(CSEMP061) VITAMIN D LEVELS IN TRANSGENDER PATIENTS: A CANADIAN PERSPECTIVE

Abstract: Objectives
In Canada, reported rates of vitamin D deficiency are as high as 70-97%(1). Current data on prevalence of vitamin D deficiency in transgender populations noted lower levels of 25(OH) vitamin D levels in transgender women compared to age-matched cisgender men prior to initiation of gender affirming hormone therapy (GAHT) and low BMD Z-scores associated with vitamin D deficiency in transgender adolescents(2,3). Furthermore, transgender individuals are burdened by a higher rate of mood disorders compared to the general population(4) and vitamin D deficiency may be associated with depression(5). Thus, it is important to ensure that transgender patients receive adequate vitamin D supplementation. Current guidelines stipulate that transgender patients should be reminded of the importance of vitamin D repletion and ensure daily intake of 1000 IU(6), but this may be insufficient if severe deficiency is more common in these patients.

Methods
A retrospective chart review of patients referred for GAHT at one endocrinology private practice office was conducted. Patients referred for initiation of GAHT, and those already established and needing transfer of care, were included. Data collected included vitamin D level, patient’s assigned sex at birth, and age. Vitamin D was classified as replete at >75nmol/L, insufficient at 50-75nmol/L, deficient at 22-49nmol/L and severely deficient if < 25nmol/L.

Results
A total of 438 patients were assessed, 394 of which had vitamin D data. Only 17.8% of patients were found to be vitamin D replete, compared to 34.3% insufficient, 33.5% deficient, and 14.5% severely deficient. There was a strong correlation between increasing age and vitamin D levels in transgender patients (R = 0.22, P< 0.0001). Patients who were transferred for ongoing on GAHT were more likely to have higher vitamin D levels than those who had yet to start (23.5% vs. 14.7%, P = 0.0372). There was no correlation between vitamin D levels and sex assigned at birth.

Conclusions
The current study demonstrates high rates of vitamin D deficiency in transgender Canadians, especially those who are younger. Current recommendations regarding vitamin D supplementation may be insufficient to adequately replenish levels in this population. This data may not be relevant to transgender patients in other regions, especially in countries at lower latitudes. To Canadian practitioners and patients, it is important as the impacts of GAHT on bone health and the effects of vitamin D on general health are still being studied.

Please note references are not included but available upon request.