Subclinical thyroid dysfunction and fracture risk: a meta-analysis

Hyperthyroidism-driven bone loss depends on BMP receptor Bmpr1a expression in osteoblasts

Hyperthyroidism is a well-known trigger of high bone turnover that can lead to the development of secondary osteoporosis. Previously, we have shown that blocking bone morphogenetic protein (BMP) signaling systemically with BMPR1A-Fc can prevent bone loss in hyperthyroid mice. To distinguish between bone cell type-specific effects, conditional knockout mice lacking Bmpr1a in either osteoclast precursors (LysM-Cre) or osteoprogenitors (Osx-Cre) were rendered hyperthyroid and their bone microarchitecture, strength and turnover were analyzed. While hyperthyroidism in osteoclast precursor-specific Bmpr1a knockout mice accelerated bone resorption leading to bone loss just as in wildtype mice, osteoprogenitor-specific Bmpr1a deletion prevented an increase of bone resorption and thus osteoporosis with hyperthyroidism. In vitro, wildtype but not Bmpr1a-deficient osteoblasts responded to thyroid hormone (TH) treatment with increased differentiation and activity. Furthermore, we found an elevated Rankl/Opg ratio with TH excess in osteoblasts and bone tissue from wildtype mice, but not in Bmpr1a knockouts. In line, expression of osteoclast marker genes increased when osteoclasts were treated with supernatants from TH-stimulated wildtype osteoblasts, in contrast to Bmpr1a-deficient cells. In conclusion, we identified the osteoblastic BMP receptor BMPR1A as a main driver of osteoporosis in hyperthyroid mice promoting TH-induced osteoblast activity and potentially its coupling to high osteoclastic resorption.

Ten tips on how to assess bone health in patients with chronic kidney disease

Patients with chronic kidney disease (CKD) experience a several-fold increased risk of fracture. Despite the high incidence and the associated excess morbidity and premature mortality, bone fragility in CKD, or CKD-associated osteoporosis, remains a blind spot in nephrology with an immense treatment gap. Defining the bone phenotype is a prerequisite for the appropriate therapy of CKD-associated osteoporosis at the patient level. In the present review, we suggest 10 practical 'tips and tricks' for the assessment of bone health in patients with CKD. We describe the clinical, biochemical, and radiological evaluation of bone health, alongside the benefits and limitations of the available diagnostics. A bone biopsy, the gold standard for diagnosing renal bone disease, is invasive and not widely available; although useful in complex cases, we do not consider it an essential component of bone assessment in patients with CKD-associated osteoporosis. Furthermore, we advocate for the deployment of multidisciplinary expert teams at local, national, and potentially international level. Finally, we address the knowledge gaps in the diagnosis, particularly early detection, appropriate "real-time" monitoring of bone health in this highly vulnerable population, and emerging diagnostic tools, currently primarily used in research, that may be on the horizon of clinical practice.

Association between serum TSH concentration and bone mineral density: an umbrella review

INTRODUCTION

The aim of this study was to summarize the results of previous studies, standardize the data, and present new statistical results in order to provide physicians with clinically significant outcomes regarding the association between serum TSH concentration and bone mineral density (BMD).

METHODS

To perform this umbrella review, a systematic search was conducted in which major online medical databases, such as PubMed, Web of Science, Embase, Scopus, Cochrane Library, and Google Scholar, were searched for meta-analyses and systematic reviews regarding the effect of TSH on BMD. Furthermore, all primary studies were screened for statistical analysis.

RESULTS

The statistical outcomes of the present study were based on the data of 75,898 patients. The pooled risk ratio of any kind of fracture in patients with subclinical hyperthyroidism was estimated to be 1.36 (95% CI: 1.18-1.56; p < 0.001). The SMD for BMD in the distal radius in male patients receiving L-thyroxine suppression therapy was estimated to be -0.61 (95% CI: -1.10-(-0.11); p = 0.02). Furthermore, the pooled risk ratio of any fracture in patients receiving L-thyroxine suppression therapy was estimated to be 1.98 (95% CI: 0.98 - 3.98; p = 0.06). In these patients, the BMD may significantly differ from that in non-treated patients. However, the difference depends on the type of bone.

CONCLUSIONS

Our data confirmed that subclinical hyperthyroidism has a detrimental effect on bones, causing decreased BMD. Based on the obtained results, the authors suggest that a reduced TSH serum level itself may be an individual factor associated with decreased BMD and, thus, with a greater risk of bone fracture. Nevertheless, it should be noted that the effects of TSH suppression therapy differ between areas of interest for assessing BMD. Furthermore, the results have shown that this issue may, in specific areas, concern not only postmenopausal women but also male patients. These conclusions should contribute to a careful consideration of the application of TSH suppressive therapy in all patients. Particular attention should be given to patients after DTC, while all the advantages and disadvantages of implementing L-thyroxine therapy should be individually considered.

Higher serum free thyroxine levels are associated with increased risk of hip fractures in older men

Overt and subclinical hyperthyroidism are associated with an increased fracture risk, but whether thyroid hormones are associated with fracture risk in individuals with normal thyroid-stimulating hormone (TSH) has mostly been investigated in women. Therefore, we investigated if serum levels of free thyroxine (FT4) or TSH are associated with fracture risk in Swedish men. We followed (median 12.2 yr) elderly men (n = 1825; mean age 75, range 69-81 yr) participating in the Gothenburg and Malmö subcohorts of the prospective, population-based MrOS-Sweden study. The statistical analyses included Cox proportional hazards regression. Men receiving levothyroxine treatment were excluded. In our total cohort, serum FT4 (per SD increase) was associated with increased risk of major osteoporotic fractures (MOFs; n = 479; fully adjusted hazard ratio [HR] 1.14, 95% CI, 1.05-1.24) and hip fractures (n = 207; HR 1.18, 95% CI, 1.04-1.33). Also, in men with normal TSH (n = 1658), FT4 (per SD increase) was significantly associated with increased risk of MOF and hip fractures. Furthermore, men in the highest FT4 quartile had a 1.5-fold increase in hip fracture risk compared with men in the three lower FT4 quartiles, both in the total population and in men with normal TSH (fully adjusted: HR 1.45, 95% CI, 1.04-2.02 and HR 1.51, 95% CI, 1.07-2.12, respectively). In contrast, the risk of MOF was not statistically different in the highest FT4 quartile compared with the three lower FT4 quartiles. Finally, serum TSH was not associated with fracture risk after full adjustment for covariates. In conclusion, serum FT4, but not serum TSH, is a predictor of hip fracture risk in elderly Swedish men. Additionally, there was an association between FT4 (per SD increase) and the risk of MOF.

Hyperthyroidism

Thyrotoxicosis causes a variety of symptoms and adverse health outcomes. Hyperthyroidism refers to increased thyroid hormone synthesis and secretion, most commonly from Graves' disease or toxic nodular goitre, whereas thyroiditis (typically autoimmune, viral, or drug induced) causes thyrotoxicosis without hyperthyroidism. The diagnosis is based on suppressed serum concentrations of thyroid-stimulating hormone (TSH), accompanied by free thyroxine and total or free tri-iodothyronine concentrations, which are raised (overt hyperthyroidism) or within range (subclinical hyperthyroidism). The underlying cause is determined by clinical assessment, detection of TSH-receptor antibodies and, if necessary, radionuclide thyroid scintigraphy. Treatment options for hyperthyroidism include antithyroid drugs, radioactive iodine, and thyroidectomy, whereas thyroiditis is managed symptomatically or with glucocorticoid therapy. In Graves' disease, first-line treatment is a 12-18-month course of antithyroid drugs, whereas for goitre, radioactive iodine or surgery are preferred for toxic nodules or goitres. Evidence also supports long-term treatment with antithyroid drugs as an option for patients with Graves' disease and toxic nodular goitre.

The impact of thyroid function on total spine bone mineral density in postmenopausal women

PURPOSE

Osteoporosis has been a widespread concern for older women, especially postmenopausal women. Thyroid function is crucial for bone metabolism. However, the relationship between thyroid function variation within thyroxine reference range and bone mineral density (BMD) remains ambiguous. The objective of this study was to evaluate the effect of subclinical hypothyroidism or hyperthyroidism on total spinal BMD in postmenopausal women.

METHODS

Based on data from the National Health and Nutrition Examination Survey (NHANES) 2007-2010, multivariable weighted logistic regression was used to evaluate the relationships between total spine BMD and TSH among postmenopausal women aged ≥50.

RESULTS

After accounting for a number of variables, this study discovered that the middle TSH tertile was associated with a decreased probability of osteoporosis. Additionally, the subgroup analysis revealed that postmenopausal women over the age of 65 or people with an overweight BMI had a clearer relationship between total spine BMD and TSH.

CONCLUSION

The total spinal BMD had a positive relationship with thyroid stimulating hormone in postmenopausal women, and that appropriate TSH level (1.38-2.32 mIU/L) was accompanied by higher total spinal BMD.

Differentiated thyroid cancer: a focus on post-operative thyroid hormone replacement and thyrotropin suppression therapy

PURPOSE

This review focuses on post-operative thyroid hormone replacement and thyrotropin suppression therapy in patients with differentiated thyroid cancer.

METHODS

A clinical review.

RESULTS

Differentiated thyroid cancers (DTC), including papillary and follicular thyroid cancers, have an excellent prognosis and their management leverages a unique set of clinical tools arising from homology to the normal thyroid follicular cell. Surgery is the cornerstone of initial management, and post-operative care often requires thyroid hormone replacement therapy, which may be approached with the intent of physiologic normalization or used pharmacologically to suppress TSH as part of a DTC treatment.

