Risk and Causes of Death among Former National Football League Players (1986–2012)

Epidemiological Principles in Claims of Causality: An Enquiry into Repetitive Head Impacts (RHI) and Chronic Traumatic Encephalopathy (CTE)

Determining whether repetitive head impacts (RHI) cause the development of chronic traumatic encephalopathy (CTE)-neuropathological change (NC) and whether pathological changes cause clinical syndromes are topics of considerable interest to the global sports medicine community. In 2022, an article was published that used the Bradford Hill criteria to evaluate the claim that RHI cause CTE. The publication garnered international media attention and has since been promoted as definitive proof that causality has been established. Our counterpoint presents an appraisal of the published article in terms of the claims made and the scientific literature used in developing those claims. We conclude that the evidence provided does not justify the causal claims. We discuss how causes are conceptualised in modern epidemiology and highlight shortcomings in the current definitions and measurement of exposures (RHI) and outcomes (CTE). We address the Bradford Hill arguments that are used as evidence in the original review and conclude that assertions of causality having been established are premature. Members of the scientific community must be cautious of making causal claims until the proposed exposures and outcomes are well defined and consistently measured, and findings from appropriately designed studies have been published. Evaluating and reflecting on the quality of research is a crucial step in providing accurate evidence-based information to the public.

Sheffield Shield Cricketers Live Longer than the Age-Matched General Australian Male Population

Background/objectives

Previous studies have shown a trend that elite athletes tend to live longer than the general population, which has been attributed to the "healthy worker hire effect" and the health benefits of exercise. There have not been any previous studies looking at survival of elite cricketers with the general population as a reference cohort. This study aimed to compare the annual mortality rates of current and retired elite male Australian cricket players to that of the age-matched general Australian male population.

Methods

Analysis of publicly accessible dates of birth, death, and cricket debut data for male Australian Sheffield Shield cricket players who played before 2022 and had not died before 1971. Included persons were Sheffield Shield players who lived primarily in Australia during and after their cricket careers. Death rates from 1971 to 2021 (inclusive) were compared to the general Australian male population.

Results

1824 Sheffield Shield players had not died prior to 1971 (798 had played before the 1971 season, 1026 debuting subsequently). There were 586 deaths in the 51 years of observations, compared to 825 expected deaths, giving a Standardized Mortality Ratio of 0.71 (95% CI 0.63-0.80).

Conclusion

Elite Australian male Sheffield Shield cricket players outlive the general male population with lower death rates. This is probably due to a combination of the healthy worker hire effect and the health benefits of exercise. This study provides evidence that in terms of longevity, it is safe to play elite-level cricket in Australia.

Graphical Abstract

A narrative review of psychiatric features of traumatic encephalopathy syndrome as conceptualized in the 20th century

Introduction

Some ultra-high exposure boxers from the 20th century suffered from neurological problems characterized by slurred speech, personality changes (e.g., childishness or aggressiveness), and frank gait and coordination problems, with some noted to have progressive Parkinsonian-like signs. Varying degrees of cognitive impairment were also described, with some experiencing moderate to severe dementia. The onset of the neurological problems often began while they were young men and still actively fighting. More recently, traumatic encephalopathy syndrome (TES) has been proposed to be present in athletes who have a history of contact (e.g., soccer) and collision sport participation (e.g., American-style football). The characterization of TES has incorporated a much broader description than the neurological problems described in boxers from the 20th century. Some have considered TES to include depression, suicidality, anxiety, and substance abuse.

Purpose

We carefully re-examined the published clinical literature of boxing cases from the 20th century to determine whether there is evidence to support conceptualizing psychiatric problems as being diagnostic clinical features of TES.

Methods

We reviewed clinical descriptions from 155 current and former boxers described in 21 articles published between 1928 and 1999.

Results

More than one third of cases (34.8%) had a psychiatric, neuropsychiatric, or neurobehavioral problem described in their case histories. However, only 6.5% of the cases were described as primarily psychiatric or neuropsychiatric in nature. The percentages documented as having specific psychiatric problems were as follows: depression = 11.0%, suicidality = 0.6%, anxiety = 3.9%, anger control problems = 20.0%, paranoia/suspiciousness = 11.6%, and personality change = 25.2%.

Discussion

We conclude that depression, suicidality (i.e., suicidal ideation, intent, or planning), and anxiety were not considered to be clinical features of TES during the 20th century. The present review supports the decision of the consensus group to remove mood and anxiety disorders, and suicidality, from the new 2021 consensus core diagnostic criteria for TES. More research is needed to determine if anger dyscontrol is a core feature of TES with a clear clinicopathological association. The present findings, combined with a recently published large clinicopathological association study, suggest that mood and anxiety disorders are not characteristic of TES and they are not associated with chronic traumatic encephalopathy neuropathologic change.

Suicide and depression in former contact sports participants: population-based cohort study, systematic review, and meta-analysis

Background

Former participants in sports characterised by low intensity repetitive head impact appear to have elevated rates of later dementia, but links with other psychological health outcomes such as depression and suicide are uncertain. We quantified the occurrence of these endpoints in former contact sports athletes against general population controls using new data from a cohort study and a meta-analysis.

Methods

The cohort study comprised 2004 retired male athletes, who had competed internationally as amateurs for Finland across a range of sports, and 1385 general population controls. All study members were linked to mortality and hospitalisation registries. In the PROSPERO-registered systematic review (CRD42022352780), we searched PubMed and Embase to October 31 2022 for cohort studies that reported standard estimates of association and precision. Study-specific estimates were aggregated in a random-effect meta-analysis. The Newcastle-Ottawa Scale was used to appraise the quality of each study.

Findings

In survival analyses of the Finnish cohort data, former boxers (depression: hazard ratio 1.43 [95% CI 0.73, 2.78]; suicide: 1.75 [0.64, 4.38]), Olympic-style wrestlers (depression: 0.94 [0.44, 2.00]; suicide: 1.60 [0.64, 3.99]), and soccer players (depression: 0.62 [0.26, 1.48]; suicide: 0.50 [0.11, 2.16]) did not have statistically higher rates of major depressive disorder or suicide at follow-up relative to controls. In the systematic review, 7 cohort studies met inclusion criteria. After aggregating results with the Finnish cohort, retired soccer players appeared to have a lower risk of depression (summary risk ratio: 0.71 [0.54, 0.93]) relative to general population controls, while the rate of suicide was statistically the same across groups (0.70 [0.40, 1.23]). Past participation in American football seemed to be associated with some protection against suicide (0.58 [0.43, 0.80]) but there were insufficient studies of depression in this sport to facilitate aggregation. The aggregation of results from the soccer and American football studies showed directionally consistent relationships and there was no indication of inter-study heterogeneity (I2 = 0%).

