Amyotrophic lateral sclerosis (ALS) is highly prevalent among young U.S. war veterans deployed post-9/11, particularly Air Force personnel, tactical operation officers, and health care workers, a recent study suggests.
The findings suggest that there is an early onset of ALS among deployed military service members, the researchers said.
Titled “Amyotrophic Lateral Sclerosis Among Veterans Deployed in Support of Post-9/11 U.S. Conflicts,” the study was published in the journal Military Medicine.
U.S. military service has long been recognized as a risk factor for the development of ALS, a progressive neurological disease. This increased risk was found in studies conducted among Gulf War veterans (GWV), as well as military veterans who had served in previous wars.
In fact, the average case rate of ALS among deployed GWV is 6.7 per million compared with 3.5 per million among individuals who were not deployed. The average annual cumulative incidence is 0.43 per 100,000 persons in the GWV population.
Most studies to date on the ALS risk have been limited to veterans who served in the Gulf War and include only a small sample of participants who served in post-9/11 U.S. wars in Iraq and Afghanistan.
Importantly, post-9/11 veterans differ from other war era veterans in regard to age, severity of injury, disability, and survival. These new veterans also have unique occupational exposures that may result in a higher risk for ALS.
However, there has been no research on the occurrence of — and risk factors associated with — ALS specific to post-9/11 deployed U.S. war veterans.
Now, a group of American researchers set out to identify the prevalence of ALS among these veterans. The team also sought to determine whether there were any certain patient characteristics, such as traumatic brain injury (TBI) or military branch or occupation, that were associated with a higher risk for ALS.
TBI has been considered a possible trigger for ALS, the researchers noted.
“Given the relatively high prevalence of TBI among Post-9/11 deployed U.S. war Veterans, it is important to examine the association of TBI with ALS in this population,” they said.
The researchers also adjusted the results for demographics and concurrent conditions previously associated with ALS, specifically metabolic disorders such as diabetes and dyslipidemia, cancer, and cardiac and cerebrovascular diseases. The results also were adjusted for other concurrent conditions common among veterans such as post-traumatic stress disorder (PTSD), depression, and anxiety.
The study included veterans deployed in support of post-9/11 conflicts who received care in the Veterans Health Administration (VHA) during the fiscal years of 2002–2015. Inpatient and outpatient data, pharmacy records, and Veterans Benefits Administration were reviewed for a total of 1,149,620 veterans. Definite ALS was found in 139 veterans, with a median age of 39.7 years.
The results indicated that the prevalence of ALS was 19.7 per 100,000 over 14 years.
This rate is significantly higher compared with the ALS prevalence reported among deployed GWV, which was 5.8 per 100,000 over 10 years after the Gulf War.
The new findings also indicate a higher estimated prevalence than that reported by the Agency for Toxic Substances and Disease Registry (ATSDR). Using the National ALS Registry, that agency demonstrated that the rate of ALS in people under the age of 60 was 11.5 per 100,000 persons in 2015. However, “our findings may not be comparable due to methodological and cohort characteristics,” the researchers said.
Interestingly, both the prevalence and cumulative incidence of definite ALS were significantly higher among Air Force personnel, tactical operation officers, and health care workers compared with general officers and administrators.
“This suggests the need for evaluating the role of occupational exposures these personnel are exposed to, such as ionizing radiation, electromagnetic fields, ozone, jet emissions, noise etc., in the pathogenesis of ALS,” the researchers said.
Such evaluation is particularly important since electromagnetic fields, high-intensity radar waves, diesel exhaustion, and electric shock have previously been reported to be risk factors for ALS.
Consistent with previous studies, there was a lower prevalence rate of ALS among Marines.
Neither TBI nor younger age, defined as younger than 45 years old, were associated with ALS. On the other hand, also consistent with previous literature, the researchers found an elevated risk for men and Caucasians.
Depression, cardiac disease, cerebrovascular disease, high blood pressure, and obstructive sleep apnea were found to be significantly associated with ALS in this population of veterans.
“This study among a cohort of relatively young Veterans showed a high ALS prevalence, suggesting an early onset of ALS among deployed military service members,” the researchers said.
“Research examining military risk factors and occupational exposures that lead to early onset of ALS is needed to determine if occupational safety approaches can reduce risk for this terminal disease,” they added.
“Furthermore, there is a need for future ALS surveillance measures in this population as more cases of ALS may develop with the aging of this cohort,” the researchers said.