Epidemiology and risk factors for illness in athletes participating in sport tournaments or competitions - a specific focus on Rugby Union

Includes bibliographical referencesBackground: Illness in athletes is an inevitable part of participation in sports, and can significantly interfere with training, during tournaments or at competition time. The incidence of illness in sports varies in different sporting codes and across different tournaments and competitions. The Super Rugby competition is a particularly demanding 16-week tournament among countries in the Southern Hemisphere, and is associated with a high incidence of illness. In this tournament, 15 rugby union teams compete and play international level matches every week, which involves travel across numerous time zones and therefore may be associated with a higher incidence of illness in players. Objective: The main objectives of this dissertation were to 1) review the epidemiology and risk factors for illness in athletes participating in tournaments or competitions, and 2) determine which intrinsic risk factors predispose players to illness during the 2010 Super Rugby tournament. Methods: This dissertation consisted of two main phases. In phase I, a systematic review of the literature was undertaken, using evidence-based criteria, to determine which risk factors predispose athletes to illness during tournaments. In phase II, a prospective cohort research study was undertaken, involving 239 players from South Africa and New Zealand, over the 16-week duration of the 2010 Super 14 Rugby Union tournament. For phase II, a pre-season medical questionnaire was administered to determine baseline medical data. Collection of data then took place each day of the competition, beginning 7 days before the first game the team played, and ending when each team played their final game. Each team physician completed a daily "medical illness log" for every player. Booklets were supplied that contained daily illness report forms. Results: The main findings of the review (phase I) were good evidence (level I and II) indicating that 1) international travel, and the duration of a tournament are extrinsic risk factors for illness in athletes, and 2) that prolonged and high intensity training, older age, and nutritional deficiencies are intrinsic risk factors for illness in athletes. The main findings of the prospective cohort study (phase II) were that an increased number of training days in the 2 weeks before the tournament was an independent risk factor for any illness, respiratory system illness, and digestive system illness; the % time spent on endurance training in the 15 weeks before the tournament was an additional independent risk factor associated with respiratory system illness; the use of anti-inflammatory medication was an independent risk factor associated with respiratory system illness. Summary and conclusion: In summary, novel intrinsic risk factors for illness in rugby players participating in the Super Rugby tournament were training more days/hours per week in the 2 weeks before the tournament, as well as endurance-type training 15 weeks before the tournament. These data can form the basis of planning preventative strategies to reduce the risk of illness in the Super Rugby tournament