Bone status in primary hyperparathyroidism assessed by regional bone mineral density from the whole body scan and QUS imaging at calcaneus

Bone disease in primary hyperparathyrodism

Nowadays, primary hyperparathyroidism (PHPT) is mostly a mild disease. Overt skeletal manifestations are rare but decreased bone mineral density (BMD) can still be demonstrated. Even in mild cases, excess parathyroid hormone (PTH) increases bone turnover leading to bone loss particularly at cortical sites. Conversely, a relative preservation of cancellous bone has been shown by histomorphometric analyses and advanced imaging techniques. An increased fracture rate has been demonstrated in untreated patients with PHPT at peripheral sites and in the spine. Parathyroidectomy (PTx) is the definitive cure for PHPT. With the restoration of normal PTH, bone resorption is quickly tapered down, while bone formation proceeds at the level of bone multicellular units, which were activated prior to PTx. The rapid refilling of the enlarged remodeling space and the subsequent matrix mineralization will result in an increase in BMD at sites rich in trabecular bone, such as lumbar spine and hip, which mainly occurs during the first 6-12 months after PTx. Cortical bone is less responsive to PTX because of the low rate of bone turnover, but sensible increases in BMD at the distal third of the radius can be observed in the long term. PTx seems to decrease the risk of fractures but more data are needed before a definitive conclusion on this important matter can be reached. Treatment with bisphosphonates can be considered for patients with low BMD who do not undergo PTx. Two-year treatment with alendronate has been shown to decrease bone turnover markers and increase BMD at the lumbar spine and hip, but not at the distal radius. Cinacalcet stably decreased serum calcium levels across a broad range of PHPT severity, but no change in BMD occurred in patients treated for up to 5.5 years.

Forearm bone mineral density in familial hypocalciuric hypercalcemia and primary hyperparathyroidism: a comparative study

Studies have shown that cancellous bone is relatively preserved in primary hyperparathyroidism (PHPT), whereas bone loss is seen in cortical bone. Familial hypocalciuric hypercalcemia (FHH) patients seem to preserve bone mineral in spite of hypercalcemia and often elevated plasma parathyroid hormone (PTH). The objective of this study was to compare total and regional forearm bone mineral density (BMD) in patients with PHPT and FHH and to examine if differences can be used to separate the two disorders. We included 63 FHH, and 121 PHPT patients in a cross-sectional study. We performed dual-energy X-ray absorptiometry scans of the forearm, hip and lumbar spine and measured a number of biochemical variables. PTH patients had significantly lower Z-scores in all parts of the forearm compared to FHH. This was also the case after adjustment for body mass index. When stratifying for age, gender and PTH, T-scores were still significantly lower in PHPT patients than in FHH patients at the total, the mid and the ultradistal forearm, but not at the proximal 1/3 forearm. In a multiple regression analysis BMD Z-score was lower in PHPT compared to FHH at the total forearm, the mid forearm and the ultradistal forearm but not the proximal forearm when adjusting for biochemical variables including PTH, 1,25(OH)(2)D and Ca(2+). These observations support that inactivating mutations in the CASR gene in bone cells in FHH may protect against forearm bone loss. Differences between the two groups in total or regional forearm BMD were inferior to the calcium/creatinine clearance ratio as a diagnostic tool to separate FHH from PHPT.

Effects of suppression of follicle-stimulating hormone secretion on bone resorption markers in postmenopausal women

CONTEXT

It has recently been proposed that the increase in bone resorption after the menopause may not be due principally to estrogen deficiency but rather to the concomitant increase in circulating FSH levels.

OBJECTIVE

The objective of the study was to test whether suppression of FSH secretion in postmenopausal women reduces levels of bone resorption markers.

DESIGN

This was a prospective study.

SETTING

The study was conducted at a clinical research unit.

PARTICIPANTS AND INTERVENTIONS

Postmenopausal women were treated with a GnRH agonist (leuprolide acetate, 7.5 mg im every 28 d; n = 21) or placebo injections (control; n = 20). Both groups received the aromatase inhibitor, letrozole, 2.5 mg/d, to eliminate variations in endogenous estrogen levels as a confounder.

MAIN OUTCOME MEASURES

Serum FSH and bone resorption markers [serum C-terminal telopeptide of type I collagen (CTX) and tartrate-resistant acid phosphatase 5b (TRAP5b)] at d 105 (3.5 months) of treatment as compared with baseline.

RESULTS

Compared with baseline, serum FSH levels did not change significantly in controls (+6%) but were reduced (-86%, into the premenopausal range) in the GnRH group. Due to the aromatase inhibitor-induced reduction in estrogen production, serum CTX and TRAP5b levels increased significantly in controls (+20 and +10%, respectively). In the GnRH group, suppression of FSH secretion did not reduce serum CTX or TRAP5b levels; rather, both markers also increased in these women (+34 and +15%, respectively; P = 0.161 and 0.266 for comparison of percent changes between groups).

CONCLUSIONS

This direct interventional study demonstrates that FSH does not regulate bone resorption in postmenopausal women.

