Low cortical bone density measured by computed tomography in children and adolescents with untreated hyperthyroidism

Changes in bone mineral density, 25-hydroxyvitamin D3 and inflammatory factors in patients with hyperthyroidism

The present study aimed to evaluate changes in bone mineral density, 25-hydroxyvitamin D³ [25-(OH)D³] and inflammatory factors in patients with hyperthyroidism, in order to determine the correlations with the pathogenesis of hyperthyroidism. A total of 55 patients with hyperthyroidism (observation group) and 53 healthy patients (control group) enrolled at Weifang People's Hospital from March 2017 to February 2018 were randomly enrolled. The thyroid function, bone mineral density, 25-(OH)D³ and inflammatory factors were measured and compared between the two groups. The measurement data are presented as mean ± standard deviation (SD), and Student t-test was performed for the comparison between two groups. Chi-square test was used for enumeration data regarding sex. Pearson correlation analysis was performed for two-variable analysis on L1, 25-(OH)D³, interleukin (IL)-2, IL-6 with FT3, respectively. In regards to the results, no difference in sex, age and body mass index (BMI) between the two groups were found but the thyroid function was markedly enhanced in the observation group compared to the control group. Bone mineral density index and 25-(OH)D³ in the observation group were significantly lower than those in the control group (P<0.05). There were significant differences in the inflammatory factors between the two groups (P<0.05). The L1, 25-(OH)D³ and IL-2 levels were significantly negatively correlated with thyroid function index and free triiodothyronine (FT3) while a statistically positive correlation was found between IL-6 and FT3 (P<0.05). In conclusion, abnormal levels of bone mineral density, 25-(OH)D³ and inflammatory factors are observed in patients with hyperthyroidism, and there are correlations between L1, 25-(OH)D³, IL-2, IL-6 and FT3 in the pathogenesis of hyperthyroidism, which provides new insight for the diagnosis of hyperthyroidism.

Low Bone Mineral Density at Initial Diagnosis in Children and Adolescents with Graves' Disease

Previous studies have reported reduced bone mineral density (BMD) in patients with hyperthyroidism. We assessed the association of BMD in children and adolescents with Graves' disease (GD) after correcting for potential confounders affecting BMD such as age, sex, and pubertal status. Forty-four children and adolescents with GD and 172 age- and sex-matched healthy controls were enrolled in this study. We analyzed auxological features, BMD, and levels of thyroid hormone, thyroid-stimulating hormone, and thyroid autoantibodies. We measured BMD by dual-energy X-ray absorptiometry at the time of diagnosis in all patients. The mean age of all patients with GD (9 boys and 32 girls) was 12.1 ± 2.2 years (range, 7.0-16.0). Their initial mean free T4 and thyroid-stimulating hormone levels were 3.51 ± 1.56 ng/dL and 0.04 ± 0.03 IU/L, respectively. The mean BMD Z-scores of the lumbar spine (LS), femoral neck, and total body less head of patients with GD were significantly lower than those of control subjects. Eleven patients (26.8%) had low bone density (LS BMD Z-scores < -2.0). To identify correlations of patient characteristics with BMD Z-scores at each site, alkaline phosphatase had a significant negative correlation with BMD Z-scores at LS and femoral neck, but not total body less head (r = -0.441; p = 0.004 and r = -0.351; p = 0.025, respectively). Children and adolescents with newly diagnosed GD had lower bone mass than their healthy peers. These results suggest that BMD measurement at initial evaluation may be necessary in this population.

Bone mineral density and bone microarchitecture after long-term suppressive levothyroxine treatment of differentiated thyroid carcinoma in young adult patients

Bone mineral density (BMD) seems not to be decreased in young patients given long-term suppressive doses of levothyroxine (LT4), but information regarding the bone microstructure in these patients is lacking. The aim of this study was to determine whether supraphysiologic doses of LT4, initiated during childhood or adolescence for treatment of differentiated thyroid carcinoma (DTC), have any detrimental effects on bone microarchitecture as evaluated by high-resolution peripheral quantitative computed tomography (HR-pQCT). Seventeen patients (27.3 ± 7.1 years old) with DTC with subclinical hyperthyroidism since adolescence and 34 healthy volunteers matched for age, sex, and body mass index were studied by dual-energy X-ray absorptiometry (DXA) to determine the areal BMD at the lumbar spine, hip, and proximal third of the radius. Volumetric BMD and structural parameters of the trabecular and cortical bone were assessed by HR-pQCT of the distal radius and distal tibia. DTC patients were given suppressive doses of LT4 starting at a mean age of 12.6 years, and the mean duration of treatment was 14.2 years. In DTC patients, clinical parameters did not correlate with DXA or HR-pQCT parameters. No differences were found between the patients and controls with respect to BMD and Z scores at any site evaluated by DXA, and no differences were found in the bone microstructure parameters evaluated by HR-pQCT. This cross-sectional study suggests that long-standing suppressive therapy with LT4 during the attainment of peak bone mass may have no significant adverse effects on bone density or microarchitecture.

Hyperthyroidism Presenting With Pathologic Fractures

Previous studies have shown that thyroid hormone directly stimulates bone resorption in in vitro organ culture, and in adults excess thyroid hormone is associated with decreased bone mineral density. There are limited data in children regarding the effect of hyperthyroidism on bone metabolism and even fewer instances in the literature of hyperthyroidism presenting with bone demineralization and fracture. We report a case of an 11-year-old boy with undiagnosed hyperthyroidism presenting with fractures and osteoporosis. This case emphasizes the importance of maintaining a broad differential diagnosis when a patient presents with a pathologic fracture.

