Sex, Gender, and Transgender: Metabolic Impact of Cross Hormone Therapy

Body Mass Index Distributions and Obesity Prevalence in a Transgender Youth Cohort - A Retrospective Analysis

PURPOSE

To evaluate differences in auxological parameters between transgender and cisgender adolescents.

METHODS

Retrospective analysis of auxological data of 269 transgender and gender diverse patients (75% assigned female at birth or AFAB, 25% assigned male at birth or AMAB) at the outpatient clinic for Pediatric Endocrinology at the Vienna General Hospital. All were treatment naïve at initial measurement. Height and weight data were compared to current World Health Organization (WHO) standards, defining a standard deviation score (SDS) of ≥ 1 ≤ 2 as overweight and > 2 as obese.

RESULTS

In our untreated transgender population (mean age 15.7 years), 20% were overweight and 17% obese. Mean BMI was 0.64 SDS above the WHO average (p < .001). This result was more pronounced in the AFAB subgroup (+0.73 SDS, p < .001) than in the AMAB group (+0.37 SDS, p = .07). The AMAB group showed markedly higher BMI variance compared to WHO standards (p < .001) and to the AFAB group (p = .03), due to a higher relative number of underweight observations. When correcting for psychiatric diagnosis, transgender patients were still significantly overweight (p < .001). In patients for whom data both pregender-affirming hormone therapy and during gender-affirming hormone therapy was available (n = 133), BMI SDS did not change significantly over time (p = .22).

DISCUSSION

We observed significantly higher rates of overweight and obesity in our adolescent transgender cohort. The reasons are likely complex and multifactorial. This makes eating and exercise behaviors central in both transgender care and future research.

Reproductive Life Span and Severe Hypoglycemia Risk in Postmenopausal Women with Type 2 Diabetes Mellitus

BACKGROUND

Estrogen promotes glucose homeostasis, enhances insulin sensitivity, and maintains counterregulatory responses in recurrent hypoglycemia in women of reproductive age. Postmenopausal women with type 2 diabetes mellitus (T2DM) might be more vulnerable to severe hypoglycemia (SH) events. However, the relationship between reproductive factors and SH occurrence in T2DM remains unelucidated.

METHODS

This study included data on 181,263 women with postmenopausal T2DM who participated in a national health screening program from January 1 to December 31, 2009, obtained using the Korean National Health Insurance System database. Outcome data were obtained until December 31, 2018. Associations between reproductive factors and SH incidence were assessed using Cox proportional hazards models.

RESULTS

During the mean follow-up of 7.9 years, 11,279 (6.22%) postmenopausal women with T2DM experienced SH episodes. A longer reproductive life span (RLS) (≥40 years) was associated with a lower SH risk compared to a shorter RLS (<30 years) (adjusted hazard ratio [HR], 0.74; 95% confidence interval [CI], 0.69 to 0.80; P for trend <0.001) after multivariable adjustment. SH risk decreased with every 5-year increment of RLS (with <30 years as a reference [adjusted HR, 0.91; 95% CI, 0.86 to 0.95; P=0.0001 for 30-34 years], [adjusted HR, 0.80; 95% CI, 0.76 to 0.84; P<0.001 for 35-39 years], [adjusted HR, 0.74; 95% CI, 0.68 to 0.81; P<0.001 for ≥40 years]). The use of hormone replacement therapy (HRT) was associated with a lower SH risk than HRT nonuse.

CONCLUSION

Extended exposure to endogenous ovarian hormone during lifetime may decrease the number of SH events in women with T2DM after menopause.

Virilizing doses of testosterone decrease circulating insulin levels and differentially regulate insulin signaling in liver and adipose tissue of females

Transgender men undergoing hormone therapy are at risk for insulin resistance. However, how virilizing testosterone therapy affects serum insulin and peripheral insulin sensitivity in transgender men is unknown. This study assessed the effect of acute, virilizing testosterone on serum insulin concentrations and insulin signaling in liver, skeletal muscle, and white adipose tissue (WAT) of female pigs as a translational model for transgender men. Females received three doses of intramuscular testosterone cypionate (TEST females; 50 mg/day/pig) or corn oil (control) spaced 6 days apart starting on the day of estrus (D0). Fasting blood was collected on D0, D3, D5, D11, and D13, and females were euthanized on D13. On D13, TEST females had virilizing concentrations of serum testosterone with normal concentrations of serum estradiol. Virilizing serum testosterone concentrations (D13) were associated with decreased serum insulin and C-peptide concentrations. Blood glucose and serum glycerol concentrations were not altered by testosterone. Virilizing concentrations of testosterone downregulated AR and ESR1 in subcutaneous (sc) WAT and upregulated transcript levels of insulin-signaling pathway components in WAT and liver. At the protein level, virilizing testosterone concentrations were associated with increased PI3K 110α in liver and increased insulin receptor (INSR) and phospho(Ser256)-FOXO1 in visceral (v) WAT but decreased phospho(Ser473)-AKT in vWAT and scWAT. These results suggest that acute exposure to virilizing concentrations of testosterone suppresses circulating insulin levels and results in increased abundance of proteins in the insulin-signaling pathway in liver and altered phosphorylation of key proteins in control of insulin sensitivity in WAT.NEW & NOTEWORTHY Acute virilizing doses of testosterone administered to females suppress circulating insulin levels, upregulate components of the insulin-signaling pathway in liver, and suppress insulin signaling in white adipose tissue. These results suggest that insulin resistance in transgender men may be due to suppression of the insulin-signaling pathway and decreased insulin sensitivity in white adipose tissue.