Subclinical thyroid dysfunction and fracture risk: a meta-analysis

The Relation Between Thyroid Function and Anemia: A Pooled Analysis of Individual Participant Data

Context

Anemia and thyroid dysfunction often co-occur, and both increase with age. Human data on relationships between thyroid disease and anemia are scarce.

Objective

To investigate the cross-sectional and longitudinal associations between clinical thyroid status and anemia.

Design

Individual participant data meta-analysis.

Setting

Sixteen cohorts participating in the Thyroid Studies Collaboration (n = 42,162).

Main Outcome Measures

Primary outcome measure was anemia (hemoglobin <130 g/L in men and <120 g/L in women).

Results

Cross-sectionally, participants with abnormal thyroid status had an increased risk of having anemia compared with euthyroid participants [overt hypothyroidism, pooled OR 1.84 (95% CI 1.35 to 2.50), subclinical hypothyroidism 1.21 (1.02 to 1.43), subclinical hyperthyroidism 1.27 (1.03 to 1.57), and overt hyperthyroidism 1.69 (1.00 to 2.87)]. Hemoglobin levels were lower in all groups compared with participants with euthyroidism. In the longitudinal analyses (n = 25,466 from 14 cohorts), the pooled hazard ratio for the risk of development of anemia was 1.38 (95% CI 0.86 to 2.20) for overt hypothyroidism, 1.18 (1.00 to 1.38) for subclinical hypothyroidism, 1.15 (0.94 to 1.42) for subclinical hyperthyroidism, and 1.47 (0.91 to 2.38) for overt hyperthyroidism. Sensitivity analyses excluding thyroid medication or high levels of C-reactive protein yielded similar results. No differences in mean annual change in hemoglobin levels were observed between the thyroid hormone status groups.

Conclusion

Higher odds of having anemia were observed in participants with both hypothyroid function and hyperthyroid function. In addition, reduced thyroid function at baseline showed a trend of increased risk of developing anemia during follow-up. It remains to be assessed in a randomized controlled trial whether treatment is effective in reducing anemia.

Relationship between perioperative thyroid function and acute kidney injury after thyroidectomy

Thyroid dysfunction may alter kidney function via direct renal effects and systemic haemodynamic effects, but information on the effect of thyroid function on postoperative acute kidney injury (AKI) following thyroidectomy remains scarce. We reviewed the medical records of 486 patients who underwent thyroidectomy between January 2010 and December 2014. Thyroid function was evaluated based on the free thyroxine or thyroid stimulating hormone levels. The presence of postoperative AKI was determined using the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. AKI developed in 24 (4.9%) patients after thyroidectomy. There was no association between preoperative thyroid function and postoperative AKI. Patients with postoperative hypothyroidism showed a higher incidence of AKI than patients with normal thyroid function or hyperthyroidism (19.4%, 6.7%, and 0%, respectively; P = 0.044). Multivariable logistic regression analysis showed that male sex (OR, 4.45; 95% CI, 1.80-11.82; P = 0.002), preoperative use of beta-blockers (OR, 4.81; 95% CI, 1.24-16.50; P = 0.016), low preoperative serum albumin levels (OR, 0.29; 95% CI, 0.11-0.76; P = 0.011), and colloid administration (OR, 5.18; 95% CI, 1.42-18.15; P = 0.011) were associated with postoperative AKI. Our results showed that postoperative hypothyroidism might increase the incidence of AKI after thyroidectomy.

Prevalence of thyroid dysfunction in a Large Southern European Population. Analysis of modulatory factors. The APNA study

CONTEXT

To study the prevalence of thyroid dysfunction in a very large unselected population.

OBJECTIVE

To determine the prevalence of abnormal thyroid function and evaluate potential modulatory factors.

DESIGN AND SETTING

The Estudio de Atención Primaria de Navarra, The APNA Study, is a cross-sectional study conducted in northern Spain. It involved 303 883 people, of 20 years of age and older, who live in the Navarra region. Participants are covered by the public healthcare system and medical records are digitalized.

MAIN OUTCOME MEASURES

The information was gathered from e-registered data regarding serum thyrotropin (TSH), thyroid hormones, thyroid antibody concentration and clinical context. Measurements were logged (demographic information and potential thyroid function modulatory factors).

RESULTS

Serum TSH (mU/L) normal range was established at 0.7-4.28. At the time of the study, 87% of the Navarra population had a TSH level within the normal range. Mean serum TSH in euthyroid individuals was higher in women (2.15) than in men (1.96) (P < .001) and higher in the obese with body mass index (BMI) ≥30 kg/m² (2.12) as compared to the non-obese BMI <30 kg/m² (2.06) (P < .001). Mean TSH for the entire population was 1.9. The native Spanish population had statistically significantly lower TSH (1.87) than non-native Spanish (2.15) (P < .001). Additionally, we observed that serum TSH levels decreased with age and an increase in the prevalence of hypothyroidism in the elderly and among people with low-income levels. The prevalence of thyroid dysfunction in Navarra was 12.3%. The prevalence of hypothyroidism (or high TSH) in the population was 8.8% (13.3% in women, 4.2% in men), and the prevalence of hyperthyroidism (or low TSH) was 4.3% (5.6% in women, 3.0% in men).

CONCLUSIONS

Nearly 15% of the general population suffers from biochemical thyroid dysfunction. The serum TSH level appears to be influenced by sex, BMI, age, ethnic origin and socio-economic status.

Scoliosis in Fibrous Dysplasia/McCune-Albright Syndrome: Factors Associated With Curve Progression and Effects of Bisphosphonates

Scoliosis is a complication of fibrous dysplasia/McCune-Albright syndrome (FD/MAS); however, risk factors and long-term outcomes are unknown. Bisphosphonates are commonly used; however, it is unknown whether their use decrease the risk of progressive scoliosis. Clinical data from the National Institutes of Health (NIH) cohort study was reviewed. Cobb angles were measured, and variables associated with scoliosis progression were identified. Of 138 subjects with available radiographs, 84 (61%) had scoliosis, including 55 (65%) classified as mild (Cobb angle >10 to ≤30 degrees), 11 (13%) as moderate (>30 to ≤45 degrees), and 18 (22%) as severe (>45 degrees). Total skeletal disease burden was highly associated with scoliosis severity (p < 0.0001). Endocrinopathies associated with scoliosis included fibroblast growth factor 23 (FGF23)-mediated hypophosphatemia (p < 0.001) and hyperthyroidism (p < 0.001). Bone turnover markers, including osteocalcin and NTX-telopeptides, were associated with severe scoliosis (p < 0.01). Associations were identified between Cobb angle and functional metrics, including leg length discrepancy (p < 0.01), hip range of motion (p < 0.05), and strength of the gluteus medius and maximus (p < 0.01). Longitudinal analyses were conducted in 69 subjects who had serial radiographs over a median 4.9-year period (range, 0.9 to 14.7 years). Twenty-two subjects were treated with bisphosphonates; there was no difference in Cobb angle progression compared to untreated subjects (0.10 versus 0.53 degrees/year, p = 0.36). Longitudinal data was available for 10 of 12 subjects treated with spinal fusion; one had instrumentation failure, but in nine subjects Cobb angles were stable with 6.1 years of follow-up (range, 0.9 to 14.7 years). Two fatalities from scoliosis-associated restrictive lung disease occurred in subjects managed non-operatively. Scoliosis occurs frequently in patients with polyostotic FD, and may be potentially fatal. The primary risk factor for progressive scoliosis is total skeletal disease burden. Treatable features that contribute to scoliosis progression include leg length discrepancy, FGF23-mediated hypophosphatemia, and hyperthyroidism. Current data do not support routine use of bisphosphonates to prevent progression of spinal curvature. Spinal fusion is frequently effective in providing long-term stability, and may be lifesaving. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

Clinical aspects of thyroid function during ageing

Globally, populations are ageing at a rapid rate. The increase in the number of older citizens is accompanied by an increased prevalence of thyroid dysfunction, one of the most common disorders in older people. However, the diagnosis of thyroid dysfunction in older people is hindered by several factors, including the scarcity of thyroid dysfunction symptoms in older people. We describe the physiological changes in thyroid function that occur with increasing age, focusing on literature regarding changes in thyroid function test results in older populations. We also discuss treatment considerations for clinical and subclinical thyroid dysfunction according to international guidelines for older people. Finally, we discuss the relationship between variations in thyroid function and common diseases of old age including cardiovascular disease, osteoporosis, cognitive impairment, and frailty and suggest directions for future research.

