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Illness during the 2010 Super 14 Rugby Union tournament – a prospective study involving 22 676 player days
  1. Martin Schwellnus1,2,
  2. Wayne Derman1,2,
  3. Tony Page3,
  4. Michael Lambert1,
  5. Clint Readhead4,
  6. Craig Roberts4,5,
  7. Ryan Kohler6,
  8. Esme Jordaan7,
  9. Robert Collins8,9,
  10. Stephen Kara10,
  11. Ian Morris11,
  12. Org Strauss12,
  13. Sandra Webb13
  1. 1Department of Human Biology, University of Cape Town, UCT/MRC Research Unit for Exercise Science and Sports Medicine, Cape Town, South Africa
  2. 2International Olympic Committee (IOC) Research Centre, Cape Town, South Africa
  3. 3Sports Medicine Department, Olympic Park Sports Medicine Centre, Melbourne, Australia
  4. 4Medical and Scientific Department, South African Rugby Union, Cape Town, South Africa
  5. 5Discipline of Sports Science, University of Kwazulu-Natal, Durban, South Africa
  6. 6Sports Medicine Department, Australian Institute of Sport, Canberra, Australia
  7. 7Biostatistics Unit, Medical Research Council, Parow, South Africa
  8. 8Sports Medicine Department, Golden Lions Rugby Union, Johannesburg, South Africa
  9. 9Section of Sports Medicine, Sports Concussion South Africa and University of Pretoria, Pretoria, South Africa
  10. 10Sports Medicine Department, Blues Super Rugby Franchise, Auckland, New Zealand
  11. 11Sports Medicine Department, Cheetahs, Bloemfontein, South Africa
  12. 12Sports Medicine Department, Bulls, Pretoria, South Africa
  13. 13Team Physician, Highlanders, Dunedin, New Zealand
  1. Correspondence to Martin Schwellnus, Department of Human Biology, UCT/MRC Research Unit for Exercise Science and Sports Medicine, Newlands, Cape Town 7700, South Africa; mschwell{at}iafrica.com

Footnotes

  • Competing interests None.

  • Ethics approval Research Ethics Committee, Faculty of Health Sciences, University of Cape Town.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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Although the epidemiology of injuries during club, provincial, national and international Rugby Union and league players participating in tournaments is well documented,1,,15 very few studies have addressed medical illness. With the maturation of Sport and Exercise Medicine as a specialty and the International Olympic Committee's (IOC) contribution to the field,16 there has been an increasing focus on the protection of the health of the athlete. It is particularly relevant to consider medical illness in elite athletes who participate in events and tournaments lasting days to a few weeks.

The incidence of medical illness in Rugby Union players during a season or during competitions has not been well studied. In one study, the incidence of illness in a group of 30 rugby players was measured over a 48-week period.17 In this study, 123 upper respiratory infections (URI) were recorded (incidence of four URI episodes per player over the period) and 25 gastrointestinal tract complaints were recorded (0.8 per player over the period). These data are consistent with reports of a high incidence of respiratory tract illness in elite athletes during sports events lasting a few days to weeks (Theron et al, unpublished data).18,,23

In the southern hemisphere, the Super Rugby tournament is conducted annually over a 16-week period. In the 2010 Super 14 Rugby tournament, 14 international rugby teams competed in the period from February 2010 to May 2010 at different playing venues in South Africa, Australia and New Zealand. Unlike other tournaments, which typically take place in one venue or in one country, this tournament is unique in that players travelled between South Africa, Australia and New Zealand over the 16-week period. This means that they were exposed to different environmental conditions including temperature, humidity, atmospheric pollution, aeroallergen exposure and diets. Players travelling between continents may also be exposed to different strains of pathogenic organisms. This tournament is also an event that is characterised by very high-intensity international standard rugby games24 on 15 weekends over the 16-week period, with an addition of three to five training sessions per week.

