Soccer, neurotrauma and amyotrophic lateral sclerosis: is there a connection?

Abstract
SUMMARYTrauma has long been hypothesized but never proven to be a risk factor for amyotrophic lateral sclerosis (ALS). This hypothesis may now have a renaissance due to recent reports in the lay press on ‘the Italian motoneuron mystery’, i.e. the disclosure of 33 diagnosed ALS cases in a subpopulation of 24 000 soccer players of the top three Italian divisions from the 1960s to 1996. Could the repetitive brain trauma that soccer players experience for controlling and advancing the ball with their heads represent an environmental risk factor for developing ALS in genetically predisposed individuals?By critically reviewing the scarce literature and ‘surrounding evidence’ (Medline, CDC, lay press, Italian health officials), we have looked for a potential relationship between (1) soccer and head trauma and (2) head trauma and subsequent development of amyotrophic lateral sclerosis. Whereas the brain traumatizing effect of soccer seems to be out of the question, the findings of the few retrospective studies on...