Normal Tempo of Bone Formation in Turner Syndrome despite Signs of Accelerated Bone Resorption

Abstract

Aims: To evaluate area bone mineral density (aBMD) and volumetric BMD (vBMD) by dual-energy X-ray absorptiometry, and relations to bone markers and hormones in adolescent women with Turner syndrome (TS). Methods: Cross-sectional study in TS patients (n = 37, 16.7 ± 3.4 years) and control group (n = 49), assessed by dual-energy X-ray absorptiometry, bone markers and hormones. TS patients were divided into a young group receiving (‘ongoing’) GH (n = 15) and an older group previously receiving (‘previous’) GH (n = 22). Results: vBMD_spine was similar in ‘ongoing GH’ TS, but higher in ‘previous GH’ TS, compared to controls. vBMD_hip was lower in ‘ongoing GH’ TS, but similar in ‘previous GH’. z scores for aBMD were uniformly reduced in ‘ongoing TS’, but near-normalized in ‘previous GH’ TS. Bone formation and resorption markers were increased in ‘ongoing GH’ TS, while ‘previous GH’ TS had elevated bone resorption markers. Conclusion: BMD increased in parallel with age in TS patients receiving optimal estradiol replacement therapy and GH according to consensus guidelines, and in controls. Young TS undergoing pubertal induction and still receiving GH have lower z score BMD than older TS patients receiving hormonal replacement therapy, where a near-normalization of BMD was achieved. TS patients previously receiving GH showed signs of increased bone resorption.

Recognition and management of adults with Turner syndrome: From the transition of adolescence through the senior years

“…The positive effects of GH therapy on bone have been shown in several studies (Cleemann et al, ; Sas et al, ). The former study showed improvement in BMD using variable dose regimen of GH.…”

“…The Guidelines (Gravholt, Andersen, et al, , section 2.5) recommend confirming ovarian dysfunction, and starting estrogen replacement between 11 and 12 years of age in order to promote normal growth and psychosocial development. Low doses of estradiol are initiated and titrated to promote secondary sexual characteristics and uterine growth without early closure of the growth plates, ensure a normal tempo of bone mineralization (Cleemann et al, ), normalize cognitive maturation (Ross, Roeltgen, Feuillan, Kushner, & Cutler Jr., ; Ross, Roeltgen, Feuillan, Kushner, & Cutler Jr., ), body composition (Cleemann et al, ), reduce lipids (Gravholt, Naeraa, et al, ) and liver enzymes (Koulouri, Ostberg, & Conway, ) and reduce cardiovascular risk in the long term (Gravholt, Naeraa, et al, ; Ostberg et al, ). Transdermal estradiol is the preferred method for estrogen administration (Gravholt, Andersen, et al, , section 6.1; Klein et al, ), but oral estradiol can also be used.…”

TRANSITION IN ENDOCRINOLOGY: Treatment of Turner's syndrome during transition

“…Young TS patients undergoing pubertal induction and still receiving GH had lower z-score BMD than older TS patients receiving HRT, where a near-normalised BMD was achieved. Patients previously receiving GH showed signs of increased bone resorption (103).…”

Dosage of estradiol, bone and body composition in Turner syndrome: a 5-year randomized controlled clinical trial

“…In a former cross-sectional study, we found a normal tempo of bone formation in a large group of girls and adolescent with TS compared to healthy controls despite signs of accelerated bone resorption (19). In the present prospective study, we hypothesized that high-dose oral 17B-estradiol in young women with TS would have beneficial effects on BMD and body composition and correct the imbalance between bone formation and bone resorption.…”

“…Increased LBM, and thus probably muscle strength, is also likely to have additional positive roles in relation to the frequent occurrence of type 2 diabetes, hypertension, impaired postural balance (32) and obesity (33). A few studies have looked at markers of bone metabolism to account for differences in the bone phenotype in TS (18,19) and found markers of bone formation and levels of vitamin D to be similar in girls with TS compared to healthy girls. However, markers of bone resorption were elevated in TS.…”