Proportionate mortality of Italian soccer players: Is amyotrophic lateral sclerosis an occupational disease?

Objectives: The objective of the study is to investigate the mortality experience of Italian soccer players and to discuss the findings in the light of possible long term effects of doping. Methods: Standardized proportionate mortality ratio (SPMR) and standardized proportionate cancer mortality ratio (SPCMR) were computed for 350 deceased subjects deriving from a list of about 24,000 active Italian soccer players from 1960 to 1996 in the three top leagues (A, B and C). Results: When considering SPMRs, there is a substantial adherence of observed to expected mortality, with the only exception of mortality for diseases of the nervous system (13 obs. vs. 6 exp.) mainly explained by an excess of amyotrophic lateral sclerosis (8 obs. vs 0.69 exp.). As far as SPCMRs are concerned, some digestive cancers (namely: colon cancer, liver cancer and pancreas cancer) show a doubled risk. Conclusions: A high risk for amyotrophic lateral sclerosis is observed among Italian soccer players. Epidemiological data on association between sport and Amyotrophic Lateral Sclerosis (ALS) are contrasting. On the basis of the overall available evidence we suggest a possible connection between dietary supplements or drugs used to enhance sporting performance and ALS pathogenesis. Further epidemiological studies are needed to confirm these specific mortality risks among soccer players.