Table 2_Linkage of jockey falls and injuries with racehorse injuries and fatalities in Thoroughbred flat racing in Victoria, Australia.docx

IntroductionRacehorse and jockey incidents on race-days frequently occur together, yet risk factors for their occurrence have historically been investigated separately. Consideration of both horses and humans in tandem is required for a One Health approach to risk reduction. Our objectives were to therefore identify modifiable risk factors for adverse outcomes that are common or conflicting to both horses and their jockeys in Thoroughbred racing.
MethodsAustralian Single National System records for the 2004/05 to 2018/19 flat racing season were merged with the corresponding Australian Racing Incident Database records. Incidence rate ratios (IRR) with 95% confidence intervals (CI) were estimated for the outcomes of racehorse musculoskeletal injury (MSI), racehorse fatality, jockey falls and jockey injury using Poisson regression. Horse-level, race-level, jockey-level and trainer-level factors associated with each adverse outcome during or post-race were identified using multivariable logistic regression.
ResultsThe incidence of MSI was 21.21 (20.84, 21.59), racehorse fatalities 0.55 (0.50, 0.61), jockey falls was 3.01 (2.80, 3.24), and jockey injuries 1.79 (1.63, 1.97) per 1000 flat race starts. There was a decrease in racehorse MSI and jockey falls over the study period but no change in racehorse fatality or jockey injury incidence. In multivariable analysis, longer race distances and higher caliber races were associated with horse (p < 0.01), but not jockey, incidents. Firmer turf surfaces were associated with greater risk of both horse incidents and jockey falls (p < 0.05). Racehorses that were of older age at their first start, and/or had prior race-day injuries had a greater risk of injury and fatality (p < 0.001, p < 0.01, respectively). The most prominent risk factor for jockey fall or injury was a racehorse incident, although overall contributing to a relatively small proportion; 8.6% (n = 42/489) of jockey falls and 15.3% (n = 24/147) of injuries. Jockeys with fewer career starts were at greater risk of falling, and those with a higher percentage of last place finishing positions were at greater risk of injury (p < 0.001).
DiscussionAs there were no conflicting risk factors identified between racehorse and jockey injury, policies aimed at reducing horse injury risk are also expected to benefit their riders.

引言
赛马日中赛马与骑师的不良事件往往相伴发生，但既往针对二者发病风险因素的研究均为独立开展。若要采用同一健康（One Health）策略降低风险，则需同时考量赛马与骑师两方面的因素。因此本研究旨在明确纯血马赛马中，同时影响赛马与骑师的共通或相斥不良结局的可干预风险因素。

方法
本研究将2004/05赛季至2018/19赛季的澳大利亚全国单一系统（Australian Single National System）平地赛马（flat racing）记录，与同期澳大利亚赛马事件数据库（Australian Racing Incident Database）的记录进行合并。采用泊松回归（Poisson regression）估算赛马肌肉骨骼损伤（musculoskeletal injury, MSI）、赛马死亡、骑师摔倒及骑师损伤这四类结局的发病率比（incidence rate ratios, IRR）及95%置信区间（confidence interval, CI）。采用多变量logistic回归（multivariable logistic regression），识别出赛中或赛后与各类不良结局相关的赛马层面、赛事层面、骑师层面及练马师层面的影响因素。

结果
每1000次平地赛马起步中，肌肉骨骼损伤发生率为21.21（95%CI：20.84, 21.59），赛马死亡率为0.55（95%CI：0.50, 0.61），骑师摔倒发生率为3.01（95%CI：2.80, 3.24），骑师损伤发生率为1.79（95%CI：1.63, 1.97）。研究期间，赛马肌肉骨骼损伤及骑师摔倒的发生率呈下降趋势，但赛马死亡率与骑师损伤发生率无明显变化。多变量分析显示，更长的赛事距离与更高规格的赛事与赛马不良事件相关（p<0.01），但与骑师不良事件无关联。更硬的草皮场地与赛马及骑师摔倒的更高风险相关（p<0.05）。首秀年龄较大、或既往在赛马日发生过损伤的赛马，其发生损伤及死亡的风险更高（分别为p<0.001、p<0.01）。引发骑师摔倒或损伤的最主要风险因素为赛马不良事件，尽管其整体贡献占比相对较小：仅8.6%（42/489）的骑师摔倒事件及15.3%（24/147）的骑师损伤事件由赛马不良事件导致。职业生涯起步次数较少的骑师摔倒风险更高，而完赛排名末位占比更高的骑师损伤风险更高（p<0.001）。

讨论
本研究未发现赛马与骑师损伤之间存在相斥的风险因素，因此旨在降低赛马损伤风险的防控策略，同时也有望使骑师获益。