Increased Risk of ALS Appears Linked to Physical Trauma at Early Age

Physical trauma at earlier ages appears associated with an increased risk of amyotrophic lateral sclerosis (ALS), according to a study titled “Physical Trauma and Amyotrophic Lateral Sclerosis: A Population-Based Study Using Danish National Registries” published in the American Journal of Epidemiology.

ALS, also known as Lou Gehrig’s disease and Charcot disease, is a motor neuron disease characterized by the progressive death of nerve cells (neurons) responsible for controlling voluntary muscles. While little is known about disease etiology, previous studies suggested that physical trauma might be associated with the development of ALS.

Researchers performed a population-based, individually matched case-control study in Denmark to determine whether cases of hospitalizations due to trauma are associated with a higher risk for developing ALS. Searching in the Danish National Patient Register, the team found 3,650 incident cases of ALS diagnosed between 1982 and 2009. Each case analyzed was matched in age and sex to population controls alive on the date of diagnosis.

The study’s authors observed an association between physical traumas occurring earlier in life and a higher rate of ALS, specifically in a first trauma before the age of 55. Moreover, there was a significant association between physical traumas that resulted in outpatient visits and ALS.

The research team emphasized that the biggest limitation of their study was in the control of behavioral confounders, such as smoking tobacco and physical activity, previously recognized as potential risk factors for ALS. Still, the national study’s comprehensive and sizable analyzed sample, together with a registry-based diagnosis of ALS and physical trauma exposures, were highlighted as the study’s strengths.

Authors note that the study is the first to report how age at the first physical trauma influences the risk for ALS. They found that traumas earlier in life are associated with a higher rate for ALS, a phenomenon that has particular importance in professions more prone to injury, including military veterans and some athletes. Future studies should focus on the type of physical trauma and patients’ age at the time of injury to fully understand how both factors interact and determine disease susceptibility.