Study author Brad A. Racette explained, “These welders are developing parkinsonian symptoms even though their exposure to manganese is below the current regulatory limits. This study suggests that we need more stringent workplace monitoring of manganese exposure, greater use of protective equipment, and monitoring and systematic assessment of workers to prevent this disabling disease.”
Welding has long been linked to Parkinsonism, which is a term to describe movement problems similar to those in Parkinson’s disease.
The study involved 886 workers from two shipyards and a heavy machinery fabrication shop. Participants were examined by neurologists and 398 of them were followed for an additional 10 years to test for Parkinson’s symptoms.
Exposure to manganese was assessed through questionnaires, and the average was estimated at a concentration of 0.14 mg manganese per cubic meter.
Fifteen percent of the workers had Parkinsonism. The researchers suggest that cumulative exposure to manganese was associated with higher scores on movement tests. Racette explained, “For example, a worker who had been a welder for 20 years before the first examination had an estimated 2.8 mg manganese per cubic meter years exposure and would be predicted to have nearly a seven-point increase on the movement test related to that welding fume exposure.”
The link between welding and Parkinson’s disease symptoms was particularly higher among those who worked in smaller confined areas where exposure to manganese was much greater.
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