Research gaps in medical treatment of transgender/nonbinary people.

With the growing number of transgender and gender-nonbinary individuals who are becoming visible, it is clear that there is a need to develop a rigorous evidence base to inform care practice. Transgender health research is often limited to HIV/AIDS or mental health research and is typically subsumed in larger studies with general LGBTQ focus. Although the number of knowledgeable health care providers remains modest, the model for the medical approach to transgender health is shifting owing to growing social awareness and an appreciation of a biological component. Gender-affirming medicine facilitates aligning the body of the transgender person with the gender identity; typical treatment regimens include hormone therapy and/or surgical interventions. While broadly safe, hormone treatments require some monitoring for safety. Exogenous estrogens are associated with a dose-dependent increase in venous thromboembolic risk, and androgens stimulate erythropoiesis. The degree to which progressing gender-affirming hormone treatment changes cancer risk, cardiac heart disease risk, and/or bone health remains unknown. Guidelines referencing the potential exacerbation of cancer, heart disease, or other disease risk often rely on physiology models, because conclusive clinical data do not exist. Dedicated research infrastructure and funding are needed to address the knowledge gap in the field.