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Member Research & Reports

Member Research & Reports

Harvard and Columbia: Trauma and PTSD Symptoms Linked to Increased Risk of Blood Clots in Women

Women who have experienced trauma and symptoms of post-traumatic stress disorder (PTSD) may be at greater risk for developing a potentially fatal blood clot disorder called venous thromboembolism (VTE) than women who have not experienced trauma, according to a study led by researchers from Harvard T.H. Chan School of Public Health and Columbia University Medical Center. It is the first study to examine whether trauma exposure and PTSD symptoms are associated with VTE in women.

The study was published online May 12 in the Journal of the American Heart Association.

PTSD is a condition that develops in some people who have lived through a threatening experience such as a sexual assault, military combat, or a natural disaster. Symptoms can include nightmares, flashbacks to the triggering event, avoiding thinking about the event, and being constantly on guard. PTSD is twice as common in women as in men. An estimated 1 in 10 women will develop the condition in their lifetime.

“Primary care providers serving populations at high risk for PTSD should screen for VTE risk and monitor the health of those with PTSD,” said senior author Dr. Karestan Koenen, professor of psychiatric epidemiology at Harvard Chan. “Our findings add to the growing evidence that the experience of extremely stressful, traumatic events and related post-traumatic stress reactions may inflict cardiovascular damage, in addition to the significant mental health burden of the condition.”

VTE — including deep vein thrombosis (when a clot forms in a deep vein, usually in the leg) and pulmonary embolism (when a clot breaks loose and travels to the lungs) — is the third most common cause of cardiovascular death in the U.S. and a leading cause of death among women who are pregnant or have recently given birth. Women who use birth control pills or menopausal hormone therapy are also predisposed to VTE. Psychological factors like depression have previously been linked to increased risk of VTE.

The researchers looked for associations between PTSD symptoms and VTE events in nearly 50,000 women participating in the Nurses’ Health Study 2 over a 22-year period. Nearly 35,000 women reported that they had experienced a traumatic event at the beginning of the study period. Of these, about 9,000 women reported one or more PTSD symptoms. There were 960 self-reported VTE events over the study period.

Compared with no trauma exposure, trauma alone and trauma with PTSD symptoms were each associated with heightened risk of VTE, with the greatest elevation in risk among those with the most PTSD symptoms. For example, the risk of VTE was nearly two-fold higher among women with trauma and six to seven PTSD symptoms than in women with no trauma exposure, after adjusting for other risk factors such as body mass index, smoking, and menopausal status. Women reporting trauma exposure without PTSD symptoms had a 60 percent higher chance of developing VTE compared to women with no trauma exposure.

“We believe that our findings have particular relevance for women’s health. VTE is a significant health concern for women, especially women of childbearing age. Our study suggests that PTSD may be an important vulnerability factor for developing VTE in women,” said first author Dr. Jennifer Sumner, an instructor in medical sciences at Columbia and visiting scientist at Harvard Chan. “Additional research should be aimed at identifying the mechanisms by which trauma and PTSD lead to cardiovascular damage, and finding ways to halt or reverse this process.”

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