United States soldiers exposed to blasts while deployed in Iraq and Afghanistan face an increased risk for adverse health outcomes throughout their lifetimes, often not associated with immediate injuries, warns a report from the Institute of Medicine (IOM), released today.
These include posttraumatic stress disorder (PTSD) and, in certain cases, traumatic brain injury (TBI), growth hormone deficiency, and persistent postconcussive symptoms including headaches.
"Acute physical and psychological health outcomes in people who survive blast explosions can be devastating, but the long-term consequences are less clear, particularly for individuals who show no external signs of injury from exposure to blast waves or may not even be aware that they were exposed," Stephen L. Hauser, MD, chair of the Department of Neurology, University of California, San Francisco, said in an IOM statement.
Dr. Hauser chaired the committee that wrote the report, "Gulf War and Health, Volume 9: Long-Term Effects of Blast Exposures."
The report is the ninth volume of a congressionally mandated series on the health effects related to military service during wartime, which began in 1998 in response to the growing concerns of ill Gulf War veterans. With this latest report, the committee focused on health consequences experienced at least 6 months after a blast.
Unique Patterns of Injury
Since the United States began combat operations in Afghanistan in October 2001, and then in Iraq in March 2003, more than 6700 US soldiers have been killed and more than 50,500 wounded, with blasts accounting for an estimated 75% of all US military casualties, the report notes.
The wars in Afghanistan and Iraq differ from previous wars in which the United States has been involved because of the enemy's use of improvised explosive devices (IEDs).
"The use of IEDs has led to an injury landscape different from that in prior US wars. The signature injury of the Afghanistan and Iraq wars is blast injury. Numerous US soldiers have returned home with devastating blast injuries and they continue to experience many challenges in readjusting to civilian life," the report notes.
Several major patterns of injury resulting from IED explosions have emerged, from injuries caused by the blast wave itself to those caused by fragments of debris propelled by the explosion to subsequent illnesses from, for example, chemical substances released by a bomb.
"When the energy from the blast shock wave is absorbed in the human body, it disrupts the natural state of the body at a basic or even molecular level, which can cause tissue damage not immediately apparent after the blast," the IOM statement notes.
Weighing the Evidence
The committee found sufficient evidence of a causal relationship between penetrating eye injuries resulting from exposure to blast and permanent blindness and visual impairment, as well as long-term effects on the genitourinary system, such as hypogonadism, infertility, voiding dysfunction, and erectile dysfunction associated with severe injury.
Sufficient evidence also exists for an association between blasts and the development of PTSD. "The association may be related to direct experience of blast or to indirect exposure, such as witnessing the aftermath of a blast or being part of a community affected by a blast," the committee notes in the report.
Sufficient evidence also exists for endocrine dysfunction in cases of serve or moderate blast-related TBI and for postconcussive symptoms and persistent headache in mild blast TBI.
The committee found some evidence that exposure to blasts can cause long-term hearing damage and muscle or bone impairment. However, they say the data on these outcomes are not strong enough to draw a direct cause-and-effect relationship.
"[T]here is inadequate/insufficient evidence to assess the direct contribution of blast to depression, substance-use disorders, and chronic pain; however, the association of PTSD with these disorders is well established," the committee says.
Recommendations for "Urgent Research"
The committee made several recommendations for research on how to prevent and better diagnose blast injuries and how to treat, rehabilitate, and support victims of battlefield trauma in the immediate aftermath and in the long term.
"As the committee evaluated the available evidence on health effects of exposure to blast, it identified a number of gaps in the evidence base. Filling the data gaps is important for advancing the understanding of how blast affects humans in the short term and the long term," the report states. "A fundamental feature of exposure to blast is that it can result in complex, multisystem injuries. Attention to those complexities has often been lacking in research studies. It is important that research on blast emphasize multisystem injury patterns and seek to understand the clinical importance of cross-system interactions."
The committee notes that most studies to date have used self-reported exposure data, rather than objective measures. Therefore, as part of their recommendations, they call on the Department of Defense to develop and deploy data collection technologies that quantitatively measure components of blast and characteristics of the exposure environment in real-time and also to link these data with self-reported exposure histories and demographic, medical, and operational information.
Similar to this, the committee also recommends that the US Department of Veterans Affairs create a registry of blast-exposed (not only blast-injured) service members to serve as a foundation for long-term studies.
The Institute of Medicine report was supported by the National Academy of Sciences and the US Department of Veterans Affairs.
"Gulf War and Health, Volume 9: Long-Term Effects of Blast Exposures." National Academies Press. Overview
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Cite this: Soldiers Face Long-Term, Not Just Acute, Harm From Blasts: IOM Report - Medscape - Feb 13, 2014.