CONCLUSION

Management of DTC and approaches to TSH suppression are tailored to an individual's risk of DTC recurrence and are adjusted to a patient's clinical status and comorbidities over time with the goal of mitigating risk and maximizing benefit.

Evaluation of Bone Turnover Markers Such as Osteoprotegerin, Sclerostin and Dickkopf-1 in Subclinical Hyperthyroidism

In this study, it was aimed to assess effects of subclinical hyperthyroidism (SH) on bone metabolism using osteoprotegerin (OPG), sclerostin, Dickkopf-1 (DKK1) and biochemical parameters. This cross-sectional prospective study included 40 patients with SH and 40 euthyroid controls. Serum OPG, sclerostin, DKK-1, type-1 procollagen, C-terminal polypeptide (CTx) and 24-hours urine N-terminal telopeptide (NTx) were measures using ELISA kit. Bone mineral density measurements were performed using dual energy X-ray absorptiometry (DEXA). Risk for 10-years hip and major fracture was estimated by Turkish version of FRAX. No significant difference was detected in age, gender, body mass index, smoking and menopause rates between SH and control groups. The risk for 10-years hip fracture and major osteoporotic fracture were estimated as 4.45% and 0.55% in SH group, respectively. The OPG levels were significantly lower in patients with SH than controls (P = 0.017). No significant difference was detected in other bone formation and degradation parameters. No significant correlation was detected between OPG level and risk for major osteoporotic fracture (P > 0.05); however, a negative correlation was detected between OPG level and risk for hip fracture (rho = 0.233; P = 0.038). Serum OPG is markedly affected in patients with SH. In addition, OPG seemed to be associated with osteoporotic fracture risk. Available data show that SH is significantly associated with risk for fracture; thus, it is important to assess risk for fracture in patients with SH.

The ageing thyroid: implications for longevity and patient care

Thyroid hormones have vital roles in development, growth and energy metabolism. Within the past two decades, disturbances in thyroid hormone action have been implicated in ageing and the development of age-related diseases. This Review will consider results from biomedical studies that have identified the importance of precise temporospatial regulation of thyroid hormone action for local tissue maintenance and repair. Age-related disturbances in the maintenance of tissue homeostasis are thought to be important drivers of age-related disease. In most iodine-proficient human populations without thyroid disease, the mean, median and 97.5 centile for circulating concentrations of thyroid-stimulating hormone are progressively higher in adults over 80 years of age compared with middle-aged (50-59 years) and younger (20-29 years) adults. This trend has been shown to extend into advanced ages (over 100 years). Here, potential causes and consequences of the altered thyroid status observed in old age and its association with longevity will be discussed. In about 5-20% of adults at least 65 years of age, thyroid-stimulating hormone concentrations are elevated but circulating concentrations of thyroid hormone are within the population reference range, a condition referred to as subclinical hypothyroidism. Results from randomized clinical trials that have tested the clinical benefit of thyroid hormone replacement therapy in older adults with mild subclinical hypothyroidism will be discussed, as well as the implications of these findings for screening and treatment of subclinical hypothyroidism in older adults.

Pituitary crosstalk with bone, adipose tissue and brain

Traditional textbook physiology has ascribed unitary functions to hormones from the anterior and posterior pituitary gland, mainly in the regulation of effector hormone secretion from endocrine organs. However, the evolutionary biology of pituitary hormones and their receptors provides evidence for a broad range of functions in vertebrate physiology. Over the past decade, we and others have discovered that thyroid-stimulating hormone, follicle-stimulating hormone, adrenocorticotropic hormone, prolactin, oxytocin and arginine vasopressin act directly on somatic organs, including bone, adipose tissue and liver. New evidence also indicates that pituitary hormone receptors are expressed in brain regions, nuclei and subnuclei. These studies have prompted us to attribute the pathophysiology of certain human diseases, including osteoporosis, obesity and neurodegeneration, at least in part, to changes in pituitary hormone levels. This new information has identified actionable therapeutic targets for drug discovery.

Thyroid hormone receptor Thra and Thrb knockout differentially affects osteoblast biology and thyroid hormone responsiveness in vitro

Thyroid hormones (TH) are important modulators of bone remodeling and thus, thyroid diseases, in particular hyperthyroidism, are able to compromise bone quality and fracture resistance. TH actions on bone are mediated by the thyroid hormone receptors (TR) TRα1 and TRβ1, encoded by Thra and Thrb, respectively. Skeletal phenotypes of mice lacking Thra (Thra0/0 ) and Thrb (Thrb-/- ) are well-described and suggest that TRα1 is the predominant mediator of TH actions in bone. Considering that bone cells might be affected by systemic TH changes seen in these mutant mice, here we investigated the effects of TR knockout on osteoblasts exclusively at the cellular level. Primary osteoblasts obtained from Thra0/0 , Thrb-/- , and respective wildtype (WT) mice were analyzed regarding their differentiation potential, activity and TH responsiveness in vitro. Thra, but not Thrb knockout promoted differentiation and activity of early, mature and late osteoblasts as compared to respective WT cells. Interestingly, while mineralization capacity and expression of osteoblast marker genes and TH target gene Klf9 was increased by TH in WT and Thra-deficient osteoblasts, Thrb knockout mitigated the responsiveness of osteoblasts to short (48 h) and long term (10 d) TH treatment. Further, we found a low ratio of Rankl, a potent osteoclast stimulator, over osteoprotegerin, an osteoclast inhibitor, in Thrb-deficient osteoblasts and in line, supernatants obtained from Thrb-/- osteoblasts reduced numbers of primary osteoclasts in vitro. In accordance to the increased Rankl/Opg ratio in TH-treated WT osteoblasts only, supernatants from these cells, but not from TH-treated Thrb-/- osteoblasts increased the expression of Trap and Ctsk in osteoclasts, suggesting that osteoclasts are indirectly stimulated by TH via TRβ1 in osteoblasts. In conclusion, our study shows that both Thra and Thrb differentially affect activity, differentiation and TH response of osteoblasts in vitro and emphasizes the importance of TRβ1 to mediate TH actions in bone.

Mechanisms and Treatment Options for Hyperthyroid-Induced Osteoporosis: A Narrative Review

Normal thyroid hormone levels are crucial for the homeostasis of many metabolic cycles and processes throughout the human body. Thyroid dysfunction, such as thyrotoxicosis, can result from many different etiologies, including Graves' disease (GD), toxic multinodular goiter (MNG), and toxic adenoma. These hyperthyroid disease states can cause devastating complications and disease, including the disruption of the bone remodeling cycle and skeletal development, which can result in osteoporosis. Osteoporosis is characterized by a decrease in bone mineral density and a propensity for fragility fractures. In addition to patients with overt hyperthyroidism, studies have provided evidence of other high-risk patient demographics, such as individuals with subclinical hyperthyroidism and postmenopausal women, who may be at an increased risk for the development of secondary osteoporosis. The treatment of patients with hyperthyroid-induced osteoporosis often requires a multifaceted management plan that may be unique to each patient's situation. Antithyroid therapy is often the first step in treating this disease and may include thioamide medications. Radioactive iodine-131 therapy (RAI) and the surgical removal of the thyroid gland may also be reasonable approaches for restoring normal thyroid function. Following thyrotoxicosis mitigation, antiresorptive drugs such as bisphosphonates, calcitonin, and selective estrogen receptor modulators (SERMs) may be used to counteract decreased bone mineral density (BMD). Additionally, the implementation of vitamin D, calcium supplements, and weight-bearing exercise may also reduce bone loss. While the effects of thyroid stimulating hormone (TSH) and triiodothyronine (T3) on bone remodeling have been studied in the past, more research is needed to identify unknown mechanisms and develop future improved treatments for this condition.

Fracture Incidence in Graves' Disease: A Population-Based Study

Background: Population-based studies have indicated an increase in bone turnover in hyperthyroidism with a subsequent decrease in bone mineral density and an increased risk of fractures, especially in postmenopausal women. However, heterogeneity between studies prevents a definitive conclusion. Graves' disease (GD) is an autoimmune disease, and it is the most common cause of hyperthyroidism. The aim of this study was to investigate fracture risk in patients with GD. Methods: A total of 2134 patients with incident GD and 21,261 age, sex- and county-matched controls were included 16-18 years after diagnosis in a retrospective cohort study. Drug and patient national registries in Sweden were used to assess the risk of developing skeletal complications. Up to 10 years of age, sex- and county-matched controls per patient were selected from databases from the National Board of Health and Welfare and Statistics Sweden. Cox proportional hazards models were fitted to estimate hazard ratios (HR) and confidence intervals [CI]. Results: There were no significant differences in fracture rates between GD and controls but after adjustment for comorbidities, the data showed higher vertebral fracture rates in male GD patients aged >52 years compared to male controls, HR = 2.83 [CI 1.05-7.64]. The rates of osteoporosis treatments as well as treatment with corticosteroids were higher in patients with GD. However, HR for the association between GD and fractures remained largely unchanged after adjustment for osteoporosis treatments and treatments with corticosteroids. Conclusions: There were no significant differences in total fracture rate between GD and the general population. However, men older than 52 years had a higher vertebral fracture rate. This study also shows that patients with treated GD receive more osteoporosis treatments compared to the general population.

