Sleep-apnea risk and subclinical atherosclerosis in early-middle-aged retired National Football League players.

PURPOSE: Limited data from former National Football League (NFL) players suggest that obstructive sleep apnea (OSA) may be highly prevalent after retirement. It remains unclear whether the high prevalence of OSA in retired players is comparable to nonathletes. This retrospective analysis compared sleep apnea (SA) risk in retired NFL players to a community cohort (CARDIA Sleep study), and examined associations between SA risk and cardiovascular risk factors, including subclinical atherosclerosis. MATERIALS AND METHODS: Retired NFL players (n=122) were matched to CARDIA Sleep participants by age ±2 years (range 37-55 years), body mass index ±2 kg/m2, race, and male sex. Participants underwent electron-beam computed tomography to measure coronary artery calcium (CAC) and completed the Berlin Questionnaire to determine SA risk. The presence of CAC was defined as an Agatston score >0. RESULTS: Retired NFL players had a greater prevalence of high SA risk than the matched CARDIA Sleep participants (27% vs 11.5%, P=0.002). Compared to the CARDIA Sleep participants, retired players were less likely to smoke, and had higher blood pressure, lower fasting glucose levels, and higher cholesterol levels. However, there was no difference in the prevalence of detectable CAC (30% vs 30%, P=1). In both players and the community cohort, SA risk was not significantly associated with CAC after controlling for age, race, and body mass index. CONCLUSION: Retired NFL players have a greater prevalence of high SA risk but similar prevalence of CAC compared with a well-matched community cohort.

Lack of blood pressure difference by race in professional American football players.

Previous findings suggest that professional American football players have higher blood pressures (BP) and a higher prevalence of pre-hypertension and hypertension than the general population. We sought to determine whether race is associated with differences in BP and prevalence of pre-hypertension and hypertension among a large sample of professional football players. BP was measured at 2009 team mini-camps for 1484 black (n = 1007) and white (n = 477) players from 27 National Football League (NFL) teams. Players were categorized into three position groups based on body mass index (BMI). There was no racial difference in mean systolic or diastolic BP in any of the three position groups. There were no racial differences in prevalence of hypertension (99 [9.8%] black players vs. 39 [8.2%] white players; P = .353) or pre-hypertension (557 [55.3%] black players vs. 264 [55.3%] white players; P = 1.0). Contrary to findings in the general population, BP and prevalence of pre-hypertension/hypertension did not vary with race in a large population of active NFL players.

Whole Genome Sequencing of a Methicillin-Resistant Staphylococcus aureus Pseudo-Outbreak in a Professional Football Team.

Two American football players on the same team were diagnosed with methicillin-resistant Staphylococcus aureus (MRSA) skin and soft tissue infections on the same day. Our investigation, including whole genome sequencing, confirmed that players did not transmit MRSA to one another nor did they acquire the MRSA from a single source within the training facility.

Repeat concussions in the national football league.

BACKGROUND: Repeat concussion is an important issue in the National Football League (NFL). An initial description of repeat injuries was published for 6 years (1996-2001). HYPOTHESIS: The characteristics and frequency of repeat concussion in the NFL have not changed in the subsequent 6 years (2002-2007). STUDY DESIGN: Case control. METHODS: From 1996 to 2007, concussions were reported using a standardized form documenting signs and symptoms, loss of consciousness and medical action taken. Data on repeat concussions were analyzed for the 12 years and compared between the 2 periods. RESULTS: In 2002-2007, 152 players had repeat concussions (vs 160 in 1996-2001); 44 had 3+ head injuries (vs 52). The positions most often associated with repeat concussion in 2002-2007 were the defensive secondary, kick unit, running back, and linebacker. The odds for repeat concussion were elevated for wide receivers, tight ends, and linebackers but lower than in the earlier period. During 2002-2007, over half of players with repeat concussion were removed from play, and fewer immediately returned (vs 1996-2001). The average duration between concussions was 1.25 years for 2002-2007 and 1.65 years for the 12-year period. Over 12 years, 7.6% of all repeat concussions occurred within 2 weeks of the prior concussion. CONCLUSIONS: The defensive secondary, kick unit, running back, and linebacker have the highest incidence of repeat concussion. During 2002-2007, more than half of players with repeat concussion were removed from play, and only a fraction immediately returned. Although concussion was managed more conservatively by team physicians in the recent 6 years, repeat concussions occurred at similar rates during both periods.

