Frequency of Self-Reported Concussion Amongst Professional and Semi-Professional Footballers in Ireland During the 2014 Season: a Cross-Sectional Study

In 2013, the American National Football League agreed to pay $765 million in compensation to more than 4500 former professional players due to concussions and head injuries sustained during their careers [1]. In 2015, this compensation was increased to $914 million and extended to 5000 former professionals [2]. In 2002, a verdict of death by industrial disease was returned following an inquest into the death of former England professional footballer Jeff Astle. This inquest identified a type of dementia that was consistent with heading the ball. Consequently, considerable media attention drew the general public’s attention to the potential dangers and long-term consequences of sports-related concussion. Head trauma and concussion are everyday occupational risks for professional and semi-professional athletes competing in contact sports. However, these risks are not limited to elite athletes. In a quantitative epidemiological study of the general population of New Zealand [3], it was found that 21% of all traumatic brain injuries were sustained during sports-related activities. Despite increased public awareness and growth in concussion-related research, a number of concerns and important gaps in our knowledge still exist.

The 5th International Conference on Concussion in Sport (Berlin 2016), defined sports-related concussion as “a traumatic brain injury induced by biomechanical forces” [4]. In the USA [5], between 1.6 and 3.8 million athletes participating in a sporting activity suffer a concussion. However, the true figure is likely to be much higher, owing to many injuries not being recognised or reported [6]. While this has been a recognised player safety and health issue for over a decade [7], little progress has been made in reporting practice. Moreover, while many instances of sports-related concussion may be deemed clinically mild, there is evidence emerging that an athlete’s ability to fully recover from a concussion may be impaired and that the effects of repeated concussions are more severe than previously understood [5].

In recent years, there has been a growth in research examining concussion in football [8], with national football associations [9], national football leagues [10] and in countries such as the Netherlands [11] and Italy [12]. Studies of high-school [13], university-level [14] and professional [15, 16] football players exist. However, the significance of parameters such as player age and playing position remains unclear [17]. Moreover, despite a growth in studies examining concussion-reporting rates and practices with professional rugby players in Ireland [18, 19] studies examining the occupational risks associated with concussion amongst Irish semi-professional and professional footballers are lacking. Finally, research examining personal safety awareness and the frequency of concussion reporting amongst professional athletes has been limited. In response, the purpose of this study was to investigate the safety awareness and concussion-reporting frequencies of a cohort of Irish professional and semi-professional footballers.

Just over one third of the participants of the study (n = 54) were professional footballers, with the remaining participants designated as semi-professional (n = 95). The majority of both professional footballers and semi-professional footballers were aged (years = a) between 18a and 29a; n = 35 (64.8%) and n = 80 (84.3%) respectively. 34 participants were aged between 30a and 39a, the majority of which were professional footballers; n = 19 (55.8%). Significantly more players from the 18a to 29a age category participated in the study as indicated by a Pearson chi-sq test (p = 0.007, OR 2.9 (1.3–6.4)) reinforced by a Fishers exact test (0.013) and the Yates correction (0.012) all to the 95% CI.

15.7% of the total population reported having officially received a verified concussion in the 2014 season (N.B. 127 out of 149 participants answered this question). There was no significant difference between professional and semi-professional players regarding self-reporting a concussion. This was confirmed via a Pearson chi-sq (p = 0.43, OR 1.5 (0.5–4.5)) and supported by a Fishers exact (0.6) and Yates correction (0.6).

Further statistical analysis indicated that when considering the defenders as a single group (n = 44, 35%) versus the rest of the players (n = 83; 65%) irrespective of professional status, there was a greater likelihood of self-reported concussion. 12 defenders self-reported concussion as opposed to 8 other players (Pearson chi-square p = 0.009, OR 3.5 (1.3–9.7)). This was further reinforced with the Fishers exact test (0.02) and the Yates correction (0.02) at the 95%CI.

Of the 127 players who responded to the questions regarding concussion within this broader study, 68 reported concussive symptoms to individuals within their support network. Of these 68 players, 20 (15.7%) were officially diagnosed with concussion. This figure is considerably higher (> 10%) than that of a similar representative study conducted with Italian footballers, which found that 5% of the population had suffered a concussion in the previous season [12]. Globally, footballers’ risk of concussion is considered to be substantial, accounting for a quarter of all injuries amongst elite male players [24, 25]. Factors impacting football players’ self-reporting, or under-reporting, of concussion include the importance of a particular match, an eagerness to return to play for big games, the possibility of being prevented from playing and the availability of quality substitutes [15]. However, the higher levels of recognition of concussive symptoms and of self-reported concussion for League of Ireland players in the 2014 season could be attributed to a number of factors. While concussion research was previously focussed on the validation of concussion assessment tools, more recent studies have emphasised the need for improved concussion education for stakeholders in football [26]. There has also been significant mainstream media interest in concussion in sport over the last few years. Consequently, it is argued that players are now more aware of concussion (types, symptoms, sources, diagnosis, treatment etc.) in general [27], and of the need to report it to relevant personnel in particular [28]—and indeed, are more likely to do so [29].

