While most of these studies reported fewer than 10 cases where both conditions occurred, the researchers found that men with Parkinson's disease were twice as likely to develop melanoma as men without Parkinson's disease.
For women, the risk of melanoma was one-and-a-half times greater if they had Parkinson's disease than if they didn't, Chen's group found.
However, since both conditions are relatively rare, the odds of having Parkinson's disease and melanoma are only about 4 percent, Chen said. "The absolute risk is not that high," he added.
Still, "it is prudent for Parkinson's disease patients to be a little cautious about their skin health," Chen said. "Be prudent, but do not be alarmed."
Limitations of the study include the fact that most of the studies were not originally designed to evaluate the association between melanoma and Parkinson's disease, and the analysis is based on a very small number of cases, the authors noted.
The authors also acknowledged that their research is preliminary and said more studies are needed to explore the relationship between the brain disorder and the potentially lethal skin cancer.
Joyce Oberdorf, CEO of the National Parkinson's Foundation, said an association between the two conditions is becoming increasingly evident, but most patients and doctors are unaware of the possible connection.
"Drawing attention to the risk is definitely required," Oberdorf said, adding that the foundation is launching a campaign to alert patients.
"We are making the recommendation that every person with Parkinson's wear sunscreen and receive an annual screening by a dermatologist for melanoma," she added.
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