The effect of vitamin D status on the severity of bone disease and on the other features of primary hyperparathyroidism (pHPT) in a vitamin D deficient region

The impact of vitamin D deficiency on clinical, biochemical and metabolic parameters in primary hyperparathyroidism

BACKGROUND

It has been suggested that vitamin D deficiency is associated with worse clinical outcomes in primary hyperparathyroidism (PHPT). We aimed to evaluate the relationship between vitamin D deficiency and clinical, biochemical and metabolic parameters in PHPT patients.

METHODS

A total of 128 patients with biochemically confirmed PHPT were included. Patients were categorized as vitamin D deficient if 25-OH vitamin D was <50nmol/L, or normal if vitamin D was ≥50nmol/L. Biochemical parameters, bone mineral densitometry (BMD), and urinary tract and neck ultrasonography were assessed.

RESULTS

In the study group, 66 (51.6%) patients had vitamin D deficiency and 60 (48.4%) had normal vitamin D levels. Nephrolithiasis and osteoporosis were found in 26.6% and 30.5% of subjects, respectively. The prevalence of metabolic syndrome (MetS), obesity (BMI≥30kg/m²) and hypertension (HTN) were higher in the vitamin D deficient group when compared to the normal group (p=0.04, p=0.01 and p=0.03, respectively). There was no difference regarding the presence of nephrolithiasis and osteoporosis between the groups. The mean adenoma size was similar in both groups.

CONCLUSIONS

Vitamin D deficiency was not associated with osteoporosis, nephrolithiasis, adenoma size or biochemical parameters in PHPT. However, vitamin D deficiency may be a risk factor for developing HTN and MetS in PHPT.

Pitfalls in the Diagnosis of Primary Hyperparathyroidism in a Sudanese Adolescent Boy; a case disguised as rickets

BACKGROUND

Juvenile primary hyperparathyroidism (PHPT) is a rare endocrine disease. Its diagnosis might be masked by clinical, biochemical, and radiological features of rickets.

CASE PRESENTATION

A 12-year-old Sudanese boy presented with progressive lower limbs deformity and difficulty in walking for six months. It was associated with fatigability, poor appetite, and generalized bone pain. On examination, he was thin, disproportionately short and pubertal, and had bilateral genu valgum deformity. X-rays showed osteopenia and signs of rickets. Biochemical workup revealed mildly elevated serum calcium, low phosphate, high alkaline phosphatase, and high parathyroid hormone with low 25-hydroxy vitamin D₃. Celiac screening, liver function test and renal profile were normal. Serum calcium rose dramatically after vitamin D therapy. Genetic testing was negative for CYP2R1 and MEN1 genes. Ultrasound neck showed left inferior parathyroid adenoma which was surgically excised. Histopathology confirmed the diagnosis of parathyroid adenoma. Postoperatively, he had hypocalcemia which was treated with calcium and alfacalcidol. Corrective surgery is planned for the genu valgum deformity which markedly improved after parathyroidectomy.

CONCLUSION

Although PHPT is extremely rare in the young population, it should be considered in patients with rickets and elevated serum calcium at baseline or after initiating vitamin D therapy.

Effect of vitamin D nutrition on disease indices in patients with primary hyperparathyroidism

In patients with primary hyperparathyroidism, the size of the adenoma is a major determinant of biochemical indices, disease severity, and manner of presentation. However, the large variation in adenoma weight, both within and between populations and a steady decline in parathyroid adenoma weights over time remain largely unexplained. Based on the results in a small number of patients almost two decades ago we proposed that vitamin D nutritional status of the patient explains both the disease manifestations and much of the variation in adenoma size. Accordingly, we examined the relationship between vitamin D nutrition, as assessed by serum levels of 25-hydroxyvitamin D, and parathyroid gland weight, the best available index of disease severity, in a large number of patients (n = 440) with primary hyperparathyroidism. A significant inverse relationship was found between serum 25-hydroxyvitamin D level and log adenoma weight (r = -0.361; p < 0.001). Also, the adenoma weight was significantly related directly to serum PTH, calcium, and alkaline phosphatase as dependent variables. In patients with vitamin D deficiency (defined as serum 25-hydroxyvitamin D levels 15 ng/mL or lower), gland weight, PTH, AP, and adjusted calcium were each significantly higher than in patients with 25-hydroxyvitamin D levels of 16 ng/mL or higher, but serum 1,25-dihydroxyvitamin D levels were similar in both groups. We interpret this to mean that suboptimal vitamin D nutrition stimulates parathyroid adenoma growth by a mechanism unrelated to 1,25-dihydroxyvitamin D deficiency. We conclude that variable vitamin D nutritional status in the population may partly explain the differences in disease presentation.