Effects on bone geometry, density, and microarchitecture in the distal radius but not the tibia in women with primary hyperparathyroidism: A case-control study using HR-pQCT

Patients with primary hyperparathyroidism (PHPT) have continuously elevated parathyroid hormone (PTH) and consequently increased bone turnover with negative effects on cortical (Ct) bone with preservation of trabecular (Tb) bone. High-resolution peripheral quantitative computed tomography (HR-pQCT) is a new technique for in vivo assessment of geometry, volumetric density, and microarchitecture at the radius and tibia. In this study we aimed to evaluate bone status in women with PHPT compared with controls using HR-pQCT. The distal radius and tibia of 54 women--27 patients with PHPT (median age 60, range 44-75 years) and 27 randomly recruited age-matched healthy controls (median age 60, range 44-76 years)--were imaged using HR-pQCT along with areal bone mineral density (aBMD) by dual-energy X-ray absorptiomentry (DXA) of the ultradistal forearm, femoral neck, and spine (L1-L4). Groups were comparable regarding age, height, and weight. In the radius, patients had reduced Ct area (Ct.Ar) (p = .008), Ct thickness (Ct.th) (p = .01) along with reduced total (p = .002), Ct (p = .02), and Tb (p = .02) volumetric density and reduced Tb number (Tb.N) (p = .04) and increased Tb spacing (Tb.sp) (p = .05). Ct porosity did not differ. In the tibia, no differences in HR-pQCT parameters were found. Moreover, patients had lower ultradistal forearm (p = .005), spine (p = .04), and femoral neck (p = 0.04) aBMD compared with controls. In conclusion, a negative bone effect of continuously elevated PTH with alteration of HR-pQCT assessed geometry, volumetric density, and both trabecular and cortical microarchitecture in radius but not tibia was found along with reduced aBMD by DXA at all sites in female patients with PHPT. © 2010 American Society for Bone and Mineral Research.

Trabecular and cortical bone separately assessed at radius with a new ultrasound device, in a young adult population with various physical activities

The aim was to evaluate a new ultrasound device in a young adult population and to assess its reproducibility via comparison to DXA measurements and geometrical measurements from high-resolution radiographs. Ninety-three subjects aged between 20 and 51 years were recruited and divided into four groups according to their gender and physical activity status: 22 male athletes, 19 male controls, 21 female athletes, and 31 female controls. Ultrasonic measurements were assessed by the prototype LD-100 (Oyo Electric Co., Kyoto, Japan) on the dominant distal radius. Attenuation in the radius (dB), cortical bone thickness (mm), radius thickness (mm), mass density of cancellous bone (mg/cm(3)), and elasticity (GPa) of cancellous bone were obtained. BMD was measured by DXA at the dominant distal radius. Radius images were obtained with a direct high-resolution digital X-ray device (BMA, D(3)A Medical Systems), and radius and cortical thicknesses were estimated using a specific software (ImageJ, Bethesda, USA), in an area site-matched with LD-100. There was a significant positive correlation between site-matched BMD measurement and LD-100 parameters (p<0.004), X-ray radius thickness, and LD-100 parameters except elasticity (p<0.05, r>0.32), X-ray cortical thickness and LD-100 attenuation and cortical thickness (p<0.01). A significantly higher attenuation, cortical and radius thicknesses were found in athletes compared to controls (p<0.05). The radius thickness measured on radiographs was significantly higher in athletes versus controls in both sexes, and cortical thickness was significantly higher in male athletes versus controls. These data suggest a positive influence of physical activity on bone cortical measurements. This study also confirmed the particular interest of bone assessment by ultrasound.

Prevalence of cortical osteoporosis in mild and severe primary hyperparathyroidism and its relationship with bone markers and vitamin D status

Studies on the prevalence of site-specific osteoporosis in patients with different clinical presentations of primary hyperparathyroidism (PHPT) are scarce in the literature. The present study aims to determine the prevalence of cortical osteoporosis in such patients by using 3-site dual-energy X-ray absorptiometry (lumbar spine, femoral neck, 1/3 radius). We studied 49 patients, 12 males and 37 females, with PHPT, who were separated into 3 groups: asymptomatic (AS), renal stone disease (RS), and osteitis fibrosa cystica (OF). Osteoporosis occurred as follows: lumbar spine-48% for AS, 17.6% for RS, and 100% for OF (p=0.0004); femoral neck-20% for AS, 12% for RS, and 85.7% for OF (p=0.0014); 1/3 radius-71% for AS, 53% for RS, and 86% for OF (p=0.2845). Serum calcium, parathyroid hormone, alkaline phosphatase, and beta-carboxy-terminal telopeptide were significantly higher in the OF group. The mean values for 25-hydroxyvitamin D were lower in OF group than AS and RS groups (15.2+/-6.3 ng/mL vs. 22.7+/-11.9 ng/mL and 20.3+/-7.0 ng/mL; p=0.2139). Based on these results, we conclude that the prevalence of osteoporosis is high in all sites studied and is almost universal in the OF patients. The great prevalence of cortical osteoporosis is seen even in young patients with less severe forms of the disease.