2018 European Thyroid Association Guideline for the Management of Graves' Hyperthyroidism

Graves' disease (GD) is a systemic autoimmune disorder characterized by the infiltration of thyroid antigen-specific T cells into thyroid-stimulating hormone receptor (TSH-R)-expressing tissues. Stimulatory autoantibodies (Ab) in GD activate the TSH-R leading to thyroid hyperplasia and unregulated thyroid hormone production and secretion. Diagnosis of GD is straightforward in a patient with biochemically confirmed thyrotoxicosis, positive TSH-R-Ab, a hypervascular and hypoechoic thyroid gland (ultrasound), and associated orbitopathy. In GD, measurement of TSH-R-Ab is recommended for an accurate diagnosis/differential diagnosis, prior to stopping antithyroid drug (ATD) treatment and during pregnancy. Graves' hyperthyroidism is treated by decreasing thyroid hormone synthesis with the use of ATD, or by reducing the amount of thyroid tissue with radioactive iodine (RAI) treatment or total thyroidectomy. Patients with newly diagnosed Graves' hyperthyroidism are usually medically treated for 12-18 months with methimazole (MMI) as the preferred drug. In children with GD, a 24- to 36-month course of MMI is recommended. Patients with persistently high TSH-R-Ab at 12-18 months can continue MMI treatment, repeating the TSH-R-Ab measurement after an additional 12 months, or opt for therapy with RAI or thyroidectomy. Women treated with MMI should be switched to propylthiouracil when planning pregnancy and during the first trimester of pregnancy. If a patient relapses after completing a course of ATD, definitive treatment is recommended; however, continued long-term low-dose MMI can be considered. Thyroidectomy should be performed by an experienced high-volume thyroid surgeon. RAI is contraindicated in Graves' patients with active/severe orbitopathy, and steroid prophylaxis is warranted in Graves' patients with mild/active orbitopathy receiving RAI.

Thyroid Stimulating Hormone and Bone Mineral Density: Evidence From a Two-Sample Mendelian Randomization Study and a Candidate Gene Association Study

With population aging, prevalence of low bone mineral density (BMD) and associated fracture risk are increased. To determine whether low circulating thyroid stimulating hormone (TSH) levels within the normal range are causally related to BMD, we conducted a two-sample Mendelian randomization (MR) study. Furthermore, we tested whether common genetic variants in the TSH receptor (TSHR) gene and genetic variants influencing expression of TSHR (expression quantitative trait loci [eQTLs]) are associated with BMD. For both analyses, we used summary-level data of genomewide association studies (GWASs) investigating BMD of the femoral neck (n = 32,735) and the lumbar spine (n = 28,498) in cohorts of European ancestry from the Genetic Factors of Osteoporosis (GEFOS) Consortium. For the MR study, we selected 20 genetic variants that were previously identified for circulating TSH levels in a GWAS meta-analysis (n = 26,420). All independent genetic instruments for TSH were combined in analyses for both femoral neck and lumbar spine BMD. In these studies, we found no evidence that a genetically determined 1-standard deviation (SD) decrease in circulating TSH concentration was associated with femoral neck BMD (0.003 SD decrease in BMD per SD decrease of TSH; 95% CI, -0.053 to 0.048; p = 0.92) or lumbar spine BMD (0.010 SD decrease in BMD per SD decrease of TSH; 95% CI, -0.069 to 0.049; p = 0.73). A total of 706 common genetic variants have been mapped to the TSHR locus and expression loci for TSHR. However, none of these genetic variants were associated with BMD at the femoral neck or lumbar spine. In conclusion, we found no evidence for a causal effect of circulating TSH on BMD, nor did we find any association between genetic variation at the TSHR locus or expression thereof and BMD. © 2018 The Authors. Journal of Bone and Mineral Research Published by WileyPeriodicals, Inc.

Subclinical thyroid dysfunction and circulating thyroid hormones are not associated with bone turnover markers or incident hip fracture in older men

OBJECTIVE

Overt thyroid dysfunction is a risk factor for osteoporosis and fractures. Subclinical hyperthyroidism has also been associated with fracture. It remains unclear whether variation in thyroid hormones within the euthyroid range modulates bone health, particularly among older men. We assessed whether thyroid stimulating hormone (TSH) and free thyroxine (FT4) are associated with bone turnover markers (BTMs) and predict hip fracture risk in community-dwelling older men without known thyroid disease.

DESIGN

Prospective cohort study.

PATIENTS

Four thousand two hundred forty-eight men aged 70-89 years.

MEASUREMENTS

Baseline blood samples were assayed for TSH, FT4, total osteocalcin (TOC), undercarboxylated osteocalcin (ucOC), N-terminal propeptide of type I collagen (P1NP) and collagen type I C-terminal cross-linked telopeptide (CTX). Incidence of hip fracture events was ascertained to 2012. Associations of TSH and FT4 with BTMs were analysed at baseline using Pearson correlation coefficients, and with incident hip fracture using Cox proportional hazards regression.

RESULTS

After excluding men with pre-existing thyroid or bone disease, there were 3, 338 men for analysis. Of these, 3, 117 were euthyroid, 135 had subclinical hypothyroidism, and 86 had subclinical hyperthyroidism. Men with subclinical thyroid disease were older, and those with subclinical hyperthyroidism had lower creatinine than the other groups. After multivariate analysis, there were no associations found between FT4, TSH or subclinical thyroid dysfunction and BTMs at baseline. Neither subclinical thyroid dysfunction, TSH nor FT4 were predictive of incident hip fracture in our study population.

CONCLUSIONS

In euthyroid older men, TSH and FT4 were not associated with BTMs or incident hip fracture. Our findings differ from those previously described in postmenopausal women.

J-Shaped Association Between Postoperative Levothyroxine Dosage and Fracture Risk in Thyroid Cancer Patients: A Retrospective Cohort Study

Long-term administration of supraphysiologic dosages of levothyroxine can have detrimental effect on the bone. We aimed to investigate fracture incidence among post-thyroidectomy thyroid cancer patients compared with a matched comparison group, and explore the association between levothyroxine dosage and fracture risk. From the Korean National Health Insurance database, virtually all thyroid cancer patients who received thyroidectomy in Korea from January 1, 2004 to December 31, 2012 were included. Matched subjects were selected by 1:1 propensity score matching. Cox proportional hazards regression analysis was used to determine relative risk of osteoporotic fracture. Of 185,956 thyroid cancer patients identified, fracture events were observed in 1096 subjects (0.56%) over a mean 4.35 years of follow-up. Compared to the matched comparison group, thyroid cancer patients had no elevated risk of osteoporotic fracture (hazard ratio [HR] 1.03; 95% confidence interval [CI], 0.94 to 1.12); however, the highest dosage group (≥170 μg/day) showed significantly higher risk (HR 1.25; 95% CI, 1.07 to 1.45), while the second quartile dosage group (115-144 μg/day) showed lower risk (HR 0.71; 95% CI, 0.59 to 0.84) compared to a matched comparison group. When the second quartile dosage group was considered as reference, increased fracture risk was observed in those who took either lower (first quartile: adjusted HR 1.31; 95% CI, 1.08 to 1.59) or higher dosage of levothyroxine (third quartile: adjusted HR 1.50; 95% CI, 1.26 to 1.79; fourth quartile: adjusted HR 1.79; 95% CI, 1.51 to 2.13). Thyroid cancer patients were more likely to be treated with osteoporosis medication (HR 1.22; 95% CI, 1.18 to 1.26) than the matched comparison group. Both high and low dosage of levothyroxine treatment was associated with a higher risk for fractures in a J-shaped dose-dependent manner in post-thyroidectomy patients. Future studies are needed to determine how to optimize thyroid-stimulating hormone (TSH) suppression and how to screen and manage fracture risk. © 2018 American Society for Bone and Mineral Research.

Thyroid function in the etiology of fatigue in breast cancer

Background

Cancer related fatigue (CRF), reported in about 90% of breast cancer patients receiving chemotherapy, and has a profound impact on physical function, psychological distress and quality of life. Although several etiological factors such as anemia, depression, chronic inflammation, neurological pathology and alterations in metabolism have been proposed, the mechanisms of CRF are largely unknown.

Methods

We conducted a pilot, prospective, case-control study to estimate the magnitude of change in thyroid function in breast cancer patients from baseline to 24 months, compared to cancer-free, age-matched controls. Secondary objectives were to correlate changes in thyroid function and obesity over time with fatigue symptoms scores in this patient population.

Results

The proportion of women with breast cancer who developed subclinical or overt hypothyroidism (TSH >4.0 mIU/L) from baseline to year 1 was significantly greater compared to controls (9.6% vs. 5%; p=0.02). Subjects with breast cancer reported significantly worse fatigue symptoms than age-matched controls, as indicated by higher disruption indices (p<0.001 at baseline, p=0.02 at year 1, p=0.09 at year 2). Additionally, a significant interaction effect on disruption index score (p=0.019), general level of activity over time (p=0.006) and normal work activity (p= 0.002) was observed in the subgroup of women with BMI>30.

