Pesticides exposure associated with parkinson's disease
Jun 26, 2006 | www.yubanet.com
In the first large-scale, prospective study to examine possible links between
chronic, low-dose exposure to pesticides and Parkinson's disease (PD),
researchers at the Harvard School of Public Health (HSPH) have shown that
individuals reporting exposure to pesticides had a 70 percent higher incidence
of PD than those not reporting exposure. No increased risk of PD was found from
reported exposure to other occupational hazards, including asbestos, coal or
stone dust, chemicals, acids, or solvents. The study will appear in the July
issue of Annals of Neurology and also appears online via Wiley Interscience (www.interscience.wiley.com).
Previous studies had suggested a link between PD and low-level exposure to
pesticides, though the data remains inconclusive. The researchers, led by
Alberto Ascherio, associate professor of nutrition and epidemiology at HSPH,
looked at data from the Cancer Prevention Study II Nutrition Cohort, a
prospective study begun in 1992 by the American Cancer Society. Some 143,325
participants who responded to a follow-up survey in 2001 were included in the
HSPH study. Researchers then contacted those individuals in the 2001 survey who
reported a diagnosis of PD to ask if their medical records could be reviewed to
confirm the diagnosis. Ultimately, Ascherio and his colleagues included in their
study a total of 413 cases of PD with onset of symptoms and diagnosis after
1992.
The researchers used exposure data collected in 1982 from the CPS II mortality
study, a study from which the Nutrition Cohort was drawn. Exposure to pesticides
was reported by 5,203 men (8.2 percent) and 2,661 women (3.3 percent). Among
those reporting exposure, after adjusting for age, sex, and other risk factors
for Parkinson's disease, there was a 70 percent higher incidence of PD than
among people who reported no exposure. Those reporting exposure were more likely
to be male than female to report their occupation as farmer, rancher or
fisherman and to be blue-collar workers, but none of these factors could account
for the increased risk of Parkinson's disease, which was similar in men or
women, and in non-farmers as well as farmers. The significant association
between pesticide exposure and Parkinson's disease among individuals who are not
farmers is most likely explained by use of pesticides at home or in gardening.
Future studies will need to examine which specific pesticides or classes of
pesticides are likely to cause Parkinson's disease.
This study was supported by a grant from the Michael J. Fox Foundation and
Kinetic Foundation. The participation of Michael Schwarzschild, a co-author, was
supported by a grant from the National Institute of Environmental Health
Sciences.