Oct. 4, 2010 -- Parkinson’s disease is not considered fatal, but people with Parkinson’s have a shorter life expectancy than the general population.

Now new research provides clues as to why some patients die sooner than others.

Researchers in Denmark closely followed the disease progression of more than 200 patients diagnosed with Parkinson’s.

They found that being diagnosed later in life, scoring poorly on movement tests, experiencing psychotic symptoms, and developing dementia were all associated with a shorter life expectancy.

And men with Parkinson’s were more likely to die early than women.

“There was a remarkable variability in time to death, ranging from 2 to 37 years after (motor symptoms began),” the researchers write in the October issue of the journal Neurology. “Our findings suggest that early prevention of motor progression, psychotic symptoms, and dementia might be the most promising strategies to increase life expectancy in Parkinson’s disease.”
About Parkinson's Disease

Nearly 1 million people in the U.S. are living with Parkinson’s disease, with between 50,000 and 60,000 new cases diagnosed each year, according to the National Parkinson’s Foundation.

Most cases occur in people over the age of 60, but some people develop the disease much earlier in life, as was the case with actor Michael J. Fox, who was diagnosed at age 30.

Parkinson’s is a chronic, progressive disease characterized by motor symptoms including tremors, muscle stiffness, and slowed movement. About a third of patients also develop dementia during the later stages of the disease.

There is no cure for Parkinson’s, but the drug levadopa and other medications can control symptoms for many years.

Because the clinical course of disease progression varies widely from patient to patient, identifying risk factors associated with early death could help doctors better target treatment strategies.

In an effort to do this, researchers from Norway’s Stravanger University Hospital analyzed data from 230 Parkinson patients participating in a larger study.

During the research period from 1993 to 2009, 211 patients died. The analysis revealed that:

    * The average time from the onset of symptoms to death was 16 years.
    * The average age at death was 81.
    * Patients with dementia were nearly twice as likely to die early as patients without memory problems.
    * Patients with a history of delusions, hallucinations, or other psychotic symptoms were almost 50% more likely to die early, compared to patients without the symptoms.
    * Men with Parkinson’s were about 60% more likely to die early than women.

 
Identifying Risk Factors for Parkinson's

The risk for early death increased by about 40% for every 10-year increase in age at diagnosis.

Parkinson’s researcher Tobias Kurth, MD, agrees that identifying risk factors for early death could help clinicians better manage the disease.

Kurth is an adjunct associate professor of epidemiology at Harvard School of Public Health.

“This is important research that adds to our understanding of the impact of specific features of Parkinson’s disease on outcomes,” he tells WebMD.

His own study of Parkinson’s-associated death matched Parkinson’s patients with people without the disease who had similar non-Parkinson’s-related illnesses.

Like the newly reported study, patients who were older when their Parkinson’s disease was diagnosed had a greater risk for early death.