Are some cases of Parkinson's Disease work related?

Last week, I participated in a research project sponsored by the Pacific Alzheimer’s Research Foundation and Canadian Institute of Health Research.  It was conducted by the Pacific Parkinson’s Research Centre at the Health Sciences Centre Hospital – UBC.  I don’t have Parkinson’s or Alzheimer’s or other neurodegenerative disease (at least not yet) but believe research is essential if we are to improve the diagnosis and treatment of Parkinson’s, Alzheimer’s and related  neurodegenerative disorders.  As a subject in the study, I will not receive any direct benefit but the knowledge gained from me and other participants may benefit others. 

The study employed a technique known as PET (Positron Emission Tomography) scanning to determine the activity of brain nerve cells.  This involved the injection of a substance labeled with a tiny amount of radioactive isotope with a very short half-life.  As the isotope decays, it emits positrons. When a positron bumps into an electron, both are annihilated releasing two gamma photons in opposite directions which are detected in the scanner.  Three dimensional images of the brain can be constructed from the data sets collected from the scanner.

I had two scans during the course of the six hours I was at the hospital. Each scan involved my head being placed in the scanner.  Keeping my head still for the hour or so for each scan was made easier by a a very stylish custom-fitted mask. 

Such studies are not cheap to run.  The isotopes, technicians, medical staff involved to get one set of readings from one test subject like me, not to mention my occupying the very expensive PET scan for literally hours are clearly cost intensive.   The actual research on the scans of all subjects involved, the analysis, peer review and publication also carry significant costs. What could possibly justify the cost?  Well, to paraphrase a poster I once saw, “If you think research is expensive—Try disability and disease!”  Clearly, the human and financial costs of neurodegenerative disorders are staggering and, by that measure, financial and personal commitment to research is the far better and cheaper choice. 

Linking that personal experience and position to the world of workers’ compensation is not a huge leap.  We may not talk a lot about neurodegenerative disorders but just about everyone knows someone with one such neurodegenerative disorder:  Parkinson’s disease.  High profile sufferers of this chronic disorder include actor Michael J. Fox and fighter Mohamed Ali.  They have helped put a face on the characteristic and progressive tremors, stiffness, and slow movements that are often the most visible signs of this disease. 

Is Parkinson’s disease or Parkinsonism work-related? There is a lot of evidence that certain work exposures are associated with an increased risk for the development of Parkinsonism.  There is evidence that chemicals in the work environment may play a role in the development of the disease.   Certain pesticides and organic solvents are clearly implicated in the development of Parkinson’s and head trauma – as a result of a work-related injury, for example—increases the risk of Parkinson’s disease.  Manganese exposure and heavy metal exposure are also associated with the development of Parkinsonism. 

As far as occupational risks are concerned, work on farms and in gas stations or work as a welders and miners have been shown to have statistically higher risks for the development of this disease. 

In the US, the ASSE reports 10,000 lawsuits by welders who have developed manganese-induced Parkinson’s disease .   I know of only a handful of workers’ compensation claims ever being submitted  for Parkinson’s disease or Parkinsonism.  Aside from a few cases reported in the US press [like the 1996 win by a welder in the California Workers’ Compensation Appeal Board], few applications for workers’ compensation have been accepted.  

Why don’t we see more workers’ compensation claims for Parkinson’s disease, Parkinsonism, and other potentially work-related neurodegenerative disorders?  The onset of the disease is often diagnosed after work careers end.  Knowledge of the association between work and the disease may not be widely known in the occupations at elevated risk.  Temporary foreign workers in agriculture, for example, may not fully understand the risks they may be exposed to in applying pesticides; even if they are aware of the risks, it is unlikely that a temporary foreign worker who may have suffered exposure here will file a claim from their home country. 

Will we see more workers’ compensation claims for neurodegenerative diseases like Parkinson’s in the future?  I predict we will.  As more workers extend their work careers into their late sixties and beyond and as the association between work, certain work-related traumas and increased risks of occupational disease including Parkinson’s increase, we are going to see more cases presented as work-related, exacerbated by work,  recognized by diagnosticians as being work-related, and ultimately presented for consideration of workers’ compensation benefits.