Pesticides: A Link to Parkinson's?
Researchers Say Pesticide Exposure and Head Trauma Are Factors in Parkinson's Disease
May 30, 2007 -- Boxing and agricultural work seemingly have little in
common, but new research suggests both occupations are linked to an increased
risk for Parkinson's disease.
The findings add to the evidence implicating pesticide exposure and repeated
head trauma as likely contributors to Parkinson's disease and related
degenerative brain disorders.
Farm workers and other study participants who reported high levels of
pesticide exposure were found to have a 41% increased risk of developing
Parkinson's disease compared with participants who reported no pesticide
And having been knocked unconscious more than once was associated with a
2.5-fold increase in Parkinson's risk, compared with having never been knocked
The findings suggest that at least some of the causes of Parkinson's disease
and related disorders are modifiable, but more research is needed to better
understand this association, researcher Finlay Dick, MD, of the Scotland's
University of Aberdeen, tells WebMD.
"One limitation of this study and most others is that people could not
recall which pesticides they had been exposed to," he says. "So we
weren't able to tease out which specific pesticides might be behind the effect
Parkinson's disease is a progressive disease of the brain that affects
balance and the body's ability to coordinate muscles and move.
Lifetime Exposure Evaluated
The European Commission-funded study included 959 patients with Parkinson's
disease and closely linked neurological disorders and 1,989 people without any
evidence of the degenerative disorder living in Scotland, Italy, Sweden,
Romania, or Malta.
All study participants completed a questionnaire designed to determine their
lifetime occupational and recreational exposure to pesticides, chemical
solvents, and the metals iron, copper, and manganese.
Researchers also gathered information on family history of Parkinson's
disease and history of head trauma leading to unconsciousness.
Reported exposures to chemical solvents or the metals iron, copper, and
manganese were not found to influence Parkinson's risk, but even minimal
exposure to pesticides was associated with a small increase in risk.
The findings were published May 30 in an online issue of the journal
Occupational and Environmental Medicine.
Identifying Specific Pesticides
The European study is not the first to link pesticide use to an increased
risk for Parkinson's disease, or to suggest that risk increases as exposures
Earlier this year, researchers from the National Institute of Environmental
Health Sciences (NIEHS) also reported that lifetime exposure to pesticides was
associated with an increased risk for the disease.
Freya Kamel, PhD, who led that study team, is conducting related research
designed to identify the specific pesticides associated with risk.
She tells WebMD that she expects to publish findings from the study within a
year or two.
"We have some ideas about which pesticides or pesticide classes are
involved, but this will be a more detailed look at the issue," she