WEDNESDAY, Dec. 1 (HealthDay News) -- Deployment to Iraq and Afghanistan significantly affects the quality and quantity of sleep of many U.S. military personnel, new research indicates.

Researchers conducted baseline sleep surveys of 41,225 members of the U.S. military before they deployed to these conflict zones. The findings are published in the Dec. 1 issue of the journal Sleep.

"This is the first large-scale, population-based study of sleep patterns in the military," Amber D. Seelig, data analyst for the Department of Deployment Health Research at the Naval Health Research Center in San Diego, said in a news release from the American Academy of Sleep Medicine. "The primary finding of this study is that deployment does appear to affect sleep patterns in our population."

Those who completed a follow-up survey during deployment were 28 percent more likely to say they had trouble falling asleep or staying asleep than those who had not yet been deployed -- 30.5 percent vs. 25 percent, the researchers found.

Those types of sleep problems were 21 percent more likely to be reported by those who completed another follow-up survey after deployment, compared to those who had not yet been deployed -- 27.1 percent vs. 25 percent.

The study also found that participants were more than two times more likely to report trouble sleeping if they had baseline symptoms of mental health conditions such as post-traumatic stress disorder or depression, or if they rated their general health as fair or poor.

Deployed and post-deployment military personnel reported sleeping significantly less than those who had not yet been deployed. But the association between deployment status and amount of sleep was no longer significant after the researchers adjusted for follow-up mental health conditions and combat exposure.

More information

The U.S. Department of Defense has more about deployment-related health concerns.