Serum Vitamin D Level Does not Affect The Sensitivity of Parathyroid Adenoma Localization Tests

The aim of the present study was to evaluate the predictive value of 25-hydroxyvitamin D, calcium and parathormone level, co-existence of thyroid nodule, thyroidectomy history and adenoma volume on the success of neck ultrasound (US) and technetium-99m sestamibi (MIBI) scan in primary hyperparathyroidism (PHP) patients. This study included 256 patients with PHP who underwent parathyroidectomy. 169 (%66) patients had vitamin D deficiency and 56 (%22) of patients had insufficiency. The sensitivity of US and MIBI studies showed no difference between vitamin D deficiency, insufficiency and replete groups (%80.5, %82 and %71 (p > 0.05) and %81, %84 and %71 respectively (p > 0.05)). Vitamin D level was not found to be an independent predictor of localization on either US or MIBI scan after adjusting for different variables (p > 0.05). Calcium level was found to be an independent predictor for US sensitivity (r²:0,033, p:0,032) and parathormone level for MIBI sensitivity (r²:0,05, p:0,025). The co-existence of nodular thyroid disease and history of thyroidectomy significantly decreased the sensitivity of US (%76 and %43). MIBI sensitivity was not impaired by nodular disease but the history of thyroidectomy also impaired the sensitivity of MIBI (%43). As a result vitamin D level does not affect the sensitivity of preoperative localization tests.

A Hungry Bone Syndrome Predicted by 18F-Fluorocholine PET/CT

Predicting hungry bone syndrome (HBS) after surgical cure of primary hyperparathyroidism (PHPT) can be challenging. A 57-year-old man diagnosed with PHPT was assessed preoperatively by F-fluorocholine PET/CT. An intense and diffuse tracer uptake of the axial and peripheral skeleton was visualized, in addition to a pathologic uptake suggestive of hyperfunctioning parathyroid gland. After the removal of a parathyroid adenoma, a severe and prolonged HBS requiring high doses of calcium and active metabolites of vitamin D was observed. This observation suggests that intense and diffuse bone uptake on F-fluorocholine PET/CT could be a predictive factor for HBS in patients with PHPT.

Pre-operative localization of abnormal parathyroid tissue by 99mTc-sestamibi in primary hyperparathyroidism using four-quadrant site analysis: an evaluation of the predictive value of vitamin D deficiency

CONTEXT

Accurate preoperative localization of abnormal parathyroid tissue aids importantly in minimally invasive parathyroidectomy in patients with primary hyperparathyroidism. Vitamin D deficiency may possibly influence the success and characteristics of pre-operative localization because it is associated with more active disease and possibly larger adenomas. This could increase the sensitivity of the sestamibi to identify abnormal parathyroid tissue, but earlier reports are conflicting. Vitamin D deficiency could also influence the nature of preoperative localization because it could lead to multi-gland stimulation of parathyroid tissue giving an appearance of multi-gland disease, which may lower accuracy of preoperative localization with sestamibi.

OBJECTIVE

To examine the relationship between vitamin D deficiency and correct parathyroid tissue localization by four-pole thyroid quadrant analysis.

DESIGN

Retrospective study.

SETTING

Referral center.

PARTICIPANTS

A total of 138 patients were divided into three groups according to the level of 25OHD; <20 ng/mL (vitamin D deficient), ≥20 to <30 ng/mL (vitamin D insufficient) and ≥30 ng/mL (vitamin D replete).

MAIN OUTCOMES

Quadrant localization using ^99mTc-sestamibi/SPECT.

RESULTS

Among those with single-gland disease, the proportion of patients with correct quadrant localization were 60.0, 68.3 and 63.5% (p = 0.778), and the accuracy of sestamibi was 89.3, 90.6 and 89.9% for the deficient, insufficiency and replete groups, respectively. Among those with multi-gland disease, the proportion of patients with correct quadrant localization were 50.0, 25.0 and 18.2% (p = 0.619) while the accuracy was 50.0, 50.0 and 45.5%, respectively. Multi-gland disease did not occur more frequently in any of the three groups (p = 0.296).

CONCLUSIONS

Vitamin D levels do not affect the accuracy of preoperative localization with sestamibi.

Primary hyperparathyroidism: Dynamic postoperative metabolic changes

OBJECTIVE

Little is known about the natural changes in parathyroid function after successful parathyroid surgery for primary hyperparathyroidism. The association of intact parathyroid hormone (iPTH) and calcium (Ca) with "temporary hypoparathyroidism" and "hungry bone syndrome" (HBS) was evaluated.

DESIGN

Potential risk factors for temporary hypoparathyroidism and HBS were evaluated by taking blood samples before surgery, intra-operatively, at postoperative day (POD) 1, at POD 5 to 7, in postoperative week (POW) 8 and in postoperative month (POM) 6.

PATIENTS

Of 425 patients, 43 (10.1%) had temporary hypoparathyroidism and 36 (8.5%) had HBS.

MEASUREMENTS

The discriminative ability of iPTH and Ca on POD 1 for temporary hypoparathyroidism and HBS.

