Aims: The association of trauma and physical activity with ALS is controversial. We explored the relation in a pilot case-control study.
Material and methods: ALS patients were selected from a university muscle disease clinic and paired with two matched controls: one from the clinic, but having different diseases, and one from the community.
Results: We found several strong and statistically significant differences between ALS cases and the matched controls. These included severe head, neck and back injury (OR = 5.3), the frequency of sweating in work (OR = 1.6) or leisure activity (also OR = 1.6), and earning a school letter (OR = 3.1). Other measures of trauma and activity, while not achieving statistical significance (p < 0.05), were in accord with these findings.
Discussion: Possible explanations include trauma and vigorous exercise precipitating ALS; trauma as an early sign of disease; or a third factor associated with ALS predisposing to injury.
Conclusions: Severe head, neck, and back injury and frequency of sweating both in work and leisure activity showed a strong association with ALS. Further study could test narrower and less common exposures with greater statistical power.