Interpretation

Based on a small cluster of studies exclusively comprising men, retired soccer players had a lower rate of later depression and former American football players had a lower risk of suicide relative to comparator groups. Whether these findings are generalisable to women requires testing.

Funding

The preparation of this manuscript was unfunded.

Examining later-in-life health risks associated with sport-related concussion and repetitive head impacts: a systematic review of case-control and cohort studies

OBJECTIVE

Concern exists about possible problems with later-in-life brain health, such as cognitive impairment, mental health problems and neurological diseases, in former athletes. We examined the future risk for adverse health effects associated with sport-related concussion, or exposure to repetitive head impacts, in former athletes.

DESIGN

Systematic review.

DATA SOURCES

Search of MEDLINE, Embase, Cochrane, CINAHL Plus and SPORTDiscus in October 2019 and updated in March 2022.

ELIGIBILITY CRITERIA

Studies measuring future risk (cohort studies) or approximating that risk (case-control studies).

RESULTS

Ten studies of former amateur athletes and 18 studies of former professional athletes were included. No postmortem neuropathology studies or neuroimaging studies met criteria for inclusion. Depression was examined in five studies in former amateur athletes, none identifying an increased risk. Nine studies examined suicidality or suicide as a manner of death, and none found an association with increased risk. Some studies comparing professional athletes with the general population reported associations between sports participation and dementia or amyotrophic lateral sclerosis (ALS) as a cause of death. Most did not control for potential confounding factors (eg, genetic, demographic, health-related or environmental), were ecological in design and had high risk of bias.

CONCLUSION

Evidence does not support an increased risk of mental health or neurological diseases in former amateur athletes with exposure to repetitive head impacts. Some studies in former professional athletes suggest an increased risk of neurological disorders such as ALS and dementia; these findings need to be confirmed in higher quality studies with better control of confounding factors.

PROSPERO REGISTRATION NUMBER

CRD42022159486.

Consensus statement on concussion in sport: the 6th International Conference on Concussion in Sport-Amsterdam, October 2022

For over two decades, the Concussion in Sport Group has held meetings and developed five international statements on concussion in sport. This 6th statement summarises the processes and outcomes of the 6th International Conference on Concussion in Sport held in Amsterdam on 27-30 October 2022 and should be read in conjunction with the (1) methodology paper that outlines the consensus process in detail and (2) 10 systematic reviews that informed the conference outcomes. Over 3½ years, author groups conducted systematic reviews of predetermined priority topics relevant to concussion in sport. The format of the conference, expert panel meetings and workshops to revise or develop new clinical assessment tools, as described in the methodology paper, evolved from previous consensus meetings with several new components. Apart from this consensus statement, the conference process yielded revised tools including the Concussion Recognition Tool-6 (CRT6) and Sport Concussion Assessment Tool-6 (SCAT6, Child SCAT6), as well as a new tool, the Sport Concussion Office Assessment Tool-6 (SCOAT6, Child SCOAT6). This consensus process also integrated new features including a focus on the para athlete, the athlete's perspective, concussion-specific medical ethics and matters related to both athlete retirement and the potential long-term effects of SRC, including neurodegenerative disease. This statement summarises evidence-informed principles of concussion prevention, assessment and management, and emphasises those areas requiring more research.

Metabolic Alterations Differentiating Cardiovascular Maladaptation from Athletic Training in American-Style Football Athletes

PURPOSE

Metabolomics identifies molecular products produced in response to numerous stimuli, including both adaptive (includes exercise training) and disease processes. We analyzed a longitudinal cohort of American-style football (ASF) athletes, who reliably acquire maladaptive cardiovascular (CV) phenotypes during competitive training, with high-resolution metabolomics to determine whether metabolomics can discriminate exercise-induced CV adaptations from early CV pathology.

METHODS

Matched discovery ( n = 42) and validation ( n = 40) multicenter cohorts of collegiate freshman ASF athletes were studied with longitudinal echocardiography, applanation tonometry, and high-resolution metabolomics. Liquid chromatography-mass spectrometry identified metabolites that changed ( P < 0.05, false discovery rate <0.2) over the season. Metabolites demonstrating similar changes in both cohorts were further analyzed in linear and mixed-effects models to identify those associated with left ventricular mass, tissue-Doppler myocardial E ' velocity (diastolic function), and arterial function (pulse wave velocity).

RESULTS

In both cohorts, 20 common metabolites changed similarly across the season. Metabolites reflective of favorable CV health included an increase in arginine and decreases in hypoxanthine and saturated fatty acids (heptadecanoate, arachidic acid, stearate, and hydroxydecanoate). In contrast, metabolic perturbations of increased lysine and pipecolate, reflective of adverse CV health, were also observed. Adjusting for player position, race, height, and changes in systolic blood pressure, weight, and pulse wave velocity, increased lysine ( β = 0.018, P = 0.02) and pipecolate ( β = 0.018, P = 0.02) were associated with increased left ventricular mass index. In addition, increased lysine ( β = -0.049, P = 0.01) and pipecolate ( β = -0.052, P = 0.008) were also associated with lower E ' (reduced diastolic function).

CONCLUSIONS

ASF athletes seem to develop metabolomic changes reflective of both favorable CV health and early CV maladaptive phenotypes. Whether metabolomics can discriminate early pathologic CV transformations among athletes is a warranted future research direction.

Multisensory perception is not influenced by previous concussion history in retired rugby union players

BACKGROUND

To assess whether concussion history adversely affects multisensory integration, we compared susceptibility to the Sound-Induced Flash Illusion (SIFI) in retired professional rugby players compared to controls.

METHODS

Retired professional rugby players ((N = 58) and retired international rowers (N = 26) completed a self-report concussion history questionnaire and the SIFI task. Susceptibility to the SIFI (i.e., perceiving two flashes in response to one flash paired with two beeps) was assessed at three stimulus onset asynchronies (70 ms, 150 ms or 230 ms).Logistic mixed-effects regression modeling was implemented to evaluate how athlete grouping, previous concussion history and total number of years playing sport, impacted the susceptibility to the SIFI task. The statistical significance of a fixed effect of interest was determined by a likelihood ratio test.

RESULTS

Former rugby players had significantly more self-reported concussions than the rower group (p < 0.001). There was no impact of athlete grouping (i.e., retired professional rugby players and retired international rowers), years participation in elite sport or concussion history on performance in the SIFI.

CONCLUSION

A career in professional rugby, concussion history or number of years participating in professional rugby was not found to be predictive of performance on the SIFI task.

Reduced death rates of elite Australian Rules footballers compared to age-matched general population

OBJECTIVES

To determine age-matched death rates of current and retired elite male Australian football players (Australian and/or Victorian Football League) with the general population.

