Low Bone Mass is Common and Associated with Delayed Estrogen Replacement Therapy in Adult Brazilian Women with Turner...

Turner syndrome is a rare chromosomal abnormality in females who typically present with short stature, hypogonadism and increased risk of osteoporosis. Areal bone densitometry (aBMD) usually underestimates bone mass in people with short stature and the bone mineral apparent density (BMAD) can be used as an adjustment for height. The study aimed to assess the frequency of low bone mass and associated factors in Brazilian women with TS at a referral center.

Cross-sectional dual-energy X-ray absorptiometry scans at the lumbar spine and femur were performed to assess bone mass. The association of aBMD, BMAD, age, height, history of fractures, karyotype, use of somatropin (rhGH) and estrogen replacement therapy (ERT) with low bone mass was tested and p-value < 0.05 was considered statistically significant.

Forty-six patients with a mean age of 32 years and height (SDS) 145 cm (-2.89) were evaluated. Five (11%) had a history of fracture. Thirty-five (83%) patients had delayed puberty (> 13 years), 4 (9%) had spontaneous menarche, 19 (41%) were treated with rhGH. Lumbar aBMD was positively correlated to height (p = 0.010). Low bone mass was more frequently detected with aBMD (49% lumbar spine and 48% femoral neck) than with BMAD (31% lumbar spine and 13% femoral neck) and was associated with estrogen status (p=0,002). All patients with delayed puberty and without ERT at the time of the study had low bone mass at the lumbar spine. In contrast, all patients with spontaneous menarche had normal bone mass at both sites. No significant correlation between treatment with rhGH or karyotype with low bone mass was observed.

Low bone mass is a common finding in a cohort of Brazilian women with TS and is associated with delayed puberal induction or start of ERT. Our results highlight the importance of early diagnosis and prompt initiation of ERT to optimise bone mass acquisition.