Transgender Individuals at Increased Risk of Type 2 Diabetes, Not Linked to Hormone Therapy

Noreen Islam, MD, MPH

A recent analysis suggests transfeminine individuals were at a 40% greater risk of developing diabetes than their cisgender counterparts, but this increase in risk was not attributable to gender-affirming hormone therapy.

A retrospective look at electronic medical record data from more than more than 50,000 patients, results of the study provide insight into the increase in risk among transfeminine patients and the apparent lack of influence undergoing gender-affirming hormone therapy had on the risk of developing type 2 diabetes among these individuals.

“Our study findings provide some reassurance that gender-affirming therapy does not increase the risk of type 2 diabetes, but our analysis was not designed to evaluate more subtle subclinical changes,” said Noreen Islam, MD, MPH, of Emory University School of Medicine, in a statement. “For this reason, health care providers should continue monitoring the metabolic status of individuals receiving gender-affirming therapy.”

As the incidence of type 2 diabetes and use of gender-affirming hormone therapy both increasing in recent years, Islam and a team of colleagues sought to assess the occurrence of type 2 diabetes among transgender persons and compare this to the rate among cisgender reference groups. To do so, they designed their study as an analysis of data from the Study of Transition Outcomes and Gender (STRONG) study and electronic medical record data from a trio of Kaiser Permanente health systems in Northern California, Southern California, and Georgia from 2006-2014.

For the purpose of analysis, up to 10 male and 10 female cisgender Kaiser Permanente patients were matched to transgender individuals in the final cohort based on race/ethnicity, year of birth, study site, and calendar year of membership based on index date. Overall, 5002 transgender individuals were identified for inclusion in the study, including 2869 trans feminine and 2133 transmasculine individuals. The patients in the transfeminine cohort were then matched to 28,300 cisgender females and 28,258 cisgender males while the transmasculine cohort were matched to 20,997 cisgender females and 20,964 cisgender males.

Investigators used Cox proportional hazards and logistic regression models to assess the incidence and prevalence of type 2 diabetes among these patient cohorts. Investigators pointed out all analyses performed were controlled for BMI.

Upon analysis, 94 incident cases of type 2 diabetes were identified among the trans feminine cohort and 44 incident cases were identified among the transmasculine cohort. Of the 94, 17 were diagnosed after initiation of gender-affirming hormone therapy. Of the 44, 12 were diagnosed after initiation of gender-affirming hormone therapy. The incidence of type 2 diabetes per 1000 person-years was 9.3 (95% CI, 7.6–11.3) among all transfeminine patients and 5.9 (95% CI, 3.6-9.4) among those who underwent gender-affirming hormone therapy. Among transmasculine individuals, the incidence rate was 6.2 (95% CI, 4.6-8.4) overall and 5.5 (95% CI, 3.1-9.7) among those who underwent gender-affirming hormone therapy after the index date.

Further analysis indicated those in the overall trans feminine cohort had a moderately greater rate of type 2 diabetes compared to the cisgender female reference group (HR, 1.4; 95% CI, 1.1-1.8), but not in comparison with the cisgender male reference group (HR, 1.2; 95% CI, 0.9-1.5). For the transmasculine cohort, the corresponding hazard ratios were 1.3 (95% CI, 0.9-1.8) compared to the cisgender female cohort and 1.2 (95% CI, 0.9-1.7) for the cisgender male cohort.

“Although more research is needed, there is little evidence that type 2 diabetes occurrence in either transgender women or transgender men is attributable to gender-affirming hormone therapy, at least in the short term,” Islam said.

This study, “Is There a Link Between Hormone Use and Diabetes Incidence in Transgender People? Data from the STRONG Cohort,” was published in the Journal of Clinical Endocrinology & Metabolism.