Epidemiological analysis of factors influencing an episode of exertional rhabdomyolysis in high school students

Background:An episode of rhabdomyolysis occurred after an endurance test in high school students in Taipei County in November 2003. Purpose:To determine the incidence, outcome, and risk factors in an episode of exertional rhabdomyolysis in high school students. Study Design:Descriptive epidemiology study. Methods:We enrolled all 225 high school students who had performed an endurance test. Using data from retrospective questionnaires, we estimated the incidence and assessed risk factors of exertional rhabdomyolysis among these students. Multiple logistic regression was used to determine risk factors associated with exertional rhabdomyolysis. Results:The completed questionnaire was returned by 70% (157 of 225) of the students. Of these, 43.3% (68 of 157) were identified as having exertional rhabdomyolysis, and the incidence was not statistically different between male and female students (P=.49). Dark urine was noted in only 25% of the students. None of the students developed acute renal failure. The risk of exertional rhabdomyolysis was significantly higher in those students who had not exercised 1 day before the endurance test (odds ratio [OR], 6.10; 95% confidence interval [CI], 2.00-18.00) and those who had performed postexercise stretching of the legs (OR, 3.13; 95% CI, 1.28-7.69) or performed complete squats during the test (OR, 3.21; 95% CI, 1.12-10.00). There were no statistically significant differences in gender, body mass index, presence of flulike symptoms, previous exercise routine, and medication history between students with or without exertional rhabdomyolysis. Conclusion:Our findings suggest that exertional rhabdomyolysis is not uncommon in strenuous eccentric exercise in both men and women, but the risk of developing acute renal failure is very low. Exercise 1 day before eccentric exercise was significantly associated with a reduced risk of exertional rhabdomyolysis, whereas postexercise stretching of the involved extremities might increase the risk. ? 2006 American Orthopaedic Society for Sports Medicine.