RESULTS

Intact parathyroid hormone (IPTH) on POD 1 showed the highest discriminative ability for temporary hypoparathyroidism (C-index = 0.952), but not for HBS. IPTH was helpful in diagnosing HBS between POD 5 and 7 (C-index = 0.708). Extending the model by including Ca resulted in little improvement of the discriminative ability for temporary hypoparathyroidism (C-index = 0.964) and a decreased discriminative ability for HBS (C-index = 0.705). Normal parathyroid metabolism was documented in 139 (32.7%) patients on POD 1 and in 423 (99.5%) 6 months postoperatively, while 2 (0.5%) patients had persistent hyperparathyroidism, one diagnosed between POD 5 and 7 and another at POW 8. No patients suffered from permanent hypoparathyroidism.

CONCLUSIONS

The necessity for Ca and vitamin D3 substitution cannot be predicted with certainty before POD 5 to 7 without serial laboratory measurements. Based on the results, a routine 8-week course of Ca and vitamin D3 treatment seems reasonable and its necessity should be evaluated in a follow-up study.

The impact of vitamin D status on hungry bone syndrome after surgery for primary hyperparathyroidism

OBJECTIVE

Prolonged hypocalcemia but normal intact parathyroid hormone (iPTH) levels after surgery for primary hyperparathyroidism (PHPT) are referred to as 'hungry bone syndrome' (HBS). The aim was to evaluate preoperative risk factors for HBS with a focus on the impact of 25-hydroxyvitamin D (25(OH)D) deficiency.

DESIGN

Patients having undergone initial successful surgery for sporadic PHPT within 6 years were considered for retrospective analysis.

METHODS

A total of 385 patients were evaluated, of whom 33 (8.6%) developed HBS influencing negatively the postoperative bone metabolism. All patients underwent biochemical evaluations two days before parathyroid surgery and were followed biochemically on a daily basis in the first postoperative week and thereafter at 8 weeks and 6 months.

CONCLUSIONS

No relationship was established between preoperative 25(OH)D deficiency and HBS. The only significant risk factor for HBS in multivariable analysis was high levels of preoperative iPTH. As HBS therefore cannot be predicted preoperatively, we recommend a consistent postoperative calcium and vitamin D supplementation to improve the bone metabolism.

Preoperative zoledronic acid therapy prevent hungry bone syndrome in patients with primary hyperparathyroidism

BACKGROUND

Hungry bone syndrome is a common complication of surgery for primary hyperparathyroidism in India which often leads to prolonged hospitalization. There are varying reports on the use and efficacy of bisphosphonates in the prevention of hungry bone syndrome.

METHODS

We retrospectively analyzed the effect of preoperative bisphosphonate therapy on rates of hungry bone syndrome in our patients with primary hyperparathyroidism. A total of 19 patients underwent surgery for primary hyperparathyroidism at our institute between January 2013 and June 2015 among whom eight did not receive preoperative bisphosphonates and 11 received intravenous zoledronic acid 4 mg, 24-48 h preoperatively.

RESULTS

There was no significant difference between the two groups with respect to age, gender, duration of symptoms, preoperative serum calcium, phosphorus, parathyroid hormone, alkaline phosphatase, and the presence of radiological evidence of hyperparathyroid bone disease also did not differ between the groups. Three out of the eight patients who did not receive preoperative zoledronic acid therapy had hungry bone syndrome but none in the zoledronic acid group. The prevalence of hungry bone syndrome tended to be lower in the zoledronic acid group (P = 0.058). The need for intravenous calcium and duration of postoperative hospital stay were significantly lesser in the zoledronic acid group.

CONCLUSION

Preoperative intravenous zoledronic acid significantly reduces the need for intravenous calcium therapy and duration of postoperative hospital stay and seems a promising option to reduce the rate of hungry bone syndrome in patients with primary hyperparathyroidism.

Impact of vitamin D deficiency on the clinical and biochemical phenotype in women with sporadic primary hyperparathyroidism

The purpose of the study was to evaluate the relationship between serum 25(OH)D and the clinical phenotype in 215 consecutive Italian Caucasian women with sporadic primary hyperparathyroidism (PHPT) not taking vitamin D supplements. The study was performed at a single Italian tertiary center. PHPT-related manifestations, serum 25(OH)D, and other parameters of calcium metabolism and bone mineral density (BMD) by DXA were recorded. Serum 25(OH)D was negatively correlated with age (r = -0.18; P = 0.006), BMI (r = -0.20; P = 0.002), PTH (r = -0.21; P = 0.001), bone-specific alkaline phosphatase (BSAP) (r = -0.27; P < 0.001), and eGFR (r = -0.22; P = 0.01), and positively with serum creatinine and 1/3 distal radius BMD (R-BMD; r = 0.17; P = 0.015). In a multivariate regression analysis, serum 25(OH)D remained significantly correlated with age (r = -0.18; P = 0.005), BMI (r = -0.23; P = 0.049), serum PTH (r = -0.01; P = 0.023), BSAP (r = -0.01; P = 0.023) and eGFR (r = -0.09; P = 0.001), but not with R-BMD. Serum 25(OHD) was higher in patients with nephrolithiasis than in those without nephrolithiasis (18.5 ± 8.8 vs. 15.6 ± 8.0 ng/ml; P = 0.029), whereas no difference was found between fractured and unfractured patients (16.8 ± 9.3 vs. 16.0 ± 7.7; P = 0.663). There was a statistically significant inverse correlation between vitamin D status [defined by quartiles of measured values as well as commonly accepted cutoffs of serum 25(OH)D] and severity of the disease, as reflected by higher PTH and BSAP, but not by meeting the latest guidelines for parathyroidectomy. In conclusion, a low vitamin D status is associated with some features reflecting a more severe biochemical and clinical phenotype of PHPT in Italian women not taking vitamin D supplements.

