A new study identifies distinct profiles for U.S. army officers and enlisted soldiers at highest risk of attempting suicide.

Researchers say the results particularly highlight the importance of focusing prevention efforts on young enlisted men and women in their first tour of duty.

"Looking at suicide attempts is one part of the story of how does one get from suicide ideation to suicide plans to suicide attempt to completed suicide," said Dr. Robert Ursano of the Uniformed Services University of the Health Sciences in Bethesda, Maryland. "The mental health and behavioral health issues that contribute to that risk is another."

For the new study, the researchers analyzed data on suicide attempts among U.S. Army soldiers from 2004 through 2009, during the wars in Iraq and Afghanistan. About four of every 1,000 active-duty U.S. Army soldiers made a suicide attempt during that time.

And in those years, the Army experienced the longest sustained increase in suicide rates relative to other military branches, such as the Marines, Navy and Air Force, the researchers note in JAMA Psychiatry.

To understand what risk factors might predict suicide attempts, they had data on more than 975,000 people on active duty. About 17 percent of those were officers. There were 9,791 suicide attempts among those soldiers during the study period.

That worked out to a rate of about 377 suicide attempts per 100,000 enlisted soldiers each year. For officers, the rate was about 28 attempts per 100,000 each year.

It's difficult to compare these rates to average Americans, because people in the Army differ from the general U.S. population in so many ways, researchers write. Also, not all suicide attempts in the general U.S. population may be reported.

Among enlisted soldiers, certain factors increased the risk of a suicide attempt.

"The highest risk is certainly in the first year of service," Ursano told Reuters Health. "In fact, likely in the first three months of service."

“We also found that suicide attempts are highest in those who never deployed or who were previously deployed," he said.

Other risk factors included having a mental health diagnosis in the prior month, being female, being age 29 or younger, having entered the army after age 25, being white or Asian, being single and not having completed high school.

It's likely that suicide attempts are less common among officers because they tend to differ from enlisted soldiers in ways relevant to risk, Ursano said. For example, officers tend to be older, married and have higher levels of education.

Still, being female, having a mental health diagnosis in the prior month and having entered the service after age 25 were also risk factors for officers. Being over age 40 was another predictor of risk.

The study cannot say why these factors contribute to suicide risk, and the next step is to look at more data from the study, Ursano said.

"There is a series of other drill downs that have to do with looking at details," he said, such as looking at when during deployment someone is most at risk.