In a previous blog post, we discussed the signs and symptoms of Parkinson’s, and how exposure to harsh chemicals has been known to cause this disabling condition. Traditionally, Parkinson’s has been thought to be an aging condition, more prominent in the elderly population. Now, in the past few decades, cases of Parkinson’s are popping up in a much younger generation – and this time, the culprit is welding fumes.
Parkinson’s disease is a neurological disorder characterized by tremors, bradykinesia, rigidity, and postural instability. These neurological dysfunctions are directly related to the body’s production of dopamine neurons, which play an important role in the brain, involving motor control, motivation, arousal, cognition and reward. In the substantia nigra, dopamine functions as a neurotransmitter—a chemical released by nerve cells to send signals to other nerve cells. When these neurons are damaged, body does not receive the proper signals that facilitate movement and motor function. While the cause of Parkinson’s is not fully understood, there is a significant body of research that implicates that environmental exposures—including welding fumes—have been associated with workers who have developed Parkinson’s disease.
In 2003, researchers came across a young man who had been treating at his local VA medical center for cognitive and motor complaints. He was 33 years old at the time, and had three years of exposure to welding fumes. Mr. R. (as the researchers identified him in their reports) had welded in tight, confined spaces on ships with mild steel. He was not provided with a respirator while working. The VA sent him to neurological specialists in Houston for further evaluation. For the prior two years, the young man had developed a tremor, slowing of movement, gait abnormalities, and a tendency to fall. According to his wife, he also had difficulty balancing his checkbook.
Two years later, Mr. R. was re-evaluated with a comprehensive neuropsychological test. While the results indicated he had intact verbal function and only mild decreases in working memory and arithmetic, they also indicated that he had severe impairments in fronto-subcortical lobe, causing irritability, anxiety, depression and early psychosis. The researchers concluded that Mr. R. had neuropsychological impairment similar to welders with significantly longer exposure to welding fumes. The constant inhalation of the fumes, the tight spaces, and the proximity to the fumes of other welders nearby all contributed to the severity and early onset of Mr. R.’s Parkinson’s condition.
The story of the 33-year old welder is but one of hundreds that bear testimony to the damaging effects of welding fumes. Another study, in 2011, examined the prevalence of Parkinson’s in 811 shipyard and fabrication welders. The researchers found a relatively high prevalence of parkinsonism in welding exposed workers, suggesting an association between exposures to manganese and other welding fume metals and parkinsonism.
Medical evidence points to the possibility that manganese, one of the components of welding fume, is a large factor in Parkinson’s disease. Much of workplace exposure to welding fumes is to insoluble forms of manganese, primarily via inhalation. Manganese is present in most manual metal arc-hard surfacing (MMA-HS) and gas metal arc-mild steel (GMA-MS) fumes. Over time, manganese particles migrate from the lung to the brain, causing progressive neurotoxicity. Manganese accumulation in certain areas of the brain damages dopamine neurons. Without these chemical messengers, motor function suffers. And because dopamine is directly related to emotional responses, the loss of dopamine neurons also results in mood disorders, as was characterized in the case of Mr. R.
The VA has not yet recognized the association between Parkinson’s and welding fumes. This certainly may have something to do with the fact that the medical experts cannot agree on the etiology of Parkinson’s, in spite of the research that has been done. While experts are reluctant to baptize welding fumes as a definitive cause of Parkinson’s, the testimonies of hundreds of welders don’t lie: there is definitely a connection, and the truth goes marching on.