Welding-related parkinsonism

Abstract

Article abstract-Objective: To determine whether welding-related parkinsonism differs from idiopathic PD. Background: Welding is considered a cause of parkinsonism, but little information is available about the clinical features exhibited by patients or whether this is a distinct disorder. Methods: The authors performed a case-control study that compared the clinical features of 15 career welders, who were ascertained through an academic movement disorders center and compared to two control groups with idiopathic PD. One control group was ascertained sequentially to compare the frequency of clinical features, and the second control group was sex-and age-matched to compare the frequency of motor fluctuations. Results: Welders were exposed to a mean of 47,144 welding hours. Welders had a younger age at onset (46 years) of PD compared with sequentially ascertained controls (63 years; p Ͻ 0.0001). There was no difference in frequency of tremor, bradykinesia, rigidity, asymmetric onset, postural instability, family history, clinical depression, dementia, or drug-induced psychosis between the welders and the two control groups. All treated welders responded to levodopa. Motor fluctuations and dyskinesias occurred at a similar frequency in welders and the two control groups. PET with 6-[18 F]fluorodopa obtained in two of the welders showed findings typical of idiopathic PD, with greatest loss in posterior putamen. Conclusions: Parkinsonism in welders is distinguished clinically only by age at onset, suggesting welding may be a risk factor for PD. These preliminary data cannot exclude a genetic contribution to susceptibility in these exposed individuals.

Occupation and Risk of Parkinsonism

“…[3][4][5][6][7] Few investigations have evaluated a direct relationship between occupational chemical exposures and PD. Toxicant-induced parkinsonism may have atypical features, 8,9 but this factor has not been investigated systematically.…”

“…Specific occupations (agriculture, education, health care, mining, and welding) and toxicant exposures (solvents and pesticides) were identified a priori as putative risk factors for parkinsonism based on mechanistic theories or information from prior publications. [3][4][5]8,9,[15][16][17][18] …”

The Divalent Metal Transporter Homologues SMF-1/2 Mediate Dopamine Neuron Sensitivity in Caenorhabditis elegans Models of Manganism and Parkinson Disease

“…High incidence of manganism has been found in manganese miners and smelters (7)(8)(9)(10). Welders appear to be particularly vulnerable to the disorder as manganese alloys used in the heating and joining of metals may result in the production and inhalation of manganese particles (11). Exposure to Mn 2ϩ -based pesticides, including maneb and mancozeb, has also been associated with the development of manganism (12)(13)(14).…”

“…Epidemiological studies suggest a significant correlation of exposure to high concentrations of Mn 2ϩ and the propensity to develop Parkinson disease (PD) 2 (6,11). PD is characterized by the loss of DA neurons in the substantia nigra and other basal ganglia (17).…”

“…Combinatorial long term exposures to Mn 2ϩ , Fe 2ϩ , and aluminum (greater than 30 years) have also been shown to lead to increased likelihood of PD (19). Acute Mn 2ϩ toxicity results in symptoms similar (but not identical) to those seen in patients with PD, including rigidity, tremors, and bradykinesia (1,7,11,20). As in PD, oxidative stress appears to play a significant role in the disorder, and the brain region most susceptible to Mn 2ϩ injury is also sensitive to oxidative stress (21)(22)(23)(24)(25)(26).…”