The more traumatic stress a person is exposed to over the course of a lifetime, the greater the chances the person has elevated levels of inflammatory markers in his or her bloodstream, say researchers at the San Francisco VA Medical Center (SFVAMC) and the University of California, San Francisco.
The study is the first to examine the association between cumulative traumatic stress and inflammation.
For the study, researchers looked at 979 patients (ages 45 to 90) with stable heart disease and analyzed their exposures to 18 different types of traumatic events, all of which involved either experiencing or watching a direct threat to life or physical integrity.
Next, researchers measured several clinical markers of inflammation that circulate in the bloodstream, and found a direct correlation between lifetime stress exposure and inflammation levels.
“This may be significant for people with cardiovascular disease, because we know that heart disease patients with higher levels of inflammation tend to have worse outcomes,” said lead author Aoife O’Donovan, a fellow in psychiatry at UCSF.
Five years later, researchers measured the surviving patients’ inflammation markers again, and discovered that the participants who had originally reported the highest levels of trauma still had the highest levels of inflammation.
“Even though we lost some study participants because they died, we still observed the same relationship in those who remained,” O’Donovan said. “This suggests that it wasn’t just the people who were the most sick at the outset who were driving this effect.”
Senior researcher Dr. Beth Cohen, a physician at SFVAMC, noted that the effect was consistent even after the researchers adjusted for psychiatric diagnoses including post-traumatic stress disorder (PTSD), anxiety and depression.
“Not everyone who is exposed to trauma develops PTSD,” said Cohen, who also is an assistant professor of medicine at UCSF. “This study emphasizes that traumatic stress can have a long-term negative impact on your health even if you don’t go on to develop PTSD. It also tells us that, as clinicians, we need to think about not just which diagnostic box someone might fit into, but what their lifetime trauma exposure has been.”
“We know that in the aftermath of traumatic stress, people become more sensitive to threats,” she continued. “This is actually pro-survival, because if you’re in a dangerous environment, that alertness can help you avoid future harm.”
However, she explained, people with heightened threat sensitivity may also have stronger inflammatory responses. “What we think is happening is that people with a history of multiple traumatic stress exposures have increased inflammatory response more often and for longer periods, and so inflammation becomes chronically high,” she said.
Cohen added that “this is a study of older people, and the cumulative effects that decades of traumatic experiences have on their bodies. If we could intervene with young people…using techniques that we know help fight stress, such as exercise, yoga and other integrative health techniques, it would be interesting to know if we might be able to prevent some of this.”
The study was published in Brain, Behavior and Immunity.
Source: University of California