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Professional Soccer and Dementia Risk—The Ugly Side of the Beautiful Game

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Abstract

While an increased risk for late-life neurodegenerative disease and dementia has consistently been observed in professional athletes with very high exposure to repetitive head impacts, such as former professional boxers and US football players, much less is known about neurologic outcomes in sports with lower head trauma exposure. Soccer, known to most of the world as football, is by far the most popular sport globally, with an estimated 270 million active players worldwide.¹ The Brazilian superstar Pelé famously referred to soccer as “the beautiful game,” inspired by the fancy footwork and orchestral movement displayed by footballers at the highest level. However, heading the ball (known as headers) is also an integral part of the game, and additional incidental head impacts occur via collisions with other players or the ground. A 2017 summit on head injury in soccer concluded that the frequency of headers increases from the youth level to the professional level.² Both overall header exposure and the force of impact generated by headers were deemed relatively low but with considerable individual variability. Linear forces generated by heading the ball can range from as low as 5g to as high as 60g. Studies have inconsistently detected acute and chronic sequelae of soccer headers,³ with some studies reporting associations between more frequent headers, worse cognitive test performance, and compromised white matter integrity on magnetic resonance imaging.

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... It has been estimated that a typical soccer player executes an average of 6-12 headers per game and engages in a minimum of 2000 headers over a 20-year professional career, alongside countless repetitive heading drills during training sessions [7]. While singular headings do not directly lead to neurological symptoms or concussions, they contribute significantly to the accumulation of sub-concussive impacts, which have been linked to potential cognitive function impairment [30][31][32][33] (Fig. 1). ...
... His affliction with CTE remained shrouded in obscurity until 2014 when his story was published in the New York Times [74] and later in a book written by his wife-"Bellini: The First Captain Champion". In the following years, his case catalysed a growing awareness of the condition, leading to the emergence of additional pathologically confirmed CTE cases among retired soccer players [6,33,72,75]. ...
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Soccer is one of the most popular sports worldwide, played by over 270 million people and followed by many more. Several brain health benefits are promoted by practising soccer and physical exercise at large, which helps contrast the cognitive decline associated with ageing by enhancing neurogenesis processes. However, sport-related concussions have been increasingly recognised as a pressing public health concern, not only due to their acute impact but also, more importantly, due to mounting evidence indicating an elevated risk for the development of neurological sequelae following recurrent head traumas, especially chronic traumatic encephalopathy (CTE). While soccer players experience less frequent concussions compared with other contact or combat sports, such as American football or boxing, it stands alone in its purposeful use of the head to hit the ball (headings), setting its players apart as the only athletes exposed to intentional, sub-concussive head impacts. Additionally, an association between soccer and amyotrophic lateral sclerosis has been consistently observed, suggesting a potential “soccer-specific” risk factor. In this review, we discuss the neurological sequelae related to soccer playing, the emerging evidence of a detrimental effect related to recurrent headings, and the need for implementation of comprehensive strategies aimed at preventing and managing the burden of head impact in soccer.
... As regards sport trauma, it has been known since almost a century that professional boxers, after or at the end of their career, may develop a progressive neurological disorder called 'punch drunk syndrome' (44). After the recognition of similar types of pathology also in football players (45,46) and other contact sport athletes (47), as well as in soldiers exposed to explosive blasts (48), both research interest and public awareness of this association have increased dramatically (49). As a matter of fact, this condition of degenerative neuropathology has been subsequently moved into the more general term of chronic traumatic encephalopathy. ...
