Cardiometabolic risk assessment in transgender individuals - differential impact of sex hormones and sex chromosomes.

Background: While transgender individuals represent a significant group seeking medical care, the differential effect of sex on cardiometabolic risk metrics is incompletely understood. Therefore, the current study aimed to characterize the impact of sex hormones and chromosomes on a contemporary panel of cardiometabolic risk biomarkers and functional cardiovascular measurements.

Methods: 17 transmen and 17 transwomen were studied at baseline (T0), 4 weeks (hormonal castration, T1), and 11 months following gender-affirming hormone treatment (T12). We analyzed carotid intima-media thickness (cIMT) and arterial stiffness, lipoproteins and other metabolites comprehensively by nuclear magnetic resonance spectroscopy and HDL-mediated cholesterol efflux capacity (CEC) from macrophages. T0 to T12 comparisons informed the impact of sex hormones, comparisons of genetic XX and XY individuals at T1 the impact of sex chromosomes.

Results: Vascular function was comparable at T12 and T0; systolic blood pressure increased in transmen (p=0.002). Transmen developed a pro-atherogenic lipoprotein profile, estrogen treatment in transwomen tended to result in improvements. Several metabolites indicating increased diabetes risk including plasma glucose were changed in transmen (p=0.025), with opposite changes in transwomen (p=0.002). Interestingly, at T1 apparent diabetes risk was lower in XX compared with XY individuals (p=0.002). CEC decreased in transwomen (p<0.01), while remaining unchanged in transmen. However, in both groups the strong positive association of apoA-I with cholesterol efflux observed at T0 was lost at T12.

Conclusions: The results are consistent with increased cardiometabolic risk in transmen, while transwomen show beneficial changes early during gender-affirming hormone therapy. Sex chromosomes have less intrinsic effects. XY individuals and transmen display an increased apparent diabetes risk. Further research of cardiometabolic risk is needed for transgender individuals.