Conclusion

Screening breast cancer patients for thyroid function status at baseline and serially post-treatment to evaluate the need for thyroid hormone replacement may provide for a novel strategy for treating chemotherapy-induced fatigue.

Thyroid Dysfunction and Anemia: A Prospective Cohort Study and a Systematic Review

BACKGROUND

Even though the association between thyroid dysfunction and anemia is commonly described, it is not known whether it is clinically relevant. This study set out to quantify the association of thyroid dysfunction on hemoglobin (Hb) concentration and risk of anemia. A systematic review (MEDLINE and EMBASE, from inception until May 15, 2017) was conducted to interpret the findings in context.

METHODS

Participants from the EPIC-Norfolk cohort with available baseline thyrotropin (TSH), free thyroxine (fT4), and Hb were included. Euthyroidism was defined as TSH 0.45-4.49 mIU/L (reference category), hypothyroidism as TSH ≥4.50 mIU/L (subclinical [SHypo] with normal fT4 or overt [OHypo] with low fT4), and hyperthyroidism as TSH ≤0.44 mIU/L (subclinical [SHyper] with normal fT4 or overt [OHyper] with elevated fT4). Anemia was defined as Hb <12 g/dL in women and Hb <13 g/dL in men. In the cross-sectional analyses, multiple linear regression was used to compare Hb across TSH categories. In the prospective analysis, participants with OHypo/OHyper at baseline were excluded, as it was assumed that they were treated for overt thyroid disease. A covariance model was used to determine change in Hb concentration from baseline to last follow-up, and multivariable Cox regression was used to analyze anemia risk.

RESULTS

In the cross-sectional population (n = 12,337), the adjusted Hb was 0.22 g/dL lower [confidence interval (CI) 0.07-0.38] in OHypo compared to euthyroids, and 0.08 g/dL lower [CI -0.23 to 0.38] in OHyper. In the prospective analysis, 460/7031 participants developed anemia over a median follow-up of 4.7 years. The adjusted mean Hb change over time was -0.04 g/dL in SHypo [CI -0.14 to 0.06] and 0.05 g/dL in SHyper [CI -0.10 to 0.20]. The adjusted hazard ratio for anemia was 0.99 [CI 0.67-1.48] in SHypo, and 0.52 [CI 0.23-1.16] in SHyper. The systematic review returned no other prospective studies on this association, but cross-sectional and case-control studies showed comparable results.

CONCLUSION

In this first prospective population-based cohort, subclinical thyroid dysfunction was not associated with a change in Hb concentration during follow-up and was not an independent risk factor for developing anemia; variations in Hb concentration in patients with overt thyroid dysfunction were not clinically relevant.

Secondary and tertiary preventions of thyroid disease

INTRODUCTION

Secondary and tertiary preventions are concerned with the recognition of the disease process in a very early stage and delay in progression to complete disease and minimization of complications and the impact of illness.

METHODS

All articles related to secondary and tertiary prevention of thyroid diseases were reviewed. Using related key words, articles published between 2001 and 2015 were evaluated, categorized, and analyzed.

RESULTS

In secondary prevention, congenital hypothyroidism and subclinical hypo and hyperthyroidism are equally important. Routine screening of patients with multinodular goiter by either ultrasonography or calcitonin is a controversial issue, while calcitonin assessments in medullary cancer and RET in family members are recommended. Screening of thyroid disease in pregnancy is limited to those with risk factors. Views regarding the importance of thyroid autoimmunity in secondary prevention are also presented. In tertiary prevention, prescribing excessive doses of levothyroxine, in the elderly in particular and appropriate care of all patients to avoid progression and complications are the key issues.

CONCLUSION

Optimization of management of thyroid diseases requires timely screening, prevention of progression to more sever disease, optimal medical care, and avoidance of iatrogenic conditions.

Initial evaluation of thyroid dysfunction - Are simultaneous TSH and fT4 tests necessary?

Objective

Guidelines for thyroid function evaluation recommend testing TSH first, then assessing fT4 only if TSH is out of the reference range (two-step), but many clinicians initially request both TSH and fT4 (one-step). Given limitations of previous studies, we aimed to compare the two-step with the one-step approach in an unselected community-dwelling study population, and develop a prediction score based on clinical parameters that could identify at-risk patients for thyroid dysfunction.

Design

Cross-sectional analysis of the population-based Busselton Health Study.

Methods

We compared the two-step with the one-step approach, focusing on cases that would be missed by the two-step approach, i.e. those with normal TSH, but out-of-range fT4. We used likelihood ratio tests to identify demographic and clinical parameters associated with thyroid dysfunction and developed a clinical prediction score by using a beta-coefficient based scoring method.

Results

Following the two-step approach, 93.0% of all 4471 participants had normal TSH and would not need further testing. The two-step approach would have missed 3.8% of all participants (169 of 4471) with a normal TSH, but a fT4 outside the reference range. In 85% (144 of 169) of these cases, fT4 fell within 2 pmol/l of fT4 reference range limits, consistent with healthy outliers. The clinical prediction score that performed best excluded only 22.5% of participants from TSH testing.

Conclusion

The two-step approach may avoid measuring fT4 in as many as 93% of individuals with a very small risk of missing thyroid dysfunction. Our findings do not support the simultaneous initial measurement of both TSH and fT4.

High Prevalence of Radiological Vertebral Fractures in Women on Thyroid-Stimulating Hormone-Suppressive Therapy for Thyroid Carcinoma

CONTEXT

Bone loss and nonvertebral fractures have been reported in patients with differentiated thyroid carcinoma (DTC) undergoing thyroid-stimulating hormone (TSH) suppressive therapy. Radiological vertebral fractures (VFs) are an early and clinically crucial marker of bone fragility.

OBJECTIVE AND DESIGN

A cross-sectional study to evaluate the prevalence and determinants of radiological VFs in women receiving l-thyroxine (L-T4) therapy for DTC.

PATIENTS AND INTERVENTIONS

A total of 179 consecutive women (median age, 59 years; n = 178 postmenopausal) who had undergone thyroidectomy for DTC and were currently receiving L-T4 were evaluated for radiological VFs and bone mineral density (BMD). There were three TSH target levels [<0.5 mU/L, group 1 (n = 83); 0.5 to 1.0 mU/L, group 2 (n = 50); >1.0 mU/L, group 3 (n = 46)].

RESULTS

VFs were found in 51 patients (28.5%), with significantly (P < 0.001) higher prevalence in group 1 (44.6%) as compared with group 2 (24.0%) and group 3 (4.3%). VF prevalence was not significantly different among patients in group 1 with normal BMD, osteopenia, or osteoporosis, whereas in groups 2 and 3, VFs were more frequent in patients with osteoporosis than in those with either osteopenia or normal BMD. In the whole population, VFs were significantly and independently associated with TSH level <1.0 mU/L; densitometric diagnosis of osteoporosis at lumbar spine, femoral neck, or total hip; age of patients; and duration of L-T4 therapy.

CONCLUSION

The prevalence of VFs was high in women with DTC who were undergoing long-term, suppressive L-T4 therapy.

Thyroid diseases and bone health

Thyroid hormones are essential for skeletal development and are important regulators of bone maintenance in adults. Childhood hypothyroidism causes delayed skeletal development, retarded linear growth and impaired bone mineral accrual. Epiphyseal dysgenesis is evidenced by classic features of stippled epiphyses on X-ray. In severe cases, post-natal growth arrest results in a complex skeletal dysplasia. Thyroid hormone replacement stimulates catch-up growth and bone maturation, but recovery may be incomplete dependent on the duration and severity of hypothyroidism prior to treatment. A severe phenotype characteristic of hypothyroidism occurs in children with resistance to thyroid hormone due to mutations affecting THRA encoding thyroid hormone receptor α (TRα). Discovery of this rare condition recapitulated animal studies demonstrating that TRα mediates thyroid hormone action in the skeleton. In adults, thyrotoxicosis is well known to cause severe osteoporosis and fracture, but cases are rare because of prompt diagnosis and treatment. Recent data, however, indicate that subclinical hyperthyroidism is associated with low bone mineral density (BMD) and an increased risk of fracture. Population studies have also shown that variation in thyroid status within the reference range in post-menopausal women is associated with altered BMD and fracture risk. Thus, thyroid status at the upper end of the euthyroid reference range is associated with low BMD and increased risk of osteoporotic fragility fracture. Overall, extensive data demonstrate that euthyroid status is required for normal post-natal growth and bone mineral accrual, and is fundamental for maintenance of adult bone structure and strength.