Over- and Undertreatment With Levothyroxine

BACKGROUND

Levothyroxine is a very commonly prescribed drug, and treatment with it is often insufficient or excessive. Nonetheless, there have been only a few reports on the determinants of inadequate levothyroxine treatment.

METHODS

Data from 2938 participants in the population-based Rhineland Study were analyzed. Putative determinants of inadequate levothyroxine treatment (overtreatment, thyrotropin level <0.56 mU/L; undertreatment, thyrotropin level >4.27 mU/L) were studied with logistic regression. The determinants of the levothyroxine dose were assessed with linear regression.

RESULTS

Overall, 23% of the participants (n = 662) stated that they were taking levothyroxine. Among these participants, 18% were overtreated and 4% were undertreated. Individuals over 70 years of age and above were four times as likely to be overtreated (OR = 4.05, 95% CI [1.20; 13.72]). Each rise in the levothyroxine dose by 25 μg was associated with an increased risk of overtreatment (OR = 1.02, 95% CI [1.02; 1.03]) and of undertreatment (OR = 1.02, 95% CI [1.00; 1.03]). Well-controlled participants (normal thyrotropin levels 0.56-4.27 mU/L) received a lower levothyroxine dose (1.04 ± 0.5 μg/kg/d) than overtreated (1.40 ±0.5 μg/kg/d) or undertreated (1.37 ±0.5 μg/kg/d) participants. No association was found between sociodemographic factors or comorbidities and the levothyroxine dose. Iodine supplementation was associated with a lower daily dose (β = -0.19, 95% CI [-0.28; -0.10]), while three years or more of levothyroxine exposure was associated with a higher daily dose (β = 0.24, 95% CI [0.07; 0.41]).

CONCLUSION

Levothyroxine intake was high in our sample, and suboptimal despite monitoring. Our findings underscore the need for careful dosing and for due consideration of deintensification of treatment where appropriate.

Hyperthyroidism: A Review

Importance

Overt hyperthyroidism, defined as suppressed thyrotropin (previously thyroid-stimulating hormone) and high concentration of triiodothyronine (T3) and/or free thyroxine (FT4), affects approximately 0.2% to 1.4% of people worldwide. Subclinical hyperthyroidism, defined as low concentrations of thyrotropin and normal concentrations of T3 and FT4, affects approximately 0.7% to 1.4% of people worldwide. Untreated hyperthyroidism can cause cardiac arrhythmias, heart failure, osteoporosis, and adverse pregnancy outcomes. It may lead to unintentional weight loss and is associated with increased mortality.

Observations

The most common cause of hyperthyroidism is Graves disease, with a global prevalence of 2% in women and 0.5% in men. Other causes of hyperthyroidism and thyrotoxicosis include toxic nodules and the thyrotoxic phase of thyroiditis. Common symptoms of thyrotoxicosis include anxiety, insomnia, palpitations, unintentional weight loss, diarrhea, and heat intolerance. Patients with Graves disease may have a diffusely enlarged thyroid gland, stare, or exophthalmos on examination. Patients with toxic nodules (ie, in which thyroid nodules develop autonomous function) may have symptoms from local compression of structures in the neck by the thyroid gland, such as dysphagia, orthopnea, or voice changes. Etiology can typically be established based on clinical presentation, thyroid function tests, and thyrotropin-receptor antibody status. Thyroid scintigraphy is recommended if thyroid nodules are present or the etiology is unclear. Thyrotoxicosis from thyroiditis may be observed if symptomatic or treated with supportive care. Treatment options for overt hyperthyroidism from autonomous thyroid nodules or Graves disease include antithyroid drugs, radioactive iodine ablation, and surgery. Treatment for subclinical hyperthyroidism is recommended for patients at highest risk of osteoporosis and cardiovascular disease, such as those older than 65 years or with persistent serum thyrotropin level less than 0.1 mIU/L.

Conclusions and Relevance

Hyperthyroidism affects 2.5% of adults worldwide and is associated with osteoporosis, heart disease, and increased mortality. First-line treatments are antithyroid drugs, thyroid surgery, and radioactive iodine treatment. Treatment choices should be individualized and patient centered.

Impaired sensitivity to thyroid hormone correlates to osteoporosis and fractures in euthyroid individuals

BACKGROUND

There is growing evidence that thyroid function affects bone metabolism and even fractures risk. However, little is known about the relationship between thyroid sensitivity and osteoporosis and fractures. Therefore, we explored the relationship between thyroid sensitivity-related indices and bone mineral density (BMD) and fractures in euthyroid US adults.

METHODS

In this cross-sectional study, 20,686 subjects from National Health and Nutrition Examination Survey (NHANES) data were extracted and analyzed during 2007 to 2010. A total of 3403 men and postmenopausal women aged 50 years or older with available data on diagnosis of osteoporosis and/or fragility fractures, bone mineral density (BMD) and thyroid function, were eligible. TSH index (TSHI), thyrotrophin T4/T3 resistance index (TT4RI/TT3RI), Thyroid feedback quantile-based index (TFQI), Parametric TFQI (PTFQI), free triiodothyronine to free thyroxine ratio (FT3/FT4), the secretory capacity of the thyroid gland (SPINA-GT) and the sum activity of peripheral deiodinases (SPINA-GD) were calculated.

RESULTS

FT3/FT4, SPINA-GD, FT4, TSHI, TT4RI, TFQI and PTFQIFT4 were significantly correlated with BMD (P < 0.001). Multiple linear regression analysis showed that FT3/FT4 and SPINA-GD was significantly positively associated with BMD, while FT4, TSHI, TT4RI, TFQI and PTFQIFT4 were negatively associated with BMD (P < 0.05 or P < 0.001). In logistic regression analysis, the odds ratio (OR) for osteoporosis of TSHI, TFQI and PTFQIFT4 were 1.314(1.076, 1.605), 1.743(1.327, 2.288) and 1.827(1.359, 2.455) respectively, and were 0.746(0.620, 0.898) for FT3/FT4 (P < 0.05).

CONCLUSIONS

In elderly euthyroid individuals, impaired sensitivity to thyroid hormones correlates to osteoporosis and fractures, independent of other conventional risk factors.

A diagnostic predictive model for secondary osteoporosis in patients with fragility fracture: a retrospective cohort study in a tertiary care hospital

Identifying secondary causes among osteoporotic patients is crucial. However, there is no simple tool for screening secondary osteoporosis. A predictive model for screening secondary osteoporosis was constructed using simple clinical and biochemical parameters. This predictive model may provide clinicians with guidance to perform further investigations for specific causes of osteoporosis.

PURPOSE

Establishing whether a fragility fracture is secondary to a specific cause of osteoporosis is crucial for treatment outcomes. Therefore, this study aimed to develop a simple screening tool for secondary osteoporosis in the elderly initially presented with fragility fractures.

METHODS

A retrospective cohort study including 456 patients with fragility hip and vertebral fractures that occurred between January 2017 and July 2022 was conducted. Demographic, clinical, biochemical, and final diagnostic data were retrieved. Potential predictors for secondary osteoporosis were determined by multivariable logistic regression analysis, and a predictive model for secondary osteoporosis was subsequently developed using identified potential predictors.

RESULTS

This study included 343 females and 113 males with a mean age of 76.9 ± 11.0 years. One hundred and twenty-one patients (26.5%) were diagnosed with secondary osteoporosis. Vitamin D deficiency (71.9%) was the most common cause of secondary osteoporosis, followed by glucocorticoid-induced osteoporosis (23.9%) and primary hyperparathyroidism (9.9%). The potential predictors for secondary osteoporosis included in the predictive model were age, body mass index (BMI), corrected calcium, phosphate, thyroid stimulating hormone, and a 10-year probability of hip fractures calculated by BMI-based FRAX®. With a cut-off level of 0.22, the proposed predictive model has an AuROC of 0.75 (95% CI 0.69 to 0.81) with a sensitivity of 77%, a specificity of 66%, and an accuracy of 68.9%.

CONCLUSION

A predictive model for screening secondary osteoporosis was constructed using simple clinical and biochemical parameters. This newly developed predictive model may provide clinicians with guidance to perform further advanced investigations for secondary causes of osteoporosis.

Selected musculoskeletal disorders in patients with thyroid dysfunction, diabetes, and obesity

Many medical conditions affect the skeletal system and constitute independent risk factors for fractures. The action of thyroid hormones is necessary to maintain adequate development, mineralization, and bone strength. Untreated hyperthyroidism can lead to a decrease in bone mineral density (BMD), osteoporosis, and pathological fractures. In hypothyroidism, the changes in the quality of bone structure lead to an increase in the frequency of fractures. Excessive body weight negatively impacts fracture risk, increases the risk of osteoarthritis and accelerates the development of rheumatoid arthritis and osteoporosis. Type 1 and type 2 diabetes are associated with an increased risk of bone fractures despite different etiopathogenesis due to the duration of the disease and the pro-inflammatory state, the incorporation of advanced glycation end products (AGEs) into the bone matrix, and microvascular disorders. This study summarizes the current literature on the influence of thyroid dysfunction, obesity, and diabetes on the skeletal system.

Levothyroxine Dosing in Older Adults: Recommendations Derived From The Baltimore Longitudinal Study of Aging

OBJECTIVE

As thyroid hormone metabolism slows with advancing age, treatment dosing requirements change. Guidelines recommend titration from a low starting dose for older adults with hypothyroidism while providing weight-based estimates for younger populations. However, rapid replacement may be appropriate with acute onset of overt hypothyroidism. Therefore, a weight-based recommendation specific to older adults is needed.