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Background and aim: The term early-onset dementia (EOD) encompasses several forms of neurodegenerative diseases characterized by symptom onset before 65 years and leading to severe impact on subjects already in working activities, as well as on their family and caregivers. Despite the increasing incidence, the etiology is still unknown, with possible association of environmental factors, although the evidence is still scarce. In this review, we aimed to assess how several environmental and lifestyle factors may be associated with the onset of this disease. Methods: We conducted a literature search in PubMed and EMBASE databases up to May 6, 2022, to retrieve epidemiological studies evaluating the effect of environmental and lifestyle factors on EOD risk. Results: We eventually included 22 studies, ten with cohort and twelve with case-control design. Traumatic injury, especially on the head/brain, some cardiovascular diseases such as atrial fibrillation and stroke, metabolic diseases including diabetes and hypercholesterolemia, and alcohol consumption have been identified as potential risk factors for EOD. Conversely, playing leisure activities including sports (without trauma), higher educational attainment and higher adherence to Mediterranean DASH-Intervention for Neurodegenerative Delay (MIND) diet appeared to be protective for EOD. Conclusions: The literature on environmental risk factors for EOD has been considerably growing in recent years. Overall, it supports an association between some environmental and lifestyle factors with disease risk. However, additional high-quality research is required to confirm these relations and its causal nature (www.actabiomedica.it).
... This supports an interpretation that patterns revealed by the PLS analysis represent group differences related to current sport participation rather than artifacts related to these differences in age. Second, roughly one-third of the control participants had previously played soccer, a 'contact' (but not a 'collision') sport, which, when played at the professional level, appears to increase the risk of neurodegenerative disease [12,88]. If the risks for amateur soccer players are similar, then it is possible that the patterns we observed in LV1 are confounded by the chronic effects of soccer competition. ...
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Contact and collision sports are believed to accelerate brain aging. Postmortem studies of the human brain have implicated tau deposition in and around the perivascular space as a biomarker of an as yet poorly understood neurodegenerative process. Relatively little is known about the effects that collision sport participation has on the age-related trajectories of macroscale brain structure and function, particularly in female athletes. Diffusion MRI and resting-state functional MRI were obtained from female collision sport athletes (n = 19 roller derby (RD) players; 23–45 years old) and female control participants (n = 14; 20–49 years old) to quantify structural coupling (SC) and decoupling (SD). The novel and interesting finding is that RD athletes, but not controls, exhibited increasing SC with age in two association networks: the frontoparietal network, important for cognitive control, and default-mode network, a task-negative network (permuted p = 0.0006). Age-related increases in SC were also observed in sensorimotor networks (RD, controls) and age-related increases in SD were observed in association networks (controls) (permuted p ≤ 0.0001). These distinct patterns suggest that competing in RD results in compressed neuronal timescales in critical networks as a function of age and encourages the broader study of female athlete brains across the lifespan.
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Introduction This paper aims to identify and compare changes in trends and research interests in soccer articles from before and during the COVID-19 pandemic. Methods We compared research interests and trends in soccer-related journal articles published before COVID-19 (2018–2020) and during the COVID-19 pandemic (2021–2022) using Bidirectional Encoder Representations from Transformers (BERT) topic modeling. Results In both periods, we categorized the social sciences into psychology, sociology, business, and technology, with some interdisciplinary research topics identified, and we identified changes during the COVID-19 pandemic period, including a new approach to home advantage. Furthermore, Sports science and sports medicine had a vast array of subject areas and topics, but some similar themes emerged in both periods and found changes before and during COVID-19. These changes can be broadly categorized into (a) Social Sciences and Technology; (b) Performance training approaches; (c) injury part of body. With training topics being more prominent than match performance during the pandemic; and changes within injuries, with the lower limbs becoming more prominent than the head during the pandemic. Conclusion Now that the pandemic has ended, soccer environments and routines have returned to pre-pandemic levels, but the environment that have changed during the pandemic provide an opportunity for researchers and practitioners in the field of soccer to detect post-pandemic changes and identify trends and future directions for research.
