Incident Diabetes Risk is Not Increased in Transgender Individuals Using Hormone Therapy: An Observational Study From the ACOG Study

Background: In trans women receiving hormone therapy, body fat and insulin resistance increases, with opposite effects in trans men. These metabolic alterations may increase or decrease the risk of developing type 2 diabetes in trans women and trans men, respectively. Currently, there is no data on the incidence of type 2 diabetes in transgender individuals. Methods: Retrospective data from the Amsterdam Cohort of Gender Dysphoria with transgender individuals on hormone therapy between 1972 and 2018 were linked to a nationwide health data registry. Because no central registry of diabetes was available, the occurrence of diabetes was deferred from the first dispense of a glucose-lowering agent. Standardized incidence ratios (SIR) were computed for trans women and trans men in comparison with respectively men and women from the general population. Findings: Compared to their birth sex in the general population, no difference in the incidence of type 2 diabetes mellitus was observed in trans women (N = 2585, 90 cases, SIR 0.94 95%CI 0.76–1.14) or trans men (N = 1514, 32 cases, SIR 1.40 95%CI 0.96–1.92). Interpretation: Despite studies reporting an increase in insulin resistance in feminizing hormone therapy and an increase in insulin sensitivity in masculinizing hormone therapy, the incidence of type 2 diabetes in transgender individuals after initiation of hormone therapy was not different compared to the general population. Earlier studies on the effect of hormone therapy on insulin sensitivity in transgender individuals might have revealed specific effects of cyproterone acetate rather than effects of estradiol. Funding: None to declare. Declaration of Interest: None to declare. Ethical Approval: The study was approved by the Medical Ethics Committee of the Amsterdam University Medical Centre