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Some Parkinson's Symptoms are Associated with Reduced Life Expectancy
- Oct 08 2010
Since levodopa became the mainstay of Parkinson’s disease (PD) therapy some 40 years ago, the life expectancy of people with PD has increased to be similar to that of the general population. A 2009 report in Movement Disorders found that people with PD had the same life expectancy as others the same age without PD, living to an average age of 77.
Yet some people live for decades after being diagnosed with Parkinson’s, whereas others live for only a few years. The authors of a new study published in the October 5, 2010 issue of Neurology wanted to understand what factors related to PD were associated with this wide range of survival times.
This study found that individuals who develop Parkinson’s at an older age, and those who have severe movement symptoms, tend to live for a shorter time after being diagnosed than people who develop the disease at a relatively young age or have milder symptoms. In addition, the researchers found that people with PD who had dementia or psychotic symptoms also had a reduced life expectancy.
The researchers, led by Elin B. Forsaa, M.D., at Stavanger University Hospital in Norway, followed 230 people with PD for 12 years, beginning in 1993, regularly evaluating the study participants’ motor and nonmotor symptoms using standardized tests.
On average, study participants had been diagnosed with PD at age 65 and lived for 16 years, to the age of 81. After the onset of motor symptoms, individuals lived from two to 37 years. By the end of the study, 19 study participants were living.
Factors that predicted a shortened life expectancy included:
- Older age at the time of PD diagnosis
- Older age in general
- Being male
- Severe movement symptoms, particularly balance and gait difficulties
- Symptoms of dementia
- Symptoms of psychosis, including hallucinations and delusions
- REM sleep behavior disorder itself did not predict a shortened life expectancy, although it is recognized as a risk factor for psychosis
- For people with PD, taking antipsychotic drugs did not increase mortality
What Does it Mean?
This study identified predictors of mortality in PD. Some of these predictors cannot be changed (e.g., gender, age or age-at-onset) but others, that can be potentially controlled, should be the focus of PD treatment and research. These include motor function and the presence of dementia and hallucinations. Focusing on interventions for preventing or delaying the progression of these predictors may be the most promising strategies for helping people with PD to live longer.
Furthermore, the fact that neither treatment with levodopa nor treatment with antipsychotics was linked to reduced life expectancy is encouraging, but more research is needed on specific antipsychotic medications to confirm these findings. This is in contrast to Alzheimer’s disease, for which antipsychotics have been shown to increase mortality.
The new report also bolsters the findings of other researchers that there are subtypes of PD that progress at different rates. Other studies have linked gait and balance difficulties, as well as a lack of tremor, to a more rapidly progressing form of PD.
In sum, the mean life expectancy of people with PD in this study is encouraging (similar to the mean life expectancy of the general population in Norway and higher than the mean life expectancy in the United States), but more work is needed to find treatments for dementia, hallucinations and motor deterioration which are all linked to shorter life expectancy.
Reference: E.B. Forsaa, M.D., J.P. Larsen, M.D., Ph.D., T. Wentzel-Larsen, M.Sc. and G. Alves, M.D., Ph.D. What predicts mortality in Parkinson disease? A prospective population-based long-term study. Neurology. October 5, 2010.(http://www.neurology.org/cgi/content/abstract/75/14/1270)
Source Date: Oct 08 2010