THE VOLUME OF SOLITARY PARATHYROID ADENOMA IS RELATED TO PREOPERATIVE PTH AND 25OH-D3, BUT NOT TO CALCIUM LEVELS

Purpose

To correlate the volume of parathyroid adenomas with the hormonal and metabolic profile at patients diagnosed with primary hyperparathyroidism (pHPTH).

Patients and Methods

Cross-sectional multicentric study, enrolling 52 patients with pHPTH from two medical institutions. Serum calcium and PTH were evaluated in all patients before surgery, whereas 25OHD3 was measured only in the 33 patients recruited form one medical unit. The volume of parathyroid adenoma was measured by using the formula of a rotating ellipsoid.

Results

We observed a significant correlation of the volume of parathyroid adenomas with PTH at patients from the two units and in the whole group (p < 0.0001), but not with serum calcium (p = 0.494). Twenty-five out of the 33 patients at whom 25OHD3 was measured had levels in the range of deficiency. 25OHD3 was not correlated with PTH or calcium levels, but was negatively correlated to the adenoma volume and positively to the PTH/volume ratio (p = 0.041 and p = 0.048, respectively).

Conclusions

The volume of parathyroid adenoma seems to be related to preoperative PTH and 25OHD3, but not to calcium level. Vitamin D deficiency is frequently found at patients with pHPTH and may contribute to particular disease profiles, including larger parathyroid adenomas.

A case of adolescent giant parathyroid adenoma presenting multiple osteolytic fractures and postoperative hungry bone syndrome

Primary hyperparathyroidism (PHPT) and postoperative hungry bone syndrome are very rare conditions in adolescents, and may be frequently misdiagnosed as a metastatic bone tumor. However, delay in diagnosis may lead to a fatal preoperative hypercalcemia and postoperative hypocalcemia. PHPT is a differential diagnosis of adolescent hypercalcemia and osteolytic fractures.

Vitamin D in Primary Hyperparathyroidism: Effects on Clinical, Biochemical, and Densitometric Presentation

CONTEXT

Vitamin D (25-hydroxyvitamin D [25OHD]) deficiency (<20 ng/mL) and insufficiency (20-29 ng/mL) are common in primary hyperparathyroidism (PHPT), but data regarding their skeletal effects in PHPT are limited.

OBJECTIVE

The objective was to evaluate the association between 25OHD levels and PHPT severity.

DESIGN, SETTINGS, AND PARTICIPANTS

This is a cross-sectional analysis of 100 PHPT patients with and without 25OHD insufficiency and deficiency from a university hospital setting.

OUTCOME MEASURES

We measured calciotropic hormones, bone turnover markers, and bone mineral density (BMD) by dual x-ray absorptiometry.

RESULTS

Lower 25OHD was associated with some (PTH: r = -0.42; P < .0001; 1,25-dihydroxyvitamin D: r = -0.27; P = .008; serum PO4: r = 0.31; P = .002) but not all (serum/urine calcium) indicators of PHPT severity. Lower 25OHD was also associated with younger age, higher body mass index, male gender, better renal function, and lower vitamin D intake. Comparison of those with deficient (<20 ng/mL; 19%) vs insufficient (20-29 ng/mL; 35%) vs replete (≥30 ng/mL; 46%) 25OHD demonstrated more severe PHPT as reflected by higher PTH (mean ± SEM, 126 ± 10 vs 81 ± 7 vs 72 ± 7 pg/mL; P < .0001) but no difference in nephrolithiasis, osteoporosis, fractures, serum or urinary calcium, bone turnover markers, or BMD after adjustment for age and weight. In women, T-scores at the 1/3 radius were lower in those with 25OHD of 20-29 ng/mL, compared to those who were vitamin D replete (P = .048). In multiple regression modeling, 25OHD (but not PTH) was an independent predictor of 1/3 radius BMD.

CONCLUSION

Vitamin D deficiency is associated with more severe PHPT as reflected by PTH levels, but effects on BMD are limited to the cortical 1/3 radius and are quite modest. These data support international guidelines that consider PHPT patients with 25OHD <20 ng/mL to be deficient. However, in this cohort with few profoundly vitamin D-deficient patients, vitamin D status did not appear to significantly impact clinical presentation or bone density.

