A research letter in this week’s issue of THE LANCET suggests that some farmers may have a genetic predisposition to the adverse health effects associated with exposure to organophosphates present in sheep dip.
Exposure to organophosphates has acute effects on health, but evidence of chronic effects is unclear. An enzyme found in blood (paroxonase, also known as PON1) is responsible for breaking down diazinonoxon, the active metabolite of diazinon, which is an organophosphate used in sheep dip.
Nicola Cherry and colleagues from the University of Manchester, UK, investigated the relation between genetic variations in the gene regulating paraoxonase and health outcomes in farmers. 175 farmers were recruited to the study, who reported ill health attributed to exposure to sheep dip. The farmers nominated 234 other farmers who also dipped sheep and whom they believed to be in good health.
The investigators calculated odds ratios for polymorphisms (alterations) in the gene regulating paraoxonase (and therefore the ability to break down toxic organophosphates). Farmers who reported poor health were nearly twice as likely than the healthy farmers to have specific alterations in the gene regulating paraoxonase.
Nicola Cherry comments: “The study was set up to test a clear hypothesis, that those whose genes produced a less efficient enzyme would, if exposed to organophosphates, be more likely to become ill. The results provide support for those who believe that repeated exposure to organophosphates may cause chronic ill health. Sheep dippers in the UK are one important group, but there are many others worldwide who are exposed to these chemicals and whose health may be affected as a result.” (quote by e-mail, does not appear in published paper).
Contact: Professor Nicola Cherry, (currently at the University of Alberta, Canada); T) +1 780 492 7849; F) +1 780 492 9677; E) Nicola.Cherry@ualberta.ca
The Lancet