ALS mystery: No one understands why veterans are affected

 

Marielle Theander Olsson/TT

 

Published 05:45

 

People who served in the US Air Force are more likely to be affected by ALS than those who work in the army, according to new research on American veterans. Archive photo. Photo: David Zalubowski /AP/TT

More men who served in the US Air Force, Navy or Coast Guard develop the fatal neurological disease ALS, compared to other veterans, a new study shows.

But what causes it is still a mystery.

ALS is a rare but incurable disease in which nerve cells in the brain and spinal cord break down. The muscles are gradually paralyzed and most of those affected usually die within two to four years.

In a new study, published in the journal Neurology, researchers at Harvard have investigated the incidence of ALS in American veterans. The study included more than 9.1 million men and nearly 785,000 women in the US Veterans Health Care System over a 24-year period. In total, 13,935 of the men and 484 of the women were affected by ALS.

The results show that the proportion of those affected differs between the branches of defense, and the difference is most clearly seen among men under 61 years of age. Among men who served in the Air Force, the incidence of ALS is 29 percent higher, compared with veterans in the Army. For the Navy and Coast Guard, the corresponding figures are 15 percent and 26 percent higher, respectively.

More officers

The researchers also found that officers are affected to a greater extent than ordinary soldiers – the incidence of ALS was 64 percent higher for men and 72 percent higher for women. However, longer military service is associated with a lower incidence of ALS.

“The results suggest that officers and employees in the Air Force, Navy or Coast Guard may have been exposed to military environments that increase the risk of ALS,” says study author Marc G. Weisskopf, a professor at the Harvard School of Public Health.

However, further research is needed to identify the factors involved, according to Weisskopf, who emphasizes that the overall risk of being affected is small.

Cause unclear

Previous studies from several countries have indicated a connection between military service and ALS, but the connection is not fully established, according to Caroline Ingre, ALS researcher and chief physician at Karolinska University Hospital.

The question of what this is due to can therefore only be answered with hypotheses.

“It has been discussed whether it is increased physical strain or emotional strain, or whether one has been exposed to chemicals, for example, in connection with combat,” says Caroline Ingre.

Another factor that may play a role is individual genetic predisposition.

– It has previously been said that well-trained or athletes are at increased risk and that it is the genetic makeup that provides the conditions to become an athlete or military that is the risk in itself, and not the professional practice.

Facts

ALS

Every year, just over 440 people get ALS (amyotrophic lateral sclerosis) in Sweden. Most are between 60 and 70 years old.

ALS is actually a collective term for several neurological diseases that all lead to the same symptom picture. It is not entirely known why people are affected, but research points to a combination of genetics and environment.

The disease breaks down the nerve cells in the brain and spinal cord that regulate the voluntary muscles. It often starts on one side of the body, with, for example, weakness in an arm, hand or foot, and then spreads until you are completely paralyzed. The muscles for speaking and swallowing, as well as the strength of the arms, legs and breathing muscles, are usually affected.

Most people with ALS die within two to four years of becoming ill, usually from respiratory failure. About one in ten lives considerably longer.

There is no cure for ALS, but there are medications that relieve symptoms and slow the progression somewhat.

Source: 1177, Karolinska University Hospital