American life expectancy declined for a second year in a row, to 78.6 years in 2016, but scientists say this figure is grimmer for people who served in the military.

New research suggests that veterans born in 1958 or later, who sustained service-related illnesses or injuries, are dying at the average age of 43 from causes mostly due to suicide, assault or accidents. The findings did not include fatalities in the field of combat.

The study was led by researchers from the U.S. Department of Veterans Affairs (VA), University of Washington School of Public Health and Stanford University School of Medicine. The findings were published March 26 in the journal Military Medicine.

“While the numbers of deaths in veterans born after 1958 were small, the findings of premature death and high proportions of intentional or accidental death, for both women and men, are very troubling,” said lead author Charles Maynard, a core investigator at the VA Puget Sound Health Care System and research professor emeritus in health services at the UW School of Public Health. “These findings further emphasize the importance of the vast array of benefits and health care services provided by the VA.”

Twenty-eight percent of deceased veterans in the study had mental health conditions connected to their service, including post-traumatic stress disorder (PTSD), anxiety and/or major depression. Among veterans with PTSD or major depression, 6.5 percent of deaths were intentional or accidental. This is twice more than deaths due to similar causes among veterans without these conditions.

Notable for those with PTSD or major depression were the many deaths due alcoholic liver disease. Also, for both women and men with major depression, significant numbers of deaths were due to suicide.

Scientists studied 605,344 veterans with service-related conditions who died between 2004 and 2014 and divided them into three age groups corresponding to periods of service. Sixty-two percent were in the oldest age group (born pre-1939), corresponding to the Korean War and World War II; 34 percent were in the middle group (born 1939 to 1958), aligning with the Vietnam War; and 4 percent were in the youngest group, which served in the post-Vietnam era, Gulf War and the conflicts in Iraq and Afghanistan.

Researchers called veterans of the Korean War and World War II “healthy survivors.” Nearly half of the deaths in the oldest group were due to cancer or cardiovascular conditions, and less than 2 percent were due to external causes, such as suicide, assault and accidents. “Their overall disability rating was lower, they had a higher proportion of officers, and a higher proportion of deaths due to cardiovascular or cerebrovascular disease,” the researchers wrote.

For veterans of the Vietnam era, more than 54,000 had diabetes and/or ischemic heart disease, conditions associated with Agent Orange exposure. During the war, the U.S. military sprayed more than 20 million gallons of Agent Orange and other herbicides over parts of southern Vietnam and along the borders of neighboring Laos and Cambodia.

In the youngest group, cardiovascular disease and cancer were responsible for about a third of deaths, and suicide, assault and accidents were responsible for nearly 33 percent.

Co-authors are Ranak Trivedi, Karin Nelson and Stephan Fihn. Trivedi is a clinical psychologist and health services researcher at the Palo Alto VA Health Care System, and assistant professor of psychiatry and behavioral sciences at Stanford University. Nelson is a physician and health services researcher at the Puget Sound VA, and an adjunct associate professor of health services and associate professor of medicine at the UW. Fihn is a physician at the Puget Sound VA and a professor of health services and medicine at the UW.

The VA’s Office of Clinical Systems Development and Evaluation supported this study. The views expressed in the study are those of the authors and do not necessarily reflect the position or policy of the VA or the United States government.