Association of Nonalcoholic Fatty Liver Disease With Osteoporotic Fractures: A Cross-Sectional Retrospective Study of Chinese Individuals

Objective: Nonalcoholic fatty liver disease (NAFLD) is related to several inflammatory or metabolic diseases. However, findings of previous studies investigating the association between NAFLD and BMD are inconsistent. Only one study reported a potential association between NAFLD and osteoporotic fracture. This study investigated whether NAFLD in older participants (>55 years) was associated with osteoporotic fracture risk. Materials and Methods: This cross-sectional, observational study included 2,695 participants (35.7% men, 614 cases of NAFLD, and 383 fractures). Standardized questionnaires, laboratory tests, and physical and ultrasonic examinations were completed. Results: After adjusting for various factors including serum triglycerides (TG), high-density cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C), multivariate logistic regression models revealed a marginal association between NAFLD and osteoporotic fracture risk in men (odds ratio [OR], 1.86; 95% confidence interval [CI], 1.06-3.27; P = 0.030) but no association in women (OR, 1.05; 95% CI, 0.74-1.48; P = 0.800). Further stratified analyses showed a significant association between NAFLD and osteoporotic fracture risk in men without high TG, low HDL-C, and high LDL-C. Conclusions: There was a significant association between NAFLD and osteoporotic fracture risk in older Chinese men, particularly men without dyslipidemia.

Association between subclinical thyroid dysfunction and change in bone mineral density in prospective cohorts

BACKGROUND

Subclinical hyperthyroidism (SHyper) has been associated with increased risk of hip and other fractures, but the linking mechanisms remain unclear.

OBJECTIVE

To investigate the association between subclinical thyroid dysfunction and bone loss.

METHODS

Individual participant data analysis was performed after a systematic literature search in MEDLINE/EMBASE (1946-2016). Two reviewers independently screened and selected prospective cohorts providing baseline thyroid status and serial bone mineral density (BMD) measurements. We classified thyroid status as euthyroidism (thyroid-stimulating hormone [TSH] 0.45-4.49 mIU/L), SHyper (TSH < 0.45 mIU/L) and subclinical hypothyroidism (SHypo, TSH ≥ 4.50-19.99 mIU/L) both with normal free thyroxine levels. Our primary outcome was annualized percentage BMD change (%ΔBMD) from serial dual X-ray absorptiometry scans of the femoral neck, total hip and lumbar spine, obtained from multivariable regression in a random-effects two-step approach.

RESULTS

Amongst 5458 individuals (median age 72 years, 49.1% women) from six prospective cohorts, 451 (8.3%) had SHypo and 284 (5.2%) had SHyper. During 36 569 person-years of follow-up, those with SHyper had a greater annual bone loss at the femoral neck versus euthyroidism: %ΔBMD = -0.18 (95% CI: -0.34, -0.02; I2 = 0%), with a nonstatistically significant pattern at the total hip: %ΔBMD = -0.14 (95% CI: -0.38, 0.10; I2 = 53%), but not at the lumbar spine: %ΔBMD = 0.03 (95% CI: -0.30, 0.36; I2 = 25%); especially participants with TSH < 0.10 mIU/L showed an increased bone loss in the femoral neck (%Δ BMD = -0.59; [95% CI: -0.99, -0.19]) and total hip region (%ΔBMD = -0.46 [95% CI: -1.05, -0.13]). In contrast, SHypo was not associated with bone loss at any site.

CONCLUSION

Amongst adults, SHyper was associated with increased femoral neck bone loss, potentially contributing to the increased fracture risk.

Sclerostin Blockade and Zoledronic Acid Improve Bone Mass and Strength in Male Mice With Exogenous Hyperthyroidism

Hyperthyroidism in mice is associated with low bone mass, high bone turnover, and high concentrations of sclerostin, a potent Wnt inhibitor. Here, we explored the effects of either increasing bone formation with sclerostin antibodies (Scl-Ab) or reducing bone turnover with bisphosphonates on bone mass and strength in hyperthyroid mice. Twelve-week-old C57BL/6 male mice were rendered hyperthyroid using l-thyroxine (T4; 1.2 µg/mL added to the drinking water) and treated with 20 mg/kg Scl-Ab twice weekly or 100 µg/kg zoledronic acid (ZOL) once weekly or phosphate-buffered saline for 4 weeks. Hyperthyroid mice displayed a lower trabecular bone volume at the spine (-42%, P < 0.05) and the distal femur (-55%, P < 0.05) compared with euthyroid controls. Scl-Ab and ZOL treatment of hyperthyroid mice increased trabecular bone volume at the spine by threefold and twofold, respectively. Serum bone formation and resorption markers were increased in hyperthyroid mice and suppressed by treatment with ZOL but not Scl-Ab. Trabecular bone stiffness at the lumbar vertebra was 63% lower in hyperthyroid mice (P < 0.05) and was increased fourfold by Sci-Ab (P < 0.001) and threefold by ZOL treatment (P < 0.01). Bone strength based on ultimate load, which was 10% lower in hyperthyroidism, was increased by Scl-Ab by 71% and ZOL by 22% (both P < 0.001). Increased proportion of low mineralized bone seen in hyperthyroid mice was restored by treatment with Scl-Ab and ZOL. Thus, bone-forming and antiresorptive drugs prevent bone loss in hyperthyroid mice via different mechanisms.

Association of Thyroid Function With Life Expectancy With and Without Cardiovascular Disease: The Rotterdam Study

IMPORTANCE

Variations in thyroid function within reference ranges are associated with an increased risk of cardiovascular disease (CVD) and mortality. However, the impact of thyroid function on life expectancy (LE) and the number of years lived with and without CVD remains unknown.

OBJECTIVE

To investigate the association of thyroid function with total LE and LE with and without CVD among euthyroid individuals.

DESIGN, SETTING, AND PARTICIPANTS

The Rotterdam Study, a population-based, prospective cohort study. We included participants without known thyroid disease and with thyrotropin and free thyroxine (FT4) levels within the reference ranges.

MAIN OUTCOMES AND MEASURES

Multistate life tables were used to calculate total LE and LE with and without CVD among thyrotropin and FT4 tertiles. Life expectancy estimates in men and women aged 50 years and older were obtained using prevalence, incidence rates, and hazard ratios for 3 transitions (healthy to CVD, healthy to death, and CVD to death), adjusting for sociodemographic and cardiovascular risk factors.

RESULTS

The mean (SD) age of the 7785 participants was 64.7 (9.8) years, and 52.5% were women. Over a median follow-up of 8.1 (interquartile range, 2.7-9.9) years, we observed 789 incident CVD events and 1357 deaths. Compared with those in the lowest tertile, men and women in the highest thyrotropin tertile lived 2.0 (95% CI, 1.0 to 2.8) and 1.4 (95% CI, 0.2 to 2.4) years longer, respectively, of which, 1.5 (95% CI, 0.2 to 2.6) and 0.9 (95% CI, -0.2 to 2.0) years longer without CVD. Compared with those in the lowest tertile, the difference in life expectancy for men and women in the highest FT4 tertile was -3.2 (95% CI, -5.0 to -1.4) and -3.5 (95% CI, -5.6 to -1.5) years, respectively, of which, -3.1 (95% CI, -4.9 to -1.4) and -2.5 (95% CI, -4.4 to -0.7) years without CVD.

CONCLUSIONS AND RELEVANCE

At the age of 50 years, participants with low-normal thyroid function live up to 3.5 years longer overall and up to 3.1 years longer without CVD than participants with high-normal thyroid function. These findings provide supporting evidence for a reevaluation of the current reference ranges of thyroid function and can help inform preventive and clinical care.

Effect of subclinical hypothyroidism on the skeletal system and improvement with short-term thyroxine therapy

The purpose of the study was to observe changes in the skeletal system of rats with subclinical hypothyroidism (SCH) and to determine whether L-thyroxine (L-T4) administration suppresses those changes. Sixty male Wistar rats were randomly divided into control, SCH, and SCH+T4 groups. SCH was induced in rats by administration of methimazole (MMI), and rats in the SCH+T4 group were treated with L-T4 after 45 days of MMI administration. The SCH group had higher thyroid-stimulating hormone (TSH) level than the control and SCH+T4 groups. There were no differences in serum thyroid hormone (FT4 and FT3) levels among the three groups. Bone mineral density; serum levels of BALP and TRACP-5b, two bone metabolic markers; and the biomechanical properties of the femurs were lower in the SCH group than in the control group. After L-T4 treatment, serum BALP and TRACP-5b levels and the femur biomechanical properties were higher in the SCH+T4 than the SCH group. Histopathological examination revealed damage to the structure of the femur trabecular bone network in rats with SCH, and L-T4 treatment improved this condition to some extent. These findings demonstrate that L-T4 treatment ameliorates the destructive effects of SCH on the skeletal system in rats.

