Occupation and risk of parkinsonism: a multicenter case-control study.
BACKGROUND
We examined risk of parkinsonism in occupations (agriculture, education, health care, welding, and mining) and toxicant exposures (solvents and pesticides) putatively associated with parkinsonism.


OBJECTIVE
To investigate occupations, specific job tasks, or exposures and risk of parkinsonism and clinical subtypes.


METHODS
Case-control.


METHODS
Eight movement disorders centers in North America.


METHODS
Inclusion criteria were parkinsonism (>or=2 cardinal signs), diagnosis within 8 years of recruitment (to minimize survival bias), and ability to participate in detailed telephone interviews. Control subjects were primarily nonblood relatives or acquaintances of patients.


METHODS
This multicenter case-control study compared lifelong occupational and job task histories to determine associations with parkinsonism and certain clinical subtypes (postural instability and gait difficulty and age at diagnosis <or=50 years).


RESULTS
Findings in 519 cases and 511 controls were analyzed. Work in agriculture, education, health care, or welding was not associated with increased risk of parkinsonism. Unexpected increased risks associated with legal, construction and extraction, or religious occupations were not maintained after adjustment for duration. Risk of parkinsonism increased with pesticide use (odds ratio, 1.90; 95% confidence interval, 1.12-3.21), use of any of 8 pesticides mechanistically associated with experimental parkinsonism (2.20; 1.02-4.75), and use of 2,4-dichlorophenoxyacetic acid (2.59; 1.03-6.48). None of the specific occupations, job tasks, or task-related exposures were associated with younger age at diagnosis (<or=50 years). Ever working in business and finance, legal occupations, construction and extraction, or transportation and material moving was associated with postural instability and gait difficulty subtype of parkinsonism. Tobacco use was inversely associated with parkinsonism risk.


CONCLUSIONS
The association of disease risk with pesticides support a toxicant-induced cause of parkinsonism.
Tanner
Caroline M
CM
Department of Clinical Research, The Parkinson's Institute, Sunnyvale, California 94085, USA. CTanner@thepi.org
Ross
G Webster
GW
Jewell
Sarah A
SA
Hauser
Robert A
RA
Jankovic
Joseph
J
Factor
Stewart A
SA
Bressman
Susan
S
Deligtisch
Amanda
A
Marras
Connie
C
Lyons
Kelly E
KE
Bhudhikanok
Grace S
GS
Roucoux
Diana F
DF
Meng
Cheryl
C
Abbott
Robert D
RD
Langston
J William
JW
D015084:2,4-Dichlorophenoxyacetic Acid / Q000009:adverse effects; D000328:Adult; D017677:Age Distribution; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D004409:Dyskinesia, Drug-Induced / Q000453:epidemiology / Q000503:physiopathology; D005260:Female; D020233:Gait Disorders, Neurologic / Q000139:chemically induced / Q000453:epidemiology / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009498:Neurotoxins / Q000009:adverse effects / Q000145:classification; D009784:Occupational Diseases / Q000453:epidemiology*; D016273:Occupational Exposure / Q000706:statistics & numerical data*; D010300:Parkinson Disease / Q000453:epidemiology*; D010575:Pesticides / Q000009:adverse effects; D012307:Risk Factors; D012997:Solvents / Q000009:adverse effects
D009498:Neurotoxins; D010575:Pesticides; D012997:Solvents; D015084:2,4-Dichlorophenoxyacetic Acid