NFL players with long careers twice as likely to report serious cognitive and mental health problems
Longer National Football League (NFL) careers and certain playing positions put former football players at higher long-term risk for serious cognitive as well as mental health problems such as confusion, memory deficits, depression, and anxiety. Players who reported the most concussion symptoms had a 22-fold risk of reporting serious long-term cognitive problems and six times the risk of having symptoms of depression and anxiety, compared with those who reported the fewest symptoms, says the analysis based on a survey of nearly 3,500 former NFL players.
Players who had the longest careers - 10 seasons or more - are twice as likely to report severe cognitive problems as compared with players who would have played a single season. Overall, one in eight players (12%) reported signs of serious cognitive problems. By comparison, about 2% of people in the general population in the US report such problems.
Nearly one in four players reported symptoms of anxiety (26%) and depression (24%), and almost one in five (18%) reported symptoms of both conditions. Career length influenced risk for depression, with every five seasons boosting the risk by nine percent. The number of seasons, however, was not linked to greater anxiety risk.
Age did not make a difference in the interplay between concussion and cognitive problems, shows analysis, published in The American Journal of Sports Medicine. Those under age 52 reported serious cognitive problems at a similar rate as the rest (13%), a finding that suggests neurocognitive decline was likely not a function of mere aging. Alarmingly, that risk remained magnified even in those 45 years and younger. According to the study, 30% of players (45 and younger), who had the most concussions, reported serious cognitive problems.
Conducted by the Harvard T.H. Chan School of Public Health and Harvard Medical School as part of the ongoing Football Players Health Study at Harvard University, the study is believed to be the first to explore the interplay between career length, position and cognitive and mental health outcomes among professional football players.
"Our findings confirm what some have suspected, which is a consistently and persistently elevated risk for men who play longer and who play in certain positions. Our results underscore the importance of preventing concussions, vigilant monitoring of those who suffer them and finding new ways to mitigate the damage from a head injury," says lead investigator of the study Andrea Roberts, a research scientist at the Harvard T.H. Chan School of Public Health.
Which position one played also mattered, says the study. The researchers found that kickers, punters, and quarterbacks had the fewest symptoms per year, followed by wide receivers, defensive backs, linemen and tight ends. The groups with the highest number of symptoms included running backs, linebackers, and special teams, according to the research team.
Former players, whose average age is 53, were asked about the number of seasons they played in the NFL, their positions and any history of blows to the head or neck followed by symptoms of concussion such as dizziness, confusion, vision problems, loss of consciousness, nausea, headaches, and seizures, among other symptoms. Based on the number and severity of symptoms, players were given a concussion score.
The study results show that players who experienced concussions had elevated risk for serious cognitive problems, depression, and anxiety, which persisted over time, as long as 20 years following injury. The researchers, however, caution that their analysis relied on players' memories of experiencing concussion rather than on diagnosis at the time of injury. The findings, they say, do not mean that everyone with a concussion will necessarily experience cognitive or mental health problems.
"Clearly, not everyone who sustains a concussion is destined for cognitive trouble, but the results of the research highlight just how critical it is to continue to find ways to prevent head injuries from occurring in the first place because of the many downstream and long-lasting effects on physical, cognitive and mental health," says Ross Zafonte, the Earle P. and Ida S. Charlton Professor of Physical Medicine and Rehabilitation and Head of the Department of Physical Medicine and Rehabilitation at Harvard Medical School. Zafonte is also principal investigator of the Football Players Health Study.
The researchers explain that many of their findings make "intuitive sense" and confirm what some might have already suspected: The longer players remain in the game, the more likely they are to suffer a head injury, which increases the risk for neurocognitive problems. It also affirms that certain positions are more prone to concussions and, therefore, players in them face a higher risk of experiencing "the downstream effects of head injury."
To assess whether the number of seasons played and position types were linked to depression, anxiety, and cognitive problems, the researchers used standard questionnaires that are commonly used to screen for the presence of such disorders. The researchers compared the proportion of players with serious cognitive problems among individuals with various career lengths - one season, two to four seasons, five to six seasons, seven to nine seasons and 10 seasons or more.
The study found that about 12.6% in the 10-plus season group (those who played 10 seasons or more) reported signs of severe cognitive problems, compared with 5.8% in the single-season category. "The risk crept up proportionally with the number of seasons played, growing progressively higher as the number of years increased. Every five seasons of play carried a nearly 20% increase in risk for serious cognitive problems," the findings state.
To evaluate the risk-position link, the researchers divided players into three groups based on the average concussion symptoms per year that players reported in each position. "Running backs, linebackers, and special teams were the groups with the highest number of symptoms," the findings state.
Those in the group with the most concussion symptoms had twice the risk for serious cognitive problems - 15% of those in this group had cognitive difficulties as compared with those reporting the fewest concussion symptoms (6%). Those with the most concussions also had a nearly 50% greater risk for depression and anxiety, compared with those playing in the group with the fewest concussion symptoms. "One in four in the first group had symptoms indicative of depression, compared with 15% of players reporting problems in the latter one, while 27% had signs of anxiety, compared with 16% in the group with the fewest concussions. Those who played in the mid-range group had a 75% higher risk of cognitive problems and a 40% elevation in risk for depression and anxiety, compared with players in the group with the fewest symptoms," says the study.
Contrary to previous reports, the new research did not find a link between starting football at a young age and cognitive problems in adulthood. The researchers say the age at which an individual started playing organized football did not affect risk. The analysis shows that outcomes were similar between those who began playing the game before age 12 and those who started later.
"The overarching goal of the Football Players Health Study is to unravel risk factors and disease mechanisms and to inform interventions that preserve and optimize player health and wellness. These latest findings confirm much of what we know, but they add much-needed granularity and specificity to risk magnitude by career length and position," says the study's senior author Marc Weisskopf, the Cecil K. and Philip Drinker Professor of Environmental Epidemiology and Physiology at the Harvard T.H. Chan School of Public Health.