PHILADELPHIA – About 20% of soldiers who return from deployment in Iraq or Afghanistan develop chronic daily headache after blast exposure or concussion, according to data from a preliminary study.
Dr. Brett Theeler and his colleagues found that newly returned soldiers who had been exposed to blast explosions within 60 feet of them and those who suffered concussion injuries with or without loss of consciousness were likely to develop headache within 1 week of their experience.
After returning to the United States, soldiers who screened positive for a concussion, blast exposure, or traumatic brain injury completed a 13-question headache survey. Chronic daily headache was defined as headaches occurring at least 15 days per month.
In the cohort of 5,270 soldiers who completed the survey, 957 screened positive for any of the risk factors: of those, 196 were classified as having chronic daily headache (CDH) and 761 did not have CDH.
The mean headache frequency was 23 days per month for the CDH group and 5 days per month for those in the non-CDH group. Headaches were migraine type in 66% of soldiers with CDH and 48% of soldiers without CDH. Most of those with CDH (55%) developed headaches within 1 week of having had a concussion, compared with 33% of those without CDH, Dr. Theeler reported at the International Headache Congress.
Soldiers with CDH were also exposed to more blasts on average than those without CDH (6 vs. 5, respectively). Although the average difference in blast exposure was small, there was a very wide range of exposures among those with CDH, “leading us to consider that there may be a dose-response relationship between blast exposure and headache,” said Dr. Theeler, a neurologist and U.S. Army captain at the William Beaumont Army Medical Center in El Paso, Tex.
More than twice as many solders with CDH also screened positive for posttraumatic stress disorder, (40% vs. 17%), he said.
Dr. Theeler said his data were preliminary and he had not yet performed any regression analyses to determine hazard ratios.
However, he published a recent article suggesting that a history of mild head trauma consistent with blast exposure was present in 50% of soldiers who screened positive for headache upon returning from Iraq or Afghanistan (Headache 2009;49:529–34).
The International Headache Society and the American Headache Society sponsored the congress.