May 24, 2015: People visit the Vietnam Veterans Memorial wall on Memorial Day weekend in Washington. (REUTERS)
Post-traumatic stress disorder (PTSD) may be more common than previously thought among female veterans of the Vietnam War era, suggests a new study.
Up to one in five women who served in the U.S. military during the 1960s and 1970s experienced PTSD at some point in their lives and many are still living with the condition, researchers found.
"We never expected the PTSD prevalence to be so high in those women who served in (Vietnam) - especially 40 years after the war ended," said lead author Kathryn Magruder, of the Johnson Veterans Affairs Medical Center in Charleston, South Carolina.
Magruder and her colleagues write in JAMA Psychiatry that PTSD was the signature illness for men who served in Vietnam, but less is known about its effect on women's health.
They add that between 5,000 and 7,500 American women served with the U.S. military in Vietnam, at least 2,000 served on bases in the region and 250,000 were stationed in the U.S.
PTSD develops after terrifying ordeals involving physical harm or the threat of physical harm, according to the U.S. National Institutes of Health. Symptoms include re-experiencing events, avoiding certain situations and being tense and easily startled.
For the new study, the researchers used data collected from 1,956 women who served in Vietnam, 657 who served near Vietnam and 1,606 who served in the U.S. between 1965 and 1973.
The women's average age was 22 when they enlisted in 1964 and 1965, and near 70 when researchers surveyed them by mail or phone in 2011 and 2012.
Most of the participants who served in Vietnam and the U.S. were members of the Army, and most of those who served in the region were in the Air Force. More than half of the women in all categories were nurses during the war.
About 20 percent of the women who served in Vietnam met the criteria for PTSD at some point in their lives, compared to about 12 percent of those who served near Vietnam and about 14 percent who served in the U.S.
About 16 percent of women who served in Vietnam still met the criteria for PTSD at the time of the surveys, compared to about 8 percent of women who had served near Vietnam and about 9 percent who had served in the U.S.
The results differ from a previous 15 percent lifetime estimate of PTSD for female Vietnam-era veterans, the study authors point out, but differences in the tools used to evaluate the participants explain that gap.
The researchers also found that few cases of PTSD started before the women joined the military.
For all the types of traumatic wartime experiences the researchers asked about, like danger, death and environment-related stress, women who served in Vietnam reported the highest rates of exposure.
"It was these experiences - especially sexual harassment and performance pressures - that explained their higher levels of PTSD," Magruder told Reuters Health by email.
Sexual harassment, she said, should not be an inevitable war zone experience.
"We need to work hard to change military culture so that . . . military sexual harassment is not a PTSD risk factor for future generations."
There is another message in the study for doctors, she added. They should not forget to ask all women if they've been in the armed services and ask about their military experiences.
"They should be vigilant to symptoms of PTSD - even in aging women veterans - and encourage them to seek appropriate treatment if warranted," Magruder said.