Brain Damage Potential from Welding Fumes Exposure

(NASA.gov)

Researchers at Washington University School of Medicine in St. Louis, Missouri have found that workers exposed to welding fumes may face increased risks of damage to the same brain area harmed by Parkinson’s disease. The study appears online 6 April 2011, in the journal Neurology (paid subscription required).

Fumes produced by welding contain manganese, an element that scientists have linked to neurological problems including Parkinson’s disease-like symptoms. In 2008, according to the Bureau of Labor Statistics, about 412,000 Americans were employed as welders or related metal workers (cutters, solderers, or brazers).

The study led by neurology professor Brad Racette involved 20 welders with no symptoms of Parkinson’s disease, 20 people with Parkinson’s disease who were not welders and 20 people who were not welders and did not have Parkinson’s. The welders were recruited from two shipyards and one metal fabrication company, and each had an average of 30,000 hours of lifetime welding exposure.

All participants were given brain positron emission tomography (PET) and magnetic resonance imaging (MRI) scans and motor skills tests, as well as examinations by a neurologist who specializes in movement disorders. The welders were also tested for blood manganese levels, which were found to be two times the upper limits of normal levels established in prior studies of general populations.

In one area of the brain, PET scans indicated that welders had an average 11.7 percent reduction in a marker of the chemical dopamine compared to people who did not weld. Dopamine helps nerve cells communicate and is decreased in specific brain regions in people with Parkinson’s disease. The welders’ motor skills test scores also showed mild movement difficulties that were not as extensive as those found in the early Parkinson’s disease patients.

Although the same area of the brain was affected as in Parkinson’s disease, the pattern of effects within this area was reversed. Parkinson’s disease normally has the greatest impact on the rear of a structure known as the putamen. In the welders, the largest drop in the marker for dopamine occurred in a structure behind the putamen known as the caudate.

While Racette notes that the results indicate early markers of neuron death among welders, they were not the same pattern found in full-fledged Parkinson’s disease. Nonetheless, says Racette, “MRI scans also revealed brain changes in welders that were consistent with manganese deposits in the brain.”

Read more: Two Pesticides Linked to Higher Rates of Parkinson’s Disease

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