XV Harry Benjamin International Gender Dysphoria Association Symposium

The State of Our Art and the State of Our Science

Changes in body fat distribution during cross-sex hormonal treatment in transsexuals

By Henk Asscheman, MD; Jolanda Elbers; Jaap Seidell and Louis Gooren, MD, Department of Endocrinology, Hospital of the Vrije Universiteit, 1007 MD Amsterdam, The Netherlands
Abstracts

Regional fat distribution differs between men and women. Compared to men, women have more subcutaneous fat, and fat is preferentially stored in fat depots on hip and thighs. The typical sex-specific fat distribution emerges during puberty and increases with age and weight increase. Men become apple-shaped and women pear-shaped.

We studied prospectively the effect of one year cross-sex hormones on fat distribution and muscle area by Magnetic Resonance Imaging, and by skinfold and circumference measurements in 20 male-to-female transsexuals (MF) treated with ethinyl estradiol 100ug/day and cyproterone acetate 100mg/day, and in 17 female-to-male transsexuals (FM) treated with testosterone esters 250mg/2 weeks i.m.

In both groups mean weight increased with 3-3.8kg (5%). In MF skinfolds (biceps, triceps, subscapular, supra-illiacal and para-umbilical) increased with 50%. Circumferences of the waist, hips and thighs increased by 5% and the waist-hip ratio increased slightly. MRI shows a large increase in subcutaneous fat areas (60%) and a lesser (20%) in visceral fat. Muscle area of the upper leg decreased by 10%

In FM skinfolds decreased 15-30% and hip circumference decreased with 2cm. However, arm and waist circumference increased. Waist-hip ratio increased significantly. MRI showed a 20-30% decrease in subcutaneous fat and a 15% increase in visceral fat. Upper leg muscle area increased by 20%.

In conclusion, estrogen/antiandrogen therapy in MF transsexuals increases subcutaneous fat in all areas and decreases muscle mass. Androgens therapy in FM transsexuals decrease subcutaneous fat, but increase the visceral fat depot and muscle mass.