Neurodegenerative Disease Mortality among Former Professional Soccer Players

Abstract

BACKGROUNDNeurodegenerative disorders have been reported in elite athletes who participated in contact sports. The incidence of neurodegenerative disease among former professional soccer players has not been well characterized. METHODSWe conducted a retrospective cohort study to compare mortality from neurodegenerative disease among 7676 former professional soccer players (identified from databases of Scottish players) with that among 23,028 controls from the general population who were matched to the players on the basis of sex, age, and degree of social deprivation. Causes of death were determined from death certificates. Data on medications dispensed for the treatment of dementia in the two cohorts were also compared. Prescription information was obtained from the national Prescribing Information System. RESULTSOver a median of 18 years, 1180 former soccer players (15.4%) and 3807 controls (16.5%) died. All-cause mortality was lower among former players than among controls up to the age of 70 years and was higher thereafter. Mortality from ischemic heart disease was lower among former players than among controls (hazard ratio, 0.80; 95% confidence interval [CI], 0.66 to 0.97; P = 0.02), as was mortality from lung cancer (hazard ratio, 0.53; 95% CI, 0.40 to 0.70; P<0.001). Mortality with neurodegenerative disease listed as the primary cause was 1.7% among former soccer players and 0.5% among controls (subhazard ratio [the hazard ratio adjusted for competing risks of death from ischemic heart disease and death from any cancer], 3.45; 95% CI, 2.11 to 5.62; P<0.001). Among former players, mortality with neurodegenerative disease listed as the primary or a contributory cause on the death certificate varied according to disease subtype and was highest among those with Alzheimer's disease (hazard ratio [former players vs. controls], 5.07; 95% CI, 2.92 to 8.82; P<0.001) and lowest among those with Parkinson's disease (hazard ratio, 2.15; 95% CI, 1.17 to 3.96; P = 0.01). Dementia-related medications were prescribed more frequently to former players than to controls (odds ratio, 4.90; 95% CI, 3.81 to 6.31; P<0.001). Mortality with neurodegenerative disease listed as the primary or a contributory cause did not differ significantly between goalkeepers and outfield players (hazard ratio, 0.73; 95% CI, 0.43 to 1.24; P = 0.24), but dementia-related medications were prescribed less frequently to goalkeepers (odds ratio, 0.41; 95% CI, 0.19 to 0.89; P = 0.02). CONCLUSIONSIn this retrospective epidemiologic analysis, mortality from neurodegenerative disease was higher and mortality from other common diseases lower among former Scottish professional soccer players than among matched controls. Dementia-related medications were prescribed more frequently to former players than to controls. These observations need to be confirmed in prospective matched-cohort studies. (Funded by the Football Association and Professional Footballers' Association.

Concussion and long-term cognitive impairment among professional or elite sport-persons: a systematic review

“…The ongoing HEalth and Ageing Data IN the Game of football (HEADING) study52 will add important information about external and internal comparison of the association between low-impact repetitive head injury and cognitive function among British-based footballers. Recently, Scottish footballers have been shown to be at increased risk of mortality from neurodegenerative diseases, and above all dementia, compared with the general population 53…”

Cognitive Ageing in Top-Level Female Soccer Players Compared to a Normative Sample from the General Population: A Cross-sectional Study

“…There is an extensive ongoing debate in the media as well as in the scientific literature on the potential negative effect of contact and collision sport participation on long-term neurocognitive function (Casson & Viano, 2019;Manley et al, 2017;Putukian et al, 2019). Specifically, it was suggested that the inherent exposure to (repeated) concussions or subconcussive blows may lead to an increased risk or earlier onset of neurodegenerative diseases and psychiatric disorders (Chiò, Benzi, Dossena, Mutani, & Mora, 2005;Kerr, Marshall, Harding, & Guskiewicz, 2012;Lehman, Hein, Baron, & Gersic, 2012;Mackay et al, 2019), declines in neurocognitive performance (Hume et al, 2017;Pearce, Rist, Fraser, Cohen, & Maller, 2018), and neuroimaging abnormalities (Koerte et al, 2016;Strain et al, 2015) in retired athletes. While most research on the topic has been conducted with American soccer players (Manley et al, 2017), similar findings have also been reported in rugby (Hume et al, 2017;Pearce et al, 2018), ice hockey (Tremblay et al, 2013), and soccer (soccer) (Chiò et al, 2005;Koerte et al, 2016;Mackay et al, 2019).…”

“…Specifically, it was suggested that the inherent exposure to (repeated) concussions or subconcussive blows may lead to an increased risk or earlier onset of neurodegenerative diseases and psychiatric disorders (Chiò, Benzi, Dossena, Mutani, & Mora, 2005;Kerr, Marshall, Harding, & Guskiewicz, 2012;Lehman, Hein, Baron, & Gersic, 2012;Mackay et al, 2019), declines in neurocognitive performance (Hume et al, 2017;Pearce, Rist, Fraser, Cohen, & Maller, 2018), and neuroimaging abnormalities (Koerte et al, 2016;Strain et al, 2015) in retired athletes. While most research on the topic has been conducted with American soccer players (Manley et al, 2017), similar findings have also been reported in rugby (Hume et al, 2017;Pearce et al, 2018), ice hockey (Tremblay et al, 2013), and soccer (soccer) (Chiò et al, 2005;Koerte et al, 2016;Mackay et al, 2019). However, other studies with retired contact sport athletes report no such effects related to the prevalence of neurodegenerative diseases and psychiatric disorders (Deshpande et al, 2017;McMillan et al, 2017;Vann Jones, Breakey, & Evans, 2014), neurocognitive performance (Esopenko et al, 2017;McMillan et al, 2017), or neuroimaging abnormalities (Zivadinov et al, 2018).…”

A map of transcriptional heterogeneity and regulatory variation in human microglia

“…The challenge of sampling also means that large scale genetic studies of microglia have not been attempted to date. Population studies have demonstrated that individuals subject to mild brain trauma are 5-fold more likely to develop Alzheimer's Disease (Mackay et al 2019). Consequently, it is of particular importance to understand the activation of human microglia in the context of acute brain injury together with the underpinning genetic contribution to neurodegeneration.…”