Low normal TSH levels are associated with low bone mineral density in healthy postmenopausal women

Context: The hormonal factors involved in the regulation of peak bone mass (PBM) in men have not been fully investigated. Apart from gonadal steroids and somatotropic hormones, thyroid hormones are known to affect bone maturation and homeostasis and are additional candidate determinants of adult bone mass. Objective: We aimed to investigate between-subject physiological variation in free and total thyroid hormone concentrations, TSH, and thyroid binding globulin (TBG) in relation to parameters of bone mass, geometry, and mineral density in healthy men at the age of PBM. Design and setting: We recruited 677 healthy male siblings aged 25-45 years in a cross-sectional, population-based study. Areal and volumetric bone parameters were determined using dual-energy x-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT). Total and free thyroid hormones, TBG, and TSH were determined using immunoassays. Results: Free and total thyroid hormone concentrations were inversely associated with bone mineral density (BMD) and bone mineral content (BMC) at the hip and total body (free triiodothyronine (FT 3 ), total T 3 (TT 3 ), and total T 4 (TT 4 )) and at the spine (FT 3 ). TBG was negatively associated with BMC and areal BMD at all sites. At the radius, cortical bone area was inversely associated with TT 3 , TT 4 , and TBG, and trabecular bone density was inversely associated with free thyroxine, TT 4 , and TBG. We observed inverse associations between cortical bone area at the mid-tibia and FT 3 , TT 3 , TT 4 , and TBG. No associations between TSH and DXA or pQCT measurements were found. Conclusion: In healthy men at the age of PBM, between-subject variation in thyroid hormone concentrations affects bone density, with higher levels of FT 3 , TT 3 , TT 4 , and TBG being associated with less favorable bone density and content.

Section: Discussionmentioning

confidence: 89%

Section: Discussionmentioning

confidence: 96%

Thyroid hormone status within the physiological range affects bone mass and density in healthy men at the age of peak bone mass

Roef

Lapauw

Goemaere

et al. 2011

“…A cross-sectional study in this cohort found a lower BMD among participants with TSH !0.5 mU/l, but did not show any relation between TSH and BMD above this TSH level (31). However, some studies report a positive relation between TSH in the normal range and BMD (32,33,34), and there have even been studies that report an association between elevated TSH and low BMD (35,36).…”

Section: Discussionmentioning

confidence: 93%

Does thyroid function influence fracture risk? Prospective data from the HUNT2 study, Norway

Svare

Nilsen

Åsvold

et al. 2013

Objective: To prospectively study the relation between TSH and risk of hip and forearm fractures. Design: A population-based cohort study. Methods: In a substudy of the second survey of the Nord Trøndelag Health Study, Norway (HUNT2, 1995-97), linked with a hospital-based fracture registry, we investigated the relation between baseline TSH and risk of hip and/or forearm fractures. Population: A total of 16 610 women and 8595 men aged 40 years or more, without previous self-reported thyroid disease and hip or forearm fractures. Results: During 12.5 years follow-up, a total of 1870 women and 342 men experienced hip or forearm fractures. Overall, there was no relation between baseline TSH and fracture risk. However, there was weak evidence that women with TSH !0.5 and O3.5 mU/l had a slightly increased risk of hip fractures (hazard ratio (HR) 1.30, 95% CI 0.97-1.94 and HR 1.19, 95% CI 0.93-1.52) compared with the reference group with TSH of 1.5-2.4 mU/l. Supplementary analyses showed higher hip fracture risk in women with TSH O4.0 mU/l and negative thyroid peroxidase antibodies (TPOAb) compared with the reference group (HR 1.75, 95% CI 1.24-2.46). Conclusion: We found no statistically significant relation between baseline TSH and subsequent fracture risk, but the data suggest a weak positive association with hip fracture risk among women with both low and high TSH. The latter association was confined to women with negative TPOAb status.

“…However, 18 of the 29 examined studies considered an upper-limit TSH value of over 4 mU/l. This variability in limits might explain the lack of association between BMI and TSH in 11 (5,9,13,16,19,23,25,28,29,33,40) of the 29 examined studies. Another source of discrepancy is the fact that almost half of the studies did not perform adjustment for potential confounders.…”

Section: Discussionmentioning

confidence: 97%

Association between serum TSH concentration within the normal range and adiposity

Souza

Sichieri²

2011

Background: Overt hypothyroidism is clearly related to body weight gain and greater adiposity, but the range of hormonal change in serum TSH concentration associated with weight gain remains a focus of debate. Aim: The aim of this review was to assess studies that evaluated the relationship between anthropometric measures and serum TSH concentration in euthyroid subjects. Methods: Studies held on the Ovid MEDLINE database were searched and original articles published from 2000 to 2010 were included. The literature search was restricted to studies conducted in humans aged 18 years or older and written in English, Spanish, or Portuguese. Studies that evaluated the association between anthropometric measures and serum TSH within the normal range as the primary objective, as well as additional analysis, were included. Results: A total of 29 studies met the inclusion criteria. Of the 29 studies, 18 showed a positive relationship between measures of adiposity and serum TSH. Despite the plausibility of this association, only two studies reported longitudinal findings. The influence of smoking on the association between serum TSH and anthropometric measures was evaluated in only three studies and remains unclear. Conclusion: Thus, further longitudinal studies are needed to better understand the mechanisms by which TSH concentration might impact body weight.