Exposure to environmental toxins and the risk of sporadic motor neuron disease: an expanded Australian case-control study.
OBJECTIVE
It remains unclear what role environmental toxins play in sporadic motor neuron disease (SMND) and its most common subtype, amyotrophic lateral sclerosis (SALS). Most previous studies of this issue have contained only small numbers of SMND cases. We sought to re-examine possible associations between toxins and SMND in a large Australian case-control study.


METHODS
Questionnaire data were available from 787 patients with SMND (614 with SALS) and 778 non-related controls. Individuals were asked whether they had been exposed to metals or chemicals/solvents at work or to herbicides/pesticides. Chi-square tests with odds ratios and 95% confidence intervals were calculated for responses, and significance levels were corrected for multiple testing.


RESULTS
Men were more likely to acquire SALS if they worked with metals (OR = 1.95, 95% CI = 1.24-3.07) or chemicals/solvents (OR = 1.96, 95% CI = 1.46-2.61) or if they had been exposed to herbicides or pesticides (OR = 1.77, 95% CI = 1.30-2.39). Women who had worked with chemicals or solvents also appeared to be at increased risk of acquiring SALS (OR = 1.71, 95% CI = 1.22-2.40).


CONCLUSIONS
These results support previous reports that exposures to metals or chemicals are associated with SMND. A suggested protocol for future multinational studies of environmental toxins and SMND is presented.
The Stacey Motor Neuron Disease Laboratory, Department of Pathology, The University of Sydney, Sydney, NSW, Australia. roger.pamphlett@sydney.edu.au
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D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001315:Australia; D016022:Case-Control Studies; D005260:Female; D015386:Hazardous Substances / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008670:Metals / Q000009:adverse effects / Q000633:toxicity; D008875:Middle Aged; D016472:Motor Neuron Disease / Q000139:chemically induced* / Q000453:epidemiology*; D016273:Occupational Exposure / Q000009:adverse effects*; D010575:Pesticides / Q000009:adverse effects; D012997:Solvents / Q000009:adverse effects; D011795:Surveys and Questionnaires
D015386:Hazardous Substances; D008670:Metals; D010575:Pesticides; D012997:Solvents