Low Bone Mineral Density in Early Pubertal Transgender/Gender Diverse Youth: Findings From the Trans Youth Care Study

Abstract

<jats:title>Abstract</jats:title> <jats:sec> <jats:title>Context</jats:title> <jats:p>Transgender youth may initiate gonadotropin-releasing hormone agonists (GnRHa) to suppress puberty, a critical period for bone-mass accrual. Low bone mineral density (BMD) has been reported in late-pubertal transgender girls prior to gender-affirming therapy, but little is known about BMD in early-pubertal transgender youth.</jats:p> </jats:sec> <jats:sec> <jats:title>Objective</jats:title> <jats:p>To describe BMD in early-pubertal transgender youth.</jats:p> </jats:sec> <jats:sec> <jats:title>Design</jats:title> <jats:p>Cross-sectional analysis of the prospective, observational, longitudinal Trans Youth Care Study cohort.</jats:p> </jats:sec> <jats:sec> <jats:title>Setting</jats:title> <jats:p>Four multi-disciplinary academic pediatric gender centers in the United States.</jats:p> </jats:sec> <jats:sec> <jats:title>Participants</jats:title> <jats:p>Early-pubertal transgender youth initiating GnRHa.</jats:p> </jats:sec> <jats:sec> <jats:title>Main Outcome Measures</jats:title> <jats:p>Areal and volumetric BMD Z-scores.</jats:p> </jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>Designated males at birth (DMAB) had below-average BMD Z-scores when compared with male reference standards, and designated females at birth (DFAB) had below-average BMD Z-scores when compared with female reference standards except at hip sites. At least one BMD Z-score was &amp;lt; -2 in 30% of DMAB and 13% of DFAB. Youth with low BMD scored lower on the Physical Activity Questionnaire for Older Children than youth with normal BMD, 2.32 ± 0.71 vs. 2.76 ± 0.61 (p = 0.01). There were no significant deficiencies in vitamin D, but dietary calcium intake was suboptimal in all youth.</jats:p> </jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>In early-pubertal transgender youth, BMD was lower than reference standards for sex designated at birth. This lower BMD may be explained, in part, by suboptimal calcium intake and decreased physical activity – potential targets for intervention. Our results suggest a potential need for assessment of BMD in pre-pubertal gender-diverse youth and continued monitoring of BMD throughout the pubertal period of gender-affirming therapy.</jats:p> </jats:sec>

Osteoporosis and Bone Health in Transgender Individuals

“…After the start of GAHT, spine aBMD and BMAD as well as Z-scores increased in all studies [38,40,42]. Hip BMAD and BMAD Z-scores increased in one study including 51 trans girls during 3 years of GAHT [38], but remained unchanged in two other studies, including 15 trans girls during a median of 5.4 years of GAHT [41] and 28 trans girls during 2 years of GAHT [40]. Nonetheless, spine and hip Z-scores remained below zero at all treatment sites in nearly all studies [38,40,42].…”

“…Before the start of GnRHa treatment, low aBMD and BMAD Z-scores as well as low spine and especially midshaft femur vBMD Z-scores have been described in trans girls, with 30% of trans girls having aBMD or vBMD Z-score < − 2 [38][39][40][41].…”

Bone health in transgender people: a narrative review

“…Low BMD Z-score in young trans adolescents has been potentially related to lifestyle, including suboptimal calcium intake, vitamin D deficiency and decreased physical activity, in particular, in transgender girls. 26 – 28 …”

The effects of gender-affirming hormone therapy on cardiovascular and skeletal health: A literature review

“…A recent study evaluating BMD in pre-pubertal transgender youth showed decreased BMD in the transgender group compared to their sex assigned at birth counterparts, suggesting the need for BMD surveillance at an even earlier stage [ 34 ].…”