DESIGN

Analysis of publicly-available birth, debut and death data for all Australian Victorian Football/Victorian Football League players who debuted prior to (and were still alive at) the start of 1971 or debuted 1971-2020.

METHODS

Wikipedia was used to source the dates of death (or record that the player was alive in 2021) for the cohort. New players became part of the cohort for analysis on debut and existing cohort members left it at death. Actual death rates (per year and per decade) were then compared to expected deaths, based on age-specific population death rates.

RESULTS

There were 5400 players and ex-players in the cohort at the start of 1971 (average age 47.3) and a further 4532 players debuted between 1971 and 2020 inclusive (a total of 9932 players). The expected deaths for the cohort in this 50-year period were 4955, but only 3914 deaths occurred (Standardized Mortality Ratio 0.79, 95 %CI 0.76-0.82). For younger members of the cohort (age <50) the discrepancy between expected (222) and actual (98) deaths was also significant (Standardized Mortality Ratio 0.44, 95 %CI 0.35-0.56).

CONCLUSIONS

We conclude that the death rates of elite male Australian footballers are lower than the reference general population, similar to other studies of elite athletes. Some of this may be explained by "healthy cohort" selection bias, a limitation which affects almost all studies in this genre.

Association of Playing College American Football With Long-term Health Outcomes and Mortality

IMPORTANCE

Exposure to repetitive head impacts from playing American football (including impacts resulting in symptomatic concussions and subconcussive trauma) is associated with increased risk for later-life health problems, including cognitive and neuropsychiatric decline and neurodegenerative disease. Most research on long-term health consequences of playing football has focused on former professional athletes, with limited studies of former college players.

OBJECTIVES

To estimate the prevalence of self-reported health conditions among former college football players compared with a sample of men in the general population as well as standardized mortality ratios (SMRs) among former college football players.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study included data from 447 former University of Notre Dame (ND) football players aged 59 to 75 years who were seniors on the rosters from 1964 to 1980. A health outcomes survey was distributed to living players and next of kin of deceased players for whom contact information was available. The survey was completed from December 2018 to May 2019.

EXPOSURE

Participation in football at ND.

MAIN OUTCOMES AND MEASURES

Prevalence of health outcomes was compared between living former players who completed the survey and propensity score-matched participants in the Health and Retirement Study (HRS). Standardized mortality ratios of all causes and specific causes of death among all former players were compared with those among men in the general US population.

RESULTS

A total of 216 living players completed the health survey (median age, 67 years; IQR, 63-70 years) and were compared with 638 participants in the HRS (median age, 66 years; IQR, 63-70 years). Former players reported a higher prevalence of cognitive impairment (10 [5%] vs 8 [1%]; P = .02), headaches (22 [10%] vs 22 [4%]; P = .001), cardiovascular disease (70 [33%] vs 128 [20%]; P = .001), hypercholesterolemia (111 [52%] vs 182 [29%]; P = .001), and alcohol use (185 [86%] vs 489 [77%]; P = .02) and a lower prevalence of diabetes (24 [11%] vs 146 [23%]; P = .001). All-cause mortality (SMR, 0.54; 95% CI, 0.42-0.67) and mortality from heart (SMR, 0.64; 95% CI, 0.39-0.99), circulatory (SMR, 0.23; 95% CI, 0.03-0.83), respiratory (SMR, 0.13; 95% CI, 0.00-0.70), and digestive system (SMR, 0.13; 95% CI, 0.00-0.74) disorders; lung cancer (SMR, 0.26; 95% CI, 0.05-0.77); and violence (SMR, 0.10; 95% CI, 0.00-0.58) were significantly lower in the ND cohort than in the general population. Mortality from brain and other nervous system cancers was significantly higher in the ND cohort (SMR, 3.82; 95% CI, 1.04-9.77). Whereas point estimates were greater for all neurodegenerative causes (SMR, 1.42; 95% CI, 0.29-4.18), amyotrophic lateral sclerosis (SMR, 2.93; 95% CI, 0.36-10.59), and Parkinson disease (SMR, 2.07; 95% CI, 0.05-11.55), the difference did not reach statistical significance.

CONCLUSIONS AND RELEVANCE

In this cohort study of former college football players, both positive and negative health outcomes were observed. With more than 800 000 former college players living in the US, additional research appears to be needed to provide stakeholders with guidance to maximize factors that improve health outcomes and minimize factors that may increase risk for later-life morbidity and mortality.

Multi-modality human phenotyping to examine subjective and objective health afflictions in former professional American-style football players: The In-Person Assessment (IPA) protocol

Background

Participation in American-style football (ASF), one of the most popular sports worldwide, has been associated with adverse health outcomes. However, prior clinical studies of former ASF players have been limited by reliance on subjective self-reported data, inadequate sample size, or focus on a single disease process in isolation.

Objective

To determine the burden of objective multi-system pathology and its relationship with subjective health complaints among former professional ASF players.

Methods

The In-Person Assessment is a case-control, multi-day, deep human phenotyping protocol designed to characterize and quantify pathology among former professional ASF players. Participants, recruited from an on-going large-scale longitudinal cohort study, will include 120 men who report either no health conditions, a single health condition, or multiple health conditions across the key domains of cardiometabolic disease, disordered sleep, chronic pain, and cognitive impairment. Data will be collected from validated questionnaires, structured interviews, physical examinations, multi-modality imaging, and functional assessments over a 3-day study period. A pilot study was conducted to assess feasibility and to obtain participant feedback which was used to shape the final protocol.

Results

This study provides a comprehensive assessment of objective multi-system pathology and its relationship with subjective health complaints among former professional ASF players.

Conclusion

The study will determine whether subjective health complaints among former professional ASF players are explained by objective explanatory pathology and will provide novel opportunities to examine the interrelatedness of co-morbidities. It is anticipated that this protocol will be applicable to other clinical and occupational populations.

High-School Football and Midlife Brain Health Problems

OBJECTIVE

To examine whether middle-aged men who played high-school football experience worse mental health or cognitive functioning than men who did not play high-school football.

DESIGN

Cross-sectional cohort study.

SETTING

Online survey completed remotely.

PARTICIPANTS

A total of 435 men between the ages of 35 and 55 completed the study, of whom 407 were included in the analyses after excluding participants who answered embedded validity items incorrectly (n = 16), played semiprofessional football (n = 2), or experienced a recent concussion (n = 10).

ASSESSMENT OF RISK FACTORS

Self-reported high school football participation, compared with those who played contact sports, noncontact sports, and no sports.

MAIN OUTCOME MEASURES

A lifetime history of depression or anxiety; mental health or cognitive problems in the past year; current depression symptoms, and post-concussion-like symptoms.