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Athletic performance is mutually dependent upon individual constraints and practical interventions. Regarding the former, it is recognised that brain activity and sleep indices can modulate movement planning and execution. Concerning the strategies used in practice, contemporary short-term prescriptions have been adopted by conditioning professionals and physiotherapists with the primary intention to acutely enhance musculoskeletal power output or accelerate post-exercise recovery processes. These includes postactivation performance enhancement (PAPE)-based plyometric warm-up and induced cooling (COOL) through ice packs, respectively. However, it remain unknown whether measures of brain dynamics and natural sleep patterns influence skill-related performance in soccer. To date, the literature does not show a consensus for PAPE effectiveness in young populations. Generally, COOL also negatively affects subsequent lower limb movements requiring high force-velocity levels. Based on these assumptions, the general aim of the current thesis was to investigate the influence of internal individual constraints (EEG and sleep-derived indices) and effects of short-term practical interventions (PAPE and COOL) on the movement kinematics and performance aspects of soccer kicking in youth academy players. A series of six studies is presented. These include a literature review, one technical note and four original experimental research articles (two observational and two interventions) in an attempt to answer the questions defined in the research programme. From the data gathered here, it was possible to provide evidence that a) kick testing in studies systematically lacked resemblance to competition environments; b) occipital brain waves during the preparatory phase determines ball placement while late frontal signalling control both ankle joint in impact phase and post-impact ball velocity; c) poor sleep quality and late chronotype preference are linked to subsequent impaired targeting ability; d) acute enhancements achieved via PAPE/plyometric conditioning are purely neuromuscular, being slightly converted into kicking mechanics or performance improvements; e) in a hot environment, repeated high-intensity running efforts impair both ball placement and velocity whilst a local 5-minutes COOL application assists recovery of overall kick parameters and f) a markerless deep learning-based kinematic system appear as reliable alternative in capturing on-field kicking motion patterns. To conclude, both internal individual constraints (EEG and sleep quality) and a short-term practical intervention (cooling quadriceps/hamstrings with ice packs) have an acute impact in kicking performance in youth soccer context. A model integrating evidence from all papers is presented alongside limitations and recommendations for future studies in this field. Keywords: Technical skill; 3-dimensional kinematics; Accuracy; EEG; Human movement; Motor Control; Biomechanics.
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Importance: Neurodegenerative disease mortality is higher among former professional soccer players than general population controls. However, the factors contributing to increased neurodegenerative disease mortality in this population remain uncertain. Objective: To investigate the association of field position, professional career length, and playing era with risk of neurodegenerative disease among male former professional soccer players. Design, setting, and participants: This cohort study used population-based health record linkage in Scotland to evaluate risk among 7676 male former professional soccer players born between January 1, 1900, and January 1, 1977, and 23 028 general population control individuals matched by year of birth, sex, and area socioeconomic status providing 1 812 722 person-years of follow-up. Scottish Morbidity Record and death certification data were available from January 1, 1981, to December 31, 2016, and prescribing data were available from January 1, 2009, to December 31, 2016. Database interrogation was performed on December 10, 2018, and data were analyzed between April 2020 and May 2021. Exposures: Participation in men's soccer at a professional level. Main outcomes and measures: Outcomes were obtained by individual-level record linkage to national electronic records of mental health and general hospital inpatient and day-case admissions as well as prescribing information and death certification. Risk of neurodegenerative disease was evaluated between former professional soccer players and matched general population control individuals. Results: In this cohort study of 30 704 male individuals, 386 of 7676 former soccer players (5.0%) and 366 of 23 028 matched population control individuals (1.6%) were identified with a neurodegenerative disease diagnosis (hazard ratio [HR], 3.66; 95% CI, 2.88-4.65; P < .001). Compared with the risk among general population control individuals, risk of neurodegenerative disease was highest for defenders (HR, 4.98; 95% CI, 3.18-7.79; P < .001) and lowest for goalkeepers (HR, 1.83; 95% CI, 0.93-3.60; P = .08). Regarding career length, risk was highest among former soccer players with professional career lengths longer than 15 years (HR, 5.20; 95% CI, 3.17-8.51; P < .001). Regarding playing era, risk remained similar for all players born between 1910 and 1969. Conclusions and relevance: The differences in risk of neurodegenerative disease observed in this cohort study imply increased risk with exposure to factors more often associated with nongoalkeeper positions, with no evidence this association has changed over the era studied. While investigations to confirm specific factors contributing to increased risk of neurodegenerative disease among professional soccer players are required, strategies directed toward reducing head impact exposure may be advisable in the meantime.
