235308 Incidence rates for mild traumatic brain injury among active duty US Military personnel between 1997 and 2007

Wednesday, November 2, 2011: 1:40 PM

Kenneth L. Cameron, PhD, MPH , John A. Feagin Jr. Sports Medicine Fellowship, Keller Army Hospital and The Johns Hopkins School of Public Health, West Point, NY
Stephen W. Marshall, PhD , Epidemiology, University of North Carolina, Chapel Hill, NC
Rodney X. Sturdivant, PhD , Department of Mathematical Sciences, United States Military Academy, West Point, NY
Andrew E. Lincoln, ScD, MS , Sports Medicine Research Center, MedStar Health Research Institute, Baltimore, MD
Mild traumatic brain injury (mTBI) has been described as the most common form of traumatic brain injury within military populations; however, few epidemiologic studies have examined incidence rates for mTBI in this population. The objective of this study was to examine trends in the incidence of mTBI among active duty US service members between 1997 and 2007. Specifically, we were interested in comparing incidence rates prior to the initiation of combat operations in Iraq and Afghanistan with subsequent years. A retrospective cohort study was conducted utilizing data extracted from the Defense Medical Surveillance System to identify all incident cases of mTBI within the study population. The primary outcome of interest was the incidence rate of mTBI per 1000 person-years. Multivariable Poisson regression was used to analyze the data. There were 98,012 mTBI cases and 14,956,955 person-years of follow-up, for an overall incidence rate of 6.55 (95%CI: 6.51, 6.59) per 1,000 person-years. There was a steady increase in the mTBI rate over time. The average change in the mTBI rate was 8.5% (95%CI: 8.2%, 8.8%) per year; however, the rate rose dramatically in the last two years of the study period. Overall, for 2006-2007 vs. 1997-2005, the rate ratio was 1.61 (95%CI: 1.58, 1.65). The greatest increase in the rate of mTBI was observed among those serving in Iraq, who experienced a 38.4% (95%CI: 35.4%, 41.1%) annual increase in new cases. The observed increase in the incidence of mTBI in this population has significant policy implications in terms of allocating appropriate healthcare resources.

Learning Areas:
Occupational health and safety
Public health or related public policy

Learning Objectives:
To evaluate changes in the incidence rate of mild traumatic brain injury over time in active duty military personnel prior to and following the initiation of combat operations in Iraq and Afghanistan.

Keywords: Mental Health, Traumatic Brain Injury

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I oversee injury epidemiology and injury prevention research within physically active military populations.
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.