Parkinson’s Disease

Parkinson’s disease (PD) is caused by the loss of cells from a very specific area of the brain. The decrease of these cells causes a sharp decrease in one of the main chemicals in the brain, dopamine, which is responsible for communication between brain cells. PD is a fairly common disease of the nervous system, occurring in 1 out of 500 people in the United States, usually in middle or older ages. The illness causes a tremor of the hands and legs, stiffness and slowness of the muscles and a shuffling walk. Many people with PD remain sharp mentally, but some develop significant memory problems. PD progresses, but usually slowly. Fortunately, treatment for PD exists to help control symptoms, though no cure is yet available.

Remarkably little is known about what causes PD. It sometimes runs in families, but most people with PD have no family history of the illness. There has been much recent interest in possible occupational and environmental causes. It has been known for over 150 years that chronic exposure to the metal manganese causes manganism, a set of symptoms that include the symptoms of PD in addition to emotional problems such as depression and/or over-excitement. Chronic manganese poisoning has occurred in a wide variety of workplaces where manganese dust and fumes appear, including mines, smelters, foundries, and farms where manganese-containing pesticides may be used.

Welders have ample opportunity for exposure to manganese. They may use manganese-coated welding rods and/or burn ferromanganese alloy steel. This opportunity for exposure to manganese certainly can lead to chronic manganese exposure and raises the issue of the risk of Parkinson’s disease. A recent study published in the prestigious journal, Neurology, studied 15 welders with Parkinson’s disease and found that such welding-associated cases did not differ from other people with PD without a known cause except that the welders were younger. This suggests that welding was responsible for the PD.

Other occupational and environmental causes of PD are also being studied. Many studies have shown that agricultural workers have an increased risk of PD, raising the issue of pesticides inducing PD. A recent Italian study showed that workers with hydrocarbon exposure had increased risk of PD. However, aside from manganese, no specific occupational or environmental agent has been linked to PD.

For a welder with PD, the following is recommended:

Stop any exposure to manganese
  Ask your neurologist about his/her knowledge about toxic causes of PD
  Apply for workers’ compensation

PD caused by welding would not be treated any differently than PD without a known cause. Making a causal connection between work as a welder and developing PD is principally based on occupational history of exposure. Testing body fluids including blood and urine for manganese is usually not helpful, especially after retirement, since the manganese has long since left the body.

To prevent PD among welders, you should avoid significant exposures to airborne manganese. That means you should:

Know whether you are welding manganese-containing materials
  Ask an industrial hygienist whether your exposure to airborne manganese is significant and find a proper way to reduce your exposure.
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