METHODS

We determined mean levothyroxine dose using actual and ideal body weight (IBW) ratios for the outcome of euthyroid on therapy relative to assay-specific and proposed age-specific ranges for independently living participants aged ≥65 years in the Baltimore Longitudinal Study of Aging. We examined risk factors to identify those at highest risk of overtreatment using regression analyses adjusted for potential covariables and clustering to account for multiple visits per individual.

RESULTS

One hundred eighty-five participants aged ≥65 years were on levothyroxine at 645 eligible visits. At euthyroid visits, participants were on an average dose of 1.09 μg/kg (1.35 μg/kg IBW), with 84% of euthyroid individuals on a dose of <1.6 μg/kg. Average euthyroid dose did not differ by sex using either actual body weight (ABW) or IBW. For obese individuals, mean euthyroid dose was lower if calculated using ABW (0.9 μg/kg vs 1.14 μg/kg; P < .01) but similar if calculated using IBW (1.42 vs 1.32 μg/kg IBW; P = .41) compared with those with a body mass index of <30.

CONCLUSION

Thyroid hormone dose per body weight estimates for replacement in older adults (1.09 μg/kg ABW or 1.35 μg/kg IBW) are one-third lower than current weight-based dose recommendations for younger populations.

Hormones and Aging: An Endocrine Society Scientific Statement

Multiple changes occur across various endocrine systems as an individual ages. The understanding of the factors that cause age-related changes and how they should be managed clinically is evolving. This statement reviews the current state of research in the growth hormone, adrenal, ovarian, testicular, and thyroid axes, as well as in osteoporosis, vitamin D deficiency, type 2 diabetes, and water metabolism, with a specific focus on older individuals. Each section describes the natural history and observational data in older individuals, available therapies, clinical trial data on efficacy and safety in older individuals, key points, and scientific gaps. The goal of this statement is to inform future research that refines prevention and treatment strategies in age-associated endocrine conditions, with the goal of improving the health of older individuals.

Thyroid and Aging

Older adults are more vulnerable to the negative effects of excess thyroid hormone and may even be protected by lower levels of thyroid hormone. The diagnosis and management of thyroid disease in older adults needs to account for aging-related changes in function and resilliance.

Thyroid Dysfunction in Periand Postmenopausal Women-Cumulative Risks

BACKGROUND

Menopausal estrogen depletion increases the risk of cardiovascular disease and of osteoporosis. Both of these risks can be increased by thyroid dysfunction as well. This cumulation of risks will be presented.

METHODS

This review is based on publications retrieved by a selective search in PubMed (publications dated January 2000 to October 2022) for clinical trials, meta-analyses, randomized controlled trials, and systematic reviews containing the keywords "menopause and thyroid disorders."

RESULTS

Hyperthyroidism and menopause have similar symptoms. Decreased levels of thyroid-stimulating hormone (TSH) are found in 8-10% of women in their fifth and sixth decades. TSH is decreased in 21.6-27.2% of women treated with L-thyroxine; decreased TSH is associated with increased cardiovascular mortality (hazard ratio [HR] 3.3, 95% confidence interval [CI]: [1.3; 8.0]) and increased mortality of all causes (HR 2.1; 95% CI: [1.2; 3.8]). Menopausal estrogen depletion accelerates the risk of cardiovascular disease and causes a disproportionate loss of bone density. In hyperthyroidism, bone density is decreased, and the risk of vertebral fractures is increased (HR 3.57; 95% CI: [1.88; 6.78]).

CONCLUSION

The risk of heart diseases and bone diseases accelerates around the time of the menopause. Early detection and treatment of hyperthyroidism, which can further elevate the risk of both of these diseases is therefore required. In perimeno - pausal and postmenopausal women who are being treated for hypothyroidism, TSH suppression must be avoided. Thyroid dysfunction is common in women; its manifestations are less obvious with advancing age, making clinical diagnosis more difficult, yet it can have major deleterious effects. Thus, the indications for measuring TSH in perimenopausal women should be kept broad, rather than restrictive.

Cardiovascular and Thyroid Late Effects in Pediatric Patients With Hodgkin Lymphoma Treated With ABVD Protocol

BACKGROUND

Hodgkin lymphoma (HL) survivors are at risk of developing a range of therapy-related complications. The goal of this study is to investigate therapy-related late-effects in HL survivors.

MATERIALS AND METHODS

We performed a cross-sectional study on 208 HL survivors who were treated at the National Cancer Institute or at the Children Cancer Hospital Egypt with doxorubicin, bleomycin, vinblastine, and dacarbazine chemotherapy.

RESULTS

Age at diagnosis ranged from 2.5 to 17.5 with a median of 8.7 years. The cumulative incidence of cardiac toxicity at 5 and 9 years were 18.7%±2.7% and 43.3%±4.4%, respectively. Preexisting cardiac abnormalities, cumulative anthracycline dose, and end of treatment cardiac status are strong predictors of late cardiotoxicity. Hypertension was observed in ~31% of patients. Young age and obesity at the time of treatment are important risk factors for hypertension. Thyroid abnormalities developed with a 5-year cumulative incidence of 2%±1%, whereas at 9 years the cumulative incidence was 27.9%±4.5%. Thyroid dysfunction was observed in 21.2% and thyroid tumors in 1.6% of cases. Subclinical hypothyroidism was the most common thyroid abnormality.

CONCLUSIONS

Cardiotoxicity, hypertension, and thyroid dysfunction are frequent late effects after doxorubicin, bleomycin, vinblastine, and dacarbazine regimen, especially if combined with radiation therapy.

How does Hashimoto's thyroiditis affect bone metabolism?

Bone marrow contains resident cellular components that are not only involved in bone maintenance but also regulate hematopoiesis and immune responses. The immune system and bone interact with each other, coined osteoimmunology. Hashimoto's thyroiditis (HT) is one of the most common chronic autoimmune diseases which is accompanied by lymphocytic infiltration. It shows elevating thyroid autoantibody levels at an early stage and progresses to thyroid dysfunction ultimately. Different effects exert on bone metabolism during different phases of HT. In this review, we summarized the mechanisms of the long-term effects of HT on bone and the relationship between thyroid autoimmunity and osteoimmunology. For patients with HT, the bone is affected not only by thyroid function and the value of TSH, but also by the setting of the autoimmune background. The autoimmune background implies a breakdown of the mechanisms that control self-reactive system, featuring abnormal immune activation and presence of autoantibodies. The etiology of thyroid autoimmunity and osteoimmunology is complex and involves a number of immune cells, cytokines and chemokines, which regulate the pathogenesis of HT and osteoporosis at the same time, and have potential to affect each other. In addition, vitamin D works as a potent immunomodulator to influence both thyroid immunity and osteoimmunology. We conclude that HT affects bone metabolism at least through endocrine and immune pathways.

Evaluation and Management of Bone Health in Patients with Thyroid Diseases: A Position Statement of the Korean Thyroid Association

Thyroid hormones play an important physiological role in maintaining adult bone structure and strength. Consequently, thyroid dysfunction is related to skeletal outcomes. Overt hyperthyroidism is an established cause of high bone turnover with accelerated bone loss, leading to osteoporosis and increased fracture risk. Hyperthyroidism induced by thyroid-stimulating hormone-suppressive therapy in patients with differentiated thyroid cancer is a cause of secondary osteoporosis. In contrast, there is a lack of evidence on the negative impact of hypothyroidism on bone health. Considering the clinical updates on the importance of bone health in thyroid dysfunction, the Task Force from the Clinical Practice Guidelines Development Committee of the Korean Thyroid Association recently developed a position statement on the evaluation and management of bone health of patients with thyroid diseases, particularly focused on endogenous hyperthyroidism and thyroid-stimulating hormone-suppressive therapy-associated hyperthyroidism in patients with differentiated thyroid cancer. Herein, we review the Korean Thyroid Association's position statement on the evaluation and management of bone health associated with thyroid diseases.

The Impact of Age- and Sex-Specific Reference Ranges for Serum Thyrotropin and Free Thyroxine on the Diagnosis of Subclinical Thyroid Dysfunction: A Multicenter Study from Japan

Background: Reference ranges for serum thyrotropin (TSH), free thyroxine (fT4), and free triiodothyronine (fT3) established without considering age- and sex-based differences are currently used to evaluate thyroid function. Therefore, we investigated age- and sex-based differences in serum TSH and thyroid hormone levels in euthyroid individuals. Methods: We performed cross-sectional analyses of retrospective data collected from two Japanese institutions. We estimated sex-specific 95% reference ranges for TSH and fT4 according to age strata. Results: We included data from 14,860 participants undergoing screening with a Siemens thyroid testing kit and 8,132 participants undergoing screening with an Abbott kit during annual health check-ups at Takasaki Hidaka Hospital. In addition, 515 participants visiting a specialized thyroid-focused hospital were evaluated using Tosoh kits. The median TSH level of women in their 30s was 1.5 mIU/L (2.5th percentile, 0.5; 97.5th percentile, 4.6) using the Siemens kit, while that of women in their 60s was 1.9 (0.7-7.8) mIU/L. The corresponding levels were lower in men; the age-associated increase was small. The median serum fT4 level of men in their 30s was 1.3 (1.0-1.7) ng/dL and that of men in their 60s was 1.2 (1.0-1.6) ng/dL. These levels gradually but significantly decreased with age. fT4 levels in women were lower than those in men and remained consistent with age. Serum fT3 levels were significantly higher in men than in women and gradually but significantly decreased with age. The Abbott and Tosoh kits showed similar results. When using the Siemens kit, ∼60% (216/358) of women diagnosed with subclinical hypothyroidism using manufacturer-recommended reference ranges had normal results when age- and sex-specific reference ranges were applied, demonstrating the high percentage of overdiagnosis, especially in those aged ≥60 years. Conversely, some middle-aged individuals with normal thyroid function were reassessed and classified as having subclinical hyperthyroidism by age- and sex-specific reference ranges. Conclusions: Age- and sex-specific reference ranges should be used to avoid over- and underdiagnosis of subclinical thyroid dysfunction and appropriate therapies.

