ALS in athletes: Are head injuries to blame?

Close up of an american football on the field, players in the background (iStock)

When Dwight Clark revealed that he had been diagnosed with amyotrophic lateral sclerosis (ALS), he said he didn’t know for sure if his eight years spent in the NFL influenced his chances of developing the neurological condition, but that he suspects it did. Science has the same suspicions.

ALS, also commonly referred to as Lou Gehrig’s disease after it ended the career of one of baseball’s most iconic figures, is a progressive neurodegenerative disease that affects nerve cells in the brain and spinal cord. Gradual, painless, progressive muscle weakness is the most common symptom of ALS, with other early indicators manifesting as unsteady gait, muscle cramps, twitches, slurred speech or uncontrollable periods of laughing or crying, according to the ALS Association.

It’s estimated that as many as 20,000 Americans are living with ALS, and men comprise 60 percent of the patient population. The majority of patients who develop ALS are between 40 and 70, with the average person living only two to five years after being diagnosed.

Only 10 percent of cases are considered familial ALS, in which more than one person in the family has the disorder, while 90 percent of the cases are considered sporadic. The disparity, along with the amount of instances among former NFL players, has caused researchers to wonder if repeated head trauma or traumatic brain injury could increase a patient’s risk for developing the fatal disorder.

“It’s difficult to give a precise answer,” Dr. Barry Boden, a surgeon at The Orthopedic Center, a division of The Centers for Advanced Orthopaedics, and a team physician for athletes at Montgomery College, told Fox News. “It’s a very complicated situation, and there are a lot of variabilities between concussions and how people respond to concussions.”

For instance, while Clark’s role as wide receiver may have left him susceptible to concussions, Pete Frates — the former Boston College baseball star who was diagnosed with ALS and became a household name after starting the ALS Ice Bucket Challenge — played in the outfield. There are also numerous painters, authors and scientists, like Ann Downer and Richard Glatzer, who have died from ALS, making the disease’s onset more mysterious.

“The force of impact and how many concussions athletes sustain are factors, but there are also genetic factors that play into things,” Boden said. “You have to follow someone for 30 years, and take into account family history of migraines or other problems.”

A 2013 report published by the Centers for Disease Control and Prevention (CDC) analyzed the instances of brain and nervous system disorders among NFL players. The data was based on athletes who spent at least five seasons playing in the league between 1959 and 1988. While the report found NFL players on average live longer than other men in the United States, other data suggested brain and nervous system disorders were three times higher among the athletes. It also found that more of the 17 players named in the report who died as a result of a neurological disorder had played a speed position, which includes quarterback, running back, halfback, fullback, wide receiver, tight end, defensive back, safety and linebacker.

The report’s authors said their results suggest that former football players may have a higher risk of developing a neurological disorder compared to someone from the general population, but that they were not able to assess if individuals who have had multiple concussions are more likely to develop a neurological disorder.

Boden said another piece of the puzzle lies in determining what a person’s threshold is for head trauma. Researchers have to pinpoint whether it takes someone 10 concussions to have a problem, or one serious concussion, for a long-term problem to arise. Often, Boden said, a common barrier among researchers is only having access to data regarding the end result rather than monitoring a patient’s full journey.

“With chronic traumatic encephalopathy (CTE) in football players, we only have the end point, we don’t always have the history of how many concussions they had or any genetic predisposition,” Boden said. “It’s certainly worrisome, and it’s certainly better to err on the side of conservatism to reduce the number of impacts, at least during practices, and restrict contact during the week.”

For now, Boden said various professional leagues like the NFL and FIFA are taking steps to reduce the amount of head trauma among athletes. However, he said, the changes must also be implemented at a lower levels of play, especially in youth leagues. As a team physician, he said he’s encouraged by the amount of increased awareness among parents and athletes, and doctors’ and coaches’ increased emphasis on concussion education.

“I think that there have been huge improvements over the last 10 years, but we still have a long way to go,” he said. “Concussions are hard to measure, and which part of the brain gets injured, and how long it takes to recover are all things that need further studying.”