Immunohistochemistry for alpha-synuclein showing positive staining (brown) of an intraneural Lewy-body in the Substantia nigra in Parkinson's disease. Credit: Wikipedia
A study of patients in a Minnesota county suggests the incidence (new cases) of parkinsonism and Parkinson disease may have increased over the past 30 years but that trend may not be genuine and must be confirmed in other populations, according to an article published online by JAMA NeurologyA previous study suggested smokers may have reduced risk of Parkinson disease (PD) and speculated the decline in smoking by men in the U.S. after a peak in the 1940s and 1950s could result in an increase in PD incidence decades later. That theory has not been tested empirically.
As a result, Walter A. Rocca, M.D., M.P.H., of the Mayo Clinic, Rochester, Minn., and coauthors studied time trends for parkinsonism and for PD in Olmsted County, Minn., from 1976 to 2005.
Parkinsonism was defined as the presence of at least two cardinal signs: rest tremor, bradykinesia, rigidity and impaired postural reflexes. PD was defined as parkinsonism with all three of the following features: no other cause, no documentation of unresponsiveness to levodopa, and no prominent or early signs of more extensive nervous system involvement.
The study included 906 patients with parkinsonism with a median age at onset of 74, of whom 501 were men. Of the 464 patients with PD with a median age of onset at 73, 275 were men.
Incidence rates of parkinsonism increased in men from 38.9 per 100,000 person-years between 1976 and 1985 to 55.9 between 1996 and 2005. Rates of PD increased in men from 18.2 between 1976 and 1985 to 30.4 between 1996 and 2005 and the increase was greater for men over 70 or older. No similar overall trends were seen for women, according to the results.
The authors note their trends should be interpreted with caution for a variety of reasons, including that they may be due to increased awareness of symptoms, improved access to care of patients, and better recognition by physicians.
The authors suggest the trends they report may suggest a possible association with a change in smoking behavior. The prevalence of smoking has declined over time. However, other important lifestyle and environmental changes also have taken place over the decades.
"Our study suggests that the incidence of parkinsonism and PD may have increased between 1976 and 2005, particularly in men 70 years old and older. These trends may be associated with the dramatic changes in smoking behavior that took place in the second half of the 20th century or with other lifestyle or environmental changes. However, the trends could be spurious and need to be confirmed in other populations," the study concludes.
"The epidemiologic observation that cigarette smoking is associated with lower PD risk is robust but the debate over whether the association is causal seems never to be resolved. Given the substantial adverse health effects of cigarette smoking and low PD incidence, it is almost impossible to directly examine this question in clinical studies. However, results of the Savica et al study and a similar previous analysis may offer indirect support for causality: the increase of PD incidence may follow decrease in cigarette smoking over the past 50 years, a trend that also affects men more than women," Honglei Chen, M.D., Ph.D., of the National Institute of Environmental Health Sciences, Triangle Park, N.C., writes in a related editorial.
More information: JAMA Neurol. Published online June 20, 2016. DOI: 10.1001/jamaneurol.2016.0947
Journal reference: Archives of Neurology
Provided by: The JAMA Network
http://medicalxpress.com/news/2016-06-incidence-parkinson-disease-years.html
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http://medicalxpress.com/news/2016-06-incidence-parkinson-disease-years.html
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Parkinson's Rates Rising Among American Men
Smoking is known to help shield against the disease, so declines in that habit may play a role, experts say
MONDAY, June 20, 2016 (HealthDay News) -- Rates of Parkinson's disease may be on the rise for U.S. men over the past three decades, and the trend could be tied to declines in smoking, a new study suggests.
"I believe this will be the first of several reports in the United States to demonstrate what the Parkinson's Disease Foundation has come to realize -- that the number of people living with Parkinson's is dramatically undercounted," said one expert who reviewed the findings, James Beck. He is vice president of scientific affairs at the Parkinson's Disease Foundation.
In the new study, a team led by the Mayo Clinic's Dr. Walter Rocca tracked long-term data on people living in Olmsted County, Minn.
The research showed that rates of Parkinson's disease nearly doubled for men between 1996 and 2005, and the increase was steepest for men aged 70 and older.
Rates of a related condition called "parkinsonism" among men also rose sharply between 1996 and 2005.
No similar increases were seen among women, the researchers said.
The increase may stem from an otherwise very positive health trend among American men over the past few decades: A steep decline in smoking.
Prior research has suggested that smoking might reduce the risk of Parkinson's. So, the decline in the habit among American men -- after peaking in the 1940s and 1950s -- might lead to higher rates of Parkinson's decades later, the researchers theorized.
The authors of the new study emphasized that this theory has not been proven, and that their findings about declining Parkinson's disease rates among men in Minnesota require further investigation.
"The trends could be spurious and need to be confirmed in other populations," according to the researchers.
Beck also noted that the Minnesota population is not particularly "ethnically diverse," so "it will be critical to see if the results hold true in other communities."
Dr. Andrew Feigin is a neurologist and Parkinson's expert at Northwell Health's Neuroscience Institute in Manhasset, N.Y. He agreed that many studies "have shown that cigarette smoking is associated with a reduced risk of Parkinson's disease, so a decline in smoking might be expected to result in an increase in [the disease]." But he also agreed that more and better studies are needed to confirm the trend.
The new report was published online June 20 in the journal JAMA Neurology.
About 1 million people in the United States suffer from Parkinson's disease. Another 50,000 to 60,000 are diagnosed with the neurodegenerative disorder each year, according to the National Parkinson Foundation. Symptoms of the disease include shaking, tremor, slowness of movement, stiffness and trouble with balance.
More information
The U.S. National Institute of Neurological Disorders and Stroke has more on Parkinson's disease.
SOURCES: James Beck, Ph.D., vice president, scientific affairs, Parkinson's Disease Foundation; Andrew Feigin, M.D., director, Laboratory of Experimental Therapeutics for Movement Disorders, The Feinstein Institute for Medical Research and neurologist, Northwell Health's Neuroscience Institute, Manhasset, N.Y.; JAMA Neurology, news release, June 20, 2016
https://consumer.healthday.com/cognitive-health-information-26/parkinson-s-news-526/parkinson-s-rates-rising-among-american-men-712049.html
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