Bone quality in endocrine diseases: determinants and clinical relevance

PURPOSE

Bone is one of the main targets of hormones and endocrine diseases are frequent causes of secondary osteoporosis and fractures in real-world clinical practice. However, diagnosis of skeletal fragility and prediction of fractures in this setting could be a challenge, since the skeletal alterations induced by endocrine disorders are not generally captured by dual-energy X-ray absorptiometry (DXA) measurement of bone mineral density (BMD), that is the gold standard for diagnosis of osteoporosis in the general population. The aim of this paper is to review the existing evidence related to bone quality features in endocrine diseases, proposing assessment with new techniques in the future.

METHODS

A comprehensive search within electronic databases was performed to collect reports of bone quality in primary hyperparathyroidism, hypoparathyroidism, hyperthyroidism, hypercortisolism, growth hormone deficiency, acromegaly, male hypogonadism and diabetes mellitus.

RESULTS

Using invasive and non-invasive techniques, such as high-resolution peripheral quantitative computed tomography or DXA measurement of trabecular bone score (TBS), several studies consistently reported altered bone quality as predominant determinant of fragility fractures in subjects affected by chronic endocrine disorders.

CONCLUSIONS

Assessment of skeletal fragility in endocrine diseases might take advantage from the use of techniques to detect perturbation in bone architecture with the aim of best identifying patients at high risk of fractures.

Subclinical hypothyroidism is not associated with femoral osteoporosis in individuals aged 50 years or older

BACKGROUND

Thyroid dysfunction and osteoporosis are conditions strongly associated with aging, and the prevalence of both conditions is expected to increase in the coming decades. Thyroid hormones regulate bone metabolism, and the role of subclinical hypothyroidism on bone mineral density (BMD) is still controversial. Hence, this study aims to assess the association of subclinical hypothyroidism with femoral osteopenia and osteoporosis in individuals aged 50 years or older.

METHODOLOGY

This retrospective cohort study was carried out with 864 outpatients having at least one result for TSH levels before the first record of dual-energy X-ray absorptiometry (DXA). The primary endpoints were osteopenia (-2.5 standard deviation (SD) <T-score <-1.0SD) and osteoporosis (T-score ≤-2.5SD). Cox proportional hazards regression assessed the association of subclinical hypothyroidism (TSH ≥4.5 mIU/L) with osteopenia and osteoporosis in unadjusted and covariate-adjusted models. Hazard ratios (HR) and 95% confidence intervals (95%CI) were calculated, and p-values <0.05 were considered statistically significant.

RESULTS

There was no significant association between subclinical hypothyroidism and femoral osteopenia in either unadjusted [HR: 1.149 (0.835-1.580); p=0.394] or fully covariate-adjusted models [HR: 1.069 (0.774-1.477); p=0.687]. Subclinical hypothyroidism was associated with femoral osteoporosis in the unadjusted analysis [HR: 1.981 (1.044-3.757); p= 0.036], but a lack of association occurred and remained after successive covariate-adjustments analyses [HR: 1.392 (0.615-3.152); p=0.428].

CONCLUSION

Subclinical hypothyroidism is not independently associated with either femoral osteopenia or osteoporosis in individuals aged 50 years or older over a four-year follow-up time.

Fracture risk and assessment in adults with cancer

Individuals with cancer face unique risk factors for osteoporosis and fractures. Clinicians must consider the additive effects of cancer-specific factors, including treatment-induced bone loss, and premorbid fracture risk, utilizing FRAX score and bone mineral densitometry when available. Pharmacologic therapy should be offered as per cancer-specific guidelines, when available, or local general osteoporosis guidelines informed by clinical judgment and patient preferences. Our objective was to review and summarize the epidemiologic burden of osteoporotic fracture risk and fracture risk assessment in adults with cancer, and recommended treatment thresholds for cancer treatment-induced bone loss, with specific focus on breast, prostate, thyroid, gynecological, multiple myeloma, and hematopoietic stem cell transplant. This narrative review was informed by PubMed searches to July 25, 2022, that combined terms for cancer, stem cell transplantation, fracture, bone mineral density (BMD), trabecular bone score, FRAX, Garvan nomogram or fracture risk calculator, QFracture, prediction, and risk factors. The literature informs that cancer can impact bone health in numerous ways, leading to both systemic and localized decreases in BMD. Many cancer treatments can have detrimental effects on bone health. In particular, hormone deprivation therapies for hormone-responsive cancers such as breast cancer and prostate cancer, and hematopoietic stem cell transplant for hematologic malignancies, adversely affect bone turnover, resulting in osteoporosis and fractures. Surgical treatments such as hysterectomy with bilateral salpingo-oophorectomy for gynecological cancers can also lead to deleterious effects on bone health. Radiation therapy is well documented to cause localized bone loss and fractures. Few studies have validated the use of fracture risk prediction tools in the cancer population. Guidelines on cancer-specific treatment thresholds are limited, and major knowledge gaps still exist in fracture risk and fracture risk assessment in patients with cancer. Despite the limitations of current knowledge on fracture risk assessment and treatment thresholds in patients with cancer, clinicians must consider the additive effects of bone damaging factors to which these patients are exposed and their premorbid fracture risk profile. Pharmacologic treatment should be offered as per cancer-specific guidelines when available, or per local general osteoporosis guidelines, in accordance with clinical judgment and patient preferences.

Control of Thyroid Dysfunction in Spanish Population Registered in the Primary Care Clinical Database: An Analysis of the Proportion of Patients with Thyrotropin Values Outside the Reference Range

Inadequate control of thyroid dysfunction is common and has deleterious health consequences. Our objective was to determine the prevalence of TSH values outside the reference range, as an indicator of inadequate control of hypothyroidism and hyperthyroidism in patients undergoing treatment for thyroid dysfunction in Spain. An observational, retrospective, non-interventional study was conducted using the Primary Care Clinical Database (BDCAP). Patients treated with thyroid hormone for hypothyroidism and with antithyroid drugs for hyperthyroidism were identified. We assessed serum TSH concentration, considering values from 0.4 to 4.0 mU/l as the reference interval. We found 360 313 people with hypothyroidism on thyroid hormone replacement and 9239 with hyperthyroidism on antithyroid drugs therapy. TSH values outside the reference range in hypothyroid subject were detected in 126 866 (35.20%) people, of whom 107 205 (29.75%) had TSH>4.0 mU/l, suggesting inappropriately low doses of levothyroxine, and 19 661 (5.46%) had TSH<0.4 mU/l, suggesting inappropriate over replacement. In the hyperthyroid group, TSH values outside the reference range were observed in 4252 (46.02%) patients. There were 2833 (30.66%) patients with TSH<0.4 mU/l, suggesting undertreatment, and 1419 (15.36%) with TSH>4.0 mU/l, suggesting overtreatment with antithyroid medication. People over 65 years of age had a lower frequency of undertreatment of hypothyroidism and a lower frequency of overtreatment and undertreatment of hyperthyroidism. In conclusion, our results suggest that inadequate control of thyroid dysfunction, due to its high frequency and its consequences for health, is a public health problem that should be addressed by clinicians and health authorities.

Subclinical hypothyroidism, outcomes and management guidelines: a narrative review and update of recent literature

Subclinical hypothyroidism (SCH) is diagnosed when serum thyroid stimulation hormone (thyrotropin; TSH) levels are above the reference range, accompanied by levels of free thyroxine within its reference range. The management of SCH remains a diagnostic and therapeutic challenge despite many years of research relating to its epidemiology, aetiology, effectiveness of treatment and safety. European Thyroid Association (ETA) guidelines for the management of SCH were published almost a decade ago. This narrative review summarizes the clinical literature relating to SCH and outcomes since the publication of these guidelines. Clinical evidence emerging during the previous decade generally supports the view that SCH is associated with adverse outcomes to an extent that is intermediate between euthyroidism and overt hypothyroidism although evidence that treatment with thyroid hormone replacement is beneficial is lacking. Accordingly, the rationale for the recommendations for intervention in the ETA guidelines based on the age of the patient, level of serum TSH, symptoms and comorbidities remains valid today.

Prevalence of thyroid dysfunction and its relationship to income level and employment status: a nationwide population-based study in Spain

PURPOSE

The influence of socioeconomic conditions on the prevalence of thyroid dysfunction in the population has been scarcely studied to date. The aim of this study has been to evaluate the influence of income level and employment status on the prevalence of hypothyroidism and hyperthyroidism.

METHODS

A cross-sectional study was performed using the population-based database BDCAP (Base de Datos Clínicos de Atención Primaria, Primary Care Clinical Database) to analyze the prevalence of thyroid dysfunction in the Spanish population classified by income groups and employment status.

