title: Risk factors for closed-head injuries during military airborne operations.
abstract: BACKGROUND
  One of the more serious adverse outcomes of military airborne operations is closed-head injuries. This investigation examined risk factors for closed-head injuries in an Army airborne infantry unit.
  
  
  METHODS
  Closed-head injuries were defined as energy exchanges in which the head contacted the ground or an object and the soldier sought medical care for external trauma, headache, loss of consciousness, or altered mental state. Injury data were obtained by investigators in the drop zone and diagnoses were confirmed by a physician. Operational data on potential injury risk factors were obtained from routine reports published by the infantry unit. Weather data were obtained using a pocket weather tracker.
  
  
  RESULTS
  There were 96,132 jumps resulting in 310 closed-head injuries for a crude incidence of 3.22/1000 jumps. In 98% of known cases the injury was associated with parachute landings. Multivariate logistic regression revealed that independent risk factors for closed-head injuries included night jumps, combat loads, higher wind speeds, higher temperatures, enlisted rank, and entanglements.
  
  
  CONCLUSIONS
  This study identifies the current incidence and extrinsic risk factors for closed-head injuries during military airborne operations. Although it is necessary to conduct airborne training under realistic conditions, trainers and commanders should be aware of these risks and plan airborne operations accordingly.
authors.affiliation: U.S. Army Institute of Public Health, Aberdeen Proving Ground, MD, USA. joseph.knapik@us.army.mil
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Knapik
authors.affiliation: U.S. Army Institute of Public Health, Aberdeen Proving Ground, MD, USA.
authors.forename: Ryan
authors.initials: R
authors.lastname: Steelman
authors.affiliation: U.S. Army Institute of Public Health, Aberdeen Proving Ground, MD, USA.
authors.forename: Kyle
authors.initials: K
authors.lastname: Hoedebecke
authors.affiliation: U.S. Army Institute of Public Health, Aberdeen Proving Ground, MD, USA.
authors.forename: Kevin L
authors.initials: KL
authors.lastname: Klug
authors.affiliation: U.S. Army Institute of Public Health, Aberdeen Proving Ground, MD, USA.
authors.forename: Shawn
authors.initials: S
authors.lastname: Rankin
authors.affiliation: U.S. Army Institute of Public Health, Aberdeen Proving Ground, MD, USA.
authors.forename: Stanley
authors.initials: S
authors.lastname: Proctor
authors.affiliation: U.S. Army Institute of Public Health, Aberdeen Proving Ground, MD, USA.
authors.forename: Bria
authors.initials: B
authors.lastname: Graham
authors.affiliation: U.S. Army Institute of Public Health, Aberdeen Proving Ground, MD, USA.
authors.forename: Bruce H
authors.initials: BH
authors.lastname: Jones
mesh_terms: D001359:Aviation; D004868:Equipment Failure; D016489:Head Injuries, Closed / Q000150:complications / Q000453:epidemiology*; D006261:Headache / Q000209:etiology; D006801:Humans; D015994:Incidence; D001523:Mental Disorders / Q000209:etiology; D008889:Military Personnel; D012307:Risk Factors; D013696:Temperature; D013997:Time Factors; D014474:Unconsciousness / Q000209:etiology; D014481:United States / Q000453:epidemiology; D016474:Weight-Bearing; D014919:Wind