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Introduction In the past decade, evidence has emerged suggesting a potential link between contact sport participation and increased risk of late neurodegenerative disease, in particular chronic traumatic encephalopathy. While there remains a lack of clear evidence to test the hypothesis that contact sport participation is linked to an increased incidence of dementia, there is growing public concern regarding the risk. There is, therefore, a pressing need for research to gain greater understanding of the potential risks involved in contact sports participation, and to contextualise these within holistic health benefits of sport. Methods and analysis Football’s InfluencE on Lifelong health and Dementia risk is designed as a retrospective cohort study, with the aim to analyse data from former professional footballers (FPF) in order to assess the incidence of neurodegenerative disease in this population. Comprehensive electronic medical and death records will be analysed and compared with those of a demographically matched population control cohort. As well as neurodegenerative disease incidence, all-cause, and disease-specific mortality, will be analysed in order to assess lifelong health. Cox proportional hazards models will be run to compare the data collected from FPFs to matched population controls. Ethics and dissemination Approvals for study have been obtained from the University of Glasgow College of Medical, Veterinary and Life Sciences Research Ethics Committee (Project Number 200160147) and from National Health Service Scotland’s Public Benefits and Privacy Panel (Application 1718-0120).
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The Fédération Internationale de Football Association (FIFA) has long had a policy that players who show signs or symptoms of a concussion should have a timely evaluation by a licensed clinician using established assessment tools and should not return to play if a concussion is diagnosed.¹ After discussions about poor adherence to this policy in the 2014 World Cup, which were highlighted in JAMA,² the FIFA Medical Committee made 3 changes to their concussion protocol (Box).³ In this analysis, the incidence, characteristics, and assessment of head collisions during the 2018 World Cup were reviewed to assess compliance with FIFA’s updated concussion protocol.
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This review seeks to summarize diffusion tensor imaging (DTI) studies that have evaluated structural changes attributed to the mechanisms of mild traumatic brain injury (mTBI) in adult civilian, military, and athlete populations. Articles from 2002 to 2016 were retrieved from PubMed/MEDLINE, EBSCOhost, and Google Scholar, using a Boolean search string containing the following terms: “diffusion tensor imaging”, “diffusion imaging”, “DTI”, “white matter”, “concussion”, “mild traumatic brain injury”, “mTBI”, “traumatic brain injury”, and “TBI”. We added studies not identified by this method that were found via manually-searched reference lists. We identified 86 eligible studies from English-language journals using, adult, human samples. Studies were evaluated based on duration between injury and DTI assessment, categorized as acute, subacute/chronic, remote mTBI, and repetitive brain trauma considerations. Since changes in brain structure after mTBI can also be affected by other co-occurring medical and demographic factors, we also briefly review DTI studies that have addressed socioeconomic status factors (SES), major depressive disorder (MDD), and attention-deficit hyperactivity disorder (ADHD). The review describes population-specific risks and the complications of clinical versus pathophysiological outcomes of mTBI. We had anticipated that the distinct population groups (civilian, military, and athlete) would require separate consideration, and various aspects of the study characteristics supported this. In general, study results suggested widespread but inconsistent differences in white matter diffusion metrics (primarily fractional anisotropy [FA], mean diffusivity [MD], radial diffusivity [RD], and axial diffusivity [AD]) following mTBI/concussion. Inspection of study designs and results revealed potential explanations for discrepant DTI findings, such as control group variability, analytic techniques, the manner in which regional differences were reported, and the presence or absence of persistent functional disturbances. DTI research in adult mTBI would benefit from more standardized imaging and analytic approaches. We also found significant overlap in white matter abnormalities reported in mTBI with those commonly affected by SES or the presence of MDD and ADHD. We conclude that DTI is sensitive to a wide range of group differences in diffusion metrics, but that it currently lacks the specificity necessary for meaningful clinical application. Properly controlled longitudinal studies with consistent and standardized functional outcomes are needed before establishing the utility of DTI in the clinical management of mTBI and concussion.