RESULTS

Middle-aged men who played high-school football did not have a higher prevalence of being prescribed medication for anxiety or depression or receiving treatment from a mental health professional. Similarly, there were no significant differences between groups on the rates in which they endorsed depression, anxiety, anger, concentration problems, memory problems, headaches, migraines, neck or back pain, or chronic pain over the past year. A greater proportion of those who played football reported sleep problems over the past year and reported being prescribed medication for chronic pain and for headaches.

CONCLUSIONS

Men who played high-school football did not report worse brain health compared with those who played other contact sports, noncontact sports, or did not participate in sports during high school.

Age of First Exposure to Contact and Collision Sports and Later in Life Brain Health: A Narrative Review

A controversial theory proposes that playing tackle football before the age of 12 causes later in life brain health problems. This theory arose from a small study of 42 retired National Football League (NFL) players, which reported that those who started playing tackle football at a younger age performed worse on selected neuropsychological tests and a word reading test. The authors concluded that these differences were likely due to greater exposure to repetitive neurotrauma during a developmentally sensitive maturational period in their lives. Several subsequent studies of current high school and collegiate contact/collision sports athletes, and former high school, collegiate, and professional tackle football players have not replicated these findings. This narrative review aims to (i) discuss the fundamental concepts, issues, and controversies surrounding existing research on age of first exposure (AFE) to contact/collision sport, and (ii) provide a balanced interpretation, including risk of bias assessment findings, of this body of evidence. Among 21 studies, 11 studies examined former athletes, 8 studies examined current athletes, and 2 studies examined both former and current athletes. Although the literature on whether younger AFE to tackle football is associated with later in life cognitive, neurobehavioral, or mental health problems in former NFL players is mixed, the largest study of retired NFL players (N = 3,506) suggested there was not a significant association between earlier AFE to organized tackle football and worse subjectively experienced cognitive functioning, depression, or anxiety. Furthermore, no published studies of current athletes show a significant association between playing tackle football (or other contact/collision sports) before the age of 12 and cognitive, neurobehavioral, or mental health problems. It is important to note that all studies were judged to be at high overall risk of bias, indicating that more methodologically rigorous research is needed to understand whether there is an association between AFE to contact/collision sports and later in life brain health. The accumulated research to date suggests that earlier AFE to contact/collision sports is not associated with worse cognitive functioning or mental health in (i) current high school athletes, (ii) current collegiate athletes, or (iii) middle-aged men who played high school football. The literature on former NFL players is mixed and does not, at present, clearly support the theory that exposure to tackle football before age 12 is associated with later in life cognitive impairment or mental health problems.

Mortality from mental disorders and suicide in male professional American football and soccer players: A meta-analysis

OBJECTIVE

To determine the risk of mortality from mental disorders and suicide in professional sports associated with repeated head impacts.

METHODS

A systematic search was performed in PubMed, Web of Science, Scopus, and SPORTDiscus (since inception to June 8, 2021) to find studies comparing the incidence of mortality from mental disorders or suicide in former or active professional athletes of sports characterized by repeated head impacts vs athletes with no such exposure or the general non-athletic population.

RESULTS

Seven retrospective studies of moderate-to-high quality that included data from boxers and from basketball, ice hockey, soccer, and National Football League (NFL) players, respectively (total = 27 477 athletes, 100% male) met all inclusion criteria. Former male NFL players (n = 13 217) had a lower risk of mortality from mental disorders (standard mortality rate [SMR] = 0.30; 0.12-0.77; p = 0.012) and suicide (SMR = 0.54; 0.37-0.78; p < 0.001) than the general population. This finding was also corroborated in male soccer players (n = 13,065; SMR = 0.55; 0.46-0.67; p < 0.001). Male athletes participating in sports associated with repeated head impacts (n = 18,606) had also a lower risk of all-cause, cardiovascular disease (CVD), and cancer mortality (all p < 0.01) than the general population.

CONCLUSIONS

Participation of male athletes in American football or soccer at the professional level might confer a certain protective effect against mortality from mental disorders or suicide, besides its association with a lower risk of all-cause, CVD, or cancer-related mortality.

Association between race and maladaptive concentric left ventricular hypertrophy in American-style football athletes

OBJECTIVES

American-style football (ASF) athletes are at risk for the development of concentric left ventricular hypertrophy (C-LVH), an established cardiovascular risk factor in the general population. We sought to address whether black race is associated with acquired C-LVH in collegiate ASF athletes.

METHODS

Collegiate ASF athletes from two National Collegiate Athletic Association Division-I programmes were recruited as freshmen between 2014 and 2019 and analysed over 3 years. Demographics (neighbourhood family income) and repeated clinical characteristics and echocardiography were recorded longitudinally at multiple timepoints. A mixed-modelling approach was performed to evaluate acquired C-LVH in black versus white athletes controlling for playing position (linemen (LM) and non-linemen (NLM)), family income, body weight and blood pressure.

RESULTS

At baseline, black athletes (N=124) were more often NLM (72% vs 54%, p=0.005) and had lower median neighbourhood family income ($54 119 vs $63 146, p=0.006) compared with white athletes (N=125). While both black and white LM demonstrated similar increases in C-LVH over time, among NLM acquired C-LVH was more common in black versus white athletes (postseason year-1: N=14/89 (16%) vs N=2/68 (3%); postseason year-2: N=9/50 (18%) vs N=2/32 (6%); postseason year-3: N=8/33 (24%) vs N=1/13 (8%), p=0.005 change over time). In stratified models, black race was associated with acquired C-LVH in NLM (OR: 3.70, 95% CI 1.12 to 12.21, p=0.03) and LM was associated with acquired C-LVH in white athletes (OR: 3.40, 95% CI 1.03 to 11.27, p=0.048).

CONCLUSIONS

Independent of family income and changes in weight and blood pressure, black race was associated with acquired C-LVH among collegiate ASF NLM and LM was associated with acquired C-LVH in white athletes.

Health Consequences of an Elite Sporting Career: Long-Term Detriment or Long-Term Gain? A Meta-Analysis of 165,000 Former Athletes

INTRODUCTION

Exercise is widely accepted to improve health, reducing the risk of premature mortality, cardiovascular disease (CVD) and cancer. However, several epidemiological studies suggest that the exercise-longevity relationship may be 'J' shaped; with elite athlete's likely training above these intensity and volume thresholds. Therefore, the aim of this meta-analysis was to examine this relationship in former elite athletes.

METHODS

38,047 English language articles were retrieved from Web of Science, PubMed and SportDiscus databases published after 1970, of which 44 and 24 were included in the systematic review and meta-analysis, respectively. Athletes were split into three groups depending on primary sport: Endurance (END), Mixed/Team, or power (POW). Standard mortality ratio's (SMR) and standard proportionate mortality ratio (SPMR) were obtained, or calculated, and combined for the meta-analysis.

