson's, which were collected between 2004 and 2010 by the Taiwan National Health Insurance Research Database.
They found that a Parkinson's diagnosis increased the chances of 16 of 19 cancers, with the exceptions being breast, ovarian and thyroid cancers. The chances of brain and skin cancer increased between 2.5 and 3.5 times, and the chances of cancers in the gastrointestinal tract, stomach, colorectal, liver, gallbladder, pancreas, lung , cervical, prostate, kidney and bladder cancers, lymphoma and/or leukemia melanoma, and other skin cancers all went up as well with a Parkinson's diagnosis.
The association between the two does not mean one causes the other, but researchers from the University of Pittsburgh wrote in a commentary piece that the association must be investigated.
"Whether PD increases cancer directly, or whether they share common antecedents or mechanisms, cannot be discerned from this study," researchers wrote in the commentary, because of gaps in data in pesticide exposure and smoking, as well as longitudinal information on the patients lives and survival rates. They later added, however, that "having now established that these complex diseases are linked, the way seems clear for careful and systematic analysis of both the intrinsic differences in cell biology as well as extrinsic factors found in the environment that link them."