Last Updated: 2008-04-18 10:37:41 -0400 (Reuters Health)

NEW YORK (Reuters Health) – Results of a family-based, case-control study support a relationship between pesticide exposure and Parkinson’s disease (PD).

In a statement issued by BioMed Central, lead author Dr. Dana Hancock from Duke University, Durham, North Carolina notes, "Previous studies have shown that individuals with Parkinson’s disease are over twice as likely to report being exposed to pesticides as unaffected individuals, but few studies have looked at this association in people from the same family or have assessed associations between specific classes of pesticides and PD."

In a study of 319 PD patients and more than 200 unaffected relatives, Dr. Hancock and colleagues found that the PD patients were significantly more likely to report direct pesticide application (odds ratio, 1.61).

"Frequency, duration, and cumulative exposure were also significantly associated with PD in a dose-response pattern," the researchers report in the online journal BMC Neurology.

Both insecticides and herbicides, most notably organochlorines, organophosphorus compounds, chlorophenoxy acids/esters, and botanicals, significantly increased the risk of PD.

"Further investigation of these specific pesticides and others may lead to identification of pertinent biological pathways influencing PD development," the authors suggest.

Dr. Hancock’s team also points out that "the strongest associations between PD and pesticides were obtained in families with no history of PD." They add, "This finding suggests that sporadic PD cases may be particularly vulnerable to the toxic effects of pesticides, but the possibility of pesticides influencing risk of PD in individuals from families with a history of PD cannot be ruled out."

BMC Neurology 2008.

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