RESULTS

Athletes lived significantly longer than the general population (male SMR 0.69 [95% CI 0.61-0.78]; female SMR 0.51 [95% CI 0.40-0.65]; both p < 0.01). There was no survival benefit for male POW athletes compared to the general population (SMR 1.04 [95% CI 0.91-1.12]). Although male athlete's CVD (SMR 0.73 [95% CI 0.62-0.85]) and cancer mortality (SMR 0.75 [95% CI 0.63-0.89]), were significantly reduced compared to the general population, there was no risk-reduction for POW athletes CVD mortality (SMR 1.10 [0.86-1.40]) or END athletes cancer mortality (SMR 0.73 [0.50-1.07]). There was insufficient data to calculate female sport-specific SMR's.

DISCUSSION

Overall, athletes live longer and have a reduced incidence of both CVD and cancer mortality compared to the general population, refuting the 'J' shape hypothesis. However, different health risks may be apparent according to sports classification, and between sexes, warranting further investigation. Trial registration PROSPERO (registration number: CRD42019130688).

Mortality of Japanese Olympic athletes in 1964 Tokyo Olympic Games

OBJECTIVES

To compare the mortality of Japanese athletes in the 1964 Tokyo Olympic Games with that of the Japanese population, and to elucidate factors associated with their mortality.

METHODS

We obtained from the Japan Sport Association study subjects' biographical information, information on lifestyles and medical data. Missing data were obtained from online databases. Standardised mortality ratio (SMR) was calculated to compare athletes' mortality with the Japanese population. Cox proportional hazards model was applied to estimate the HR for each category of body mass index (BMI), smoking history and handgrip strength. This analysis was limited to male athletes due to the small number of female athletes.

RESULTS

Among 342 (283 men, 59 women) athletes, deaths were confirmed for 70 (64 men, 6 women) athletes between September 1964 and December 2017. Total person years was 15 974.8, and the SMR was 0.64 (95% CI 0.50 to 0.81). Multivariate analysis performed on 181 male athletes. Mortality was significantly higher for BMI≥25 kg/m2 than for 21-23 kg/m2 (HR: 3.03, 95% CI 1.01 to 9.07). We found no statistically significant associations between smoking history and mortality; the HR (95% CI) for occasional and daily smokers were 0.82 (0.26 to 2.57) and 1.30 (0.55 to 3.03) compared with never smokers. We also found no statistically significant associations between handgrip strength and mortality (P for trend: 0.51).

CONCLUSION

Japanese athletes in the 1964 Tokyo Olympic Games lived longer than the Japanese population. BMI≥25 kg/m2 was associated with higher mortality, but smoking history and handgrip strength were not associated with mortality.

Female and male US Olympic athletes live 5 years longer than their general population counterparts: a study of 8124 former US Olympians

Objective

To quantify US female and male Olympic athletes’ longevity and the years of life lost or saved due to multiple causes of death as compared with the US general population.

Methods

Former US athletes who had participated in the summer or winter Olympic Games at least once between 1912 and 2012 were included. Olympians’ date of birth, death and the underlying causes of death were certified by the National Death Index. The Olympians’ overall and cause-specific mortality were compared with the US general population based on the US life tables, adjusted by sex, period and age. Mortality differences between the populations were quantified using the years lost/years saved (YS) method.

Results

8124 US Olympians (2301 women and 5823 men) lived 5.1 years longer (YS 95% CI 4.3 to 6.0) than the general population, based on 2309 deaths observed (225 women, 2084 men). Different causes of death contributed to longevity for Olympians as follows: 2.2 years were saved (1.9 to 2.5) from cardiovascular diseases (CVDs); cancer, 1.5 years (1.3 to 1.8); respiratory diseases (eg, influenza, pneumonia), 0.8 years (0.7 to 0.9); external causes (eg, accidents, homicides), 0.5 years (0.4 to 0.6); endocrine and metabolic diseases (eg, diabetes, hyperlipidaemia), 0.4 years (0.2 to 0.5) and digestive system diseases (eg, cirrhosis, hepatic failure), 0.3 years (0.2 to 0.4). Mortality rates due to nervous system disorders (eg, Alzheimer’s and Parkinsons’s diseases) and mental illness (eg, dementia, schizophrenia) were not different from the general population.

Conclusion

US Olympians lived longer than the general population, an advantage mainly conferred by lower risks of CVD and cancer. Nervous system disorders and mental illness did not differ between US Olympians and the general population.

Weight Gain, Hypertension, and the Emergence of a Maladaptive Cardiovascular Phenotype Among US Football Players

Importance

Former US football athletes are at increased risk of cardiovascular (CV) morbidity and mortality compared with the general population and other professional athletes. However, responsible maladaptive CV phenotypes have not been fully characterized.

Objective

To address the emergence and progression of multiple independent factors associated with CV risk across serial years of collegiate US football participation.

Design, Setting, and Participants

Collegiate US football athletes from 2 National Collegiate Athletic Association Division I programs were recruited as freshmen between June 2014 and June 2017 and analyzed at multiple points throughout 3 complete years of collegiate US football participation (until January 2019). Excluded athletes were those who did not complete any season of US football training because of injury, illness, or leaving the team. Factors associated with CV risk assessed clinically, by transthoracic echocardiography, and by vascular applanation tonometry were recorded.

Exposures

The exposure of interest was seasonal US football exposure, including training, competition, and the training environment.

Main Outcomes and Measures

Primary outcome measures were left ventricular mass index and geometry (cardiac structure), early diastolic myocardial relaxation velocity (E'; diastolic function), and pulse-wave velocity (arterial stiffness).

Results

Of 186 individuals recruited as freshmen, 126 athletes were included in analyzed data. Collegiate US football athletes (62 white individuals [49%]; 63 black individuals [50%]; 77 nonlinemen [61%]; 49 linemen [39%]; 126 male individuals [100%]) weighed a mean (SD) of 101.1 (21.0) kg, with a mean systolic blood pressure of 129.1 (11.6) mm Hg at baseline of the freshman season. Adjusting for race, height, and player position, there were significant increases in weight (mean [SE] Δ, 4.74 [0.6] kg; P < .001), systolic blood pressure (mean [SE] Δ, 11.6 [1.6] mm Hg; P < .001), and pulse-wave velocity (mean [SE] Δ, 0.24 [0.09] m/s; P = .007), and significant declines in E' (mean [SE] Δ, -1.7 [0.3] cm/s; P < .001) across 3 years of US football participation. Weight gain was associated with both arterial stiffening (increased pulse-wave velocity, β = 0.01 [SE, 0.004]; P = .003) and the development of concentric left ventricular hypertrophy (odds ratio, 1.09 [95% CI, 1.05-1.14]; P < .001); increased systolic blood pressure was also associated with arterial stiffening (β = 0.01 [SE, 0.003]; P = .007) and the development of concentric left ventricular hypertrophy (odds ratio, 1.04 [95% CI, 1.01-1.07]; P = .02).

