Frax score calculations in postmenopausal women with subclinical hypothyroidism

Higher prevalence of thyroid-specific autoantibodies (TPOAb and TgAb) is related to a higher prevalence of fractures in females: results from NHANES 2007-2010

A retrospective analysis was conducted using data from the NHANES. Bone mineral density (BMD) was compared in different thyroid-specific autoantibodies groups. Strengths of associations were calculated by using binary logistic regression models. Higher titers of thyroid-specific autoantibodies (TgAb and/or TPOAb) may lead to decreased BMD. Higher prevalence of TgAb and TPOAb significantly associated with fractures in females but not in males.

PURPOSE

Hashimoto's thyroiditis is characterized by elevated thyroid-specific autoantibodies. It is currently believed that osteoporosis is not only a disease with abnormal mineral metabolism but also with immune abnormalities. This study investigated the relationship between thyroid-specific autoantibodies and osteoporosis, including the bone mineral density (BMD) values and fractures.

METHODS

A retrospective analysis was conducted using data from the National Health and Nutrition Examination Survey (2007-2010). BMD was compared in different thyroid-specific autoantibodies groups. The associations between thyroid-specific autoantibodies and fractures were explored. Strengths of associations were calculated by binary logistic regression models. Candidate variables for binary logistic regression model were selected after screened in univariate analysis (variables with P < 0.05).

RESULTS

A total of 3865 study participants were included in this analysis; 224 participants were TgAb positive and 356 were TPOAb positive. A total of 392 participants reported hip, spine or wrist fractures. Participants with higher prevalence of TgAb or TPOAb had lower BMD. In females, significant cigarettes use, higher prevalence of TgAb and TPOAb, and the BMD of the total femur and femoral neck were significantly associated with fractures. Higher prevalence of TPOAb was particularly associated with a higher possibility of hip or spine fractures. In males, significant cigarettes use, 25OHD3, the BMD values of the total femur, femoral neck and total spine were significantly associated with fractures.

CONCLUSION

Higher prevalence of thyroid-specific autoantibodies may lead to decreased BMD. In females, higher prevalence of TgAb and TPOAb significantly associated with fractures and TPOAb especially relating to the fractures of hip and spine. Males patients with vitamin D deficiency or insufficiency associated a higher possibility of fractures.

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.

The effect of levothyroxine in comparison with placebo on serum osteocalcin levels in patients with subclinical hypothyroidism

BACKGROUND AND OBJECTIVE

Subclinical hypothyroidism can potentially develop to overt hypothyroidism. Thyroid hormones have substantial roles in metabolism and glucose homeostasis and thus are closely related to determinant factors of metabolic syndromes, such as obesity and insulin resistance. Osteocalcin is considered a predictor of metabolic conditions in thyroid diseases. This study aimed to investigate the effect of levothyroxine vs. placebo on serum osteocalcin levels in patients with subclinical hypothyroidism.

METHODS

This randomized clinical trial was performed on 30 patients with subclinical hypothyroidism who were referred to the endocrine clinics of Ghaem and Imam Reza hospitals in Mashhad, Iran. After giving informed consent, patients were randomly divided into intervention (50 µg/day levothyroxine for 2 months) and control (placebo) groups. Serum levels of osteocalcin, thyroid hormones, lipid profile, insulin, and fasting glucose, as well as other clinical and anthropometric data, were measured at baseline and at the end of the study. SPSS was used to analyze the data and P<0.05 was considered significant.

RESULTS

Mean age in the intervention and control groups was 35.07 ± 9.94 and 31.30 ± 4.30, respectively (P=0.20). There was no significant difference between osteocalcin levels before and after the intervention in either of the groups (P=0.54). TSH level was significantly decreased in the levothyroxine group after the intervention (P<0.01). T4 level was significantly increased in the intervention group (P=0.02).

CONCLUSION

Levothyroxine had no significant effect on increasing the levels of serum osteocalcin in patients with subclinical hypothyroidism. We have registered the trial in the Iranian registry of clinical trials (IRCT) with the registration code IRCT20171129037677N1.

The Influence of Thyroid Pathology on Osteoporosis and Fracture Risk: A Review

Thyroid hormones are important factors that regulate metabolism and cell differentiation throughout the human body. A complication of thyroid pathology is represented by an alteration of the bone metabolism which can lead to osteoporosis and fragility fractures, known to have a high mortality rate. Although there is a consensus on the negative impact of hyperthyroidism on bone metabolism, when referring to hypothyroidism, subclinical hypothyroidism, or subclinical hyperthyroidism, there is no general agreement. The aim of our review was to update clinicians and researchers about the current data regarding the bone health in hypothyroidism, subclinical hypothyroidism, and subclinical hyperthyroidism patients. Thyroid disorders have an important impact on bone metabolism and fracture risk, such that hyperthyroidism, hypothyroidism, and subclinical hyperthyroidism are associated with a decreased bone mineral density (BMD) and increased risk of fracture. Subclinical hypothyroidism, on the other hand, is not associated with osteoporosis or fragility fractures, and subclinical hyperthyroidism treatment with radioiodine could improve bone health.

