Risk Factors For Time-loss Injuries In The United States Army Ordnance School Advanced Individual Training

Only one previous study (Henderson, Milit Med 165, 9:647, 2000) has examined risk factors in Advanced Individual Training (AIT) where soldiers go to receive their specialty training after Basic Combat Training (BCT). PURPOSE: This study examined risk factors for time loss injuries during United States Army Ordnance School AIT. METHODS: Participants were soldiers (n= 3759 men, n=498 women) attending Ordnance AIT. Injuries were obtained from an injury surveillance system in the medical clinic serving the AIT soldiers. Potential injury risk factors included entry-level fitness, demographics, and lifestyle variables. Fitness variables included maximal effort performance on push-ups, sit-ups and a 2-mile run. A health questionnaire provided data on age, race, rank, previous injury, previous illness, and tobacco use. Fitness variables were converted to four quartiles (Q) based on the distribution of scores where Q1=high performance and Q4=low performance. AIT entry and completion dates were obtained from an Army Personnel system. Backward stepping Cox regression examined associations between time loss injury and potential injury risk factors. Multivariate hazard ratios (HR) and 95% confidence intervals (95%CI) were calculated. RESULTS: For men, higher risk of injury was independently associated with race (HR (Native American/Caucasian) = 1.3, 95%CI = 1.1-1.7), previous injury (HR (yes/no) = 2.1, 95%CI = 1.8-2.6), frequent cigarette use before entering the Army (HR (yes/no) = 1.5, 95%CI = 1.3-1.7), lower push-up performance (HR (Q4/Q1) = 1.3, 95%CI = 1.1-1.5), lower sit-up performance (HR (Q3/Q1) = 1.3, 95%CI = 1.1-1.5) and slower 2-mile run time (HR (Q4/Q1)= 1.3, 95%CI = 1.1-1.6). For women, higher risk of injury was independently associated with race (HR (Asian/Caucasian) = 0.6, 95%CI = 0.5-0.9), previous injury (HR (yes/no) = 1.7, 95%CI = 1.2-2.3), and slower 2-mile run time (HR (Q4/Q1) = 2.0, 95%CI = 1.4-2.9). CONCLUSIONS: Modifiable risk factors for time loss injury in Ordnance AIT include prior BCT injury, tobacco use, and aerobic fitness. Enhanced injury prevention in BCT, smoking cessation and fitness training prior to entry are potential strategies to reduce injuries.