|
|||||
|
|
A case-crossover study of intensive racing and training schedules and risk of catastrophic musculoskeletal injury and lay-up in California Thoroughbred racehorses |
|
| Authors: | Leah Estberg Ian A Gardner Susan M Stover and Bill J Johnson |
| Institution: | a California Veterinary Diagnostic Laboratory System, School of Veterinary Medicine, University of California, P.O. Box 1770, Davis, CA, 95617, USA b Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA, 95616, USA c Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, CA, 95616, USA |
| Abstract: | The objective of this study was to investigate the relationship between intensive racing and training schedules and risk of either catastrophic musculoskeletal injury (CMI) or lay-up from racing in California Thoroughbreds. Thoroughbred racehorses that sustained a CMI during racing or training and either were subsequently euthanized or died on a California racetrack during 1991 and 1992 were studied using a case-crossover study design. Each study subject (case) provided its own self-matched control information in the form of ‘typical’ exposure frequency, determined or estimated from historic information. Periods of rapid average daily accumulation of high-speed exercise distance were identified for each horse from official race and training histories with a sliding 60-day window. Those window frames containing an average daily rate of distance accumulation exceeding 75th percentile cutoff values were classified as exposed frames followed by 30 days of increased risk, or hazard periods. All remaining days (excluding periods of layoff from racing) were considered non-hazard time at risk. The relative risk (RR) of CMI within 30 days following a period of rapid accumulation of high-speed exercise distance (during a hazard period) was 4.2 (95% confidence interval CI]= 3.0, 5.8). Of these 214 cases, 84 (39%) were injured during a hazard period whereas on average only 22% of total career time at risk was hazard time for these horses. A second analysis was performed for horses with at least 1 lay-up period from racing of ≥ 60 days. RR for a lay-up beginning during a hazard period was estimated for the last lay-up experienced by each horse. The RR for lay-up beginning during a hazard period was 4.8 (95% CI = 2.9, 8.1). Of these 98 cases, 32 (33%) of the lay-ups began during a hazard period whereas on average, only 22% of at-risk time up to last lay-up was hazard time for these horses. |
| Keywords: | Horse Musculoskeletal injury Exercise Case-crossover |
| 本文献已被 ScienceDirect 等数据库收录！ | |