Validation of FRAX and the impact of self-reported falls among elderly in a general population: the HUNT study, Norway

Fracture Risk Assessment Tool (FRAX) without bone mineral density (BMD) for hip fracture prediction was validated in a Norwegian population 50-90 years. Fracture risk increased with higher FRAX score, and the observed number of hip fractures agreed well with the predicted number, except for the youngest and oldest men. Self-reported fall was an independent risk factor for fracture in women.

INTRODUCTION

The primary aim was to validate FRAX without BMD for hip fracture prediction in a Norwegian population of men and women 50-90 years. Secondary, to study whether information of falls could improve prediction of fractures in the subgroup aged 70-90 years.

METHODS

Data were obtained from the third survey of the Nord-Trøndelag Health Study (HUNT3), the fracture registry in Nord-Trøndelag, and the Norwegian Prescription Database (NorPD), including 15,432 women and 13,585 men. FRAX hip without BMD was calculated, and hip fractures were registered for a median follow-up of 5.2 years. The number of estimated and observed fractures was assessed, ROC curves with area under the curve (AUC), and Cox regression analyses. For the group aged 70-90 years, self-reported falls the last year before HUNT3 were included in the Cox regression model.

RESULTS

The risk of fracture increased with higher FRAX score. When FRAX groups were categorized in a 10-year percentage risk for hip fracture as follows, <4, 4-7.9, 8-11.9, and ≥12%, the hazard ratio (HR) for hip fracture between the lowest and the highest group was 17.80 (95% CI: 12.86-24.65) among women and 23.40 (13.93-39.30) in men. Observed number of hip fractures agreed quite well with the predicted number, except for the youngest and oldest men. AUC was 0.81 (0.78-0.83) for women and 0.79 (0.76-0.83) for men. Self-reported fall was an independent risk factor for fracture in women (HR 1.64, 1.20-2.24), and among men, this was not significant (1.09, 0.65-1.83).

CONCLUSIONS

FRAX without BMD predicted hip fracture reasonably well. In the age group 70-90 years, falls seemed to imply an additional risk among women.

The Rotterdam Study: 2018 update on objectives, design and main results

The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in The Netherlands. The study targets cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric, dermatological, otolaryngological, locomotor, and respiratory diseases. As of 2008, 14,926 subjects aged 45 years or over comprise the Rotterdam Study cohort. Since 2016, the cohort is being expanded by persons aged 40 years and over. The findings of the Rotterdam Study have been presented in over 1500 research articles and reports (see www.erasmus-epidemiology.nl/rotterdamstudy ). This article gives the rationale of the study and its design. It also presents a summary of the major findings and an update of the objectives and methods.

THYROID AND AGING

OBJECTIVE

Review physiologic thyroid function changes with aging and emphasize careful interpretation of tests in the aging population.

METHODS

Literature review.

RESULTS

Using age-specific thyroid-stimulating hormone (TSH) reference ranges should minimize or avoid the unnecessary diagnosis of thyroid disease in elderly patients. Subclinical thyroid dysfunction and abnormal TSH with normal thyroid levels may improve with time, so careful monitoring of thyroid function is recommended. Overt thyroid disease should always be treated.

CONCLUSION

Clinical judgement is always warranted to decide how and when to treat subclinical thyroid disease in the elderly.

ABBREVIATIONS

FT4 = free thyroxine; rT3 = reverse triiodothyronine; T3 = triiodothyronine; T4 = thyroxine; TFT = thyroid function test; TSH = thyroid-stimulating hormone.

Thyroid Function Tests in the Reference Range and Fracture: Individual Participant Analysis of Prospective Cohorts

CONTEXT

Hyperthyroidism is associated with increased fracture risk, but it is not clear if lower thyroid-stimulating hormone (TSH) and higher free thyroxine (FT4) in euthyroid individuals are associated with fracture risk.

OBJECTIVE

To evaluate the association of TSH and FT4 with incident fractures in euthyroid individuals.

DESIGN

Individual participant data analysis.

SETTING

Thirteen prospective cohort studies with baseline examinations between 1981 and 2002.

PARTICIPANTS

Adults with baseline TSH 0.45 to 4.49 mIU/L.

MAIN OUTCOME MEASURES

Primary outcome was incident hip fracture. Secondary outcomes were any, nonvertebral, and vertebral fractures. Results were presented as hazard ratios (HRs) with 95% confidence interval (CI) adjusted for age and sex. For clinical relevance, we studied TSH according to five categories: 0.45 to 0.99 mIU/L; 1.00 to 1.49 mIU/L; 1.50 to 2.49 mIU/L; 2.50 to 3.49 mIU/L; and 3.50 to 4.49 mIU/L (reference). FT4 was assessed as study-specific standard deviation increase, because assays varied between cohorts.

RESULTS

During 659,059 person-years, 2,565 out of 56,835 participants had hip fracture (4.5%; 12 studies with data on hip fracture). The pooled adjusted HR (95% CI) for hip fracture was 1.25 (1.05 to 1.49) for TSH 0.45 to 0.99 mIU/L, 1.19 (1.01 to 1.41) for TSH 1.00 to 1.49 mIU/L, 1.09 (0.93 to 1.28) for TSH 1.50 to 2.49 mIU/L, and 1.12 (0.94 to 1.33) for TSH 2.50 to 3.49 mIU/L (P for trend = 0.004). Hip fracture was also associated with FT4 [HR (95% CI) 1.22 (1.11 to 1.35) per one standard deviation increase in FT4]. FT4 only was associated with any and nonvertebral fractures. Results remained similar in sensitivity analyses.

CONCLUSIONS

Among euthyroid adults, lower TSH and higher FT4 are associated with an increased risk of hip fracture. These findings may help refine the definition of optimal ranges of thyroid function tests.

Cervical Burst Fracture in a Patient with Contiguous 2-Level Cervical Stand-Alone Cages

BACKGROUND

Cervical stand-alone interbody cages have seen increasingly wider use over the plate-and-screw construct in single-level anterior cervical discectomy and fusion (ACDF) in the treatment of cervical disc herniation and degenerative spondylotic conditions. Despite positive clinical outcomes, the efficacy and safety of using these devices in contiguous multilevel ACDF has remained controversial. This report discusses a burst fracture seen as a complication in multilevel cervical stand-alone cage use.

CASE DESCRIPTION

A 39-year-old woman with a history of C5-C6 and C6-C7 ACDF with contiguous stand-alone interbody cages 2 years prior, presented with recurrent arm and neck pain with myelopathy. Computed tomography scan revealed a burst fracture of the C6 vertebral body with retropulsion of fragments compressing the spinal cord.

CONCLUSIONS

This case suggests that use of cervical stand-alone cages in contiguous levels may cause late complications despite good instrumentation and illustrates the need for more careful consideration of technique selection in multilevel ACDF.

Low Thyroid Stimulating Hormone Levels Are Associated with Low Bone Mineral Density in Femoral Neck in Elderly Women

BACKGROUND AND AIMS

To determine the relationship between thyroid stimulating hormone (TSH) and bone mineral density (BMD) in elderly women.

METHODS

This is a retrospective cross-sectional population cohort study of women aged ≥65 years. All 1097 subjects had no overt thyroid dysfunction, 47 had subclinical hyperthyroidism and 100 had subclinical hypothyroidism. Overall, 167 had normal BMD, 594 had osteopenia and 336 had osteoporosis.

RESULTS

The femoral neck (FN) BMD was lower in women with lower TSH, with a high prevalance of osteoporosis and osteopenia (p = 0.036).The prevalence of osteoporosis and osteopenia was significantly low in the lowest quartile compared with the third quartile (p = 0.023) and the fourth quartile (p = 0.002), and the second low quartile, compared with the fourth quartile (p = 0.028). The differences were not significant among subclinical hyperthyroid, subclinical hypothyroid and euthyroid women. Low TSH was related to low BMDs at FN by multiple logistic regression analysis corrected for age and BMI. TSH in the lower two quartiles were independently related to osteoporosis (OR: 1.960, p = 0.023 and OR: 1.800, p = 0.037) and osteopenia (OR: 2.108, p = 0.005 and OR: 1.723, p = 0.030). Low TSH quartile (β: 0.007, p = 0.013) predicting low BMDs at FN.

CONCLUSION

Low TSH was independently related to decreased BMDs at FN in elderly women without overt thyroid dysfunction.