Conclusions and Relevance

Collegiate US football athletes who gain weight and develop increased systolic blood pressure levels are at risk for the development of a pathologic CV phenotype characterized by concentric left ventricular hypertrophy, arterial stiffening, and reduced left ventricular diastolic function. Future work aimed at optimizing CV health in this population, who are young but uniquely at risk, is warranted.

Nonsteroidal Anti-inflammatory Drugs and Cardiovascular Risk in American Football

INTRODUCTION

Nonsteroidal anti-inflammatory drugs (NSAIDs) are associated with adverse cardiovascular outcomes and reportedly overused in American-style football (ASF). However, assessment of ASF NSAID use in the context of cardiovascular risk has not been performed. We sought to characterize NSAID use patterns and the association with cardiovascular risk in a diverse cohort of high school and collegiate ASF athletes.

METHODS

A total of 226 ASF athletes, 60 endurance athletes, and 63 nonathletic controls were studied pre- and postseason with echocardiography, vascular applanation tonometry, and clinical data assessment. Qualitative NSAID use throughout the season was recorded at postseason.

RESULTS

ASF athletes gained weight (Δ0.86 ± 3.9 kg, P < 0.001), increased systolic blood pressure (SBP, Δ3.1 ± 12 mm Hg, P < 0.001) and pulse wave velocity (Δ0.2 ± 0.6 m·s, P < 0.001), and decreased E' (Δ-1.4 ± 2.8 cm·s, P < 0.001) across one athletic season. Seventy-seven percent (n = 173) of ASF athletes reported that sport-specific NSAID use began in middle school. ASF NSAID use was more frequent with "weekly" (n = 42.19%) and "daily" (n = 32.14%) use compared with endurance athletes (P < 0.001) and controls (P = 0.02). ASF NSAID use increased in parallel with postseason SBP and weights. "Daily" ASF NSAID users demonstrated the highest postseason SBP (137 ± 13 vs 128 ± 13 mm Hg, P = 0.002) and weight (109.0 ± 18.6 vs 95.8 ± 20.5 kg, P = 0.002) compared with "never/rare" users. Adjusting for player position, SBP, pulse wave velocity, and E', increased weight (odds ratio = 1.04, 95% confidence interval = 1.0-1.08, P = 0.037) was associated with more frequent NSAID use.

CONCLUSIONS

Habitual NSAID use commonly begins during adolescence, before full physical maturation, and is associated with cardiovascular risk, particularly increased weight, in ASF athletes. NSAID use frequency should be considered when risk stratifying high-risk ASF athletes.

Association of Professional Football Cumulative Head Impact Index Scores With All-Cause Mortality Among National Football League Players

Importance

Long-term adverse health outcomes, particularly those associated with repetitive head impacts, are of growing concern among US-style football players in the US and Canada.

Objective

To assess whether exposure to repetitive head impacts during a professional football career is associated with an increase in the risk of all-cause mortality.

Design, Setting, and Participants

This retrospective cohort study included 13 912 players in the 1969 to 2017 National Football League (NFL) seasons. All cause-mortality up until July 1, 2018, was included. Data collection was performed from July 13, 2017, to July 1, 2018, as reported in the Pro Football Reference.

Exposures

The main exposure was a professional football cumulative head impact index (pfCHII). The pfCHII was measured by combining cumulative padded practice time and games played summed during seasons of play reported in the Pro Football Reference and a player position risk adjustment from helmet accelerometer studies.

Main Outcomes and Measures

Demographic characteristics except for the pfCHII were calculated for 14 366 players with complete follow-up. The pfCHII was calculated for 13 912 players (eliminating the 454 specials teams players). Cox proportional hazards regression was used to compare hazard ratios (HRs) of death by repetitive head impacts. Analyses were unadjusted and adjusted for birth year, body mass index, and height.

Results

Among 14 366 NFL players who had follow-up for analysis, the mean (SD) age was 47.3 (14.8) years, the mean (SD) body mass index was 29.6 (3.9), and 763 of 14 366 players (5.3%) had died. Among 13 912 players in the pfCHII analysis, the median pfCHII was 32.63 (interquartile range, 13.71-66.12). A 1-log increase in pfCHII was significantly associated with an increased hazard of death for the 1969 to 2017 seasons (HR, 2.02; 95% CI, 1.21-3.37; P = .01) after adjustment. The quadratic pfCHII was also statistically significant (HR, 0.91; 95% CI, 0.85-0.98; P = .01), indicating that the hazard of death increased at a decreasing rate, whereas the pfCHII increased.

Conclusions and Relevance

The findings suggest that an increase in repetitive head impacts is associated with an increased hazard of death among NFL players. Reduction in repetitive head impacts from playing football or other activities through additional rule and equipment changes may be associated with reduced mortality.

A career in sport does not eliminate risk of cardiovascular disease: A systematic review and meta-analysis of the cardiovascular health of field-based athletes

OBJECTIVES

To determine the prevalence of cardiovascular disease (CVD) risk factors in current field-based athletes.

DESIGN

Meta-analysis.

METHODS

This review was conducted and reported in accordance with PRISMA and pre-registered with PROSPERO. Articles were retrieved via online database search engines, with no date or language restriction. Studies investigating current field-based athletes (>18years) for CVD risk factors according to the European Society of Cardiology and American Heart Association were screened. Full texts were screened using Covidence and Cochrane criteria. Eligible articles were critically appraised using the AXIS tool. Individual study estimates were assessed by random-effect meta-analyses to examine the overall effect.

RESULTS

This study was ascribed a 1b evidence level, according to the Oxford Centre for Evidence-based Medicine. 41 studies were identified, including 5546 athletes from four sports; American football; soccer; rugby and baseball mean ages: 18-28. Despite participation in sport, increased body mass was associated with increased total cholesterol, low-density lipoprotein, triglycerides, hypertension, systolic blood pressure, and decreased high-density lipoprotein. Linemen had increased prevalence of hypertension compared to non-athletes. Conflicting findings on fasting glucose were prevalent. There were inconsistencies in screening and reporting of CVD risk factors. Sport specific anthropometric demands were associated with elevated prevalence of CVD risk factors, most notably: elevated body mass; dyslipidemia; elevated systolic blood pressure and; glucose.

CONCLUSIONS

There are elevated levels of risk for CVD in some athletes, primarily football players. Lifestyle behaviours associated with elite athleticism, particularly football linemen potentially expose players to greater metabolic and CVD risk, which is not completely offset by sport participation.

Chronic traumatic encephalopathy research viewed in the public domain: What makes headlines?

