Hospital-Diagnosed Traumatic Head Injury and Associated Risk of Developing ALS

Although a strong association of ALS with THI experienced ≤1 year before ALS diagnosis was evident, our results suggest that this is due to reverse causation. When restricting the analysis to a period deemed relevant for causative events leading to ALS development, no association was observed. Consequently, we do not consider THI an important ALS risk factor. This study was limited by the inability to consider minor THIs not receiving hospital attendance. Future research should explore alternative models to unfold this possible ALS risk factor.