The incidence and nature of medical illness in elite athletes competing in a tournament has not been studied during a prolonged period (16 weeks) where multiple journeys of international air travel across many time zones occur. Therefore, the main aim of this study was to document the incidence of medical illness in rugby players participating in the 2010 Super 14 Rugby tournament. One of the other specific aims was to document information that will be of clinical relevance to assist the team physician in future planning during a tournament of this nature. This information included the following: incidence of time-loss illness (illness resulting in loss of a practice or a match), system/s affected by illness, most common illness by specific diagnosis, most common presenting symptoms and their duration before presentation, and the suspected cause of illness.

Methods

Type of study

This was a prospective cohort study over a 16-week period during the 2010 Super 14 Rugby Union tournament.

Selection of participants

The UCT/MRC Research Unit for Exercise Science and Sports Medicine conducted the study, together with the South African Rugby Football Union and with the co-operation of the team physicians of eight of the participating rugby teams from South Africa and New Zealand. Before the start of the tournament, research ethics approval for the study was obtained from the University of Cape Town Health Sciences Research Ethics Committee (REC 008/2010). Detailed information about all the components of the study was provided to the team physicians of the South African (five teams) and some of the New Zealand (three teams) participating teams. All the players (n=259) participating in the eight teams were approached (28–36 players per team) to participate in this prospective study through their team physicians who were given detailed information about the nature of the research study. Each team physician was able to explain the details of the study as well as all the potential risks and benefits of the study by providing players with a detailed subject information sheet. Written informed consent was obtained from players to participate in the study.

A system of coding each player and team anonymously was used to ensure anonymity. Each team was allocated a random code (letter of the alphabet) and each player in the team was randomly allocated a number (0 to 36). Only the team and player code were listed on the documentation. An independent party drew the codes and these were kept in sealed envelopes and safe storage until after the competition.

Illness data collection

Data collection took place on a daily basis during the competition. Each team physician was requested to complete a ‘daily medical illness log’ for each player during the competition. This commenced when the team assembled a few days before the first game and ended after a team played their last game. A booklet was provided that contained daily illness report forms (one page per day). This daily medical illness report form was first piloted during the 2009 Confederations Cup Football tournament21 and similar forms have been used in surveys at international sports competitions.20 22,,24

A medical illness was defined as ‘any non-trauma related symptom or sign presenting in a player that required medical attention from the team physician on a specific day’. The information of every medical illness that was included on the daily report form was the same as that which a team physician would obtain normally during clinical care of an athlete. This information included the following: presenting symptom/s or sign/s, duration of symptoms (days), the specific final clinical diagnosis (a list of common diagnoses was provided for each system), the predicted number of days lost from practices or matches and the suspected cause of illness (a list of common categories of causes was provided). The team physician obtained all these data through clinical assessment.

The team doctors of each team kept the booklet of daily illness forms secure and the completed booklets with daily forms were only submitted to the central research office at the end of the competition. Regular contact between the central research office and the participating team doctors occurred during the competition using either email or telephonic contact. Following the completion of the competition, all the daily illness report booklets were analysed. There was 100% compliance in the return of completed booklets.

Calculation of the player days

The number of team and player days was calculated as follows: eight teams (daily squad size varied from 28–36 players per team) participated in the study during the tournament over about 16 weeks. The start and finishing dates of the tournament were different for each team as these were dependent on the date of the first and last match played (some teams started a few days later or were knocked out before the quarter final, semifinal or final). The total tournament days for each team and the daily squad size were therefore variable. On each day, the team physician reported the ‘daily squad size’ for that day as this could vary (squad sizes were often reduced during times of international travel). The total player days for each team (table 1) were therefore calculated as follows: total team tournament days × daily squad size (for each day).

Table 1

Total number of player days per team, country and overall

Calculation of the incidence of illness

All illness incidence data were calculated as illness per 1000 player days. During the tournament, illness data were recorded in a total of 22 676 player days (table 1). The incidence per 1000 player days was reported for all illnesses, illnesses in different systems and common specific diagnoses. In addition, time-loss illnesses were reported. Both new and repeat illnesses were included in the incidence reports. A repeat illness was defined as ‘any illness in the same player with the same final diagnostic code that was recorded within 7 days’. A time-loss illness was defined as ‘an illness resulting in one or more lost training or match days’. The nature, frequency and duration of presenting symptoms as well as the suspected cause of the illness were also documented.

