Transgender individuals may be at higher risk of heart attack and death due to cardiovascular disease, a new review from George Washington University (GWU) stated. Sex hormones, which are administered as a part of transgender hormone therapy, may be tied to the increased risk.

The review titled "Cardiovascular Health in Transgender People" was published in Reviews in Endocrine and Metabolic Disorders on Aug. 3.

Numerous studies that followed trans men and trans women, on hormone therapy, were examined by author Dr. Michael S. Irwig, associate professor of medicine at the GWU School of Medicine and Health Sciences

"Many transgender patients take either testosterone or estrogen for masculinization or feminization," he said. "Some studies have suggested that transgender people have an increased risk for heart attack and death due to cardiovascular disease."

For instance, one recent study published in the Annals of Internal Medicine found trans women may have a higher risk of suffering from blood clots and stroke. Venous thromboembolism, a type of blood clot, was linked to a five-fold higher risk.

The new review also compared estrogen therapy and testosterone therapy. A higher incidence of heart attack (or myocardial infarction) and stroke was found among trans women when compared to trans men. This suggested a link between estrogen therapy and an increased risk for cardiovascular events.

“In clinical studies that followed transgender patients, rates for myocardial infarction were consistently higher in transgender women on estrogen therapy than in transgender men on testosterone,” Dr. Irwig said.

“The relationship between endogenous sex hormones and heart disease is complex. In cisgender women, estrogen may have a protective effect.”

Compared to their counterparts, data and figures regarding trans men on testosterone therapy were relatively limited. Dr. Irwig, however, noted this therapy could potentially increase systolic blood pressure as well as diastolic blood pressure in trans men.

"For lipids, hormone therapy may increase triglycerides in both trans women and men. In trans men, testosterone therapy also may increase LDL-cholesterol and decrease HDL-cholesterol," he wrote in the paper.

Yet, these health risks are not high enough to avoid hormone therapy, which is a crucial step when considering the psychosocial benefits it provides to trans individuals.

Dr. Richard Greene from the New York University School of Medicine previously explained hormone therapy is "lifesaving" and denying it can increase the risk of depression and suicidal ideation in some patients.

Such findings should not be used to deny hormone therapy but rather, to explain the risks carefully to patients and encourage more research in this field.

"There need to be more studies focused on trans-identified people so we can learn risks specific to them and provide better care," he said.