Body Mass Index and Serum γ-glutamyltransferase Level as Risk Factors for Injuries Related to Professional Horse Racing: A Prospective Study

Abstract

Objectives: Prevention of horse-related injuries is considered difficult because horse behavior is unpredictable. Therefore, risk factors for injuries related to professional horse racing need to be investigated. We conducted a study to determine whether body mass index (BMI) and γ-glutamyltransferase (GGT) levels are associated with professional horse racing-related injuries. Methods: A baseline healthy survey of 546 male grooms and exercise riders aged 40-70 yr working at Miho Training Center, the largest racing-horse training facility in Japan, was performed in May 2003. A total of 93 occupational injuries occurred from June 1, 2003 to December 31, 2005. The Cox proportional hazards model was used to examine associations between the risk of injury and BMI and GGT. Results: Grooms and exercise riders with BMI <20 kg/m² or with BMI ≥25 kg/m² compared to BMI=20.0-22.9 kg/m² had 2.5 to 3.5-fold higher age-adjusted risks of injuries. The multivariate hazard ratios (95% confidence interval) after adjustment for age, GGT, smoking habit, and history of injuries were 3.5 (1.5 to 8.4) and 2.4 (1.2 to 4.8) for grooms, 3.1 (1.2 to 8.2) and 1.9 (0.4 to 10.1) for exercise riders, respectively. The age-adjusted hazard ratio of injuries for persons with GGT ≥100 IU/l was 2.0 to 2.5-fold higher than for those with GGT <60 IU/l. The multivariate hazard ratios were 1.9 (1.0 to 3.6) for grooms and 2.5 (1.0 to 6.2) for exercise riders. Conclusions: Low and high BMI and high GGT were associated with professional horse racing-related injuries.