Summary of findings from studies of former elite and professional athletes from Europe and Australia
| Study | Country | N | Group | Age | Exposure | Topic/Outcome | Significant Findings/ risk |
| Piantella et al123 | Australia | 58 (8 women) (no concussion=41; concussion=17) | Jockeys | Concussion: 31.2 (1.8) No concussion: 36.1 (1.5) | Concussions | Professional jockeys tested twice over a 5-year interval did not show evidence of clear decline or impairment (as defined by two or more reliably worsened test scores). | No |
| Taioli128 | Italy | 5389; 63 had died | Soccer | At death: 36.3 (10.3) | Sports participation | No significant difference in risk for suicide as manner of death than general population. Greater risk for ALS. | No for suicide Yes, greater for ALS |
| Russell et al122 | Scotland | Soccer=7676 Controls=23 028 | Scottish Soccer | At first hospitalisation: soccer: M=52.3, SD=13.6; controls: M=46.8, SD=14.7 | Sports participation | Hospitalisation for psychiatric and substance abuse problems less common in former soccer players. No difference in suicide. | Yes, lesser for psychiatric and substance abuse No for suicide |
| Belli et al129 | Italy | 24 000; 350 had died | Italian Soccer | At death: M=50.8, SD=15.2 | Sports participation | ALS more common in former soccer players; other disease of the nervous system not more common. | Yes, greater for ALS No for other diseases |
| Pupillo et al130 | Italy | 23 586; 34 cases of ALS | Italian Soccer | M=45.0, SD=12.6 at diagnosis | Sports participation | ALS more common in former Italian soccer players. | Yes/Greater |
| Chio et al132 | Italy | 7325; 5 cases of ALS | Italian Soccer | Age of onset M=43.4 (SD=9.1; range 33–56) | Sports participation | ALS more common in former Italian soccer players. | Yes/Greater |
| Chio et al133 | Italy | 7325; 5 cases of ALS | Italian Soccer | Age of onset M=41.6 years (SD=7.5, range 33–56 years). | Sports participation | ALS more common in former Italian soccer players. | Yes/Greater |
| Russell et al120 | Scotland | Soccer=7676; controls=23 028 | Scottish Soccer | NR | Sports participation | Neurodegenerative disease mortality greater in former soccer players, varied by position played and increased with career length. | Yes/Greater |
| Mackay et al124 | Scotland | Soccer=7676, 1180 deaths; controls=23 028, 3807 deaths | Scottish Soccer | At death: soccer M=67.9, SD=13.0; controls M=64.7, SD=14.0 | Sports participation | Neurodegenerative disease mortality greater in former soccer players (eg, AD, ALS and PD). | Yes/Greater |
The two studies by Chio et al used the same cohort of players,132 133 and the three studies with former Scottish players used the same cohort.120 122 124 Many of these studies are ecological analyses with positive associations being important hypothesis-generating findings; more meticulously designed cohort studies with better control for confounding factors are needed.
AD, Alzheimer’s disease; ALS, amyotrophic lateral sclerosis; M, mean; NR, not reported; PD, Parkinson’s disease.