Evidence on increased or decreased rates of diabetes among trans men and women remains unclear, BUT the evidence that they face higher rates of cardiovascular disease continues to mount.
This is according to a study by Dr. Dorte Glintborg, et al in The European Journal of Endocrinology, which showed that, compared with cisgender individuals, transgender men and women were at increased risk of cardiovascular disease with the main outcome measure the cardiovascular diagnosis (any CVD), including medicine prescriptions for CVD during 2000–2018.
For this study, the researchers used Danish health registers to determine cardiovascular outcomes (ICD-10 codes) and medicine prescriptions regarding CVD medicine. The Danish transgender cohort (N= 2671) included persons with International Classification of Diseases-10 diagnosis code of ‘gender identity disorder’ (1583), which implied contact to a Danish centre of gender identity and persons who had had a legal sex change (n = 1088), which implied that they had contacted the legal system and changed their gender. In total, the transgender study cohort included 1270 persons who were assigned female at birth (AFAB, transgender men) and 1401 were assigned male at birth (AMAB, transgender women).
The control population (N= 26 710) were matched to the transgender population by age (n = 5 controls of same and n = 5 controls of other birth sex) of the respective transgender case. The cohort was young – median age at study inclusion was 22 years for AFAB and 26 years for AMAB. By definition younger people generally have much lower rates of CV disease, but in this study hypertension (high blood pressure) and dyslipidaemia (abnormal blood fats) were the most common problems and could usually be treated a visit to the person’s general practitioner and receiving a prescription.
The mean follow-up time was 4.5 years for AFAB and 5.7 years for AMAB. The increased risk of any CVD was significantly higher in both transgender men and women as compared with control men or women. Transgender males (AFAB) had a 2.2 times increased risk of CVD compared with control men and a 63% increased risk compared with control women. Transgender females (AMAB) had a 93% increased risk of any CVD versus control men, and a 73% increased risk compared with control women.
Analysis of the use of gender-affirming hormone treatment (GAHT) suggested around a third of the increased risk for CVD outcomes in transgender males could be attributed to GAHT – previous research has also associated the use of hormones such as testosterone with increased cardiovascular risk. Yet in transgender females, use of GAHT (oestrogen in combination with testosterone blocker), could not explain increased CVD risk.
“While increased rates of cardiovascular disease might normally go hand-in-hand with increased rates of diabetes, for trans men (assigned female at birth AFAB), use of testosterone usually increases lean body mass and this could be protecting against an increased risk of diabetes,” said Glintborg.
“For transwomen (assigned male at birth, AMAB), hormone treatments such as oestrogen will increase fat mass and lower lean body mass, and increased oestrogen is usually associated with increased risk of autoimmune disease and inflammation. Some studies found a higher risk of type 2 diabetes in transgender women, but this could not be confirmed by others.”
According to the researchers, several other factors apart from body fat/leanness and muscle mass could affect risk of vascular and metabolic diseases in transgender populations, and so there may still be a need for more long-term data.
“Indeed, it has been discussed that mental support as part of transgender care could relieve minority stress and could be protective against development of cardiovascular disease,” said Glintborg, who similarly stated that “lifestyle changes during hormone treatment and especially higher physical activity in transgender men could protect against T2D.”
What is worth stressing for the researchers though is that “cardiovascular and metabolic outcomes were more prevalent in transgender persons compared to controls. Gender-affirming hormone therapy exposure could contribute to the elevated cardiovascular risk in transgender men, assigned female at birth.”