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In retired professional Association football (soccer) players with a past history of repetitive head impacts, chronic traumatic encephalopathy (CTE) is a potential neurodegenerative cause of dementia and motor impairments. From 1980 to 2010, 14 retired footballers with dementia were followed up regularly until death. Their clinical data, playing career and concussion history were prospectively collected. Next-of-kin consented for six to have post-mortem brain examination. Of the 14 male participants, 13 were professional and 1 was a committed amateur. All were skilled headers of the ball and had played football for an average of 26 years. Concussion rate was limited in six cases to one episode each during their careers. All cases developed progressive cognitive impairment with an average age at onset of 63.6 years and disease duration of 10 years. Neuropathological examination revealed septal abnormalities in all six post-mortem cases, supportive of a history of chronic repetitive head impacts. Four cases had pathologically confirmed CTE; concomitant pathologies included Alzheimer’s disease (N=6), TDP-43 (N=6), cerebral amyloid angiopathy (N=5), hippocampal sclerosis (N=2), corticobasal degeneration (N=1), dementia with Lewy bodies (N=1) and vascular pathology (N=1), all would have contributed synergistically to the clinical manifestations. The pathological diagnosis of CTE was established in four individuals according to the latest consensus diagnostic criteria. This finding is probably related to their past prolonged exposure to repetitive head impacts from head-to-player collisions and heading the ball thousands of time throughout their careers. Alzheimer’s disease and TDP-43 pathologies are common concomitant findings in CTE, both of which are increasingly considered as part of the CTE pathological entity in older individuals. Association Football is the most popular sport in the world and the potential link between repetitive head impacts from playing football and CTE as indicated from our findings is of considerable public health interest. Clearly a definitive link cannot be established in this clinico-pathological series, but our findings support the need for further systematic investigation including large scale case-control studies to identify at risk groups of footballers which will justify for the implementation of protective strategies.
Article
Objective To develop evidence-informed, expert consensus research diagnostic criteria for Traumatic Encephalopathy Syndrome (TES), the clinical disorder associated with neuropathologically diagnosed Chronic Traumatic Encephalopathy (CTE). Methods A panel of 20 expert clinician-scientists in neurology, neuropsychology, psychiatry, neurosurgery, and physical medicine and rehabilitation, from 11 academic institutions, participated in a modified Delphi procedure to achieve consensus, initiated at the First NINDS Consensus Workshop to Define the Diagnostic Criteria for TES, April, 2019. Prior to consensus, panelists reviewed evidence from all published cases of CTE with neuropathological confirmation and they examined the predictive validity data on clinical features in relation to CTE pathology from a large clinicopathological study (n = 298). Results Consensus was achieved in 4 rounds of the Delphi procedure. Diagnosis of TES requires: 1) substantial exposure to repetitive head impacts (RHI) from contact sports, military service, or other causes; 2) core clinical features of cognitive impairment (in episodic memory and/or executive functioning) and/or neurobehavioral dysregulation; 3) a progressive course; and 4) that the clinical features are not fully accounted for by any other neurologic, psychiatric, or medical conditions. For those meeting criteria for TES, functional dependence is graded on 5 levels, ranging from independent to severe dementia. A provisional level of certainty for CTE pathology is determined based on specific RHI exposure thresholds, core clinical features, functional status, and additional supportive features, including delayed onset, motor signs, and psychiatric features. Conclusions New consensus diagnostic criteria for TES were developed with a primary goal of facilitating future CTE research. These criteria will be revised as updated clinical and pathological information and in vivo biomarkers become available.
Article
Although chronic traumatic encephalopathy (CTE) garners substantial attention in the media and there have been marked scientific advances in the last few years, much remains unclear about the role of genetic risk in CTE. Two athletes with comparable contact-sport exposure may have varying amounts of CTE neuropathology, suggesting that other factors, including genetics, may contribute to CTE risk and severity. In this review, we explore reasons why genetics may be important for CTE, concepts in genetic study design for CTE (including choosing controls, endophenotypes, gene by environment interaction, and epigenetics), implicated genes in CTE (including APOE, MAPT, and TMEM106B), and whether predictive genetic testing for CTE should be considered.
