WEDNESDAY, Jan. 4 (HealthDay News) -- Men appear more likely to die from Parkinson's disease than women, Hispanics and Asians with the neurologic disorder, a large U.S. study reveals.

The researchers also found that those patients who suffered from dementia had a higher death rate from Parkinson's disease.

The findings stem from an analysis of 138,000 Parkinson's patients across the United States who were Medicare beneficiaries between 2002 and 2008.

Led by Dr. Allison Willis from Washington University School of Medicine in St. Louis, the study appears in the January issue of the Archives of Neurology.

During the six-year study period, overall, 64 percent of the patients died. Nearly 70 percent had developed dementia in that time.

Black patients had the highest death rate, at more than 66 percent, while white patients had a slightly lower rate of almost 65 percent.

By contrast, Hispanic and Asian Parkinson patients faced death rates of roughly 55 percent and 51 percent, respectively.

The team also found that those patients who had both dementia and Parkinson's were less likely to survive. The incidence of dementia was highest among black Parkinson's patients at more than 78 percent. Hispanics, whites, and Asians had dementia rates of about 73 percent, 69 percent and 67 percent, respectively.

"We demonstrate that dementia occurs commonly in patients with incident [Parkinson's disease] 65 years and older; this had the strongest effect on age-adjusted survival among the variables that we studied," the authors said in a journal news release. "Our data highlight the need for prevention of, or treatment, for dementia in patients with PD because of its effect on survival."

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For more on Parkinson's, visit the U.S. National Library of Medicine.