Exposure to pesticides near workplace triggers Parkinson's disease risk three-fold, researchers say.
In a follow up study, the researchers at the UCLA School of Public Health found that the combined exposure to pesticides ziram, maneb and paraquat near any workplace increased the risk of Parkinson's disease (PD) threefold, while combined exposure to ziram and paraquat alone was associated with an 80 percent increase in risk.
"Our estimates of risk for ambient exposure in the workplaces were actually greater than for exposure at residences," said Dr. Beate Ritz, senior author and a professor of epidemiology at the UCLA School of Public Health.
"And, of course, people who both live and work near these fields experience the greatest PD risk. These workplace results give us independent confirmation of our earlier work that focused only on residences, and of the damage these chemicals are doing," added Ritz.
In addition, Ritz noted, this is the first study that provides strong evidence in humans that the combination of the three chemicals confers a greater risk of Parkinson's than exposure to the individual chemicals alone. Because these pesticides affect different mechanisms leading to cell death, they may act together to increase the risk of developing the disorder: Those exposed to all three experienced the greatest increase in risk.
"Our results suggest that pesticides affecting different cellular mechanisms that contribute to dopaminergic neuron death may act together to increase the risk of PD considerably," said Ritz.
The study is detailed in the European Journal of Epidemiology.