Statistical analysis of data

Standard descriptive statistical analyses were conducted, using uni- and bi-variate analysis where appropriate. Data were in the form of counts, which represented the number of illnesses for each day the team remained in the tournament. The counts were assumed to have a Poisson distribution and were therefore modelled using generalised linear modelling in SAS 9.3. The data were slightly overdispersed (mean was 1.6 times the variance) and this was accounted for in the modelling.

Results

Overall incidence of illness

In the 16-week study period, a total number of 469 illnesses were reported in 187 of the 259 players (72.2% of players). Of these, 402 (87.6%) were new illnesses and 57 (12.4%) were repeat illnesses. The overall incidence of illness was 20.7 per 1000 player days (95% CI 18.5 to 23.1). The incidence of illness (per 1000 player days) in each system, and the incidence of common specific diagnoses in each system are depicted in table 2 (there were missing data in three of the 469 illnesses). The most common system affected by illness was the respiratory system (30.9%), followed by the digestive system (27.5%) and the skin and subcutaneous tissue (22.5%).

Table 2

The frequency (percentage of all 466 illnesses reported in affected systems) and the incidence (per 1000 player days) of illness in each system and for common specific diagnoses

The most common specific diagnosis was that of gastroenteritis (infective and non infective) (19.8%), followed by acute respiratory tract infection (15.9%) and skin infection (16.3%). Infections (11.2 per 1000 player days: 95% CI 9.9 to 12.7) accounted for 54.5% of all illnesses (table 3). Of clinical relevance was the observation that respiratory, gastrointestinal and skin infections accounted for 51% of all illnesses (table 3).

Table 3

The frequency (percentage of all illness reported; n=466) and the incidence (per 1000 player days) of infective illness

Incidence of time-loss illness

The number of illnesses (and % of illnesses per system and specific diagnosis) reported for no time loss, 1 day time loss and >1 day time by affected system and for common specific diagnoses is depicted in table 4 (time-loss data were not reported in 11 of the 469 illnesses). There was no time loss (days off training or matches) in 384 (83.8%) of reported illnesses, while 44 (9.6%) of illnesses resulted in time loss of 1 day, and 30 (6.5%) in loss of more than 1 day. Gastrointestinal tract illness (35/74, 47.3%), in particular infective gastroenteritis (32/74; 43.2%) as well as respiratory tract infections (25/74; 33.8%) resulted in most time-loss illnesses.

Table 4

Time-loss illness (no time loss days, 1 day loss and >1 day time loss) in each system and for common diagnoses (number and percentage of illnesses per system or specific diagnosis; missing data in eight of the 466 reported illnesses)

The number (and %) of infective illnesses resulting in no time loss, 1 day time loss and >1 day time loss by affected system is depicted in table 5. Respiratory tract infections resulted in the majority of time-loss illness >1 day, while gastro-enteritis only resulted in time loss of 1 day in the majority of cases.

Table 5

Time-loss illness (no time loss days, 1 day loss and >1 day time loss) for infections (number and percentage of illnesses per system or specific diagnosis; n=249; there were missing data in five of the 254 reported infections)

Symptoms and cause of illness

The most common presenting symptom of illness was pain (22.9%), followed by diarrhoea (17.8%), sore throat (12.5%), fatigue (5.1%), pruritus (9.7%) and cough (5.9%) (table 6).

Table 6

The frequency of the symptoms of illness (number and percentage of all illnesses reported; n=466)

In 22.6% of all illnesses, other presenting symptoms were reported. The duration of symptoms (same day, 1–3 days or >3 days) before reporting in each system and for common specific diagnoses is depicted in table 7.

Table 7

The duration of symptoms (number and percentage of illnesses per system or specific diagnosis) before illnesses were reported (n=403; missing data in 63)

The majority of symptoms (51.1%) were present >1 day before reporting – most commonly 1–3 days before reporting (45.7%). More specifically, the majority (>60%) of symptoms of skin disease and ear disease were reported only after 1–3 days. The duration of symptoms (same day, 1–3 days or >3 days) before reporting infective illness for each system is depicted in table 8. It is important to note that in 58.4% of all infective illnesses, symptoms of infective illness were present for at least 1 day before reporting.

