In the U.S. military, women may be nearly 10 times more likely than men to experience sexual assault or harassment, a study of recent veterans suggests.

Researchers from the Department of Veterans Affairs (VA) surveyed more than 20,000 men and women who served during the conflicts in Iraq and Afghanistan. About 41 percent of women and 4 percent of men reported suffering some form of sexual harassment during their time in the military.

"Research among both civilians and those who have served in the military consistently find that rates of sexual assault and sexual harassment are higher among women than among men," lead study author Shannon Barth of the VA said by email.

"Despite the higher prevalence among women veterans, given the far greater number of men who have served in the military, there are significant numbers of both men and women who have experienced (sexual trauma)," Barth added.

One in five U.S. women and one in 71 men report being raped at some point in their lifetime, and among both genders, about one in 20 people experience other forms of sexual coercion and unwanted sexual advances, according to the Centers for Disease Control and Prevention.

Barth and colleagues assessed sexual trauma in the military as part of a health survey of recent veterans conducted between 2009 and 2011. Of 60,000 veterans invited to participate, 20,563 completed the questionnaire.

One survey item related to sexual trauma asked whether service members received uninvited or unwanted sexual attention such as touching, cornering, and pressure for sexual favors or inappropriate verbal remarks. Another item asked if anyone ever used force or the threat of force to initiate unwanted sex.

For both men and women, sexual harassment was far more common than assault, the study found.

Roughly 41 percent of women and 4 percent of men experienced sexual harassment, while about 9 percent of women and less than 1 percent of men said they were assaulted.

"It's not surprising that sexual trauma was so much more prevalent among women compared to men in this study, given that there are so many more men in the military than women and most are heterosexual," said Dr. Daniel Grossman, a researcher at Ibis Reproductive Health and the University of California, San Francisco.

Deployed men had lower risk of sexual trauma exposure than men who weren't deployed, but deployment status made no difference for women, the study also found. Veterans with combat exposure during deployment were more likely to experience sexual trauma.

Among women, Marines and Navy veterans had increased risk for military sexual trauma compared with Air Force veterans.

"In our research with recently deployed women, we heard that certain aspects of military culture, including widespread sexism and the fact that men often outrank women, contributed to an environment that was conducive to sexual trauma," Grossman, who wasn't involved in the current study, said by email.

One shortcoming of the study is that researchers relied only on the survey data, and not on follow-up clinical screenings to assess the extent of possible exposure to sexual trauma, the researchers acknowledge in the American Journal of Preventive Medicine.

Gender disparities also don't tell the entire story, noted Dr. Timothy Hoyt, director of an intensive outpatient behavioral health program at Madigan Army Medical Center in Tacoma, Washington.

Data from comprehensive health screenings done by the VA show that more than 100,000 service members have reported experiencing military sexual trauma, with cases evenly split between men and women, Hoyt, who wasn't involved in the study, said by email.

Since 2002, the VA has implemented universal screening for sexual trauma, the study authors note.

"All of these survivors need comprehensive care, regardless of gender," Hoyt said. If appropriate services are provided, he added, "the burden of this trauma on survivors can be significantly reduced."