While football fans may pay more attention to who gets the first down or fumbles the ball on the goal line, many researchers are more interested in which NFL players will receive medical treatment in the future.

According to a new study published in the journal Neurology, professional football players are three times more likely to have neurodegenerative diseases than the general population. This risk increased even more when researchers looked exclusively at Alzheimer’s disease and amyotrophic (amm-eee-oh-TRO-fic) lateral sclerosis, also called Lou Gehrig’s disease or ALS.

The researchers surveyed nearly 3,500 retired NFL players who were in the league between 1959 and 1988. The National Institute for Occupational Safety and Health, a division of the Centers for Disease Control and Prevention, had been following this group of players since the early ’90s. But for this study, they specifically focused on the autopsies of 334 players to evaluate their ultimate neurological outcomes.

After looking at the death certificates, researchers concluded that Alzheimer’s and Lou Gehrig’s diseases played a noticeable role in the deaths. Among the 334 players, seven had died with Alzheimer’s and another seven with ALS.

The numbers might seem small, but these diseases are generally rare, especially at a younger age. The average age of the players who had died was 57.

Researchers also found that players in speed positions, such as wide receivers and running backs, were three times more likely to develop neurodegenerative disease than players in other positions.

In recent years, the NFL has put more focus on protecting players, especially from head injuries, so perhaps these statistics will eventually go the way of leather helmets.