Osler noted, ‘It is much more important to know what sort of a patient has a disease than what sort of a disease a patient has’. In amyotrophic lateral sclerosis (ALS), a previously functional motor system undergoes a catastrophic, typically rapid degeneration, with a median survival from symptom onset of 3 years.1 Understanding who is at high risk for what appears as a sporadic disorder for most is axiomatic to any long-term vision of primary prevention. Huisman et al2 now present a questionnaire-led, population-based, case–control study of 636 patients and 2166 controls in relation to premorbid physical activity.

ALS abruptly ended the career of American …