Antecedent trauma and amyotrophic lateral sclerosis in young adult men.

Antecedent trauma has been implicated as a risk factor for many neurologic disorders, including amyotrophic lateral sclerosis (ALS). Aging is a dynamic, exponentially increasing risk factor for many disorders, also including ALS. Consequently, the relative significance of other risk factors diminishes correspondingly with increasing age. Gompertzian risk analysis suggests that only in a young susceptible individual could the age-dependent risk be low enough to relate the development of ALS to a non-age-dependent risk factor, such as preceding trauma. This point is illustrated by the case histories of three young adult men who developed ALS within 2 years following trauma.