Hormonal treatment exerts an important effect on body composition, whereby overall an increase in fat mass and a decrease in muscle mass is seen in trans people taking oestrogen treatments and a decrease in fat mass and an increase in muscle mass in trans people taking testosterone treatments. These changes as well as direct effects of hormonal treatment can have an influence on glucose metabolism. In addition to the effects of hormonal treatment, other factors associated with the transition, such as changes in diet and exercise, also play an important role.

The effects of hormonal treatment on glucose metabolism, the risk of developing diabetes and the effect on diabetes control are not yet well known.

Studies on the effects of oestrogen treatment on insulin sensitivity showed a decrease in insulin sensitivity (Elbers et al., 2003; Wierckx et al., 2014). Among those taking testosterone, studies (Wierckx et al., 2014) found an improvement in insulin sensitivity parameters, some (Elbers et al., 2003) found no effect, while others (Polderman et al., 1994) found a decline. The different results in the studies may also be due to, among other things, differences in populations, duration of follow-up and type of hormonal treatment.

These changes in insulin sensitivity in trans people undergoing gender affirming hormonal treatment do not seem to lead to an increasing incidence of diabetes mellitus in the short term (Wierckx et al., 2014). A case control study in Belgium (Wierckx et al., 2013) did show an increased prevalence for type 2 diabetes mellitus compared to the Belgian population, but this was not corrected for risk factors for developing diabetes mellitus. Moreover, there may also be a screening bias.

The effects of hormonal therapy on diabetes treatment in transgender patients have not yet been studied. Due to the possible effects of hormonal therapy on glucose metabolism, it is recommended to provide for a close follow-up. In addition, a well-controlled glucose metabolism is also very important peri-operatively to optimize wound healing and to reduce the risk of infection.​

A doctor showing a patient a syringe used to inject insulin
Photo: The Gender Spectrum Collection

References:

  • ​Elbers JM, Giltay EJ, Teerlink T, Scheffer PG, Asscheman H, Seidell JC & Gooren LJ. Effects of sex steroids on components of the insulin resistance syndrome in transsexual subjects. Clinical Endocrinology 2003; 58 562–571.
  • Polderman KH, Gooren LJ, Asscheman H, Bakker A, Heine RJ. Induction of insulin resistance by androgens and estrogens. J Clin Endocrinol Metab 1994 79: 265-271
  • Wierckx K, Elaut E, Declerq E, Heylens G, De Cuypere G, Kaufman JM, T’Sjoen G. Prevalence of cardiovascular disease and cancer during cross-sex hormone therapy in a large cohort of trans persons: a case control study. Eur J Endocrinol 2013; 169: 471-478.
  • Wierckx K, Van Caenegem E, Schreiner T, Haraldsen I, Fisher A, Toye K, Kaufman JM, T’Sjoen G 2014 Cross-sex hormone therapy is safe and effective at short-time follow-up: results from the European Network for the Invesitgation of Gender Incongruence. J Sex Med. 2014; 11 (8): 1999-2011.