People with gender incongruence experience a tension between their gender identity and the gender assigned at
birth. Many opt for medical help, where gender-affirming hormone therapy (GAHT) may be initiated. Since 2009
Ghent University Hospital, Dept. of Endocrinology initiated the multicenter ENIGI study (European Network for the Investigation of Gender Incongruence), in which the effects and safety of GAHT are investigated. Extensive research over the last 15 years shows that GAHT is generally safe, effective and well tolerated, and that it improves the quality of life of transgender individuals. However, little is known
about its longer-term effects.Therefore, the current focus is on the ENIGI-10 study (10 stands for at least 10 years of hormonal transition) that aims to assess the long-term effects of GAHT on overall health, with a particular focus on cardiovascular and metabolic
health. Study participants in ENIGI-10 will also be be compared with Belgian, non-transgender (cisgender) controls from a previous population-based study,  ASKLEPIOS (PI Prof. Dr. E. Rietzschel). Extension of the project to study participants with >20y follow-up is also being further considered. As visiting professor at SDU, Odense, Denmark, there is additional international collaboration on the cardiovascular and metabolic topic. 

Moreover, the clinical interest in the transgender target group has many side projects, also because male-female differences on a genetic or hormonal level can be investigated. Immunological differences (asthma as a clinical endpoint), effects of vaccination, but also HIV prevalence (Test-and-Tell study), effects of GAHT on voice (in collaboration with the head and neck surgery and speech therapy department UZ Gent) and HPV-screening incl. imaging of pelvic organs after prolonged GAHT are among the research projects. 
In collaboration with Basic and Translational Endocrinology (BaTE) Laboratory, Department of Basic and Applied Medical Sciences, a mouse model for adolescents in transition is being used to document progesterone addition on estrogen treatment. 
Also in close collaboration with the Laboratory of Hormonology of the Department of Clinical Biology (UZ Gent), the clinical relevance of oxy-androgens measuring is being investigated, also with application to the transgender target group.