RESULTS

Of the 40,613,229 people registered in the BDCAP in 2020, there were 2,596,041 (6.39%) with a diagnosis of hypothyroidism and 418,722 (1.03%) with hyperthyroidism. The prevalence of hypothyroidism in people with high income (≥ 100,000 euros/year), medium income (18,000-99,999 euros/year), low income (< 18,000 euros/year), and very low income were, respectively, 4.23%, 5.74%, 6.75%, and 7.01% (P < 0.001). The prevalence of hyperthyroidism in the same income groups also showed an increasing trend as income decreased (0.65%, 0.94%, 1.08%, and 1.10%; P < 0.001). Unemployed people had higher frequencies of hypothyroidism (7.35%) and hyperthyroidism (1.22%) than working people (5.80 and 1.00%, respectively) and inactive people (4.21 and 0.52%, respectively; P < 0.001).

CONCLUSION

Socioeconomic conditions are related to the prevalence of thyroid dysfunction. Low-income or unemployed people have a higher frequency of both hypothyroidism and hyperthyroidism.

Modification of TSH-related genetic effects by indicators of socioeconomic position

OBJECTIVE

Thyroid-stimulating hormone (TSH) is influenced by genetic and environmental factors such as socioeconomic position (SEP). However, interactions between TSH-related genetic factors and indicators of SEP have not been investigated to date. The aim of the study was to determine whether education and income as SEP indicators may interact with TSH-related genetic effect allele sum scores (GESTSH_2013 and GESTSH_2020) based on two different GWAS meta-analyses that affect TSH values in a population-based study.

METHODS

In 4085 participants of the Heinz Nixdorf Recall Study associations between SEP indicators, GESTSH and TSH were quantified using sex- and age-adjusted linear regression models. Interactions between SEP indicators and GESTSH were assessed by GESTSH × SEP interaction terms, single reference joint effects and calculating genetic effects stratified by SEP group.

RESULTS

Participants within the highest education group showed the strongest genetic effect with on average 1.109-fold (95% CI: 1.067-1.155) higher TSH values per GESTSH_2013 SD, while in the lowest education group, the genetic effect was less strong (1.061-fold (95% CI: 1.022-1.103)). In linear regression models including interaction terms, some weak indication for a positive GESTSH_2013 by education interaction was observed showing an interaction effect size estimate of 1.005 (95% CI: 1.000-1.010) per year of education and GESTSH_2013 SD. No indication for interaction was observed for using income as SEP indicator. Using the GESTSH_2020, similar results were observed.

CONCLUSION

Our results gave some indication that education may affect the expression of TSH-related genetic effects. Stronger genetic effects in high-education groups may be explained by environmental factors that have an impact on gene expression and are more prevalent in high SEP groups.

Do bone turnover markers reflect changes in bone microarchitecture during treatment of patients with thyroid dysfunction?

PURPOSE

This study aimed to compare changes in the bone turnover markers (BTMs)-C-terminal telopeptide of type I collagen (CTX-I) and procollagen I N-terminal peptide (PINP)-with changes in the bone microarchitecture, assessed by high-resolution peripheral quantitative computed tomography (HR-pQCT), during treatment of patients with thyroid dysfunction.

METHODS

In women with newly diagnosed hypo- or hyperthyroidism, HR-pQCT variables, obtained from the tibia and the radius, were compared with BTMs. Data were collected at diagnosis and after at least 12 months of euthyroidism.

RESULTS

73 women completed the study (hypothyroidism, n = 27; hyperthyroidism, n = 46). Among hyperthyroid patients, correlations were found between changes in BTMs and HR-pQCT variables, primarily for cortical variables in the tibia, i.e. cortical thickness (CTX-I, p < 0.001; PINP, p < 0.001), and volumetric bone mass density (vBMD) (CTX-I, p < 0.001; PINP, p < 0.001). Moreover, correlations between BTMs and estimated bone strength were found. In the hypothyroid subgroup, no significant findings existed after adjustment. Following treatment, less decrease in tibial vBMD was seen among patients with increasing CTX-I compared to those with a decreasing CTX-I level (p = 0.009). Opposite findings applied to PINP, as patients with decreasing PINP showed an increase in tibial vBMD, in contrast to a decline in this parameter among patients with increasing PINP (p < 0.001).

CONCLUSION

Changes in CTX-I and PINP correlated with HR-pQCT variables during the treatment of women with thyroid dysfunction. To some extent, these BTMs reflected the restoration of bone microarchitecture. CTX-I seems to be the most sensitive BTM in treatment-naïve thyroid diseases, while PINP is more useful for monitoring during treatment.

TRIAL REGISTRATION NUMBER

NCT02005250. Date: December 9, 2013.

Association between thyroid function, nursing home admission and mortality in community-dwelling adults over 80 years

PURPOSE

Thyroid deficiency may reduce mortality in older adults, but older adults prioritize independence over merely staying alive. We investigated the association between thyroid dysfunction and nursing home admission and all-cause mortality in community-dwelling older adults over 80.

METHODS

We conducted a retrospective population-based open cohort study using data from laboratory registries covering 75% of Denmark supplemented by national registries. We included all community-dwelling older adults over 80 years with a first TSH measurement between 1996 and 2019. Participants with prior thyroid disorders or medication affecting the thyroid were excluded. Participants were followed from inclusion until nursing home admission, death or loss to follow-up due to emigration.

RESULTS

We included 272,495 participants at baseline. Median follow-time was 3.71 years in analyses of nursing home admissions and 4.00 years for all-cause mortality. Hypothyroidism was associated with lower nursing home admission (TSH 5-10 mIU/l: HR 0.85, 95% CI: 0.80-0.91, P < 0.001); TSH >10 mIU/l HR 0.68, 95% CI: 0.54-0.85, P = 0.001) and with reduced all-cause mortality (TSH >10 mIU/l: HR 0.81, 95% CI: 0.70-0.93, P = 0.002). The association between hyperthyroidism and nursing home admission was of little clinical significance while hyperthyroidism was associated with increased all-cause mortality hazard both for low (HR 1.16, 95% CI 1.13-1.19, P < 0.001) and suppressed (HR 95% CI: 1.14 1.07-1.21, P < 0.001) TSH.

CONCLUSION

Hypothyroidism is associated with a reduced nursing home admission hazard and to a lesser extent all-cause mortality in community-dwelling adults over 80 years, while hyperthyroidism is associated with increased all-cause mortality but not hazard of nursing home admission.

Effects of TSH suppressive therapy on bone mineral density (BMD) and bone turnover markers (BTMs) in patients with differentiated thyroid cancer in Northeast China: a prospective controlled cohort study

PURPOSE

This study aimed to evaluate the effects of thyroid-stimulating hormone (TSH) suppressive therapy on bone mineral density (BMD) and bone turnover markers (BTMs) in differentiated thyroid cancer (DTC) patients after postoperative 1-2 years in Northeast China.

METHODS

Five male, sixteen premenopausal, and eight postmenopausal female DTC patients receiving TSH suppressive therapy after thyroidectomy were enrolled. Patients were matched with healthy controls in a ratio of 1:2. All participants completed postoperative 1-year follow-up, and postmenopausal women completed 2-year follow-up. We measured BMD of the lumbar spine (LS), femoral neck (FN), and total hip (TH) using dual-energy X-ray absorptiometry (DXA). Bone formation marker P1NP and bone resorption marker β-CTX were also evaluated. Fracture risks were assessed by FRAX.

RESULTS

There was no difference in BMD and BTMs between DTC patients and controls in the male group at 1-year follow-up. In the premenopausal women, the baseline P1NP was significantly lower in DTC patients than in the controls. The LS-BMD, FN-BMD, and TH-BMD in DTC patients were all higher than those in controls at 1-year follow-up. The difference in FN-BMD was not significant after adjusting for baseline P1NP. In the postmenopausal women, no differences in BMD and BTMs were observed between DTC patients and controls at the 1-year and 2-year follow-up.

CONCLUSION

Our study indicated that postoperative 1-year TSH suppressive therapy did not show detrimental effects on BMD and BTMs in men, premenopausal, and postmenopausal DTC patients. The 2-year postoperative TSH suppressive therapy did not lead to additional loss of bone mass in postmenopausal DTC patients.

Assessment of the relationship between subclinical hypothyroidism and blood lipid profile: reliable or not?

BACKGROUND

The relationship between subclinical hypothyroidism (SCH) and blood lipid metabolism is controversial. This study is intended to evaluate the relationship between SCH and blood lipid profiles using well defined diagnostic criteria.

METHODS

Data from 11,512 physical examinees in our hospital who had finished two tests with an interval of at least 3 months were analyzed, including 685 cases of SCH as stipulated in this study. In addition to common physical examination indicators, other parameters such as thyroid function indices and blood lipids were measured twice with an interval of at least 3 months. Subjects were diagnosed with SCH only when their levels of TT3, TT4, FT3 and FT4 were normal and TSH levels were increased on both tests, which meant these subjects were in a state of SCH for at least 3 months. The results of blood lipids for the second time were analyzed.

RESULTS

Statistically significant differences were found in age, sex, BMI, hemoglobin, total cholesterol (TC), low density lipoprotein (LDL-C), high density lipoprotein (HDL-C), and BFP between the SCH and control groups (P < 0.001). However, there were no statistically significant differences in age, sex, blood pressure, blood lipids, blood glucose or BMI between patients with mild SCH and those with severe SCH (P > 0.05). After balancing the age and sex ratio, no factors were confirmed to be statistically significant independent factors of SCH. None of the parameters showed statistically significant differences between patients with mild SCH and those with severe SCH (P > 0.05).