MANAGEMENT OF ENDOCRINE DISEASE: Subclinical thyrotoxicosis: prevalence, causes and choice of therapy

Subclinical thyrotoxicosis is a condition affecting up to 10% of the population in some studies. We have reviewed literature and identified studies describing prevalences, causes and outcomes of this condition. Treatment should be considered in all subjects if this biochemical abnormality is persistent, especially in case of symptoms of thyrotoxicosis or in the presence of any complication. In particular, treatment should be offered in those subclinically thyrotoxic patients with a sustained serum TSH below 0.1 U/L. However it is important to recognise that there are no large controlled intervention studies in the field and thus there is no high quality evidence to guide treatment recommendations. In particular, there is no evidence for therapy and there is weak evidence of harm from thyrotoxicosis if serum TSH is in the 0.1-0.4 IU/L range. In this review, we describe the different causes of subclinical thyrotoxicosis, and how treatment should be tailored to the specific cause. We advocate radioactive iodine treatment to be the first-line treatment in majority of patients suffering from subclinical thyrotoxicosis due to multinodular toxic goitre and solitary toxic adenoma, but we do generally not recommend it as the first-line treatment in patients suffering from subclinical Graves' hyperthyroidism. Such patients may benefit mostly from antithyroid drug therapy. Subclinical thyrotoxicosis in early pregnancy should in general be observed, not treated. Moreover, we advocate a general restriction of therapy in cases where no specific cause for the presumed thyroid hyperactivity has been proven.

Subclinical hypothyroidism: Should we treat?

Subclinical hypothyroidism (also known as compensated hypothyroidism or mild hypothyroidism) is a condition associated with a raised serum concentration of thyroid stimulating hormone (TSH) but a normal serum free thyroxine (FT4). It is common, affecting about 10% of women above the age of 55 years. Autoimmunity is the commonest cause of subclinical hypothyroidism. About 2.5% of patients with subclinical hypothyroidism progress to clinically overt hypothyroidism each year; the rate of progression is higher in patients with thyroid autoantibodies and higher thyroid stimulating hormone levels. However, thyroid function normalises spontaneously in up to 40% cases. Only a small minority of patients with subclinical hypothyroidism have symptoms, and the evidence to support that levothyroxine ameliorate the symptoms in these patients is weak. Subclinical hypothyroidism in younger patients (<65 years) is associated with an increased risk of coronary heart disease, heart failure and cerebrovascular disease. The risk increases with increasing levels of thyroid stimulating hormone, and is particularly high in patients with TSH levels ≥10.0 mu/L. There is lack of evidence from randomised controlled trials as to whether levothyroxine treatment can prevent these risks, although a large observational study of the UK general practice research database has shown that levothyroxine may reduce the risk of coronary heart disease in younger patients (<70 years). Therefore, the decision whether to treat or not to treat subclinical hypothyroidism should be made after careful consideration of the patient's age, the presence of symptoms, the presence of thyroid antibodies and other risk factors such as cardiovascular disease.

Psoriasis, fracture risk and bone mineral density: the HUNT Study, Norway

BACKGROUND

An association between psoriasis and osteoporosis has been reported.

OBJECTIVES

To investigate, in a large prospective population-based Norwegian study, whether psoriasis is associated with increased risk of forearm or hip fracture; to investigate the cross-sectional association between psoriasis and bone mineral density (BMD) T-score in a subpopulation.

METHODS

Hospital-derived fracture data from Nord-Trøndelag County (1995-2013) were linked to psoriasis information, BMD measurements and lifestyle factors from the third survey of the Nord-Trøndelag Health Study 2006-08 (HUNT3); socioeconomic data from the National Education Database; and use of medication from the Norwegian Prescription Database.

RESULTS

Among 48 194 participants in HUNT3, we found no increased risk of forearm or hip fracture in 2804 patients with self-reported psoriasis [overall age- and sex-adjusted hazard ratio 1·03, 95% confidence interval (CI) 0·82-1·31]. No clear association was found between psoriasis and mean BMD T-score; overall age- and sex-adjusted differences in total hip, femoral neck and lumbar spine BMD T-scores were 0·02 (95% CI -0·11 to 0·14), 0·05 (95% CI -0·06 to 0·17) and 0·07 (95% CI -0·09 to 0·24), respectively. No clear association was found between psoriasis and prevalent osteoporosis in either total hip, femoral neck or lumbar spine; overall age- and sex-adjusted odds ratio was 0·77 (95% CI 0·54-1·10). Associations did not change substantially after adjustment for education, smoking, systemic steroid use and body mass index.

CONCLUSIONS

We found no association between psoriasis and risk of fracture. The study did not indicate reduced BMD T-score or higher prevalence of osteoporosis among patients with psoriasis.

Pituitary-bone connection in skeletal regulation

Pituitary hormones have traditionally been thought to exert specific, but limited function on target tissues. More recently, the discovery of these hormones and their receptors in organs such as the skeleton suggests that pituitary hormones have more ubiquitous functions. Here, we discuss the interaction of growth hormone (GH), follicle stimulating hormone (FSH), thyroid stimulating hormone (TSH), adrenocorticotrophic hormone (ACTH), prolactin, oxytocin and arginine vasopressin (AVP) with bone. The direct skeletal action of pituitary hormones therefore provides new insights and therapeutic opportunities for metabolic bone diseases, prominently osteoporosis.

Thyroid function and autoimmunity are associated with the risk of vertebral fractures in postmenopausal women

Overt or subclinical thyroid dysfunction may affect the risk of fragility fractures. The aim of the present study was to assess the association of thyroid function and autoimmunity with vertebral fractures (VF) in a large sample of Greek postmenopausal women. This cross-sectional study recruited 335 euthyroid postmenopausal women, aged 35-79 years. Euthyroidism was verified by serum thyroid-stimulating hormone (TSH) within the laboratory reference range (0.4-4.5 μIU/mL). VFs were diagnosed by lumbar spine lateral radiographs, according to quantitative procedures. Serum free triiodothyronine (FT3), free thyroxine (FT4), TSH, as well as levels of anti-thyroglobulin (anti-TG) and thyroid peroxidase antibodies (anti-TPO) were compared according to the presence of VFs. Multivariate logistic regression showed that the presence of VFs was predicted independently by ln-TSH levels (OR = 0.290, p = 0.037) and positive anti-TG antibodies (OR = 3.308, p = 0.026) in models adjusted for age, menopausal age, and ln-HOMA-IR. Stepwise logistic regression analysis showed that the presence of VFs was predicted by menopausal age (OR = 1.120, p = 0.001), ln-TSH (OR = 0.312, p = 0.052), and thyroid autoimmunity (anti-TG and anti-TPO positive: OR = 6.637, p = 0.007) in a model that also included age and ln-HOMA-IR. Women with lower circulating TSH had higher risk of having a VF, independently of age, menopausal age, and insulin resistance. The presence of positive anti-TG/anti-TPO antibodies also indicated an elevated risk of fracture. Levels of thyroid hormones had no apparent effect on the risk of fracture. Further studies are necessary to establish the significance of our findings.

Hormonal and systemic regulation of sclerostin

The Wnt/β-catenin signaling pathway plays an essential role in osteoblast biology. Sclerostin is a soluble antagonist of Wnt/β-catenin signaling secreted primarily by osteocytes. Current evidence indicates that sclerostin likely functions as a local/paracrine regulator of bone metabolism rather than as an endocrine hormone. Nonetheless, circulating sclerostin levels in humans often reflect changes in the bone microenvironment, although there may be exceptions to this observation. Using existing assays, circulating sclerostin levels have been shown to be altered in response to both hormonal stimuli and across a variety of normal physiological and pathophysiological conditions. In both rodents and humans, parathyroid hormone provided either intermittently or continuously suppresses sclerostin levels. Likewise, most evidence from both human and animal studies supports a suppressive effect of estrogen on sclerostin levels. Efforts to examine non-hormonal/systemic regulation of sclerostin have in general shown less consistent findings or have provided associations rather than direct interventional information, with the exception of mechanosensory studies which have consistently demonstrated increased sclerostin levels with skeletal unloading, and conversely decreases in sclerostin with enhanced skeletal loading. Herein, we will review the existent literature on both hormonal and non-hormonal/systemic factors which have been studied for their impact on sclerostin regulation.

Study protocol; Thyroid hormone Replacement for Untreated older adults with Subclinical hypothyroidism - a randomised placebo controlled Trial (TRUST)

BACKGROUND

Subclinical hypothyroidism (SCH) is a common condition in elderly people, defined as elevated serum thyroid-stimulating hormone (TSH) with normal circulating free thyroxine (fT4). Evidence is lacking about the effect of thyroid hormone treatment. We describe the protocol of a large randomised controlled trial (RCT) of Levothyroxine treatment for SCH.

