The BBC ran a story today about how a certain industrial solvent, trichloroethylene (TCE), is likely to be an environmental factor in causing some incidences of Parkinson’s. The research behind this finding involved quizzing 99 pairs of twins, one of whom had Parkinson’s, and the other of whom did not. It was an international study – encompassing the United States of America, Canada, Germany and Argentina – but, even so, I am impressed that they managed to find that many sets of twins that met their criteria.
A lead time of up to 40 years is cited. The use of TCE has been reduced in recent years, so it seems reasonable to assume that most of these incidences were of relatively late onset; consider a 20 year old worker being exposed to the solvent in his or her workplace (let’s say, in the 1970s or 80s); 30 or 40 years later, he or she is diagnosed with Parkinson’s. It’s a long lead time, and there must be many people who suffered equivalent exposure who do not now have Parkinson’s. However, it is evidently a significant risk factor.
The value of research like this is that it highlights specific risk factors; it may be that TCE will be treated with additional caution (it already seems to be labelled as something quite nasty and likely to be carcinogenic). It may also be valuable as a future research aid – perhaps it will be possible to trace the route by which TCE affects the body’s chemistry in order to cause the loss of dopamine-making neurons. This knowledge may then help us understand other causes of Parkinson’s.
I very much doubt that TCE was a significant factor in my own diagnosis. I have not knowingly been exposed to the chemical, certainly not to any significant degree.