Concussions involving 7 or more days out in the national football league.

BACKGROUND: Positions, signs, symptoms, and medical management of National Football League players with concussions involving 7 or more days out (7+) from play were compared for two 6-year study periods (2002-2007 vs 1996-2001). HYPOTHESIS: More players were held out 7+ days in the 2002-2007 period without significant difference in concussion signs and symptoms. STUDY DESIGN: Cohort. METHODS: From 1996 through 2007, National Football League team physicians reported concussion signs and symptoms, medical action taken, and follow-up management. RESULTS: During the 2002-2007 period, 143 (16.7%) and 33 (3.86%) concussed players were out 7+ days and 21+ days, respectively, compared with 73 (8.2%) and 7 (0.79%) in the 1996-2001 period, a significant difference (z = 5.39, P < .01). The positions with the highest fraction of 7+ days out were the quarterback (24.5% vs 16.1%), linebacker (19.7% vs 4.6%), and wide receiver (19.5% vs 8.2%) in the later versus earlier period. The player positions with the highest odds for being out 7+ days were quarterback (odds ratio = 1.80 vs 4.02), linebacker (odds ratio = 1.28 vs 0.65), and wide receiver (odds ratio = 1.25 vs 1.15). The highest incidence of 7+ days out occurred after passing plays (32.2% vs 37.0%), followed by kickoffs (18.9% vs 21.9%). The majority of players with 7+ days out were removed from the game on the day of injury (74.8% vs 72.6%); a smaller fraction were returned to play on the day of injury in the later 6 years (3.5% vs 6.8%). CONCLUSIONS: The positions with the highest odds for being out 7+ days with concussion were quarterbacks, linebackers, and wide receivers. In the more recent 6-year period, more players were managed conservatively by being held out 7+ days, even though the signs and symptoms of their concussions were similar to those in the earlier period.

Twelve years of national football league concussion data.

BACKGROUND: Concussion in the National Football League (NFL) remains an important issue. An initial description of the injury epidemiology involved 6 years from 1996 to 2001. HYPOTHESIS: The increased attention to concussions may have resulted in team physicians being more conservative in treating players in recent years. STUDY DESIGN: Two consecutive 6-year periods (1996-2001 and 2002-2007) were compared to determine changes in the circumstances associated with the injury, the patterns of signs and symptoms, and the players' time loss from participation in the NFL. METHODS: During 2002-2007, concussions were recorded by NFL team physicians and athletic trainers using the same standardized reporting form used from 1996 to 2001. Player position, type of play, concussion signs and symptoms, loss of consciousness, and medical action taken were recorded. RESULTS: There were 0.38 documented concussions per NFL game in 2002-2007-7.6% lower than the 0.42 in the earlier period (1996-2001). The injury rate was lower in quarterbacks and wide receivers but significantly higher in tight ends during the second 6 years. The most frequent symptoms were headaches and dizziness; the most common signs were problems with information processing and immediate recall. During 2002-2007, a significantly lower fraction of concussed players returned to the same game, and more were removed from play. Most concussed players (83.5%) returned to play in < 7 days; the percentage decreased to 57.4% with loss of consciousness. The number of players returning in < 7 days was 8% lower during 2002-2007 and 25% lower for those with loss of consciousness. CONCLUSION: The most recent 6 years of NFL concussion data show a remarkable similarity to the earlier period. However, there was a significant decrease in the percentage of players returning to the same game, and players were held out of play longer. CLINICAL RELEVANCE: There was a more conservative management of concussion in NFL players from 2002 to 2007 even though the clinical signs and symptoms remained similar to the earlier 6-year period.

Prevalence of cardiovascular disease risk factors among National Football League players.

