LGBTQ+ Health Updates

LGBTQ+ Health Updates

November 20, 2019
4 min read
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Insulin sensitivity goes in ‘opposite directions’ for transgender men, women after HT

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After undergoing 1 year of gender-affirming hormone therapy, transgender men appear to experience increased insulin sensitivity whereas insulin sensitivity tends to decrease for transgender women, according to findings published in Diabetes Care.

Samyah Shadid

“It is unclear to what extent men and women differ in insulin sensitivity. We found some, but not all, parameters of insulin insensitivity to improve with masculinization and to deteriorate with feminization in transgender people. It is, however, too early to conclude that men are more insulin sensitive than women,” Samyah Shadid, MD, PhD, professor of endocrinology in the department of endocrinology at Ghent University Hospital in Belgium, told Endocrine Today. “The results were somewhat surprising because the other — very few — available studies found deterioration in both groups, and we would have expected the opposite, if anything. Our study was relatively large; however, not all parameters changed into the same direction, and there was some confounding effect from changed physical activity in transgender men more than transgender women.”

Shadid and colleagues collected baseline data on height, weight, lean mass, waist circumference, fasting plasma glucose, fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR), fasting glucose-dependent insulinotropic polypeptide (GIP) and GLP-1 from 35 transgender men (mean age, 26.1 years) and 55 transgender women (mean age, 34.4 years) who participated in the European Network for the Investigation of Gender Incongruence study. Participants then initiated gender-affirming HT, and at 1 year the measurements and calculations were made again. Participants also completed an OGTT at baseline and at 1 year.

The researchers found that among transgender men, average body weight was 65.9 kg at 1 year compared with 63.1 kg at baseline (P < .01), average BMI was 24.1 kg/m2 at 1 year compared with 23.2 kg/m2 at baseline (P < .05), average waist to hip ratio was 0.79 at 1 year compared with 0.76 at baseline (P < .05), average truncal lean mass was 24.4 kg at 1 year compared with 22.8 kg at baseline (P < .001), average fat free mass was 49.8 kg at 1 year compared with 45.2 kg at baseline (P < .001) and average leg lean mass was 8.3 kg at 1 year compared with 7.4 kg at baseline (P < .001). Fasting GLP-1 went from 18 pmol/L at baseline to 17.8 pmol/L at 1 year among transgender men (P < .05). Fasting insulin and HOMA-IR tended to decrease, according to the researchers.

Insulin syringe 2019 adobe 
After undergoing 1 year of gender-affirming hormone therapy, transgender men appear to experience increased insulin sensitivity whereas insulin sensitivity tends to decrease for transgender women.
Source: Adobe Stock

Among transgender women, the researchers noted that there was no significant change in body weight but that it “tended to increase.” In addition, the researchers found that average BMI was 24.2 kg/m2 at 1 year compared with 23.7 kg/m2 at baseline (P < .05), average fat percentage was 24.5% at 1 year compared with 18.6% at baseline (P < .001), average fat free mass was 58.2 kg at 1 year compared with 60.5 kg at baseline (P < .001), average waist to hip ratio was 0.84 at 1 year compared with 0.87 at baseline (P < .01). The researchers also found that average fasting insulin levels were 11.2 mU/L at 1 year compared with 7.8 mU/L at baseline (P < .001), average HOMA-IR was 2.4 at 1 year compared with 1.7 at baseline (P < .01) and average GIP was 2.2 pmol/L at 1 year compared with 3.6 pmol/L at baseline (P < .01).

“Even though not all parameters and markers changed significantly, nor into the same direction, the fact that the changes in insulin sensitivity largely tended toward opposite directions in both groups suggests that, at least in our study cohort, people were more insulin sensitive under male than under female hormone exposition,” the researchers wrote. – by Phil Neuffer

For more information:

Samyah Shadid, MD, PhD, can be reached at Samyah.Shadid@uzgent.be.

Disclosures: Shadid reports she has served on scientific advisory panels for Novo Nordisk and received research support from AstraZeneca and Boehringer Ingelheim. Please see the study for all other authors’ relevant financial disclosures.