Quantitative computer tomography in children and adolescents: the 2013 ISCD Pediatric Official Positions

In 2007, International Society of Clinical Densitometry Pediatric Positions Task Forces reviewed the evidence for the clinical application of peripheral quantitative computed tomography (pQCT) in children and adolescents. At that time, numerous limitations regarding the clinical application of pQCT were identified, although its use as a research modality for investigation of bone strength was highlighted. The present report provides an updated review of evidence for the clinical application of pQCT, as well as additional reviews of whole body QCT scans of the central and peripheral skeletons, and high-resolution pQCT in children. Although these techniques remain in the domain of research, this report summarizes the recent literature and evidence of the clinical applicability and offers general recommendations regarding the use of these modalities in pediatric bone health assessment.

Normalization of cortical bone density in children and adolescents with hyperthyroidism treated with antithyroid medication

We assessed bone size and bone density (BD) measurements using computed tomography (CT) in children and adolescents with hyperthyroidism treated with antithyroid medication. We found that cortical BD appeared to improve at 1 year and normalize at 2 years in all tested patients.

INTRODUCTION

Our previous study demonstrated that cortical BD in children and adolescents with untreated hyperthyroidism was significantly decreased as compared to age-, sex- and ethnicity-matched healthy controls. The present report evaluated whether attainment of euthyroidism by medical antithyroid treatment was able to improve or normalize cortical BD in these patients.

METHODS

Anthropometrics and three-dimensional CT bone measurements including cross-sectional area (CSA), cortical bone area (CBA) and cortical BD at midshaft of the femur (cortical bone), and CSA and BD of L(1) to L(3) vertebrae (cancellous bone) in 15 children and adolescents after 1- and 2-year treatments with antithyroid medication were reviewed and compared to their pretreatment results.

RESULTS

All patients were euthyroid at 1 and 2 years after medical antithyroid treatment. After adjusting for age, height, weight and Tanner stage, a significant increase in cortical BD in all patients (15/15) was found after 1 year of treatment (P < 0.001). Normalization of cortical BD was demonstrated in all tested patients (10/15) after 2 years. There were no significant changes in the other cancellous or cortical bone parameters.

CONCLUSION

Cortical BD was improved at 1 year and normalized at 2 years in hyperthyroid patients rendered euthyroid with antithyroid medication.

Bone size and density measurements in prepubertal children with Turner syndrome prior to growth hormone therapy

Using computed tomography (CT), we found the decreases in bone size of vertebrae and femur, cortical bone area (CBA) of femur and bone density (BD) of vertebrae in prepubertal female with Turner syndrome (TS) compared to those of controls.

INTRODUCTION

Bone mineral density results from previous studies utilizing single-photon absorptiometry (SPA) or dual-energy X-ray absorptiometry (DXA) in children with TS are controversial. The present study used CT to assess the differences in cancellous and cortical bone size and BD between prepubertal TS patients prior to growth hormone therapy and historical age and ethnicity-matched female controls.

METHODS

Anthropometrics and CT bone measurements including cross-sectional area (CSA) and BD of lumbar vertebrae and femur and CBA of femur in prepubertal TS females were reviewed and compared with those in controls.

RESULTS

Twenty-two prepubertal TS patients had delayed bone age, were shorter and lighter than controls (Ps < 0.001). After adjusting for weight, height and skeletal age, vertebral BD and CBA of the femur were lower in patients than in controls (P < 0.001 and P = 0.021, respectively). However, after additional adjusting for puberty, results were not different from controls. While a positive correlation between vertebral BD and age was noted in controls (r = 0.367, P = 0.092), a significant negative correlation was noted in patients (r = -0.615, P = 0.002).

CONCLUSIONS

While the decrease in vertebrae and femur sizes of patients with TS appeared to be secondary to their small body size, the decreased BD of vertebrae and CBA of femur were likely secondary to estrogen deficiency.

The effects of L-thyroxin replacement therapy on bone minerals and body composition in hypothyroid children

INTRODUCTION

Prolonged treatment with levothyroxine 4 (L-T4) is a well known risk factor for osteoporosis. Patients on L-T4 replacement occasionally have a subnormal TSH, which carries a risk of development of bone loss. Thyroid hormones directly affect bone cells, stimulating osteoclastic and osteoblastic activity with a predominance of bone resorption and decrease of bone mineral density (BMD).

MATERIAL AND METHODS

The study included 35 hypothyroid patients with mean age 11.57 ±5.06, while 26 age- and sex-matched children served as controls. Dual energy X-ray absorptiometry (DXA) was done to detect the bone mineral density (BMD), bone mineral content (BMC) and Z score in lumbar and femur neck regions. Body composition was also studied by DXA. Calcium, phosphorus, osteocalcin as a bone formation marker, osteoprotegerin as an indicator of osteoclast activity and urinary deoxypyridinoline as a bone collagen breakdown marker were assessed.

RESULTS

No significant differences were detected in lumbar Z score (-0.12 ±0.66) and femur Z score (-0.17 ±0.58) compared to controls (-0.33 ±0.74 and -0.21 ±0.53 respectively). Bone mineral density and BMC were not significantly different from controls. No significant difference was detected between cases and controls in body composition. A positive correlation was detected between BMD and age (r=0.857, p<0.01), and with the period of treatment (r=0.766, p<0.01). A positive correlation was found between BMD and total body fat (r=0.693, p<0.01), and with abdominal fat (r=0.667, p<0.01).

CONCLUSIONS

Levothyroxine 4 treatment in hypothyroid children does not alter bone metabolism and body composition.