CONTEXT: Concern exists about the cardiovascular health implications of large size among professional football players and those players who aspire to professional status. OBJECTIVES: To assess cardiovascular disease (CVD) risk factors in active National Football League (NFL) players and to compare these findings with data from the Coronary Artery Risk Development in Young Adults (CARDIA) study. DESIGN, SETTING, AND PARTICIPANTS: A cross-sectional study of 504 active, veteran football players from a convenience sample of 12 NFL teams at professional athletic training facilities between April and July 2007. Data were compared with men of the same age in the general US population (CARDIA study, a population-based observational study of 1959 participants aged 23 to 35 years recruited in 1985-1986). MAIN OUTCOME MEASURES: Prevalence of CVD risk factors (hypertension, dyslipidemia, glucose intolerance, and smoking). RESULTS: The NFL players were less likely to smoke when compared with the CARDIA group (0.1% [n = 1]; 95% confidence interval [CI], 0%-1.4%; vs 30.5% [n = 597]; 95% CI, 28.5%-32.5%; P < .001). Despite being taller and heavier, NFL players had significantly lower prevalence of impaired fasting glucose (6.7% [n = 24]; 95% CI, 4.6%-8.7%; vs 15.5% [n = 267]; 95% CI, 13.8%-17.3%; P < .001). The groups did not differ in prevalence of high total cholesterol and low-density lipoprotein cholesterol (LDL-C), low high-density lipoprotein cholesterol (HDL-C), or high triglycerides. Hypertension (13.8% [n = 67]; 95% CI, 11.0%-16.7%; vs 5.5% [n = 108]; 95% CI, 4.6%-6.6%) and prehypertension (64.5% [n = 310]; 95% CI, 58.3%-70.7%; vs 24.2% [n = 473]; 95% CI, 22.3%-26.1%) were significantly more common in NFL players than in the CARDIA group (both P < .001). Large size measured by body mass index (BMI) was associated with increased blood pressure, LDL-C, triglycerides, and fasting glucose, and decreased HDL-C. CONCLUSIONS: Compared with a sample of healthy young-adult men, a sample of substantially larger NFL players had a lower prevalence of impaired fasting glucose, less reported smoking, a similar prevalence of dyslipidemia, and a higher prevalence of hypertension. Increased size measured by BMI was associated with increased CVD risk factors in this combined population.

Concussion in the National Football League: an overview for neurologists.

The authors' studies have yielded a great deal of data regarding the biomechanics of head injury and the clinical picture of mild traumatic brain injury (MTBI) in the National Football League (NFL). The research has demonstrated the link between the effects of biomechanical forces on the brain and the clinical symptomatology of the concussed players. New insights into the mechanisms of injury are leading to new ways of protecting football players from the effects of MTBI. The clinical data validate the effectiveness of the current NFL physician approach to the evaluation and treatment of the player who sustains MTBI. There are still many more questions to answer and much more knowledge to be gained from continuing research in this area.

Concussion in the national football league: an overview for neurologists.

The authors' studies have yielded a great deal of data regarding the biomechanics of head injury and the clinical picture of mild traumatic brain injury (MTBI) in the National Football League (NFL). The research has demonstrated the link between the effects of biomechanical forces on the brain and the clinical symptomatology of the concussed players. New insights into the mechanisms of injury are leading to new ways of protecting football players from the effects of MTBI. The clinical data validate the effectiveness of the current NFL physician approach to the evaluation and treatment of the player who sustains MTBI. There are still many more questions to answer and much more knowledge to be gained from continuing research in this area.

Concussion in professional football: biomechanics of the struck player--part 14.