Objective: To determine chronic traumatic encephalopathy (CTE)-related publication characteristics associated with higher Altmetric scores.Methods: A systematic review of the CTE literature was conducted using PubMed. Publications were coded for: journal impact factor (JIF); publication type (primary versus non-primary data collection); discussion of American football; contact sport-CTE association conclusion (yes versus no/neutral); and Altmetric score. Multivariable ordinal logistic regression identified predictors of higher Altmetric scores.Results: Most of the 270 CTE-related publications did not include primary data collection (60%). The median Altmetric score was 12 (range = 0-3745). Higher Altmetric scores were associated with primary data collection [Odds ratio (OR)_Adjusted = 2.29; 95% confidence interval (CI) = 1.35-3.89] and discussing American football (OR_Adjusted = 2.11; 95%CI = 1.24-3.59). Among publications concluding contact sport-CTE associations, higher Altmetric scores were associated with higher JIF (3-point-JIF-increase OR_Adjusted = 2.11; 95%CI = 1.24-3.59); however, the association of higher Altmetric scores with higher JIF was not found among neutral publications or those concluding no contact sport-CTE associations (3-point-JIF-increase OR_Adjusted = 1.07; 95%CI = 0.94-1.22).Conclusions: Most CTE-related publications (60%) did not involve primary data collection. Publication characteristics such as higher JIF and concluding contact sport-CTE associations were associated with higher Altmetric scores. It is important for the academic community to consider strategies to counter publication and promotion bias in the presentation of CTE literature.

Interactive Effects of Racial Identity and Repetitive Head Impacts on Cognitive Function, Structural MRI-Derived Volumetric Measures, and Cerebrospinal Fluid Tau and Aβ

BACKGROUND

Factors of increased prevalence among individuals with Black racial identity (e.g., cardiovascular disease, CVD) may influence the association between exposure to repetitive head impacts (RHI) from American football and later-life neurological outcomes. Here, we tested the interaction between racial identity and RHI on neurobehavioral outcomes, brain volumetric measures, and cerebrospinal fluid (CSF) total tau (t-tau), phosphorylated tau (p-tau181), and Aβ1 - 42 in symptomatic former National Football League (NFL) players.

METHODS

68 symptomatic male former NFL players (ages 40-69; n = 27 Black, n = 41 White) underwent neuropsychological testing, structural MRI, and lumbar puncture. FreeSurfer derived estimated intracranial volume (eICV), gray matter volume (GMV), white matter volume (WMV), subcortical GMV, hippocampal volume, and white matter (WM) hypointensities. Multivariate generalized linear models examined the main effects of racial identity and its interaction with a cumulative head impact index (CHII) on all outcomes. Age, years of education, Wide Range Achievement Test, Fourth Edition (WRAT-4) scores, CVD risk factors, and APOEε4 were included as covariates; eICV was included for MRI models. P-values were false discovery rate adjusted.

RESULTS

Compared to White former NFL players, Black participants were 4 years younger (p = 0.04), had lower WRAT-4 scores (mean difference = 8.03, p = 0.002), and a higher BMI (mean difference = 3.09, p = 0.01) and systolic blood pressure (mean difference = 8.15, p = 0.03). With regards to group differences on the basis of racial identity, compared to White former NFL players, Black participants had lower GMV (mean adjusted difference = 45649.00, p = 0.001), lower right hippocampal volume (mean adjusted difference = 271.96, p = 0.02), and higher p-tau181/t-tau ratio (mean adjusted difference = -0.25, p = 0.01). There was not a statistically significant association between the CHII with GMV, right hippocampal volume, or p-tau181/t-tau ratio. However, there was a statistically significant Race x CHII interaction for GMV (b = 2206.29, p = 0.001), right hippocampal volume (b = 12.07, p = 0.04), and p-tau181/t-tau ratio concentrations (b = -0.01, p = 0.004).

CONCLUSION

Continued research on racial neurological disparities could provide insight into risk factors for long-term neurological disorders associated with American football play.

Blood Biomarker Profiling and Monitoring for High-Performance Physiology and Nutrition: Current Perspectives, Limitations and Recommendations

Blood test data were traditionally confined to the clinic for diagnostic purposes, but are now becoming more routinely used in many professional and elite high-performance settings as a physiological profiling and monitoring tool. A wealth of information based on robust research evidence can be gleaned from blood tests, including: the identification of iron, vitamin or energy deficiency; the identification of oxidative stress and inflammation; and the status of red blood cell populations. Serial blood test data can be used to monitor athletes and make inferences about the efficacy of training interventions, nutritional strategies or indeed the capacity to tolerate training load. Via a profiling and monitoring approach, blood biomarker measurement combined with contextual data has the potential to help athletes avoid injury and illness via adjustments to diet, training load and recovery strategies. Since wide inter-individual variability exists in many biomarkers, clinical population-based reference data can be of limited value in athletes, and statistical methods for longitudinal data are required to identify meaningful changes within an athlete. Data quality is often compromised by poor pre-analytic controls in sport settings. The biotechnology industry is rapidly evolving, providing new technologies and methods, some of which may be well suited to athlete applications in the future. This review provides current perspectives, limitations and recommendations for sports science and sports medicine practitioners using blood profiling and monitoring for nutrition and performance purposes.

Arrhythmias and Adaptations of the Cardiac Conduction System in Former National Football League Players

Background

Habitual high‐intensity endurance exercise is associated with increased atrial fibrillation (AF) risk and impaired cardiac conduction. It is unknown whether these observations extend to prior strength‐type sports exposure. The primary aim of this study was to compare AF prevalence in former National Football League (NFL) athletes to population‐based controls. The secondary aim was to characterize other conduction system parameters.

Methods and Results

This cross‐sectional study compared former NFL athletes (n=460, age 56±12 years, black 47%) with population‐based controls of similar age and racial composition from the cardiovascular cohort Dallas Heart Study‐2 (n=925, age 54±9 years, black 53%). AF was present in 28 individuals (n=23 [5%] in the NFL group; n=5 [0.5%] in the control group). After controlling for other cardiovascular risk factors in multivariable regression analysis, former NFL participation remained associated with a 5.7 (95% CI: 2.1–15.9, P<0.001) higher odds ratio of AF. Older age, higher body mass index, and nonblack race were also independently associated with higher odds ratio of AF, while hypertension and diabetes mellitus were not. AF was previously undiagnosed in 15/23 of the former NFL players. Previously undiagnosed NFL players were rate controlled and asymptomatic, but 80% had a CHA₂DS₂‐VASc score ≥1. Former NFL players also had an 8‐fold higher prevalence of paced cardiac rhythms (2.0% versus 0.25%, P<0.01), compared with controls. Furthermore, former athletes had lower resting heart rates (62±11 versus 66±11 beats per minute, P<0.001), and a higher prevalence of first‐degree atrioventricular block (18% versus 9%, P<0.001).

