@article{ref1,
title="Severely increased risk of amyotrophic lateral sclerosis among Italian professional football players",
journal="Brain: a journal of neurology",
year="2005",
author="Chio, Adriano and Benzi, Gianmartino and Dossena, Maurizia and Mutani, Roberto and Mora, Gabriele",
volume="128",
number="Pt 3",
pages="472-476",
abstract="The cause of amyotrophic lateral sclerosis (ALS) is still unknown. A possible relationship between ALS and sport participation has been supposed, but never definitely demonstrated. We studied a cohort of 7325 male professional football (soccer) players engaged by a football team from the Italian First or Second Division in the period 1970-2001. ALS cases were identified using different concurrent sources. Standardized morbidity ratios (SMRs) were calculated. During the 137,078 person-years of follow-up, five ALS cases were identified (mean age of onset, 43.4 years). Three cases had a bulbar onset, significantly more than expected (P = 0.003). Since the number of expected cases was 0.77, the overall SMR was 6.5 [95% confidence interval (CI), 2.1-15.1]. The SMR was significantly increased for an ALS onset before 49 years, but not for older subjects. A significant increase of the SMR was found in the periods 1980-1989 and 1990-2001, whereas no ALS case was found in the 1970-1979 period. A dose-response relationship between the duration of professional football activity and the risk of ALS was found (>5 years, 15.2, 95% CI, 3.1-44.4; < or =5 years, 3.5, 95% CI, 0.4-12.7). Our findings seem to indicate that playing professional football is a strong risk factor for ALS.<p /> <p>Language: en</p>",
language="en",
issn="0006-8950",
doi="10.1093/brain/awh373",
url="http://dx.doi.org/10.1093/brain/awh373"
}