OBJECTIVE: Impacts causing concussion in professional football were simulated in laboratory tests to determine collision mechanics. This study focuses on the biomechanics of concussion in the struck player. METHODS: Twenty-five helmet impacts were reconstructed using Hybrid III dummies. Head impact velocity, direction, and helmet kinematics-matched game video. Translational and rotational accelerations were measured in both players' heads; 6-axis upper neck responses were measured in all striking and five struck players. Head kinematics and biomechanics were determined for concussed players. Head displacement, rotation, and neck loads were determined because finite element analysis showed maximum strains occurring in the midbrain after the high impact forces. A model was developed of the helmet impact to study the influence of neck strength and other parameters on head responses. RESULTS: The impact response of the concussed player's head includes peak accelerations of 94 +/- 28 g and 6432 +/- 1813 r/s2, and velocity changes of 7.2 +/- 1.8 m/s and 34.8 +/- 15.2 r/s. Near the end of impact (10 ms), head movement is only 20.2 +/- 6.8 mm and 6.9 +/- 2.5 degrees. After impact, there is rapid head displacement involving a fourfold increase to 87.6 +/- 21.2 mm and 29.9 +/- 9.5 degrees with neck tension and bending at 20 ms. Impacts to the front of the helmet, the source of the majority of National Football League concussions, cause rotation primarily around the z axis (superior-inferior axis) because the force is forward of the neck centerline. This twists the head to the right or left an average of 17.6 +/- 12.7 degrees, causing a moment of 17.7 +/- 3.3 Nm and neck tension of 1704 +/- 432 N at 20 ms. The head injury criterion correlates with concussion risk and is proportional to deltaV(4)/d(1.5) for half-sine acceleration. Stronger necks reduce head acceleration, deltaV, and displacement. Even relatively small reductions in deltaV have a large effect on head injury criterion that may reduce concussion risks because changes in deltaV change head injury criterion through the 4th power. CONCLUSION: This study addresses head responses causing concussion in National Football League players. Although efforts are underway to reduce impact acceleration through helmet padding, further study is needed of head kinematics after impact and their contribution to concussion, including rapid head displacement, z-axis rotation, and neck tension up to the time of maximum strain in the midbrain. Neck strength influences head deltaV and head injury criterion and may help explain different concussion risks in professional and youth athletes, women, and children.

Concussion in professional football: summary of the research conducted by the National Football League's Committee on Mild Traumatic Brain Injury.

PIn 1994 the National Football League (NFL) initiated a comprehensive clinical and biomechanical research study of mild traumatic brain injury (TBI), a study that is ongoing. Data on mild TBIs sustained between 1996 and 2001 were collected and submitted by NFL team physicians and athletic trainers, and these data were analyzed by the NFL's Committee on Mild Traumatic Brain Injury. At the same time, analysis of game videos was performed for on-field mild TBIs to quantify the biomechanics involved and to develop means to improve the understanding of these injuries so that manufacturers could systematically improve and update their head protective equipment. The findings and analysis of the Committee have been presented in a series of articles in Neurosurgery.

Concussion in professional football: performance of newer helmets in reconstructed game impacts--Part 13.

OBJECTIVE: The performance of five newer helmets was compared with the baseline VSR-4 helmet in 10 reconstructed cases of National Football League (NFL) collisions causing concussion. The laboratory reconstructions were conducted to determine changes in concussion risk with newer football helmets. METHODS: In 60 laboratory tests, translational and rotational head accelerations were measured in the striking and struck players represented by Hybrid III dummies. Six-axis upper neck loads and moments were measured in five cases with the struck player and five with the striking player. Biomechanical responses and concussion risks were evaluated for each collision to determine changes with newer helmet designs. RESULTS: Thirty-two out of 50 reconstructed cases showed greater than 10% reduction in severity index with newer helmets compared with the VSR-4; four cases increased. The average reduction in concussion risk with newer helmets was 10.8% (range, 6.9-16.7%) based on severity index. The reduction was 9.7% (range, 6.5-13.9%) based on translational acceleration and 18.9% (range, 10.6-23.4%) with rotational acceleration. Neck responses in the struck player showed a general reduction in moment and force with newer helmets. CONCLUSION: With newer football helmets, there was a trend toward 10 to 20% lower risks of concussion in reconstructed National Football League game collisions. However, a few designs and cases showed increased responses. The evaluation of football helmets to the proposed National Operating Committee on Standards for Athletic Equipment concussion standard should lead to more uniform reductions in concussion risk with future football helmets.

Concussion in professional football: recovery of NFL and high school athletes assessed by computerized neuropsychological testing--Part 12.

OBJECTIVE: Acute recovery from concussion (mild traumatic brain injury) is assessed in samples of NFL and high school athletes evaluated within days of injury. METHODS: All athletes were evaluated within days of injury using a computer-based neuropsychological test and symptom inventory protocol. Test performance was compared to preinjury baseline levels of a similar but not identical group of athletes who had undergone preseason testing. Statistical analyses were completed using Multivariate Analysis of Variance (MANOVA). RESULTS: NFL athletes demonstrated a rapid neuropsychological recovery. As a group, NFL athletes returned to baseline performance in a week with the majority of athletes having normal performance two days after injury. High school athletes demonstrated a slower recovery than NFL athletes. CONCLUSION: Computer-based neuropsychological testing was used within the overall medical evaluation and care of NFL athletes. As found in a prior study using more traditional neuropsychological testing, NFL players did not demonstrate decrements in neuropsychological performance beyond one week of injury. High school players demonstrated more prolonged neuropsychological effects of concussion.