Conclusions

Former NFL participation was associated with an increased AF prevalence and slowed cardiac conduction when compared with a population‐based control group. Former NFL athletes who screened positive for AF were generally rate controlled and asymptomatic, but 80% should have been considered for anticoagulation based on their stroke risk.

Mortality Among Professional American-Style Football Players and Professional American Baseball Players

Importance

Studies of American-style football players have suggested lower overall mortality rates compared with general populations, but with possibly increased neurodegenerative mortality. However, comparisons with general populations can introduce bias. This study compared mortality between US National Football League (NFL) and US Major League Baseball (MLB) players, a more appropriate comparison group of professional athletes.

Objective

To compare all-cause and cause-specific mortality between NFL and MLB players.

Design, Setting, and Participants

In this retrospective cohort study, the setting was US mortality from January 1, 1979, through December 31, 2013. The dates of analysis were January 2016 to April 2019. Participants were 3419 NFL and 2708 MLB players with at least 5 playing seasons.

Exposures

Participation in the NFL compared with the MLB.

Main Outcomes and Measures

Vital status and causes of death from the National Death Index from 1979 through 2013 were obtained. Cox proportional hazards regression models using age as the timescale were used to calculate hazard ratios (HRs) and 95% CIs to examine all-cause and cause-specific mortality among NFL players compared with MLB players, adjusted for race and decade of birth.

Results

By the end of follow-up, there were 517 deaths (mean [SD] age, 59.6 [13.2] years) in the NFL cohort and 431 deaths (mean [SD] age, 66.7 [12.3] years) in the MLB cohort. Cardiovascular and neurodegenerative conditions, respectively, were noted as underlying or contributing causes in 498 and 39 deaths in the NFL and 225 and 16 deaths in the MLB. Compared with MLB players, NFL players had significantly elevated rates of all-cause (HR, 1.26; 95% CI, 1.10-1.44), cardiovascular disease (HR, 2.40; 95% CI, 2.03-2.84), and neurodegenerative disease (HR, 2.99; 95% CI, 1.64-5.45) mortality. Comparing hypothetical populations of 1000 NFL and 1000 MLB players followed up to age 75 years, there would be an excess 21 all-cause deaths among NFL players, as well as 77 and 11 more deaths with underlying or contributing causes that included cardiovascular and neurodegenerative conditions, respectively.

Conclusions and Relevance

This study found that NFL players had elevated all-cause, cardiovascular, and neurodegenerative mortality rates compared with MLB players, although the absolute number of excess neurodegenerative deaths was still small. Factors that vary across these sports (eg, body habitus and head trauma) as opposed to those common across sports (eg, physical activity) could underlie the differences.

A Systematic Review of Etiological Risk Factors Associated With Early Mortality Among National Football League Players

Background:

Multiple risks predispose professional football players to adverse health outcomes and, in extreme cases, early death; however, our understanding of etiological risk factors related to early mortality is limited.

Purpose:

To identify etiological risk factors associated with all-cause and cause-specific mortality among National Football League (NFL) players.

Study Design:

Systematic review; Level of evidence, 3.

Methods:

Articles examining all-cause and cause-specific mortality risk factors among previous NFL players were identified by systematically searching: PubMed, PsycINFO, Web of Science, and Google Scholar from 1990 to 2017. Study eligibility and quality were evaluated using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines.

Results:

A total of 801 nonduplicated studies were identified through our search strategy. Of these, 9 studies examining 11 different risk factors were included in the systematic review. Overall, the risk of all-cause and cause-specific mortality was lower among NFL players than among the general male population in the United States. Nonwhite athletes, those in power positions, and those with a high playing-time body mass index (≥30 kg/m²) were associated with elevated all-cause and cardiovascular mortality risks.

Conclusion:

Methodological issues associated with the examined all-cause and cause-specific mortality risk factors preclude a definitive conclusion of etiological protective or risk effects. Comparison groups less prone to selection bias (“healthy worker effect”) and a life-course approach to the evaluation of suspected risk factors are warranted to identify etiological factors associated with early mortality among NFL players.

Prevalence of sleep disorders and sleep problems in an elite super rugby union team

The aim of this study was to determine the prevalence of sleep disorders in an elite rugby union team using in-laboratory polysomnography (PSG) and sleep questionnaires. Twenty-five elite rugby union players underwent a night of PSG during the "off-season" of the Super Rugby competition to assess their sleep. Of interest were measurements that detected the presence of obstructive sleep apnea (OSA; apnea-hypopnea index ≥5 events/hr) and the presence of moderate-severe periodic leg movements during sleep (PLMs; ≥15 events/hr). Players completed sleep-related questionnaires to assess daytime sleepiness, perception of insomnia, risk of OSA, and the presence of restless legs syndrome (RLS) and underwent basic anthropometric assessments including body mass index and neck circumference. OSA was present in 24% (n=6) of players and PLMs ≥15 events/hr in 12% (n=3). Questionnaire responses showed that all players had insomnia defined subthreshold insomnia and excessive daytime sleepiness, two players were identified as being at risk for OSA and none were classified as having RLS. In conclusion, sleep disorders and excessive sleepiness are common in elite rugby union players. A process to identify and manage sleep disorders should be considered by teams to optimise their physical recovery, athletic performance and to safeguard their health.

Chronic Traumatic Encephalopathy in Professional American Football Players: Where Are We Now?

Repetitive head trauma provides a favorable milieu for the onset of inflammatory and neurodegenerative processes. The result of long-lasting head trauma is chronic traumatic encephalopathy (CTE), a disease process well-recognized in boxers, military personnel, and more recently, in American football players. CTE is a chronic neurodegenerative disease with hallmarks of hyperphosphorylated tau (p-tau) aggregates and intercellular lesions of neurofibrillary tangles. The criteria for CTE diagnosis requires at least 1-2 focal perivascular lesions of p-tau in the cerebral cortex, at the depth of the sulci. These pathognomonic lesions aggregate within neurons and glial cells such as astrocytes, and cell processes within the vicinity of small blood vessels. CTE presents in a distinct topographical distribution pattern compared to other tauopathies such as AD and other age-related astrogliopathies. CTE also has an insidious onset, years after repetitive head trauma. The disease course of CTE is characterized by cognitive dysfunction, behavioral changes, and can progress to altered motor function with parkinsonian-like manifestations in later stages. This short review aims to summarize CTE in professional football, epidemiology, diagnosis based on neuroanatomical abnormalities, cognitive degeneration, and adverse mental health effects, as well as gaps in the literature and future directions in diagnostics, therapeutics, and preventive measures.