Neurodegenerative Disease Mortality among Former Professional Soccer Players.
Level 3 - non-randomized controlled study
Retrospective matched cohort study
PubMed 31633894 · doi:10.1056/NEJMoa1908483
What was done
A retrospective cohort study compared mortality and dementia medication prescriptions between 7,676 former Scottish male professional soccer players and 23,028 general population controls matched on sex, age, and social deprivation. Over a median 18-year follow-up, causes of death were identified from death certificates (with adjustment for competing risks from cancer and ischemic heart disease), and dementia medication data were obtained from the Scottish national Prescribing Information System.
What was found
During follow-up, 1,180 players (15.4%) and 3,807 controls (16.5%) died. Former players had lower all-cause mortality prior to age 70, lower ischemic heart disease mortality (HR 0.80; 95% CI, 0.66 to 0.97; P=0.02), and lower lung cancer mortality (HR 0.53; 95% CI, 0.40 to 0.70; P<0.001). However, primary neurodegenerative disease mortality was 1.7% in players versus 0.5% in controls (subhazard ratio, 3.45; 95% CI, 2.11 to 5.62; P<0.001). As a primary or contributory cause, hazard ratios were highest for Alzheimer's disease (HR 5.07; 95% CI, 2.92 to 8.82; P<0.001) and lowest for Parkinson's disease (HR 2.15; 95% CI, 1.17 to 3.96; P=0.01). Dementia-related medications were prescribed more frequently to players (OR 4.90; 95% CI, 3.81 to 6.31; P<0.001). Goalkeepers did not differ significantly from outfield players in neurodegenerative mortality (HR 0.73; 95% CI, 0.43 to 1.24; P=0.24) but received fewer dementia-related medications (OR 0.41; 95% CI, 0.19 to 0.89; P=0.02).
Why it matters
This study provides large-scale epidemiological evidence linking professional soccer play to significantly increased risks of neurodegenerative disease mortality and dementia medication use, despite general cardiovascular and longevity advantages in mid-life.
Limits
The study is retrospective and relies on death certificate reporting and prescription registries, both subject to diagnostic and coding inaccuracies. The cohort was restricted to Scottish male professional players from historical eras, limiting generalizability to female athletes, amateur players, and modern eras with differing ball technologies and concussion protocols. Specific exposure details, such as heading frequency or head injury history, were not measured.
Cited by
- supports Three epidemiological studies (in Italy, Spain, and Scotland) have linked professional soccer playing to an increased risk of ALS.