The influence of thyroid disorders on bone density and biochemical markers of bone metabolism

Background Thyroid dysfunction, predominantly hyperthyroidism, has been previously linked to impaired bone mass density (BMD) and increased risk of fractures. On the other hand, data in the field of hypothyroidism (HT) are missing. The purpose of the present study was to investigate the impact of thyroid disorders on bone density serum and urine calcium (Ca) and phosphate (P) as well as serum osteocalcin and alkaline phosphatase and urine hydroxyproline in a series of post-menopausal women. Materials and methods The study was conducted in the Reproductive Endocrinology Outpatient Clinic of our hospital. A consecutive series of post-menopausal women was included, after excluding patients under hormone treatment (including levothyroxine supplementation) and those who received raloxifene, tamoxifen or tibolone during the study period as well as those who received treatment during the previous 12 months were excluded from the present study. Results Overall, 188 women were included in the present study. Among them, 143 women had normal thyroid function, 32 women had hyperthyroidism and 13 women had HT. Correlation of thyroid function indices with osteoporosis indices revealed statistically significant correlations between thyroxine (T4) and free triiodothyronine (T3) with T-, Z-scores and BMD. Logistic regression analysis concerning the impact of HT and hyperthyroidism on T-score, Z-score and bone mass density revealed that both pathological entities negatively affect bone health (p < 0.05). Conclusion The findings of our study suggest that not only hyperthyroidism, but also HT negatively affects BMD. Future studies should investigate this association and corroborate our findings.

Effects of Bone Marrow Mesenchymal Stem Cells-Conditioned Medium on Tibial Partial Osteotomy Model of Fracture Healing in Hypothyroidism Rats

Background

Hypothyroidism is associated with dysfunction of the bone turnover with reduced osteoblastic bone formation and osteoclastic bone resorption. Mesenchyme stem cells (MSCs) secrete various factors and cytokines that may stimulate bone regeneration. The aim of this study was to determine the effects of MSCs-conditioned medium (CM) in hypothyroidism male rats after inducing bone defect.

Methods

: In this study, 24 male rats were randomly assigned to three groups: (I) hypothyroidism+bone defect (HYPO), (II) hypothyroidism+bone defect+CM (HYPO+CM), and (III) no hypothyroidism+bone defect (control). Four weeks after surgery, the right tibia was removed, and immediately, biomechanical and histological examinations were performed.

Results

The results showed a significant reduction in bending stiffness (32.64±3.99), maximum force (14.63±1.89), high stress load (7.59±2.31), and energy absorption (12.68±2.12) at the osteotomy site in hypothyroidism rats in comparison to the control and hypothyroidism+condition medium groups (P<0.05). There was also a significant decrease in the trabecular bone volume (3.86±3.88) and the number of osteocytes (5800±859.8) at the osteotomy site in hypothyroidism rats compared to the control and hypothyroidism+condition medium groups (P<0.01 and P<0.02, respectively).

Conclusion

The present study suggests that the use of the CM can improve the fracture regeneration and accelerates bone healing at the osteotomy site in hypothyroidism rats.

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.

Thyrotropin serum levels are differentially associated with biochemical markers of bone turnover and stiffness in women and men: results from the SHIP cohorts

In two large German population-based cohorts, we showed positive associations between serum thyrotropin (TSH) concentrations and the Fracture Risk Assessment score (FRAX) in men and positive associations between TSH concentrations and bone turnover markers in women.

INTRODUCTION

The role of thyroid hormones on bone stiffness and turnover is poorly defined. Existing studies are confounded by differences in design and small sample size. We assessed the association between TSH serum concentrations and bone stiffness and turnover in the SHIP cohorts, which are two population-based cohorts from a region in Northern Germany comprising 2654 men and women and 3261 men and women, respectively.

METHODS

We calculated the bone stiffness index using quantitative ultrasound (QUS) at the calcaneus, employed FRAX score for assessment of major osteoporotic fractures, and measured bone turnover markers, N-terminal propeptide of type I procollagen (P1NP), bone-specific alkaline phosphatase (BAP), osteocalcin, and type I collagen cross-linked C-telopeptide (CTX) in all subjects and sclerostin in a representative subgroup.

RESULTS

There was no association between TSH concentrations and the stiffness index in both genders. In men, TSH correlated positively with the FRAX score both over the whole TSH range (p < 0.01) and within the reference TSH range (p < 0.01). There were positive associations between TSH concentrations and P1NP, BAP, osteocalcin, and CTX (p < 0.01) in women but not in men. There was no significant association between TSH and sclerostin levels.

CONCLUSIONS

TSH serum concentrations are associated with gender-specific changes in bone turnover and stiffness.

The influence of thyroid dysfunction on bone metabolism

Loss of bone mineral density due to osteoporosis is the main cause of fragility fractures and leads to dropped quality of life and increased mortality. Disturbance of balance between bone formation and bone resorption is dangerous, can cause loss of bone mass and disruption of it's architecture. Correct development, achievement of peak bone mass and normal functioning of human skeleton depend on different factors. The pivotal role in bone metabolism play thyroid hormones. Both excess as well as deficiency of fT4 and fT3 can be potentially deleterious for bone tissue. The aim of this study is to review the current literature concerning the role of thyroid hormones on bone metabolism.