A diagnosis of amyotrophic lateral sclerosis (ALS) is devastating. Victims of this fatal neurological disease lose almost all muscle control, even the ability to breathe on their own. That’s why it might seem alarming that a new report from the Institute of Medicine, released today, suggests a possible connection between military service and later development of ALS, also known as Lou Gehrig’s disease (after its most famous victim). But the chairman of the committee that wrote the report cautions against overreaction. “It’s a rare disease, and it’s rare in veterans,” says Dr. Richard Johnson, a neurologist at the Johns Hopkins University School of Medicine. “I served in the military, and it didn’t cross my mind that this would increase my risk of the disease.”
The report analyzed five studies that examined a potential link between military service and ALS. Three of the studies focused on Persian Gulf War veterans and found that their risk of developing ALS was as much as two times higher than that of the general population or veterans of the same era (1990-91) who served outside the Persian Gulf. Another study found that veterans who served from 1910 to 1982 had 1.5 times higher risk of ALS. The fifth study found no association. However, there were methodological problems with several of the studies and Johnson says much more research is needed before scientists can establish a real connection—if there is one.
Future research, Johnson says, should follow up on other characteristics of people who served in the military, such as intensive physical activity and cigarette smoking, both of which slightly increase the risk of ALS. Other possible factors include a higher rate of fractures and exposure to environmental toxins, like lead, Johnson says. The new report, he says, “is just a clue of what directions to go in.”
Ideally, researchers could compare two different groups of veterans—Americans and British soldiers, for example—to see if there are any common traits among those who eventually get ALS. A major problem, Johnson says, is that any study has to encompass a very large group of subjects since ALS is rare (an estimated 5,000 Americans are diagnosed each year). For now, he says, no one should get too worried, including current members of the military and their families. “This is not an increase in risk that should change anything you’re doing,” he says.