Lower Vitamin D Levels in Surgical Hyperparathyroidism versus Thyroid Patients

Low vitamin D levels have been shown to be associated with primary hyperparathyroidism, but it is unclear whether vitamin D deficiency may be an etiologic factor in the development of primary hyperparathyroidism. To investigate this, we compared preoperative vitamin D levels of patients undergoing surgery for primary hyperparathyroidism with those of patients undergoing surgery for benign thyroid disease. With Institutional Review Board approval, data were collected prospectively on patients undergoing parathyroidectomy or thyroidectomy by one surgeon between March 2006 and July 2011. Patients were excluded if they underwent simultaneous thyroid and parathyroid surgery, had secondary or tertiary hyperparathyroidism, if no preoperative vitamin D level was measured, or if they took vitamin D supplements. Inclusion criteria were met by 219 patients who underwent parathyroidectomy and 186 patients who underwent thyroid surgery. Patient age, sex, race, and preoperative vitamin D levels (vitamin D 25-OH; normal, 32 to 100 pg/mL) were collected. Statistical analysis was performed using linear regression. Vitamin D levels were significantly lower in the parathyroid group compared with the thyroid group (23.8 vs 28.5 pg/mL; P < 0.001). This difference was also observed after adjustment for age, sex, and race with a mean difference of 4.87 pg/mL ( P < 0.001). Statistically significant associations between lower vitamin D levels and patients younger than 50 years ( P = 0.048), male sex ( P = 0.03), and nonwhite race were identified ( P < 0.001). Patients with primary hyperparathyroidism are more likely to have lower vitamin D levels than a control surgical population. Further study is needed to determine whether low vitamin D levels may be an etiologic factor associated with the development of hyperparathyroidism.

Influence of vitamin D status on vertebral fractures, bone mineral density, and bone turnover markers in normocalcemic postmenopausal women with high parathyroid hormone levels

OBJECTIVE

The aims of the study were to analyze whether there is an association between serum PTH and the prevalence of vertebral fractures and its possible dependence on vitamin D status, and to assess the influence of serum 25-hydroxyvitamin D (25OHD) in the relationship between PTH and bone mineral density (BMD) or bone turnover markers (BTMs).

DESIGN, PARTICIPANTS, AND SETTING

A total of 820 postmenopausal women were recruited after excluding those with any known condition that could influence serum PTH levels, except for a possible low serum 25OHD. Serum PTH and 25OHD concentrations, as well as vertebral fracture prevalence, BMD, and BTM (CTX and PINP) values were recorded. Serum PTH levels were divided into tertiles, and women were grouped into those in the highest tertile (>58 pg/ml) and those below. Serum 25OHD levels were stratified in 3 categories (<20, 20-30, and >30 ng/ml).

RESULTS

Vertebral fracture prevalence was greater in women with PTH above 58 pg/ml (odds ratio [OR], 1.72; 95% confidence interval [CI], 1.04-2.84). After stratifying by 25OHD, this difference was only significant in women below 20 ng/ml (OR, 2.00; 95% CI, 1.02-3.87), those with 25OHD between 20 and 30 ng/ml showing a trend toward this (OR, 1.99; 95% CI, 0.92-4.36). Differences in BMD or BTM between women above and below 58 pg/ml of PTH were also observed only in those below 20 ng/ml.

CONCLUSION

Elevated PTH levels are associated with increased prevalence of vertebral fractures, low bone mass, or higher BTM only in the presence of hypovitaminosis D. An adequate nutritional status in the vitamin appears to protect the bone from the deleterious effect of a high PTH.

Hungry bone syndrome: still a challenge in the post-operative management of primary hyperparathyroidism: a systematic review of the literature

Hungry bone syndrome (HBS) refers to the rapid, profound, and prolonged hypocalcaemia associated with hypophosphataemia and hypomagnesaemia, and is exacerbated by suppressed parathyroid hormone (PTH) levels, which follows parathyroidectomy in patients with severe primary hyperparathyroidism (PHPT) and preoperative high bone turnover. It is a relatively uncommon, but serious adverse effect of parathyroidectomy. We conducted a literature search of all available studies reporting a 'hungry bone syndrome' in patients who had a parathyroidectomy for PHPT, to identify patients at risk and address the pitfalls in their management. The severe hypocalcaemia is believed to be due to increased influx of calcium into bone, due to the sudden removal of the effect of high circulating levels of PTH on osteoclastic resorption, leading to a decrease in the activation frequency of new remodelling sites and to a decrease in remodelling space, although there is no good documentation for this. Various risk factors have been suggested for the development of HBS, including older age, weight/volume of the resected parathyroid glands, radiological evidence of bone disease and vitamin D deficiency. The syndrome is reported in 25-90% of patients with radiological evidence of hyperparathyroid bone disease vs only 0-6% of patients without skeletal involvement. There is insufficient data-based evidence on the best means to treat, minimise or prevent this severe complication of parathyroidectomy. Treatment is aimed at replenishing the severe calcium deficit by using high doses of calcium supplemented by high doses of active metabolites of vitamin D. Adequate correction of magnesium deficiency and normalisation of bone turnover are required for resolution of the hypocalcaemia which may last for a number of months after successful surgery. Preoperative treatment with bisphosphonates has been suggested to reduce post-operative hypocalcaemia, but there are to date no prospective studies addressing this issue.

