Table 4.
Summary of results from studies reporting data on the frequency of PD
| Characteristics | Quality assessment | Summary of findings | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| N. of subjects | Results | |||||||||
| Fist author, year | Sport | Source of cases | Reference population | Exposure | Selection | Comparability | Outcome/exposure | n. cases among the exposed/total exposed | n. cases among the reference group/total reference | Data ORs/HRs (95%CIs) or SIRs/PRs/SMRs/SPMRs |
| Cohort studies | ||||||||||
| Russell 2021 [84] | Soccer | Hospital records, prescriptions and death certificates with ICD-9 and ICD-10 codes | Random sample of matched individuals (3:1 ratio) from the community health index database | Having been a soccer player in the Scottish League as documented in the archives of the Scottish Football Museum and individual league clubs | *** | ** | ** | 28/7676 players | 45/23028 non players |
frequency of PD diagnosis HR 2.09 (95% CI 1.20–3.61) p = 0.009 |
| Mackay 2020 [82] | Soccer | Death certificates with ICD-9 and ICD-10 codes (primary and contributory cause) for PD from electronic health records | Controls from general population matched to the players according to sex, age, and degree of social deprivation | Former professional soccer players born before January 1, 1977 | ** | ** | ** | 28/7676 players |
44/23028 non players |
PD HR for death (95% CI): 2.15 (1.17–3.96) p = 0.01 |
| Nguyen 2019 [79] |
American football baseball |
Death certificates from 1979 to 2013 classified with ICD underlying (U) and underlying or contributing (U&C) | MLB cohort: from LBD of all players that appeared in ≥ 1 game at a professional level in 1871–2006 | NFL cohort: from NIOSH consisting in players who played ≥ 1 season in 1959–1988 | ** | ** | ** |
NFL U: 3/2708 U&C: 14/3419 |
MLB U: 3/2708 U&C: 5/2708 |
HR (95%CI) U: 3.08 (0.76–12.42) U&C: 3.45 (1.21–9.83) |
| Janssen 2017 [77] |
American football basketball swimming wrestling |
3-step procedure: screening of medical index through REP tool, review of diagnoses, Diagnosis confirmed by senior neurologist | Varsity athletes (football vs non-football) enrolled in the Mayo and Rochester High Schools in 1956 to 1970 | Varsity activity in football, basketball, swimming or wrestling documented in the yearbooks | ** | * | ** | 3/296 football players | 3/190 non-football athletes |
Incidence rate ratio (IRR) parkinsonism (95% CI) football: 2.08 (0.57–5.32) Non-football:0.86 (0.23–2.19) p > 0.99 |
| Lehman 2012 [74] | American football | Death certificates with ICD code for PD in effect at death | US male mortality rates (1960–2007) for 119 cause of death categories | Having played in the National Football League for at least 5 seasons between 1959 and 1988 | **** | ** | * |
U: 2/3439 players C: 3/3439 players |
– |
PD SMR-U: 2.14 (0.26–7.75) SMR-U&C: 4.31 (1.73–8.87) |
| Savica 2012 [75] | American football | Medical records confirmed by a neurologist |
Having been a band, glee club or choir member as for the yearbooks of the only 2 high schools in Rochester in 1946–1956 Expected incidence calculated based on previously published rates for that area |
Having been a football player as for the yearbooks of the only 2 high schools in Rochester in 1946–1956 | *** | ** | ** | 10/438 players | 5/140 non-players |
HR (95%CI) 0.48 (0.17–1.42) (p = 0.19) SIR (95%CI) observed vs expected players: 2.36 (1.13–4.34) non-players: 4.94 (1.61–11.51) |
| Lolekha, 2010 [73] | Boxing |
2-phase procedure: screening with validated Tanner’s questionnaire and Sevillano weighted score and diagnosis with UKPDSBB clinical diagnostic criteria |
Several populations | Registered retired boxers from the Sports Authority of Thailand, the Boxer’s Club of Thailand and the old Thai Boxing Foundation | *** | * | – | 8/704 boxers | – |
8/704 Parkinsonism (5 PD, 1 PSP, 2 vascular parkinsonism) crude prevalence: 0.71% (95% CI 0.09–1.33) comparable to general populations |
| Schulte 1996 [43] | Athletes (any) | Death certificates with ICD-9 code for NDs | Deaths for all causes 1982–1991, and proportion of NDs deaths in all occupations | Occupation and industry coded as “writers, artists, entertainers, and athletes” according to the 1980 Bureau of the Census classification | **** | ** | * | 128 deaths (white female writers, artists, entertainer, or athletes)/130420 total deaths | PMR: 128 (95% CI 107–152) | |
| Case–control studies | ||||||||||
| Park, 2005 [44] |
Athletes (any) dancers |
Death certificates with ICD-9 code for NDs | Deaths for all other causes (excluding CNS neurologic, degenerative, and neoplasms of brain, lymphatic or hematopoietic tissue) | Certificates, coded according to the 1980 Bureau of Census (BOC) system | *** | ** | ** |
33,678 PD total deaths: 2,614,346 |
– | MOR 1.26 (95% CI 0.76–1.97) |
MLB US Major League Baseball, LBD Lahman Baseball Database, HR hazard ratio, IRR incidence rate ratio, SMR standardized mortality ratio, SIR standardized incidence ratio, PMR proportionate mortality ratio, MOR mortality odds ratio, CI confidence interval, U underlying, U&C underlying and contributing, PSP progressive supranuclear palsy