Compared with the general population, male professional soccer players face a higher risk of neurodegenerative diseases, particularly if they are in nongoalkeeper positions and/or have careers lasting >15 years, according to study findings published in JAMA Neurology.
The risk for neurodegenerative disease mortality in former professional soccer players is higher compared to the general population. Yet, identifying the contributing factors tied to this increased risk for this particular group has remained unknown.
The UK researchers identified male former professional soccer players from Scotland born between 1900 and 1977 from the Record of Pre-War Scottish League Players version 2 and the Record of Post-War Scottish League Players version 6.
Population-based health record linkage data were used to examine the risk of neurodegenerative diseases among the former soccer players (n=7676) compared with a matched general population control group (n=23,028). The overall data featured 1,812,722 person-years of follow-up (overall median follow-up, 18 years).
Over the follow-up period, approximately 5.0% of former professional soccer players (n=386) and 1.6% of the matched population control (n=366) were diagnosed with a neurodegenerative disease (hazard ratio [HR], 3.66; 95% CI, 2.88-4.65; P <.001).
While the risk of neurodegenerative disease was higher in goalkeepers than it was in the matched control arm, there was no significant difference between the 2 groups (HR, 1.83; 95% CI, 0.93-3.60; P =.08). However, outfield players had a significantly greater risk of neurodegenerative disease compared with matched controls (HR, 3.83; 95% CI, 3.11-4.73; P <.001), even following adjustment for deaths from non-neurodegenerative conditions. Outfield players also had a higher risk of neurodegenerative disease compared with goalkeepers (odds ratio [OR], 2.22; 95% CI, 1.35-3.64; P =.002).
Additionally, the risk of neurodegenerative disease was lower for forward positions (HR, 2.79; 95% CI, 2.06-3.78; P <.001) and higher for defenders (HR, 4.98; 95% CI, 3.18-7.79; P <.001; OR, 1.52; 95% CI, 1.12-2.07; P =.008).
In the cohort, the average length of a professional outfield soccer player’s career was 8.6 years. Careers typically spanned between player ages of 20.0 years and 28.5 years. Neurodegenerative disease risk increased with increasing career durations (P =.01). The risk of neurodegenerative disease was significantly lower in players with short career length compared with matched controls (HR, 2.26; 95% CI, 1.51-3.37; P <.001). In contrast, the risk increased in players with longer careers (HR, 5.20; 95% CI, 3.17-8.51; P <.001).
Limitations of this study included the lack of data regarding soccer players’ participation in other contact sports as well as the lack of data regarding the players’ extended participation in nonprofessional soccer beyond retirement age. Additionally, it is likely that some people in the general population control group played soccer nonprofessionally, which may also be associated with increased risk of neurodegenerative disease.
While the investigators of this retrospective study suggest that further research is necessary to examine the risks associated with amateur soccer, they add that “adopting a precautionary principle approach to mitigate risk of neurodegenerative disease by reducing exposure to traumatic brain injury and head impacts in soccer and wider sports might be advised.”
Disclosures: Some study authors declared affiliations. Please refer to the original article for a full list of disclosures.
Russell ER, Mackay DF, Stewart K, MacLean JA, et al. Association of field position and career length with risk of neurodegenerative disease in male former professional soccer players. JAMA Neurol. Published online August 2, 2021. doi:10.1001/jamaneurol.2021.2403