METHODS

Participants are community-dwelling subjects aged ≥65 years with SCH, diagnosed by elevated TSH levels (≥4.6 and ≤19.9 mU/L) on a minimum of two measures ≥ three months apart, with fT4 levels within laboratory reference range. The study is a randomised double-blind placebo-controlled parallel group trial, starting with levothyroxine 50 micrograms daily (25 micrograms in subjects <50Kg body weight or known coronary heart disease) with titration of dose in the active treatment group according to TSH level, and a mock titration in the placebo group. The primary outcomes are changes in two domains (hypothyroid symptoms and fatigue / vitality) on the thyroid-related quality of life questionnaire (ThyPRO) at one year. The study has 80% power (at p = 0.025, 2-tailed) to detect a change with levothyroxine treatment of 3.0% on the hypothyroid scale and 4.1% on the fatigue / vitality scale with a total target sample size of 750 patients. Secondary outcomes include general health-related quality of life (EuroQol), fatal and non-fatal cardiovascular events, handgrip strength, executive cognitive function (Letter Digit Coding Test), basic and instrumental activities of daily living, haemoglobin, blood pressure, weight, body mass index and waist circumference. Patients are monitored for specific adverse events of interest including incident atrial fibrillation, heart failure and bone fracture.

DISCUSSION

This large multicentre RCT of levothyroxine treatment of subclinical hypothyroidism is powered to detect clinically relevant change in symptoms / quality of life and is likely to be highly influential in guiding treatment of this common condition.

TRIAL REGISTRATION

Clinicaltrials.gov NCT01660126 ; registered 8th June 2012.

Population-Based National Prevalence of Thyroid Dysfunction in Spain and Associated Factors: Di@bet.es Study

BACKGROUND

The aim of this study was to investigate the national prevalence of thyroid dysfunction in Spain and its association with various clinical, environmental, and demographic variables.

METHODS

The study included 4554 subjects (42.4% men) with a mean age of 50 years (range 18-93 years), who were participants in a national, cross-sectional, population-based survey conducted in 2009-2010. Data gathered included clinical and demographic characteristics, physical examination, and blood sampling. Thyrotropin, free thyroxine, free triiodothyronine, and thyroid peroxidase antibody (TPOAb) concentrations were analyzed by electrochemiluminescence. Urinary iodine (UI) levels were measured in an isolated urine sample.

RESULTS

The prevalence of treated hypothyroidism, untreated subclinical hypothyroidism, and untreated clinical hypothyroidism was 4.2% [confidence interval (CI) 3.6-4.9%], 4.6% [CI 4.0-5.2%], and 0.3% [CI 0.1-0.5%], respectively. The prevalence of total hypothyroidism (including all fractions) was 9.1% [CI 8.2-10.0%]. The prevalence of total hyperthyroidism was 0.8% [CI 0.6-1.1]. A total of 7.5% [CI 6.7-8.3%] of the population tested positive for TPOAbs (≥50 IU/mL). In multivariate logistic regression models, TPOAbs were strongly associated with both hypothyroidism (p < 0.001) and hyperthyroidism (p = 0.005), whereas high UI levels (>200 μg/g creatinine) were associated with hypothyroidism (p < 0.001). The positive association between UI and hypothyroidism remained for both treated (p < 0.001) and untreated (p < 0.05) hypothyroidism, whereas it was especially significant for non-autoimmune (TPOAbs negative) forms (p < 0.001). At UI levels ≥200 μg/g, there was a positive correlation between UI and thyrotropin levels (β = 0.152, p < 0.001) and a negative correlation between UI and free triiodothyronine levels (β = -0.134, p = 0.001).

CONCLUSION

According to the data, a large proportion (10%) of the Spanish population has some evidence of thyroid dysfunction. High TPOAb concentrations were associated with both hypo- and hyperthyroidism, whereas high UI concentrations were associated with hypothyroidism.

Low Normal TSH levels are Associated with Impaired BMD and Hip Geometry in the Elderly

Subclinical hyperthyroidism is known to be associated with the risk of fractures in elderly people. However, there are few studies assessing whether low normal thyroid-stimulating hormone (TSH) levels affect bone density and geometry. Here, we aimed to assess the influence of the TSH level on bone mineral density (BMD) and geometry in elderly euthyroid subjects. This was a cross-sectional cohort study. A total of 343 men and 674 women with euthyroidism were included and analyzed separately. The subjects were divided into tertiles based on the serum TSH level. The BMD and geometry were measured using dual-energy X-ray absorptiometry and a hip structural analysis program. Multiple regression analysis was used to compute the odds ratios of osteoporosis in the lower TSH tertile group and the association between geometry parameters and the TSH level. We found that the femoral neck and total hip BMDs were lower in the lower TSH tertile group. In women, the cross-sectional area and cortical thickness of the femur were negatively associated with the TSH level in all three regions (the narrow neck, intertrochanter, and femoral shaft); however, in men, these geometry parameters were significantly associated with the TSH level only in the intertrochanter region. The buckling ratio, a bone geometry parameter representing cortical instability, was significantly higher in the lower TSH tertile group in all three regions in women, but not in men. Our results indicated that lower TSH levels in the euthyroid range are related to lower BMD and weaker femoral structure in elderly women.

Urinary free cortisol and androgens in the population-Hormone interactions and the relationship with body composition and bone status

OBJECTIVE

Abnormal secretion of thyroid hormones, growth hormone, cortisol and androgens influences body composition. We hypothesised that higher cortisol excretion, in combination with higher androgen and IGF-I concentrations, had a synergistic, favourable effect on body mass and bone.

DESIGN, PATIENTS AND METHODS

This was a cross-sectional study on a population sample of 290 women and 93men. The mean age was 65.4±7.2yearsinwomen and 59.7±10.0yearsinmen. Body composition was assessed with bioimpedance, and skeletal health with calcaneal quantitative ultrasound and fracture rate. The influence of urinary free cortisol (UFC), serum DHEAs (women), testosterone (men), free T4andIGF-I on the outcome was studied with regression analyses adjusted for age and body mass index.

RESULTS

In women, higher concentrations of UFC, DHEAs, IGF-I and lower free T4, were associated with higher fat-free mass. Only a higher UFC concentration was associated with favourable calcaneal measurements. In men, higher testosterone was associated with higher fat-free mass and lower fat mass. Higher IGF-I concentration, but not UFC, was independently associated with higher fat-free mass in men. Interaction analyses did not reveal any additive effects of hormones on body composition or bone in either sex. In both men and women, only age was associated with osteoporotic fractures.

CONCLUSION

Serum concentrations of androgens together with IGF-I were positively associated with body composition in both sexes. Urinary cortisol was positively associated with fat-free mass and bone status in women only. Increasing age, but not hormones, was the major determinant of osteoporotic fractures in this population sample.

Thyroid Function Within the Reference Range and the Risk of Stroke: An Individual Participant Data Analysis

CONTEXT

The currently applied reference ranges for thyroid function are under debate. Despite evidence that thyroid function within the reference range is related with several cardiovascular disorders, its association with the risk of stroke has not been evaluated previously.

DESIGN AND SETTING

We identified studies through a systematic literature search and the Thyroid Studies Collaboration, a collaboration of prospective cohort studies. Studies measuring baseline TSH, free T₄, and stroke outcomes were included, and we collected individual participant data from each study, including thyroid function measurements and incident all stroke (combined fatal and nonfatal) and fatal stroke. The applied reference range for TSH levels was between 0.45 and 4.49 mIU/L.

RESULTS

We collected individual participant data on 43 598 adults with TSH within the reference range from 17 cohorts, with a median follow-up of 11.6 years (interquartile range 5.1-13.9), including 449 908 person-years. Age- and sex-adjusted pooled hazard ratio for TSH was 0.78 (95% confidence interval [CI] 0.65-0.95 across the reference range of TSH) for all stroke and 0.83 (95% CI 0.62-1.09) for fatal stroke. For the free T₄ analyses, the hazard ratio was 1.08 (95% CI 0.99-1.15 per SD increase) for all stroke and 1.10 (95% CI 1.04-1.19) for fatal stroke. This was independent of cardiovascular risk factors including systolic blood pressure, total cholesterol, smoking, and prevalent diabetes.

CONCLUSION

Higher levels of TSH within the reference range may decrease the risk of stroke, highlighting the need for further research focusing on the clinical consequences associated with differences within the reference range of thyroid function.

Serum Thyroid Function, Mortality and Disability in Advanced Old Age: The Newcastle 85+ Study

CONTEXT

Perturbations in thyroid function are common in older individuals but their significance in the very old is not fully understood.

OBJECTIVE

This study sought to determine whether thyroid hormone status and variation of thyroid hormones within the reference range correlated with mortality and disability in a cohort of 85-year-olds.

DESIGN

A cohort of 85-year-old individuals were assessed in their own homes (community or institutional care) for health status and thyroid function, and followed for mortality and disability for up to 9 years.

SETTING AND PARTICIPANTS

Six hundred and forty-three 85-year-olds registered with participating general practices in Newcastle and North Tyneside, United Kingdom.