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.

Updated recommendations for the diagnosis and management of osteoporosis: a local perspective

Postmenopausal osteoporosis and osteoporosis in elderly men are major health problems, with a significant medical and economic burden. Although osteopenia and osteoporosis are more common locally than in the West, fracture rates are generally less than in Western countries. Vitamin D deficiency is common in the region and contributes adversely to bone health. Vitamin D deficiency should be suspected and treated in all subjects with ostopenia or osteoporosis. The use of risk factors to determine fracture risk has been adopted by the World Health Organization and many international societies. Absolute fracture risk methodology improves the use of resources by targeting subjects at higher risk of fractures for screening and management. The King Faisal Specialist Hospital Osteoporosis Working Group recommends screening for women 65 years and older and for men 70 years and older. Younger subjects with clinical risk factors and persons with clinical evidence of osteoporosis or diseases leading to osteoporosis should also be screened. These guidelines provide recommendations for treatment for postmenopausal women and men older than 50 years presenting with osteoporotic fractures for persons having osteoporosis-after excluding secondary causes-or for persons having low bone mass and a high risk for fracture. The Working Group has suggested an algorithm to use at King Faisal Specialist Hospital that is based on the availability, cost, and level of evidence of various therapeutic modalities. Adequate calcium and vitamin D supplement are recommended for all. Weekly alendronate (in the absence of contraindications) is recommended as first-line therapy. Alternatives to alendronate are raloxifene or strontium ranelate. Second-line therapies are zoledronic acid intravenously once yearly, when oral therapy is not feasible or complicated by side effects, or teriparatide in established osteoporosis with fractures.

Hyperparathyroidism and malnutrition with severe vitamin D deficiency

BACKGROUND

Vitamin D deficiency and its associated problems are common in developing Asian countries and countries of the Middle East. Various factors, including poor nutritional status and other compounding factors such as dietary, cultural, ethnic, and environmental factors, play a major role in contributing to the poor calcium and vitamin D homeostasis. Vitamin D deficiency is thought to exacerbate signs and symptoms of hyperparathyroidism (HPT). In this overview, we present evidence of the impact of vitamin D and calcium deficiency on primary HPT (PHPT).

METHODS

We performed an evidence-based review of articles published in the English language between January 1960 and June 2008.

RESULTS

Level IV evidence suggests widespread calcium and vitamin D deficiency in developing countries (issue 1). Limited level IV evidence suggests malnutrition as a primary cause of calcium and vitamin D deficiency (issue 2). Level IV evidence suggests that calcium and vitamin deficiencies cause secondary HPT and possibly PHPT as well (issues 3 and 4). A literature search revealed only six studies that correlated vitamin D levels with clinical, biochemical, and pathologic features of PHPT (issue 5). These studies provide level IV evidence suggesting that vitamin D deficiency causes some specific clinical features of PHPT as well as exacerbating other features of the disease.

CONCLUSIONS

In the developing countries, which have severe vitamin D and calcium deficient population, PHPT patients present with advanced disease and particularly severe bone symptoms. There is presently only level IV evidence of vitamin D status affecting the clinical severity of PHPT.

Vitamin D and primary hyperparathyroidism (PHPT)

Vitamin D deficiency and PHPT are two common conditions, especially in postmenopausal women. Vitamin D deficiency is said to be even more frequent in PHPT patients than in the general population due to an accelerated conversion of 25OHD into calcitriol or 24-hydroxylated compounds. Although several studies have reported worsening of PHPT phenotype (larger tumours, higher PTH levels, more severe bone disease) when vitamin D deficiency coexists whereas vitamin D supplementation in PHPT patients with a serum calcium level<3 mmol/L has been shown to be safe (no increase in serum or urinary calcium) and to decrease serum PTH concentration, that many physicians are afraid to give vitamin D to already hypercalcemic PHPT patients. On the other hand, it is possible that, in some patients, a persistent vitamin D deficiency induces, in the long-term, an autonomous secretion of PTH (i.e. tertiary hyperparathyroidism). The mechanism by which this could occur is unclear however. Finally, as many, otherwise normal, subjects with vitamin D insufficiency may have an increased serum PTH level we believe that those with vitamin D insufficiency should be excluded from a reference population for serum PTH levels. By doing that, we found that the upper normal limit for serum PTH was 25-30% lower than in the whole population.

