by Erin Walden
Edited by Jeanne Zheng
Cardiovascular health risks are often used as an argument against Hormone Replacement Therapy (HRT) for transgender people. Many articles and news sources have claimed that since HRT (and puberty blockers for transgender children) are not well studied and may lead to higher risks of cardiovascular events (such as myocardial infarction, stroke, and venous thromboembolism/pulmonary embolus), they should not be administered [1,2]. However, there are many misconceptions about the risks of HRT and, often, arguments against HRT ignore the benefits they have for the well-being and safety of trans people. On the other hand, these risks should not be ignored; rather, they should be seen as reasons why the health of transgender individuals should be researched more.
HRT is a way for transgender and gender-nonconforming individuals to develop secondary sex characteristics that more closely align with their gender identity. Steroid hormones like testosterone and estrogen can change secondary sex characteristics (body hair, facial structure, fat distribution, vocal pitch, etc.) by acting on steroid receptor proteins within cells to control gene expression. This will then alter protein expression, leading to changes in secondary sex characteristics.
A review paper from August 2018, “Cardiovascular health in transgender people,” by Michael S. Irwig, professor of Medicine at The George Washington University School of Medicine & Health Sciences, looked at recent research on cardiovascular health of transgender people in an attempt to address what has been studied and what has not .
Dr. Irwig lays out some limitations to studying cardiovascular outcomes and events in trans individuals undergoing hormone therapy. These limitations include the young age at which many trans individuals start hormone therapy (when their risk for heart health issues is relatively low), lack of long-term follow-up, relatively small numbers of cardiovascular events within populations, and low numbers of study participants. Hormones used during HRT (especially estrogens) vary by country so it is difficult to conduct large, world-wide studies. Hormone administration also varies from person to person with oral, transdermal (application through the skin), sublingual (under the tongue), or intramuscular methods being the most popular. Testosterone is not taken orally because it has damaging effects on liver health.
Dr. Irwig’s review found that “in an age-adjusted comparison with cisgender people, trans people appear to have an increased risk for myocardial infarction (heart attack) and death due to cardiovascular disease.” It is not yet clear whether HRT affects the risk of stroke. However, the rates of myocardial infarction and stroke were higher in trans women than trans men. There is strong evidence that estrogen therapy for trans women increases the risk of venous thromboembolism (a blood clot that forms most often in the deep veins of the leg, groin or arm and travels in the circulation, lodging in the lungs) over five-fold.
In trans men, testosterone therapy consistently increases systolic blood pressure (maximum pressure during one heartbeat) and may increase diastolic blood pressure (minimum pressure between two heartbeats). In terms of lipids, hormone therapy may increase triglycerides for trans people on any kind of HRT. Testosterone therapy also may increase LDL-cholesterol (“bad” cholesterol) and decrease HDL-cholesterol (“good” cholesterol).
A study that compared the health status of trans (n = 691) and cisgender (n = 150,765) adults in the United States showed that the adjusted odds ratio for myocardial infarction was increased at 1.82. This study did show an increased risk for heart attack in transgender individuals; however, of the 691 trans people in this study, 489 were white, and health status was self reported, which may have affected the results. Gender was also not taken into account.
Aside from this, there is convincing evidence that estrogen therapy increases the risk for venous thromboembolism (VTE) in both cisgender and transgender women. Many centers providing trans-specific care do not prescribe or recommend ethinyl estradiol (EE - a synthetic derivative of estradiol) or conjugated equine estrogens (CEE), which are both taken orally, due to concerns about thrombosis risk. However, a lot of existing data on thrombosis risk in trans women taking estrogens come from older studies that were conducted at a time when estrogens like CEE and EE were widely used. This shows that concerns raised by these data should be treated with a degree of caution since these types of estrogen are not commonly used anymore.
In looking at these studies, Dr. Irwig notes that, “given that hormone therapy is an integral part of the management of trans patients, more research is needed on the effects and risks of hormone therapy in older populations and on the safest forms of estrogen therapy in terms of type, dosing and route of delivery” . It is true that these therapies are a core component of trans healthcare, and they are necessary for the well-being of transgender people.
Access to healthcare (including HRT) is important for trans people. Transgender suicide rates are reported to be over nine times higher than the average population. According to Crisis Text Line, a free, 24/7 support service for those in crisis, texters identifying as trans are 50% more likely to mention suicide in their conversations with the hotline. Among young people, the Trevor project reports that 7% of cisgender youth compared to 35% of transgender youth attempted suicide in the past year . Rates of suicidal ideation are also increased in adults, with 48% of all transgender adults reporting that they have considered suicide in the past 12 months, compared to 4% of the overall US population .
However, supporting trans people in their transition and accepting their gender identity has a positive impact on mental health. In a 2014 British study, gender transition “was shown to drastically reduce instances of suicidal ideation and attempts.” The study reported that “67 percent of respondents thought about suicide more before they transitioned and only 3 percent thought about suicide more post-transition” . Those with supportive families were less likely to report currently experiencing serious psychological distress (31%) in contrast to those with unsupportive families (50%) . Those who had a professional (such as psychologists, counselors, and religious advisors) try to stop them from being transgender were far more likely to be currently experiencing serious psychological distress (47%) than those who did not have the experience (34%) . Clearly, acceptance (including access to gender-affirming healthcare) is an important step to help trans people live better lives.
Unfortunately, access to HRT treatment is limited, with the most vulnerable transgender people experiencing the greatest gaps in care. Physicians should honor transgender patients’ rights to express their gender identity by providing desired medical interventions in line with the established standard of care. Gatekeeping can exacerbate disparities in access to safe and reliable hormone treatment. Particularly among transgender youth, being perceived as the gender they identify as can be a matter of safety and survival.
Ultimately, the point is not to deny transgender people the gender-affirming care they need and that helps them to thrive, but to put more effort and funding into studying these treatments, so that they can be better equipped and prepared to navigate their futures. Cardiovascular risks for transgender people should be studied in greater detail and cardiovascular health should be monitored more regularly; at the same time, these risks should not be used to deny trans people their right to care.