Table 8

The duration of symptoms (number and percentage) before infective illnesses were reported (n=226; missing data in 28)

The suspected cause of illness (number and percentage of all illnesses by system or common specific diagnoses) is listed in table 9.

Table 9

The cause of illness (number and percentage of illnesses per system or specific diagnosis; n=464; missing data in two)

The most common suspected cause of illness was infection (58.7%), followed by environmental causes (17.7%), pre-existing illness (4.3%) and exercise-related causes (4.1%). In 15.2%, other causes were listed. Infection was the most common suspected cause for illness in the respiratory system, digestive system and the skin and subcutaneous tissue. Environmental causes were listed as the most common single suspected cause for allergic rhinitis (90.5%), sleep disorders (55.6%) and allergic dermatitis (50%) (table 9).

Discussion

The main findings of this study were (1) that over 70% of elite Rugby Union players participating in this 16-week rugby tournament, at some point, reported an illness to their team physician, (2) that the incidence of illness in the 16-week tournament was 20.7 per 1000 player days, (3) that the most common system affected by illness was the respiratory system, followed by the digestive system and the skin and subcutaneous tissue, (4) the most common specific diagnoses were infections (58.7% of all illnesses) – notably gastroenteritis, acute respiratory tract infections and skin infections, (5) that the majority of illnesses (83.8%) did not result in any time loss from training or matches, (6) that pain, diarrhoea and sore throat were the most common presenting symptoms and (7) that in 51.1% cases, symptoms were present at least 1 day or more before they were reported to the team physician.

To our knowledge, this is the first study to report the incidence (per 1000 player day exposure) in Rugby Union players (20.7 per 1000 player days) during a tournament. Our data show that it is very likely that a player will report with at least one illness in the 16-week period (over 70% of players). Furthermore, we show that a team physician travelling with a squad size of 30 players can expect to see one player with an illness every 1.6 days.

In other sporting codes, there are only two studies in which the incidence of illness has been reported per exposure (1000 player days) during tournaments.20 The overall incidence of illness reported during this 16-week tournament (20.7/1000 player days) is slightly higher than that reported during the 2-week Confederations Cup Football tournament in 2009 (16.9/1000 player days) and considerably higher than that reported during the 4-week 2010 Fédération Internationale de Football Association World Cup football tournament (7.7/1000 player days). The precise reason/s for the higher incidence of illness during the Super 14 tournament is not clear, but could be related to a number of possible factors including the following: the longer duration of the tournament (16 weeks vs 2–4 weeks), high-intensity weekly matches and training sessions, travelling across multiple time zones (up to 11 h difference between South Africa and New Zealand venues), varying climatic and environmental conditions in different countries and playing venues, and the nature of the sport (rugby union vs football). Furthermore, it is common for all Super Rugby franchises to have their own training facility base where players are in close proximity to one another for 4–6 h per day for about 4 days per week. At these facilities, players eat two meals together (breakfast and lunch) and make use of communal shower and ablution facilities. This environment could also facilitate the spread of infection in teams and may account for the higher illness incidence seen in this study. Other factors such as the general pretournament health of the rugby players may also be a factor. All these, and other factors, to identify the reason/s for the high incidence of illness would require further scientific study.

In this study, we identified that the most common system affected by illness was the respiratory system (30.9%), followed by the digestive system (27.5%) and the skin and subcutaneous tissue (22.5%). These data are very similar to those reported in a number of other studies including football players,20 track and field athletes,23 Winter Olympic Games22 and aquatic sports.21 It is of interest to again note that, as in other studies, team physician reported that infective illness (gastrointestinal, respiratory tract) is the most common cause for illness in athletes during a tournament. However, a novel finding from this study was that in Rugby Union players, skin infections are very common and this has not been reported in any studies to date. The precise reasons for this are not clear but may be related to personal hygiene in a confined environment as well as frequent contacts between players during rugby matches.25 This finding has relevance to the design of curricula content in Sport and Exercise Medicine. It is also suggested that dermatology be included in the team physician training programs offered by organisations and international federations.