Biochemical effects of calcifediol supplementation in mild, asymptomatic, hyperparathyroidism with concomitant vitamin D deficiency

It has been proposed to cautiously supplement with vitamin D to any patient with asymptomatic primary hyperparathyroidism (PHTP) and a plasma 25-hydroxyvitamin D [25(OH)D] concentration <50 nmol/l. Evidence about the safeness of this intervention is limited to two studies. Our aim was to prospectively assess the biochemical effects of one-year 25(OH)D supplementation in this context. Twenty-seven patients were included in this study. Calcifediol was started at a dose of 480-960 IU/24 h (8-16 microg/24 h) and adjusted up to a maximum of 960 IU/24 h (16 microg/24 h). Basal calcium, phosphate, albumin, total alkaline phosphatase (ALP), creatinine, 24 h calcium urinary excretion, intact PTH (iPTH) and 25(OH)D were measured before and during vitamin D supplementation. The mean basal 25(OH)D was 28.7 +/- 8.0 nmol/l, and at 12 months was 71.5 +/- 32.5 nmol/l (P = 0.00 vs. baseline). After 3, 6 and 12 months iPTH levels were 141.7 +/- 108.4 ng/l (P = 0.00 vs. baseline), 131.1 +/- 95.7 ng/l (P = 0.03 vs. baseline) and 162.2 +/- 139.3 ng/l (P = ns vs. baseline). Mean calcium did not change. Mean urinary calcium excretion increased significantly (basal: 5.7 +/- 2.9 mmol/24 h, 12 months: 7.9 +/- 4.9 mmol/24 h, P = 0.02). Cautious calcifediol supplementation significantly increased mean 25(OH)D and temporarily reduced mean iPTH. It did not change mean serum calcium, but urinary calcium excretion increased significantly. We suggest that serum calcium and 24 h calciuria be measured at regular intervals in patients with PHTP, while on calcifediol supplementation.

Do patients undergoing parathyroidectomy for primary hyperparathyroidism in San Francisco, CA, and Bursa, Turkey, differ?

BACKGROUND

To compare the preoperative clinical symptoms and associated conditions and findings in operations in age- and sex-matched patients with primary hyperparathyroidism (PHPT) living in the two different regions of the world to determine whether PHPT differs in various countries.

METHODS

Fifty-two patients from Bursa, Turkey were matched with 52 age and sex matched patients from San Francisco, USA. Patients' preoperative symptoms, biochemical and radiologic findings and surgical procedures were documented.

RESULTS

More patients in the American Group (15%) had preoperatively persistant or recurrent hyperparathyroidism, P = 0.016. Serum parathyroid hormone levels were higher in Turkish group (546 +/- 75.33 pg/mL) than in American group (146 +/- 75.33 pg/mL). More Turkish patients had osteoporosis (P < 0.05). The size of parathyroid adenomas was significantly greater in Turkish patients (25.2 +/- 1.18 mm) than in American patients (17.5 +/- 1.18 mm), P < 0.001.

CONCLUSIONS

Patients with PHPT from Bursa, Turkey have higher plasma parathyroid hormone levels, larger parathyroid adenomas and more severe bone disease than in age and sex matched patients with PHPT in San Francisco.

Primary hyperparathyroidism and the skeleton

Today, primary hyperparathyroidism (PHPT) in the developed countries is typically a disease with few or no obvious clinical symptoms. However, even in the asymptomatic cases the endogenous excess of PTH increases bone turnover leading to an insidious reversible loss of cortical and trabecular bone because of an expansion of the remodelling space and an irreversible loss of cortical bone due to increased endocortical resorption. In contrast trabecular bone structure and integrity to a large extent is maintained and there may be a slight periosteal expansion. Most studies have reported decreased bone mineral density (BMD) in PHPT mainly located at cortical sites, whereas sites rich in trabecular bone only show a modest reduction or even a slight increase in BMD. The frequent occurrence of vitamin D insufficiency and deficiency in PHPT and increased plasma FGF23 levels may also contribute to the decrease in BMD. The effect of smoking is unsolved. Epidemiological studies have shown that the relative risk of spine and nonspine fractures is increased in untreated PHPT starting up to 10 years before the diagnosis is made. Successful surgery for PHPT normalizes bone turnover, increases BMD and decreases fracture risk based on larger epidemiological studies. However, 10 years after surgery fracture risk appears to increase again due to an increase in forearm fractures. There are no randomized controlled studies (RCTs) demonstrating a protective effect of medical treatment on fracture risk in PHPT. Less conclusive studies suggest that vitamin D supplementation may have a beneficial effect on plasma PTH and BMD in vitamin D deficient PHPT patients. Hormone replacement therapy (HRT) and maybe SERM appear to reduce bone turnover and increase BMD. However, their nonskeletal side-effects preclude their use for this purpose. Bisphosphonates reduce bone turnover and increase BMD in PHPT as in osteoporosis and may be a therapeutical option in selected patients with low BMD. Obviously, there is a need for larger RCTs with fractures as end-points that appraise this possibility. Calcimimetics reduce plasma calcium and PTH in PHPT but has no beneficial effect on bone turnover or BMD. In symptomatic hypercalcaemic PHPT with low BMD where curative surgery is impossible or contraindicated a combination of a calcimimetic and a bisphosphonate may be an undocumented therapeutical option that needs further evaluation.

