Study Links Allergies To Parkinson's Disease

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http://www.sciencedaily.com/releases/2006/08/060808091749.htm

Source: Mayo Clinic

Date: August 8, 2006

More on: Parkinson's Research, Parkinson's, Allergy,

Chronic Illness, Caregiving, Elder Care

Study Links Allergies To Parkinson's Disease

Science Daily — Researchers from Mayo Clinic have discovered that

allergic rhinitis is associated with the development of Parkinson's

disease later in life. Findings will be published in the Aug. 8

issue of the journal Neurology.

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" The association with Parkinson's disease is increased to almost

three times that of someone who does not have allergic rhinitis, "

says Bower, M.D., Mayo Clinic neurologist and lead study

investigator. " That's actually a pretty high elevation. "

Previous studies had shown that people who regularly take

nonsteroidal anti-inflammatory drugs, such as ibuprofen, are less

likely to develop Parkinson's disease. These results prompted the

Mayo Clinic investigators to look further into the links between

diseases characterized by inflammation and Parkinson's. They studied

196 people who developed Parkinson's disease, matched with people of

similar age and gender who did not develop Parkinson's. The study

was conducted in Olmsted County, Minn., home of Mayo Clinic, over a

20-year period.

The researchers examined these groups to determine if those who

developed Parkinson's disease had more inflammatory diseases. They

found that those with allergic rhinitis were 2.9 times more likely

to develop Parkinson's. They did not find a similar association

between inflammatory diseases such as lupus, rheumatoid arthritis,

pernicious anemia or vitiligo and Parkinson's disease. The

researchers hypothesize that they may not have found significant

links between these diseases and Parkinson's disease due to the

relatively small number of those in the population who have these

diseases, and thus the small number with these diseases in their

population sample study. They also did not find the same association

with Parkinson's disease in patients with asthma that they

discovered in those with allergic rhinitis.

Dr. Bower says that this study did not examine patients' types of

allergies or when they developed allergies.

The investigators theorize that a tendency toward inflammation is

the key link between the diseases.

" People with allergic rhinitis mount an immune response with their

allergies, so they may be more likely to mount an immune response in

the brain as well, which would produce inflammation, " Dr. Bower

says. " The inflammation produced may release certain chemicals in

the brain and inadvertently kill brain cells, as we see in

Parkinson's. "

Dr. Bower explains that this study does not prove that allergies

cause Parkinson's disease; instead, it points to an association

between the two diseases. He advises that allergy patients can do

little to reduce the potential risk for Parkinson's.

" I wouldn't worry if you have allergies, " he says. " Treat the

allergy symptoms you have to alleviate them at the time. At this

point, we have no good evidence that this treatment will protect you

from possibly developing Parkinson's disease later. "

Dr. Bower and colleagues hope, however, that the clues in this study

may give scientists a strong hint about inflammation's role in

Parkinson's.

" This is exciting, because we may be able to develop medications to

block the inflammation, " he says.

Parkinson's is a complex disease, says Dr. Bower, because many

factors can contribute to its development and its causes can differ.

The complexity can be compared to heart attacks, which can be caused

by hypertension, high cholesterol or smoking, among other factors.

Thus, allergic rhinitis would now be considered one among many

possible risk factors for development of Parkinson's disease.

Parkinson's disease affects nerve cells (neurons) in the part of the

brain that controls muscle movement. People with Parkinson's disease

often experience trembling, muscle rigidity, difficulty walking, and

problems with balance and coordination. These symptoms generally

develop after age 50, although the disease also affects a small

percentage of younger people. The normal lifetime risk to develop

Parkinson's disease for men and women combined is 1.7 percent.

Note: This story has been adapted from a news release issued