CONCLUSION

After defining rigorous criteria for the diagnosis of SCH, no definite association between SCH and TC, LDL-C or HDL-C was confirmed in this study. SCH may have no relationship to the most concerning blood lipid profile.

Risk factors for fracture in patients with fibrous dysplasia of the proximal femur

OBJECTIVE

The primary aim of this retrospective observational clinical study was to explore the risk factors for fracture in patients with fibrous dysplasia (FD) of the proximal femur.

METHODS

We investigated body mass index, bilateral radiographs on both sides, femoral neck shaft angle measurements, and markers of bone metabolism in patients with FD of the proximal femur according to whether or not they had sustained a hip fracture. Nine clinical parameters (age, sex, clinical classification, anatomic classification, femoral neck shaft angle, and procollagen type 1 N-terminal propeptide, C-terminal telopeptide of type I collagen, and osteocalcin levels) were selected for univariate analysis. Factors that were significant in univariate analysis were then subjected to multivariate logistic analysis.

RESULTS

Clinical classification, anatomic classification, femoral neck shaft angle, and the osteocalcin level were identified to be statistically significant risk factors for fracture in univariate analysis. Anatomic classification, femoral neck shaft angle, and the osteocalcin level remained significant risk factors in multivariate analysis.

CONCLUSIONS

Anatomic classification, femoral neck shaft angle, and the osteocalcin level are important risk factors for fracture in patients with FD of the proximal femur and could be used to guide implementation of a fracture prevention strategy in these patients.

Approach to adult patients with primary hypothyroidism in some special situations: a position statement from the Thyroid Department of the Brazilian Society of Endocrinology and Metabolism (SBEM)

Primary hypothyroidism is a common disorder in clinical practice. The management of most cases of hypothyroidism is usually straightforward, but the best approach in some special situations may raise questions among physicians. This position statement was prepared by experts from the Brazilian Society of Endocrinology and Metabolism to guide the management of three special situations, namely, hypothyroidism in the elderly, subclinical hypothyroidism in patients with heart disease, and difficult-to-control hypothyroidism. The authors prepared the present statement after conducting a search on the databases MEDLINE/PubMed, LILACS, and SciELO and selecting articles with the best evidence quality addressing the selected situations. The statement presents information about the current approach to patients in these special situations.

Association Between Subclinical Thyroid Dysfunction and Fracture Risk

IMPORTANCE

Clinical hyperthyroidism accelerates bone resorption without compensatory bone formation, reducing bone density and increasing the risk of fracture. The association between subclinical hyperthyroidism and fracture risk is less clear.

OBJECTIVE

To investigate the association of endogenous subclinical thyroid dysfunction and fracture risk, independent of clinical confounders.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study included 10 946 participants from the Atherosclerosis Risk in Communities Study, an ongoing prospective cohort study of community-dwelling individuals conducted from 1987-1989 through December 31, 2019, in Washington County, Maryland; Forsyth County, North Carolina; Jackson, Mississippi; and the suburbs of Minneapolis, Minnesota. Participants were not taking thyroid medications and had no history of fractures.

EXPOSURES

Thyrotropin and free thyroxine levels were measured at visit 2 (1990-1992). Subclinical hyperthyroidism was defined as a thyrotropin level lower than 0.56 mIU/L, subclinical hypothyroidism as a thyrotropin level higher than 5.1 mIU/L, and euthyroidism as a thyrotropin level of 0.56 to 5.1 mIU/L, with normal free thyroxine levels from 0.85 to 1.4 ng/dL.

MAIN OUTCOMES AND MEASURES

Incident fracture was ascertained using hospitalization discharge codes through 2019 and linkage to inpatient and outpatient Medicare claims through 2018.

RESULTS

Of 10 946 participants (54.3% women; mean [SD] age, 57 [5.7] years), 93.0% had euthyroidism, 2.6% had subclinical hyperthyroidism, and 4.4% had subclinical hypothyroidism. During a median follow-up of 21 years (IQR, 13.0-27.3 years), there were 3556 incident fractures (167.1 per 10 000 person-years). The adjusted hazard ratios of fracture were 1.34 (95% CI, 1.09-1.65) for those with subclinical hyperthyroidism and 0.90 (95% CI, 0.77-1.05) for those with subclinical hypothyroidism compared with individuals with euthyroidism. Among those with normal free thyroxine levels, thyrotropin levels in the lower-than-normal range were significantly associated with higher fracture-related hospitalization risk; fracture risk was greater among individuals with thyrotropin concentrations below 0.56 mIU/L.

CONCLUSIONS AND RELEVANCE

This community-based cohort study suggests that subclinical hyperthyroidism was an independent risk factor associated with fracture. The increased risk for fracture among individuals with a thyrotropin level lower than 0.56 mIU/L highlights a potential role for more aggressive screening and monitoring of patients with subclinical hyperthyroidism to prevent bone mineral disease.

Subclinical thyroid dysfunction and incident diabetes: a systematic review and an individual participant data analysis of prospective cohort studies

OBJECTIVE

Few prospective studies have assessed whether individuals with subclinical thyroid dysfunction are more likely to develop diabetes, with conflicting results. In this study, we conducted a systematic review of the literature and an individual participant data analysis of multiple prospective cohorts to investigate the association between subclinical thyroid dysfunction and incident diabetes.

METHODS

We performed a systematic review of the literature in Medline, Embase, and the Cochrane Library from inception to February 11, 2022. A two-stage individual participant data analysis was conducted to compare participants with subclinical hypothyroidism and subclinical hyperthyroidism vs euthyroidism at baseline and the adjusted risk of developing diabetes at follow-up.

RESULTS

Among 61 178 adults from 18 studies, 49% were females, mean age was 58 years, and mean follow-up time was 8.2 years. At the last available follow-up, there was no association between subclinical hypothyroidism and incidence of diabetes (odds ratio (OR) = 1.02, 95% CI: 0.88-1.17, I2 = 0%) or subclinical hyperthyroidism and incidence of diabetes (OR = 1.03, 95% CI: 0.82-1.30, I2 = 0%), in age- and sex-adjusted analyses. Time-to-event analysis showed similar results (hazard ratio for subclinical hypothyroidism: 0.98, 95% CI: 0.87-1.11; hazard ratio for subclinical hyperthyroidism: 1.07, 95% CI: 0.88-1.29). The results were robust in all sub-group and sensitivity analyses.

CONCLUSIONS

This is the largest systematic review and individual participant data analysis to date investigating the prospective association between subclinical thyroid dysfunction and diabetes. We did not find an association between subclinical thyroid dysfunction and incident diabetes. Our results do not support screening patients with subclinical thyroid dysfunction for diabetes.

SIGNIFICANCE STATEMENT

Evidence is conflicting regarding whether an association exists between subclinical thyroid dysfunction and incident diabetes. We therefore aimed to investigate whether individuals with subclinical thyroid dysfunction are more prone to develop diabetes in the long run as compared to euthyroid individuals. We included data from 18 international cohort studies with 61 178 adults and a mean follow-up time of 8.2 years. We did not find an association between subclinical hypothyroidism or subclinical hyperthyroidism at baseline and incident diabetes at follow-up. Our results have clinical implications as they neither support screening patients with subclinical thyroid dysfunction for diabetes nor treating them in the hope of preventing diabetes in the future.

Independent Skeletal Actions of Pituitary Hormones

Over the past years, pituitary hormones and their receptors have been shown to have non-traditional actions that allow them to bypass the hypothalamus-pituitary-effector glands axis. Bone cells-osteoblasts and osteoclasts-express receptors for growth hormone, follicle stimulating hormone (FSH), thyroid stimulating hormone (TSH), adrenocorticotrophic hormone (ACTH), prolactin, oxytocin, and vasopressin. Independent skeletal actions of pituitary hormones on bone have been studied using genetically modified mice with haploinsufficiency and by activating or inactivating the receptors pharmacologically, without altering systemic effector hormone levels. On another front, the discovery of a TSH variant (TSH-βv) in immune cells in the bone marrow and skeletal action of FSHβ through tumor necrosis factor α provides new insights underscoring the integrated physiology of bone-immune-endocrine axis. Here we discuss the interaction of each pituitary hormone with bone and the potential it holds in understanding bone physiology and as a therapeutic target.

Bone geometry in older adults with subclinical hypothyroidism upon levothyroxine therapy: A nested study within a randomized placebo controlled trial

The effect of levothyroxine (LT4) therapy for subclinical hypothyroidism (SHypo) on appendicular bone geometry and volumetric density has so far not been studied. In a nested study within the randomized, placebo-controlled Thyroid Hormone Replacement for Subclinical Hypothyroidism (TRUST) trial, we assessed the effect of LT4 therapy on bone geometry as measured by peripheral quantitative computed tomography (pQCT). In the TRUST trial, community-dwelling adults aged ≥65 years with SHypo were randomized to LT4 with dose titration vs. placebo with mock titration. We analyzed data from participants enrolled at the TRUST site in Bern, Switzerland who had bone pQCT measured at baseline and at 1 to 2 years follow-up. The primary outcomes were the annual percentage changes of radius and tibia epi- and diaphysis bone geometry (total and cortical cross-sectional area (CSA) and cortical thickness), and of volumetric bone mineral density (bone mineral content (BMC) and total, trabecular and cortical volumetric bone mineral density (vBMD)). We performed linear regression of the annual percentage changes adjusted for sex, LT4 dose at randomization and muscle cross-sectional area. The 98 included participants had a mean age of 73.9 (±SD 5.4) years, 45.9% were women, and 12% had osteoporosis. They were randomized to placebo (n = 48) or LT4 (n = 50). Annual changes in BMC and vBMD were similar between placebo and LT4-treated groups, without significant difference in bone geometry or volumetric bone mineral density changes, neither at the diaphysis, nor at the epiphysis. For example, in the placebo group, epiphyseal BMC (radius) decreased by a mean 0.2% per year, with a similar decrease of 0.5% per year in the LT4 group (between-group difference in %ΔBMC 0.3, 95% CI -0.70 to 1.21, p = 0.91). Compared to placebo, LT4 therapy for an average 14 months had no significant effect on bone mass, bone geometry and volumetric density in older adults with subclinical hypothyroidism. TRIAL REGISTRATION: The trial was registered on ClinicalTrials.gov numbers NCT01660126 (TRUST Thyroid trial) and NCT02491008 (Skeletal outcomes).

