New study finds no increased risk of heart and brain infarctions for transgender women

Contrary to previous research, transgender women who use the hormone oestradiol for their transition do not have an increased risk of heart attack and stroke compared to men in the general Dutch population. This is shown by a large-scale study from Amsterdam UMC, with data from more than 4,000 transgender individuals, published today in the European Heart Journal. The researchers suspect that the hormone treatment transgender women receive has a protective effect on the heart and blood vessels.

In transgender people, the sex assigned at birth does not match their experienced gender identity. Many of them therefore choose hormone treatment to develop physical characteristics that better align with their gender identity, such as breast growth or a lower voice. For transgender women, hormone treatment consists of the female hormone estradiol, often in combination with a testosterone blocker. For transgender men, it is the male hormone testosterone.

In transgender women, but also in women from the general population, estradiol appears to have a protective effect on the heart and blood vessels.

Earlier studies suggested a higher risk of heart attack and stroke for transgender women compared to people with the same birth sex, that is, men from the general population. We did not really understand this. Now, however, we find no increased risk of heart and brain infarctions for transgender women who use estradiol. These findings fit well with what we know about the presumed protective effects of estradiol on the heart and blood vessels. With this research, we have solved a paradox that has occupied us for a long time."

Martin den Heijer, professor of endocrinology, Amsterdam UMC

Previous studies on cardiovascular disease in transgender people were often small-scale and limited to short periods, which could explain the earlier contradictory research results. The researchers from Amsterdam UMC now analyzed data from more than 4,000 transgender individuals and compared this with data from Statistics Netherlands (CBS), which collects health data from the entire Dutch population. This makes it the largest study in this field to date.

Factors other than hormone use

Transgender men who use testosterone do have an increased risk of heart attack and stroke, compared to women from the general Dutch population. That is in line with previous studies. Mees van Zijverden, physician-researcher at Amsterdam UMC: "We know that testosterone use in transgender men can lead to slightly higher blood pressure and poorer cholesterol levels, which increases the risk of cardiovascular disease."

Nevertheless, these changes do not seem to be sufficient to explain the increase in risk. The researchers think that factors other than hormone use probably also play a role in the increased risk of cardiovascular disease in transgender men. "That is why we also looked at lifestyle and socio-economic factors in the study, such as education level, employment history and income. However, these factors were found to explain only a small part of the increased risk," says van Zijverden. More research is therefore needed into the exact causes of the increased risk in transgender men.

"If we have a better understanding of the factors that play a role, we can improve care for transgender people. The number of transgender people who use hormones is growing worldwide. This group is also getting older. This means that cardiovascular disease will become an increasingly important point of attention in the future," adds van Zijverden

For now, according to the researchers, it is important that transgender men and healthcare providers are aware of the increased risk of cardiovascular disease, so that attention is paid to maintaining a healthy lifestyle. It is also important that risk factors, such as high blood pressure or cholesterol, are monitored in transgender men. Of course, this remains important for transgender women as well.