This higher levels of reporting are of interest because, while increased concussion incidence and reporting by players may impact team selection in the short term, the potential recurrence of concussion can impact career opportunities and trajectory in the long term. A career in professional football is characterised by chronic insecurity and uncertainty [30]. For professional footballers, missing a game through injury can have considerable short-term consequences in terms of getting back into the team as well as more significant long-term implications in terms of securing of a professional contract [30]. Furthermore, the threat of deselection is more significant for professional footballers and players may hide injuries, not impacting performance, from medical staff and managers [30]. The moderately higher reporting levels of semi-professional footballers in this study could be due, in part, to this cohort possessing alternative occupations, employment opportunities and sources of income. In contrast to the findings of recent research in professional football in England [15], Irish semi-professional footballers may be less risk averse, may connect their personal actions with the risk and may be more aware of the long-term impact of concussion. Thus, while concussion education has improved considerably recently, changing the culture of underreporting will require ongoing efforts over many years [29]. As we know, concussion injuries may have an associated stigma, viewed as a ‘less serious injury than a leg break’ (15:201). In this regard, there is a need for further player and manager education linking the short-term decision to ignore concussion symptoms with the long-term potential risks.

This study’s results indicate that certain playing positions have a greater likelihood of receiving a concussion than others. These results are similar to those of studies carried out with professional rugby league players, in which it was noted that the ball carrier (attacker) was found to be at greater risk of sustaining a concussion than the tacklers (defender), probably because rugby league is a full contact sport [31]. An Irish study carried out with rugby union players came to a similar conclusion, with a higher proportion of concussions being sustained by attacking players; however, interestingly, the severity of concussions was greater for defending players [17]. Regarding the age ranges of both the professional and semi-professional players in this study, the professional players had an older age range and their experiences with concussion over their careers may be influencing the reporting practices of the younger members of their teams.

Despite semi-professional footballers accounting for over two thirds of the concussions reported in the study, professional status does not appear to have an association with concussion. While professional sport is a unique ‘work’ environment, legislation to protect workers is still applicable, depending on the jurisdiction. When considering concussion as an occupational injury for professional athletes, comparison with other occupational sectors can give an insight into how injuries are perceived in professional sport. Across the EU, concussion accounted for 17% of all workplace injuries in 2013 [32]. In contrast, the Irish Central Statistics Office (CSO) noted that concussion, grouped with several other occupational injuries (including amputation, internal injury, burn, scald or frostbite) made up only 7% of all workplace injuries in 2013 [33]. While it is not possible to obtain an exact figure for the number of workplace concussions, it is worth noting that the total number of injuries in this group nationally was 1300. Consequently, 20 concussions could be considered high for professional and semi-professional footballers as one defined occupational group. Given that concussion in professional sport can be considered an occupational risk, it is imperative that professional athletes’ awareness of this risk should be evaluated more rigorously [34].

There are a number of issues to bear in mind when interpreting the results of the current study. One methodological limitation is the sample size. In this regard, it must be noted that gaining access to professional football players and clubs normally presents difficulties for researchers, as professional football clubs are often quite wary of social science researchers [15] and when exploring sensitive issues such as concussion in particular. Moreover, it is often difficult to secure the cooperation of professional leagues, professional football associations and governing bodies. Consequently, concussion-related research in football utilising professional football players, though growing [11, 15, 16], is limited. A second limitation concerns recall error. Asking athletes to recall symptoms from the previous year when they may not have been able to recognise them or were unwilling to report them can lead to bias, which has implications for the internal validity of the study [35, 36]. However, this study occurred immediately after the preceding season when the players had returned to pre-season training, thus minimising recall duration [35]. Despite its limitations, retrospective recall does ‘allow an athlete the opportunity to reveal symptoms that may not have been identified prospectively’ (14: 337). However, mitigating measures to enhance validity and minimise self-report limitations such as miscomprehension, measurement error and conscious bias [34, 35] were adopted. For instance, participants were provided with clear instructions and an overview of the rationale of the study. It was also assumed that participants were ‘honest in their responses without a societal response bias’ (15: 202). Situational limitations, such as confidentiality [34], were addressed by excluding coaches, managers and support staff. This, coupled with the anonymous nature of the survey, allowed the players to participate and answer truthfully without fear of and potential negative repercussions [34]. This could be a factor in the higher reporting levels evidenced in this study.

This research is the first and largest investigation of the self-reported frequency of, and attitudes towards, concussion amongst Irish senior professional and semi-professional footballers. This study has indicated that professional status does not have a significant bearing on the likelihood of recognising concussive symptoms or of reporting a concussion. Further research is needed to ascertain whether professional footballers perceive concussion as an occupational risk, and whether they appreciate that accepting such risks can have long-term implications for health (i.e. that cumulative sporting injuries can potentially lead to debilitating health conditions). As a questionnaire may not be an effective tool for exploring attitudes towards concussion, it has been argued that understanding player’ views on self-reporting concussion would require qualitative research [15].