Concussion in professional football: helmet testing to assess impact performance--part 11.

OBJECTIVE: National Football League (NFL) concussions occur at an impact velocity of 9.3 +/- 1.9 m/s (20.8 +/- 4.2 mph) oblique on the facemask, side, and back of the helmet. There is a need for new testing to evaluate helmet performance for impacts causing concussion. This study provides background on new testing methods that form a basis for supplemental National Operating Committee on Standards for Athletic Equipment (NOCSAE) helmet standards. METHODS: First, pendulum impacts were used to simulate 7.4 and 9.3 m/s impacts causing concussion in NFL players. An instrumented Hybrid III head was helmeted and supported on the neck, which was fixed to a sliding table for frontal and lateral impacts. Second, a linear pneumatic impactor was used to evaluate helmets at 9.3 m/s and an elite impact condition at 11.2 m/s. The upper torso of the Hybrid III dummy was used. It allowed interactions with shoulder pads and other equipment. The severity of the head responses was measured by a severity index, translational and rotational acceleration, and other biomechanical responses. High-speed videos of the helmet kinematics were also recorded. The tests were evaluated for their similarity to conditions causing NFL concussions. Finally, a new linear impactor was developed for use by NOCSAE. RESULTS: The pendulum test closely simulated the conditions causing concussion in NFL players. Newer helmet designs and padding reduced the risk of concussion in 7.4 and 9.3 m/s impacts oblique on the facemask and lateral on the helmet shell. The linear impactor provided a broader speed range for helmet testing and more interactions with safety equipment. NOCSAE has prepared a draft supplemental standard for the 7.4 and 9.3 m/s impacts using a newly designed pneumatic impactor. No helmet designs currently address the elite impact condition at 11.2 m/s, as padding bottoms out and head responses dramatically increase. CONCLUSIONS: The proposed NOCSAE standard is the first to address helmet performance in reducing concussion risks in football. Helmet performance has improved with thicker padding and fuller coverage by the shell. However, there remains a challenge for innovative designs that reduce risks in the 11.2 m/s elite impact condition.

Concussion in professional football: comparison with boxing head impacts--part 10.

OBJECTIVE: This study addresses impact biomechanics from boxing punches causing translational and rotational head acceleration. Olympic boxers threw four different punches at an instrumented Hybrid III dummy and responses were compared with laboratory-reconstructed NFL concussions. METHODS: Eleven Olympic boxers weighing 51 to 130 kg (112-285 lb) delivered 78 blows to the head of the Hybrid III dummy, including hooks, uppercuts and straight punches to the forehead and jaw. Instrumentation included translational and rotational head acceleration and neck loads in the dummy. Biaxial acceleration was measured in the boxer's hand to determine punch force. High-speed video recorded each blow. Hybrid III head responses and finite element (FE) brain modeling were compared to similarly determined responses from reconstructed NFL concussions. RESULTS: The hook produced the highest change in hand velocity (11.0 +/- 3.4 m/s) and greatest punch force (4405 +/- 2318 N) with average neck load of 855 +/- 537 N. It caused head translational and rotational accelerations of 71.2 +/- 32.2 g and 9306 +/- 4485 r/s. These levels are consistent with those causing concussion in NFL impacts. However, the head injury criterion (HIC) for boxing punches was lower than for NFL concussions because of shorter duration acceleration. Boxers deliver punches with proportionately more rotational than translational acceleration than in football concussion. Boxing punches have a 65 mm effective radius from the head cg, which is almost double the 34 mm in football. A smaller radius in football prevents the helmets from sliding off each other in a tackle. CONCLUSION: Olympic boxers deliver punches with high impact velocity but lower HIC and translational acceleration than in football impacts because of a lower effective punch mass. They cause proportionately more rotational acceleration than in football. Modeling shows that the greatest strain is in the midbrain late in the exposure, after the primary impact acceleration in boxing and football.