What did the media say?
The media reported that there was now strong evidence that exposure to pesticides significantly increases the risk of Parkinson’s disease.
What did the research show?
The reports were based on a US study. Researchers recruited 319 patients with Parkinson’s disease (PD) and more than 200 of their relatives and some others who did not have the condition. The design was intended to provide clues as to whether the disease is caused by interaction between genetic and environmental factors, as previously suggested by some researchers.
Subjects were surveyed using a structured, 30 to 45-minute telephone environmental risk factor survey, which asked about their direct exposure to pesticides.
Overall, individuals with PD were 1.6 times more likely to report direct pesticide application than their unaffected relatives, said the authors. This was after controlling for factors such as sex, smoking status and caffeine intake.
They said the strongest associations were between use of herbicides and insecticides, such as organochlorides and organophosphates.
What did the researchers say?
Lead author Dana Hancock, from Duke University Medical Center, North Carolina, said: ‘Previous studies have shown that individuals with PD 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.
‘Biological evidence is presently insufficient to conclude that pesticide exposure causes PD. Further investigation of these specific pesticides and others may lead to identification of pertinent biological pathways influencing PD development.’
What does this mean for nursing practice?
Kieran Breen, director of research at the Parkinson’s Disease Society (PDS), said: ‘We still don’t know exactly what causes Parkinson’s. It’s most likely to be a combination of genetic susceptibility and environmental factors.
‘The PDS has recently carried out a survey of more than 10,000 people with Parkinson’s and only 9% of them told us that they had ever had long term exposure, of more than one year, to pesticides or herbicides. Of the 3,000 carers surveyed, most of whom were family members, less than 2% had had similar exposure.
‘This demonstrates that pesticides may be contributing to nerve cell death in some people with Parkinson’s, but is unlikely to be the only cause.’
BMC Neurology (2008) 8: 6