Changes in hormonal and metabolic parameters in transgender subjects on cross-sex hormone therapy: A cohort study

•Gender identity disorder is a persistent cross-gender identification with uneasiness of living in an incongruent gender.•During cross-sex hormone therapy, hormonal and metabolic changes occur both in male-to-female and female-to-male subjects.•Metabolic changes during cross-sex hormone therapy appear, overall, to be modest, confirming its safety. Gender identity disorder is defined as a strong and persistent cross-gender identification that is associated with a remarkable uneasiness of living in an incongruent gender (gender dysphoria). We performed a retrospective study on the hormonal and metabolic effects of cross-sex hormone therapy (CSHT) in a small cohort of transgender patients. Retrospective study. Hormonal and biochemical parameters at baseline (i.e. before commencement of CSHT) and while on CSHT in 32 patients (21 male to female [MtF], 11 female to male [FtM]) referred to our Endocrinology Unit for gender dysphoria between January 2012 and February 2017. Compared with baseline, in MtF patients systolic blood pressure, red cell count, hemoglobin, hematocrit and total testosterone decreased significantly, while 17-β estradiol and SHBG increased significantly and trendwise significantly, respectively. In FtM patients, total testosterone, red cell count, hemoglobin, hematocrit, creatinine, ɣ-glutamyl transferase and alkaline phosphatase increased significantly, while fasting plasma glucose decreased trendwise significantly. In MtF patients 17-β estradiol correlated positively with SHBG and alkaline phosphatase and negatively with total cholesterol and HDL-c, whereas total testosterone correlated positively with systolic blood pressure, red cell count and hematocrit, and negatively with SHBG. In FtM patients total testosterone correlated positively with creatinine and alkaline phosphatase, while 17-β estradiol correlated positively with HDL-c. Our data are partly in line with other studies concerning the impact of CSHT on hormonal and metabolic parameters in transgender people. Metabolic changes appear, overall, to be modest, confirming the safety of CSHT.