A study conducted in Taiwan found Parkinson's disease appears to be linked with 16 different types of cancer, researchers say.
The finding is significant because most previous research on such associations was conducted among Western populations, they say.
Some 25 epidemiological studies conducted during the past 5 decades years have shown individuals with Parkinson's faced a reduced risk of cancers compared with people without Parkinson's, but the researchers wanted to conduct their study on an East Asian population, since recent research has suggested genetic factors and backgrounds play a significant role in the development of many diseases, including cancers.
Researchers at the National Taiwan University College of Medicine in Taipei utilized the Taiwan National Health Insurance Research Database to select a study cohort of more than 62,000 patients diagnosed with Parkinson's between 2004 and 2010, and a control participant group of around 124,000 without Parkinson's.
While the study yielded no association of Parkinson's with an increased level of risk for breast, thyroid or ovarian cancer, Parkinson's did appear to have a risk association with 16 other forms of cancer.
Those included lung cancers, cancerous brain tumors, lymphoma/leukemia, urinary tract cancers, plus some hormone-associated cancers and melanoma and related types of skin cancers, the researchers report in the journal JAMA Oncology.
"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," the researchers wrote. "In our cohort, only breast, ovarian and thyroid cancers show no association with PD."
Whether the findings could be applied for other East Asian populations will require further studies, the researchers pointed out.
Still, the Taiwan study raises some important points to consider, they said.
"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 researchers wrote.
Their study did have limitations, they acknowledge, including a possible underestimation of Parkinson's incidence, not including smoking status or exposure to pesticides in their analysis, and the possibility of undiscovered genetic correlations.