The majority of illnesses did not result in any time loss. However, infective illness, notably respiratory tract infections and gastro-enteritis were responsible for the majority of time-loss illnesses. Prevention and early diagnosis of these illnesses therefore becomes particularly important and should be the focus of further research in this area. As in previous studies,20,,23 the most common presenting symptom in players was pain. Diarrhoea was also common, and was possibly related to travel.

A further novel aspect of this study was the measurement of the duration of symptoms prior to players reporting them to the team physician. We observed that in about 50% of illnesses, the symptoms were present for at least 1 day before reporting them to the team physician. Indeed, in some instances (5%) respiratory tract illness was reported to the team physician more than 3 days after symptoms were noted. This finding has important clinical implications, as respiratory tract infection (of which viral origin is most common) is typically droplet spread and is highly contagious in the early stages of illness.26 It has been previously documented that good sanitation, early recognition and isolation of ill players can successfully reduce infections and illness in a team setting. Therefore, team physicians should be encouraged to educate both players and accompanying staff to report symptoms that could be associated with any infective illness as soon as possible so that appropriate treatment and isolation where possible may be initiated. This may also be of particular importance in symptoms of skin and ear disease, which were often only reported after 1–3 days.

What this study adds

Illness accounts for a significant proportion of consultations with a team physician travelling with elite athletes but there are very few data. Illness in elite Rugby Union players participating in a 16-week tournament involving international travel has not been studied. The results of this study show that a large % of players suffered from illness during the tournament, affecting mainly the respiratory and gastrointestinal tracts. Symptoms of illness are often not reported immediately to team physicians and this may affect player care.

The strengths of this study are first, it is, to our knowledge, the largest epidemiological study (>22 000 player days) of illness surveillance to be reported in elite athletes. Second, it is the study with the longest duration (about 16 weeks) of follow-up of a group of elite athletes (Rugby Union players) who participated in a physically demanding tournament. Third, there was excellent compliance from participating team physicians (100% return of daily booklets with <1% missing illness data). We believe that these data will make a significant contribution to the practicing rugby team physicians who travel with teams during tournaments. The wider application of these data to team physicians from other sporting codes is possible but the fact that we only studied Rugby Union players could be one of the limitations of this study. Another possible limitation in the present study is the reliance on the clinical diagnosis of the team physician rather than confirmation of nature and cause of illness by special investigations. This is a limitation that is similar to all epidemiological surveillance studies to date. In future, more accurate diagnoses that are confirmed by special investigations would be important. Similarly, the accuracy of data regarding time-loss illness is limited because the team physician, in some cases, estimated the time loss (days) at the time of diagnosis. This is a limitation in the majority of injury studies and in all the reported illness studies, in sport settings, to date.

In summary, this prospective cohort study in eight Rugby Union teams who participated in a 16-week tournament showed that the incidence of illness is higher than that previously reported in similar studies in football (soccer) players. The majority of illnesses affect the respiratory, digestive and skin and subcutaneous system, and are mostly infective in nature. Team physicians need to be aware that in approximately half the illness cases seen, symptoms were already present the day before a player reports them and this has implications for containing the spread of an infective illness by early isolation of players with symptoms.

Acknowledgments

The authors appreciate the cooperation of the team physicians and their medical staff who gave their time to collect the data for this project on a daily basis: Dr Rob Collins, Dr Stephen Kara, Dr Ryan Kohler, Dr Ian Morris, Dr Tony Page, Dr Craig Roberts, Dr Org Strauss and Dr Sandra Webb. The authors also would like to thank the players and the administrators for their support with the project. The authors wish to thank Sr Marisce Blackaller-Smal for her assistance with this project, particularly the data management and co-ordination of the submission of the manuscript.

References

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Footnotes

  • Competing interests None.

  • Ethics approval Research Ethics Committee, Faculty of Health Sciences, University of Cape Town.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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