Welding-related parkinsonism: clinical features, treatment, and pathophysiology.
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 < 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-[18F]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.
Racette
B A
BA
Departments of Neurology and Neurological Surgery (Neurology), Washington University School of Medicine, St. Louis, MO 63110, USA. racetteb@neuro.wustl.edu
McGee-Minnich
L
L
Moerlein
S M
SM
Mink
J W
JW
Videen
T O
TO
Perlmutter
J S
JS
D000328:Adult; D017668:Age of Onset; D000368:Aged; D016022:Case-Control Studies; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives; D005260:Female; D006801:Humans; D008297:Male; D008345:Manganese / Q000009:adverse effects; D008875:Middle Aged; D017072:Neostriatum / Q000473:pathology; D009784:Occupational Diseases / Q000453:epidemiology* / Q000473:pathology / Q000628:therapy; D016273:Occupational Exposure; D010300:Parkinson Disease / Q000453:epidemiology* / Q000473:pathology / Q000628:therapy; D012307:Risk Factors; D014055:Tomography, Emission-Computed; D014896:Welding
C043437:fluorodopa F 18; D008345:Manganese; D004295:Dihydroxyphenylalanine