Researchers in the U.S. say they have found evidence that exposure to pesticides may be linked to the development of Parkinson's disease (PD).
In a new study a team from Harvard School of Public Health (HSPH) has found that people who stated in 1992 that they had been in contact with pesticides were 70 per cent more likely to develop Parkinson's within the next 10 years.
Previous studies have suggested a link between PD and low-level exposure to pesticides, but the data is inconclusive.
The study is the first large-scale, prospective study to examine possible links between chronic, low-dose exposure to pesticides and Parkinson's disease.
The researchers, led by Alberto Ascherio, associate professor of nutrition and epidemiology at HSPH, looked at data from a study begun in 1992 by the American Cancer Society linking diet and cancer.
In a follow-up survey in 2001, some 143,325 participants responded and of these, 413 had developed Parkinson's since the start of the study.
The team then contacted those who reported a diagnosis of PD and examined their medical records to confirm the diagnosis.
Among the original questions had been one about exposure to pesticides, to which 5,203 men and 2,661 women had said yes.
The researchers found that 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.
The finding are significant and are validated by the fact that the participants were questioned about their exposure to pesticides long before they developed Parkinson's disease.