Amyotrophic lateral sclerosis (ALS) incidence and mortality rates are nearly 4 times higher in National Football League (NFL) players compared with the US male population, according to a study published in JAMA Network Open.

“To our knowledge, this study represents the largest investigation of ALS risk in NFL athletes,” researchers wrote. “These findings indicate that athletes who played in the NFL have a nearly 4 times greater rate of developing, and dying from, ALS.”

The cohort study included all 19,423 football players who debuted in the NFL between 1960 and 2019 and played at least 1 professional game.

Some 38 of the players developed ALS, and 28 died during the study window, researchers reported. Among the NFL players, compared with the US male population, the standardized incidence ratio was 3.59, and the standardized mortality ratio was 3.94, after adjusting for age race.

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Athletes diagnosed with ALS played with the NFL an average 7.0 years compared with 4.5 years for matched athletes without ALS, according to the study, suggesting that longer NFL careers are associated with increased ALS rates. ALS status did not differ with markers of NFL fame, body mass index, position played, birth location, or race.

“ALS is a fatal disease with a significant socioeconomic and public health burden. Identifying potential exposure-related risk factors that can be modified or reduced is important so that these risks can be minimized and eliminated…” researchers wrote. “Further study is therefore warranted to clarify the causal mechanisms underlying the association between duration of professional football play and incidence of ALS.”

Daneshvar DH, Mez J, Alosco ML, et al. Incidence of and mortality from amyotrophic lateral sclerosis in National Football League athletes. JAMA Netw Open. Published online December 1, 2021. doi: 10.1001/jamanetworkopen.2021.38801