By Linda Carroll
Between 2003 and 2011, rates of insomnia and obstructive sleep apnea diagnosis among U.S. Army soldiers increased by more than 600 percent, a new study finds.
Those who were deployed were twice as likely as non-deployed soldiers to be diagnosed with insomnia or sleep apnea, according to the study published online May 18 in the journal Sleep. Combat exposure independently increased the risk of insomnia, but not sleep apnea, the study authors report.
"This study found extraordinary increases in insomnia and (sleep apnea) in U.S. Army soldiers from 2003-2011 when the U.S. was intensively engaged in multiple conflicts," write Harris R. Lieberman, a researcher with the Military Nutrition Division at the U.S. Army Research Institute of Environmental Medicine in Natick, Massachusetts, and his colleagues.
"Given the substantial risk of insomnia and (sleep apnea) among deployed soldiers it is essential to determine the underlying mechanisms responsible," conclude the authors.
To get a sense of how deployment and combat might impact sleep, the researchers analyzed data from the entire population of soldiers who served in the U.S. Army from 1997 through 2011, a total of 1,357,150 men and women. The data came from the Total Army Injury and Health Outcomes Database.
Evaluating sleep in soldiers is important, the researchers write, because "insufficient and/or disordered sleep is associated with numerous long-term physical- and mental-health problems, including an increased risk of hypertension, diabetes, obesity, heart attack, stroke, depression, anxiety, substance abuse, PTSD, suicide and all-cause mortality."
Soldiers were deemed to have been deployed if they served outside the U.S. at any time during their military service. They were considered to have been exposed to combat if they were in a unit that had a combat-related death.
The researchers determined that clinical diagnoses of insomnia increased by 652 percent between 2003 and 2011, while sleep apnea diagnoses increased by 600 percent during the same period. The overall incidence of insomnia was 11.9 percent, while sleep apnea was 5.1 percent.
After accounting for factors such as gender, age, body mass, race/ethnicity, marital status, military rank and time in the service, the researchers determined that the risk of insomnia among deployed soldiers was more than twice that of those who were not deployed. And the risk was greatest, among soldiers who had been deployed for a total of 11-20 months. They were 2.27 times more likely to develop insomnia compared to those who were not deployed.
Deployed soldiers were also 2.14 times more likely than those not deployed to develop sleep apnea. And among deployed soldiers, those who saw combat were 1.2 times more likely to develop insomnia compared to those not exposed to combat. Combat exposure did not affect the likelihood of a soldier developing sleep apnea, the researchers found.
The authors note that certain medical conditions, including post-traumatic stress disorder and traumatic brain injury explained some of the association between deployment and insomnia, but not all of it. The increase in obstructive sleep apnea is "more difficult to explain," they write, but the causes of the sharp rise in both conditions should be studied further.
The new study is "fascinating" and "does a great job laying out the problem," said Matthew R. Ebben, an associate professor of psychology and clinical neurology at NewYork-Presbyterian and Weill Cornell Medicine in New York City. "The percentage increases in insomnia and sleep apnea over the time period are astounding."
The study, Ebben said, raises important questions: "Are these wars necessary and what are we doing to the people engaged in them on our behalf? What happens to these folks after they separate from the military?"
(c) Copyright Thomson Reuters 2019. Click For Restrictions - https://agency.reuters.com/en/copyright.html