Update on subclinical thyroid dysfunction

Subclinical thyroid dysfunction is defined by serum thyroid-stimulating hormone (TSH) levels either greater or less than the reference range with normal thyroxine (T4) concentrations, and consists of subclinical hypothyroidism (SCH) and subclinical hyperthyroidism (SCHyper). For the proper diagnosis of SCH, it is most important to be able to correctly evaluate the serum TSH levels, which have numerous unique characteristics. We also need to be versed in TSH harmonization, which was recently launched world-wide. In this review, we will attempt to determine the best clinical approaches to the treatment of subclinical thyroid dysfunction based on recent guidelines published from several countries and novel findings of several recent large-scale clinical studies.

The association between blood PFAS concentrations and clinical biochemical measures of organ function and metabolism in participants of the Canadian Health Measures Survey (CHMS)

Per- and poly-fluoroalkyl substances (PFAS) are ubiquitous and may persist in human tissue for several years. Only a small proportion of PFAS have been studied for human health effects. We tested the association between human blood levels of six PFAS and several clinical measures of organ and metabolic function in a nationally representative sample of 6768 participants aged 3-79 years old who participated in the Canadian Health Measures Survey. Cross-sectional associations were assessed by generalized linear mixed models incorporating survey-specific sampling weights. An increase in perfluorooctanoic acid (PFOA) equivalent to the magnitude of its geometric mean (GM) of 2.0 μg/L was associated with percentage (95% CI) increases in serum enzymes reflecting liver function: aspartate aminotransferase (AST) 3.7 (1.1, 6.4), gamma-glutamyl transferase (GGT) 11.8 (2.5, 21.8), alanine aminotransferase (ALT) 3.2 (0.5, 5.9), and bilirubin 3.6 (2.7, 4.5). A GM increase in perfluorodecanoic acid (PFDA) of 0.2 μg/L was positively associated with percentage increases in GGT, triglycerides, low-density lipoprotein (LDL) cholesterol, total cholesterol, and calcium with respective increases of 15.5 (2.2, 30.4), 7.0 (1.0, 13.2), 10.7 (5.5, 16.1), 2.8 (0.2, 5.3), and 0.8 (0.3, 1.3). PFOA, perfluorooctane sulfonate (PFOS), PFDA and perfluorononanoic acid (PFNA) were positively associated with GGT. All six congeners were positively associated with at least one biomarker of lipid metabolism, and 5 of 6, PFOA, PFOS, PFDA, perfluorohexane sulfonate (PFHxS) and PFNA were positively associated with serum calcium. Exposure to selected PFAS is associated with clinical blood tests reflecting metabolism and the function of several organ systems. These relatively small changes may possibly indicate early pathology that is clinically inapparent and may possibly be of significance in a general population or in individuals exposed to very high levels of PFAS.

The Association Between Subclinical Thyroid Dysfunction and Recurrence of Atrial Fibrillation After Catheter Ablation

Objective

The aim of this study was to evaluate the association between subclinical thyroid dysfunction and the recurrence of atrial fibrillation (AF) after radiofrequency catheter ablation (RFCA).

Methods

We examined the association between subclinical thyroid dysfunction and the recurrence of AF at a large university-affiliated cardiac arrhythmia center in China. Data were collected from consecutive patients who underwent RFCA for AF, excluding those with a history of hypothyroidism, hyperthyroidism, or ongoing medical treatment for hypothyroidism or hyperthyroidism, biochemically defined overt thyroid disease, and long-term use of amiodarone before admission. The primary end point was the recurrence of AF in a time-to-event analysis. We compared outcomes in patients who had subclinical hyperthyroidism or hypothyroidism with those who had euthyroid state, using a multivariable Cox model with inverse probability weighting and propensity score matching.

Results

In all, 93 patients were excluded from 435 consecutive patients who underwent RFCA for AF. Of the remaining 342 patients for the analysis, the prevalence of subclinical hyperthyroidism and subclinical hypothyroidism were 26 (7.6%) and 41 (12.0%), respectively; during a median follow-up of 489 days, 91 patients (26.6%) developed a primary end point event. In the main analysis of the multivariable Cox model, only subclinical hyperthyroidism [hazard ratio: 3.07, 95% confidence interval (CI): 1.54–6.14] was associated with an increased risk of end point event after adjusting for potential confounders. However, the association between subclinical hypothyroidism and the end point event was not significant (hazard ratio: 0.66, 95% CI: 0.31–1.43). Results were consistent either in multiple sensitivity analyses or across all subgroups of analysis. Compared with individuals with free triiodothyronine (fT3) in the lowest quintile, those with fT3 in the highest quintile had an HR of 2.23 (95% CI: 1.16–4.28) for recurrence of AF. With the increase of thyroid-stimulating hormone (TSH), a reduction in the risk of recurrence of AF was detected in the adjusted model, and the hazard ratio (HR) per standard deviation (SD) increase was 0.82 (95% CI: 0.68–0.98).

Conclusion

In this retrospective cohort study involving patients who underwent RFCA for AF, patients with subclinical hyperthyroidism were associated with a markedly higher prevalence of recurrence of AF, whereas patients with subclinical hypothyroidism had a similar recurrence rate of AF compared to those with the euthyroid state.

The impact of the management strategies for patients with subclinical hypothyroidism on long-term clinical outcomes: An umbrella review

AIM

This umbrella review summarises and compares synthesised evidence on the impact of subclinical hypothyroidism and its management on long-term clinical outcomes.

METHODS

We conducted comprehensive searches on MEDLINE, EMBASE, Scopus, Web of Science, Cochrane Database of Systematic Reviews, JBI Evidence Synthesis, the PROSPERO register, Epistemonikos Database and PDQ Evidence from inception to February and July 2021 using keywords on subclinical hypothyroidism, treatment with levothyroxine, monitoring and primary outcomes (all-cause mortality, cardiovascular events, stroke, frailty fractures and quality of life). Only systematic reviews and meta-analyses on adult patient populations were considered. Study selection, data extraction and quality appraisal using AMSTAR-2 were done independently by two reviewers and discrepancies were resolved through discussion. Overlap across the selected reviews was also assessed, followed by a narrative synthesis of findings.

RESULTS

A total of 763 studies were identified from literature searches; 20 reviews met inclusion criteria. Methodological quality ratings were high (n = 8), moderate (n = 7), and low (n = 5), but no reviews were excluded on this basis. Though there was slight overlap across all reviews, some pairwise comparisons had high corrected covered area scores. Compared to euthyroidism, untreated subclinical hypothyroidism was associated with a higher risk of cardiovascular events or death if Thyroid Stimulating Hormone was above 10mIU/L at baseline. Treatment was associated with a lower risk of death from all causes for patients younger than 70 years and possibly better cognitive and quality of life scores than untreated individuals. Evidence on the risk of strokes and fractures was inconclusive.

CONCLUSION

In the long term, treatment of subclinical hypothyroidism may be beneficial for some patient groups. However, the findings of this review are negatively impacted by the relative sparseness and poor quality of available evidence. Additional large and adequately powered studies are needed to investigate this topic further.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO (CRD42021235172).

Frequency, determinants and costs of thyroid function testing in a laboratory serving a large population

OBJECTIVE

To assess the rationale and frequency of thyroid function testing and to analyse factors that influence serum thyrotropin (TSH) levels.

PATIENTS, DESIGN AND MAIN OUTCOME MEASURES

Serum TSH levels were evaluated in a hospital laboratory serving a population of 604 000 in 2018. Patients on medications or with conditions affecting thyroid function were excluded. Frequency of thyroid function testing by age and sex was assessed and the relationship between serum TSH with potential predictor variables was analysed using ordinary least square regression analysis allowing for potential non-linearity.

RESULTS

Twenty-eight percent of the local population had their thyroid function tested at least once in 2018 with significant differences by sex (28.2% women vs 23.4% men) and by age groups, with less than 2% of <16-year-old people and more than 50% of >80-year-old people being tested. Most of the symptoms commonly attributed to thyroid dysfunction were not higher in the thyroid dysfunction groups. Serum TSH levels were higher in older people particularly after the age of 60 years, in women (by 0.1 mIU/L), during the early hours of the morning, and in winter and spring seasons. There was remarkable uniformity in the frequency of subclinical thyroid dysfunction, as well as substantial cost savings, if TSH reference intervals were recalculated across sexes, age groups, time-periods and seasons.

CONCLUSIONS

Serum TSH is frequently tested in the population but is not a good discriminant of symptoms attributed to thyroid dysfunction. Furthermore, considering the influence of factors on TSH reference limits could significantly impact patient care and resource utilisation.