|Research into pesticides and health|
PAN UK is often asked for the latest research on a particular pesticide, or on a particular disease or environmental problem. It is not always possible to give straightforward answers to these questions.
There is a huge amount of research going on: new papers on pesticides and health impacts are published almost every day. But with hundreds of pesticide active ingredients used worldwide, and the many possible health effects which need to be considered, there is much that is still uncertain.
Interpreting scientific papers is complex because every study has its limitations, and one study alone is never the whole story. For example, a study might come up with a particular result just by chance. This can then give rise to ‘false positives’ where an exposure appears to be linked with a health problem, but actually isn’t, and conversely, ‘false negatives’ whereby an exposure seems to be safe. The smaller the number of people in the study the less reliable it is.
Another difficulty is that the study might show a link between pesticide use and a particular health problem – but that doesn’t necessarily mean that the pesticide is causing the problem. It might be because people using the pesticide were also using another chemical, or because they spent a lot of time out of doors, and so on. A good study will attempt to take into account these 'confounding factors'.
If a number of well designed studies are pointing to a link between a pesticide and a health problem, then the link becomes more compelling. Where there are lots of studies on an issue, it can be very helpful to look for reviews. A review will take all the studies on a topic, assess their quality, and attempt to sum up the state of the evidence on that topic.
There are many other pitfalls to look out for when looking at research, and many reasons why scientists may disagree on the significance of the same data. PAN UK believes that sometimes it is necessary to act on the precautionary principle and withdraw a pesticide where there are serious concerns about health, even when the scientific research is incomplete or contradictory.
For those wishing to look into the research into pesticides and health problems, some useful websites are listed in the links section.