MAIN OUTCOMES

All-cause mortality, cardiovascular mortality, and disability according to thyroid disease status and baseline thyroid hormone parameters (serum TSH, FT₄, FT₃, and rT₃). Models were adjusted for age, sex, education, body mass index, smoking, and disease count.

RESULTS

After adjustment for age and sex, all-cause mortality was associated with baseline serum rT₃ and FT₃ (both P < .001), but not FT₄ or TSH. After additional adjustment for potential confounders, only rT₃ remained significantly associated with mortality (P = .001). Baseline serum TSH and rT₃ predicted future disability trajectories in men and women, respectively.

CONCLUSIONS

Our study is reassuring that individuals age 85 y with both subclinical hypothyroidism and subclinical hyperthyroidism do not have a significantly worse survival over 9 years than their euthyroid peers. However, thyroid function tests did predict disability, with higher serum TSH levels predicting better outcomes. These data strengthen the argument for routine use of age-specific thyroid function reference ranges.

RANKL/Osteoprotegerin System and Bone Turnover in Hashimoto Thyroiditis

Hypothyroidism is associated with changes in bone metabolism. The impact of hypothyroidism and the associated autoimmunity on the mediators of bone turnover in Hashimoto's thyroiditis (HT) is not known. In this study, we assessed the levels of OPG, RANKL, and IL-6 along with markers of bone formation as osteocalcin (OC) and markers of bone resorption as type 1 collagen C telopeptide (CTX) and tartrate-resistant acid phosphatase isoform 5b (TRAcP 5b) in 30 hypothyroid and 30 euthyroid premenopausal HT patients and 20 healthy premenopausal controls. We found that TRAcP 5b (p = 0.006), CTX (p = 0.01), OC (p = 0.017), and IL-6 (p < 0.001) levels were lower in the hypothyroid group compared to euthyroid HT patients and controls. OPG levels were higher (p < 0.001) and RANKL levels were lower (p = 0.021) in hypothyroid and euthyroid HT patients compared to controls. TSH was negatively correlated with IL-6 (rho = -0.434, p < 0.001), OC (rho = -0.313, p = 0.006), TRAcP 5b (rho = -0.335, p = 0.003), and positively correlated with OPG (rho = 0.248, p = 0.029). RANKL/OPG ratio was independently associated with the presence of HT. In conclusion, bone turnover is slowed down by hypothyroidism in premenopausal patients with HT. Thyroid autoimmunity might have a unique impact on OPG/RANKL levels apart from the resultant hypothyroidism.

2016 American Thyroid Association Guidelines for Diagnosis and Management of Hyperthyroidism and Other Causes of Thyrotoxicosis

BACKGROUND

Thyrotoxicosis has multiple etiologies, manifestations, and potential therapies. Appropriate treatment requires an accurate diagnosis and is influenced by coexisting medical conditions and patient preference. This document describes evidence-based clinical guidelines for the management of thyrotoxicosis that would be useful to generalist and subspecialty physicians and others providing care for patients with this condition.

METHODS

The American Thyroid Association (ATA) previously cosponsored guidelines for the management of thyrotoxicosis that were published in 2011. Considerable new literature has been published since then, and the ATA felt updated evidence-based guidelines were needed. The association assembled a task force of expert clinicians who authored this report. They examined relevant literature using a systematic PubMed search supplemented with additional published materials. An evidence-based medicine approach that incorporated the knowledge and experience of the panel was used to update the 2011 text and recommendations. The strength of the recommendations and the quality of evidence supporting them were rated according to the approach recommended by the Grading of Recommendations, Assessment, Development, and Evaluation Group.

RESULTS

Clinical topics addressed include the initial evaluation and management of thyrotoxicosis; management of Graves' hyperthyroidism using radioactive iodine, antithyroid drugs, or surgery; management of toxic multinodular goiter or toxic adenoma using radioactive iodine or surgery; Graves' disease in children, adolescents, or pregnant patients; subclinical hyperthyroidism; hyperthyroidism in patients with Graves' orbitopathy; and management of other miscellaneous causes of thyrotoxicosis. New paradigms since publication of the 2011 guidelines are presented for the evaluation of the etiology of thyrotoxicosis, the management of Graves' hyperthyroidism with antithyroid drugs, the management of pregnant hyperthyroid patients, and the preparation of patients for thyroid surgery. The sections on less common causes of thyrotoxicosis have been expanded.

CONCLUSIONS

One hundred twenty-four evidence-based recommendations were developed to aid in the care of patients with thyrotoxicosis and to share what the task force believes is current, rational, and optimal medical practice.

Recent Advances in Autoimmune Thyroid Diseases

Autoimmune thyroid disease (AITD) includes hyperthyroid Graves disease, hypothyroid autoimmune thyroiditis, and subtle subclinical thyroid dysfunctions. AITD is caused by interactions between genetic and environmental predisposing factors and results in autoimmune deterioration. Data on polymorphisms in the AITD susceptibility genes, related environmental factors, and dysregulation of autoimmune processes have accumulated over time. Over the last decade, there has been progress in the clinical field of AITD with respect to the available diagnostic and therapeutic methods as well as clinical consensus. The updated clinical guidelines allow practitioners to identify the most reasonable and current approaches for proper management. In this review, we focus on recent advances in understanding the genetic and environmental pathogenic mechanisms underlying AITD and introduce the updated set of clinical guidelines for AITD management. We also discuss other aspects of the disease such as management of subclinical thyroid dysfunction, use of levothyroxine plus levotriiodothyronine in the treatment of autoimmune hypothyroidism, risk assessment of long-standing antithyroid drug therapy in recurrent Graves' hyperthyroidism, and future research needs.

AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY POSITION STATEMENT ON THYROID DYSFUNCTION CASE FINDING

Hypothyroidism and hyperthyroidism can be readily diagnosed and can be treated in a safe, cost-effective manner. Professional organizations have given guidance on how and when to employ thyroid-stimulating hormone testing for the detection of thyroid dysfunction. Most recently, the United States Preventive Services Task Force did not endorse screening for thyroid dysfunction based on a lack of proven benefit and potential harm of treating those with thyroid dysfunction, which is mostly subclinical disease. The American Association of Clinical Endocrinologists (AACE) is concerned that this may discourage physicians from testing for thyroid dysfunction when clinically appropriate. Given the lack of specificity of thyroid-associated symptoms, the appropriate diagnosis of thyroid disease requires biochemical confirmation. The Thyroid Scientific Committee of the AACE has produced this White Paper to highlight the important difference between screening and case-based testing in the practice of clinical medicine. We recommend that thyroid dysfunction should be frequently considered as a potential etiology for many of the nonspecific complaints that physicians face daily. The application and success of safe and effective interventions are dependent on an accurate diagnosis. We, therefore, advocate for an aggressive case-finding approach, based on identifying those persons most likely to have thyroid disease that will benefit from its treatment.

Symptoms of thyrotoxicosis, bone metabolism and occult atrial fibrillation in older women with mild endogenous subclinical hyperthyroidism

OBJECTIVE

The objective of this study was to evaluate symptoms of thyrotoxicosis, bone turnover, bone mineral density (BMD) and occult atrial fibrillation (AF) in women ≥65 years with mild endogenous subclinical hyperthyroidism (SCH).

DESIGN

Cross-sectional and case-control study.

PATIENTS

Signs and symptoms of thyrotoxicosis, serum carboxyterminal telopeptide (CTx) and procollagen type I N-terminal propeptide (PINP), BMD, resting electrocardiogram (ECG) and 72-h ECG monitoring were evaluated in 180 women ≥65 years, including 90 with mild SCH (TSH between 0·1 and 0·4 mIU/l) and 90 euthyroid controls matched for age and body mass index.

RESULTS

Symptom Rating Scale scores did not differ between patients and controls. None of the patients with SCH scored 20 points, a score compatible with clinical thyrotoxicosis. Eighty patients with SCH (89%) obtained seven or fewer points, a score compatible with euthyroidism. No difference in serum CTx or PINP concentrations was observed between patients and controls. There was also no correlation between these markers and TSH, free T4 or total T3 levels. Finally, no difference in femoral neck or lumbar spine BMD was observed between patients with SCH and controls. Three patients with SCH (3·3%) and two euthyroid women (2·2%) had known AF or AF in the resting ECG. ECG monitoring for 72 h revealed episodes of occult AF in 1/87 patients with SCH and in 1/88 euthyroid women (1·1%).

CONCLUSIONS

Mild endogenous SCH (TSH between 0·1 and 0·4 mIU/l) was not associated with symptoms of thyrotoxicosis, altered bone metabolism or a higher prevalence of occult AF in women ≥65 years.