Article
Purpose: Sport-related head impact biomechanics research has been male-centric and focused primarily on American football and ice hockey, which do not address popular sports in which both sexes participate. The purpose of this study was to quantify college female and male lacrosse and soccer head impact biomechanics. Methods: Head impact biomechanics were collected from college lacrosse and soccer players across two Division 1 college athletic programs (96 female athletes, 141 male athletes; age, 19.8 ± 1.3 yr; height, 174.8 ± 9.2 cm; mass, 72.4 ± 11.7 kg). We deployed helmetless head impact measurement devices (X2 Biosystems xPatch) before each event. Peak linear and rotational accelerations were log-transformed for random intercepts general linear mixed models, and subsequently categorized based on impact magnitude for additional categorical analyses. Results: Most linear (69.4%) and rotational (72.3%) head impact accelerations sustained by our study cohort were categorized as mild. On average, male athletes sustained impacts with higher linear accelerations than females (P = 0.04), and lacrosse athletes sustained higher linear acceleration impacts than soccer athletes (P = 0.023). Soccer athletes sustained significantly higher-magnitude impacts during competitions versus practices (linear, P < 0.001, rotational, P < 0.001), whereas lacrosse athletes sustained higher-magnitude impacts during practices versus competition (linear, P < 0.001; rotational, P < 0.001). Male athletes sustained higher accelerations in competitions versus practice (linear, P = 0.004; rotational, P < 0.001), whereas female athletes sustained higher accelerations in practice versus competitions (linear, P < 0.001; rotational, P = 0.02). There were no interactions between sex and sport on impact magnitude. Conclusions: Male athletes and lacrosse athletes experience higher-magnitude head impacts. Given the limited literature in this area, future research should continue characterizing head impact biomechanics in women's and nonhelmeted sports as well as validate nonhelmeted head impact technologies.
Article
Background: Neurodegenerative 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. Methods: We 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. Results: Over 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). Conclusions: In 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.).
Article
There has been an increased focus and awareness of head injury and sport-related concussion (SRC) across all sports from the medical and scientific communities, sports organisations, legislators, the media and the general population. Soccer, in particular, has been a focus of attention due to the popularity of the game, the frequency of SRC and the hypothesised effects of repetitive heading of the ball. Major League Soccer, US Soccer and the National Women’s Soccer League jointly hosted a conference entitled, ‘Head Injury in Soccer: From Science to the Field’, on 21–22 April 2017 in New York City, New York. The mission of this conference was to identify, discuss and disseminate evidence-based science related to the findings and conclusions of the fifth International Conference on Concussion in Sport held by the Concussion in Sport Group and apply them to the sport of soccer. In addition, we reviewed information regarding the epidemiology and mechanism of head injuries in soccer at all levels of play, data regarding the biomechanics and effects of repetitive head impacts and other soccer-specific considerations. We discussed how to release the information raised during the summit to key stakeholders including athletes, parents, coaches and healthcare providers. We identified future areas for research and collaboration to enhance the health and safety of soccer (football) players.
Article
The relationship between soccer and chronic traumatic encephalopathy (CTE) is not well established. Clinicopathological correlation in an 83-year-old retired center-back soccer player, with no history of concussion, manifesting typical Alzheimer-type dementia. Examination revealed mixed pathology including widespread CTE, moderate Alzheimer's disease, hippocampal sclerosis, and TDP-43 proteinopathy. This case adds to a few CTE cases described in soccer players. Furthermore, it corroborates that CTE may present clinically as typical Alzheimer-type dementia. Further studies investigating the extent to which soccer is a risk for CTE are needed.
Systematic review and meta-analysis of the effects of football heading
  • A P Kontos
  • R Braithwaite
  • Spd Chrisman
Kontos AP, Braithwaite R, Chrisman SPD, et al. Systematic review and meta-analysis of the effects of football heading. Br J Sports Med. 2017;51(15): 1118-1124. doi:10.1136/bjsports-2016-096276
Duration of American football play and chronic traumatic encephalopathy.
  • Mez