Diagnosis and treatment of vitamin D deficiency

The recent discovery--in a randomised, controlled trial--that daily ingestion of 1100 IU of colecalciferol (vitamin D) over a 4-year period dramatically reduced the incidence of non-skin cancers makes it difficult to overstate the potential medical, social and economic implications of treating vitamin D deficiency. Not only are such deficiencies common, probably the rule, vitamin D deficiency stands implicated in a host of diseases other than cancer. The metabolic product of vitamin D is a potent, pleiotropic, repair and maintenance, secosteroid hormone that targets > 200 human genes in a wide variety of tissues, meaning it has as many mechanisms of action as genes it targets. A common misconception is that government agencies designed present intake recommendations to prevent or treat vitamin D deficiency. They did not. Instead, they are guidelines to prevent particular metabolic bone diseases. Official recommendations were never designed and are not effective in preventing or treating vitamin D deficiency and in no way limit the freedom of the physician--or responsibility--to do so. At this time, assessing serum 25-hydroxy-vitamin D is the only way to make the diagnosis and to assure that treatment is adequate and safe. The authors believe that treatment should be sufficient to maintain levels found in humans living naturally in a sun-rich environment, that is, > 40 ng/ml, year around. Three treatment modalities exist: sunlight, artificial ultraviolet B radiation or supplementation. All treatment modalities have their potential risks and benefits. Benefits of all treatment modalities outweigh potential risks and greatly outweigh the risk of no treatment. As a prolonged 'vitamin D winter', centred on the winter solstice, occurs at many temperate latitudes, < or = 5000 IU (125 microg) of vitamin D/day may be required in obese, aged and/or dark-skinned patients to maintain adequate levels during the winter, a dose that makes many physicians uncomfortable.

Vitamin D deficiency and primary hyperparathyroidism

Temporally associated with the improvement in vitamin D nutrition in many Western countries in the mid-20th century, there was a change in many characteristics of primary hyperparathyroidism. Osteitis fibrosa cystica became a rare manifestation of what is now frequently an asymptomatic disease. At the same time, in patients with the disease, levels of PTH and parathyroid adenoma weights have fallen dramatically. In view of these observations and others, an association between vitamin D deficiency and severity of primary hyperparathyroidism has been proposed. Data support an association on two distinct levels. First, regardless of the clinical severity of primary hyperparathyroidism, the disease seems to be more severe in those with concomitant vitamin D deficiency. Second, vitamin D deficiency and insufficiency seem to be more prevalent in patients with primary hyperparathyroidism than in geographically matched populations. The association between vitamin D deficiency and primary hyperparathyroidism has clear implications. Co-existing vitamin D deficiency may cause the serum calcium level to fall into the normal range, which can lead to diagnostic uncertainty. With regard to management, preliminary data on vitamin D repletion in patients with mild primary hyperparathyroidism suggest that, in some cases, correction of vitamin D deficiency may be accomplished without worsening the underlying hypercalcemia. Vitamin D-deficient patients undergoing parathyroidectomy are also at increased risk of postoperative hypocalcemia and "hungry bone syndrome," which underscores the importance of preoperative assessment of vitamin D status in all patients with primary hyperparathyroidism.

Correlations between Vitamin D Status and Biochemical/Clinical and Pathological Parameters in Primary Hyperparathyroidism

BACKGROUND

To determine the prevalence of vitamin D deficiency and the effects of vitamin D status on parathyroid adenoma weight, clinical and biochemical indices in patients with primary hyperparathyroidism (pHPT) were studied.

METHODS

Eighty patients with pHPT who underwent surgical treatment and in whom the presence of parathyroid adenoma were confirmed histopathologically were studied retrospectively from recorded data files. Patients were divided into three groups: patients with 25-hydroxyvitamin D (25-OHD) concentrations < 15 ng/ml (group 1, n = 44), patients with 25-OHD concentrations > 15-25 ng/ml (group 2, n = 9), and patients with 25-OHD concentrations > 26 ng/ml (group 3, n = 27). Serum calcium, phosphate, alkaline phosphatase, creatinine, and albumin levels and urinary calcium excretion were determined by auto-analyzer. Plasma 25-OHD and parathyroid hormone (PTH) levels were determined by immunoradiometric assay using commercially available kits.

RESULTS

No statistically significant differences were observed with respect to serum calcium, phosphorus, albumin, and creatinine concentrations between these groups. Serum PTH, alkaline phosphatase concentrations, urinary calcium excretion, parathyroid adenoma weight, and postoperative sixth month PTH concentrations were significantly higher in group 1 patients than in group 2 and group 3 patients. Significant correlations were observed between parathyroid adenoma weight and serum 25-OHD concentrations (r = -0.348, P = 0.020); parathyroid adenoma weight and urinary calcium excretion (r = 0.348, P = 0.021). Multiple regression analysis revealed that parathyroid adenoma weight, serum 25-OHD, and preoperative PTH concentrations correlated independently and significantly with postoperative sixth month PTH concentrations.

CONCLUSIONS

Vitamin D deficiency leads to more severe bone disease, increased parathyroid tumor growth, and delayed postoperative recovery of parathyroid function in patients with primary hyperparathyroidism.