Vitamin D status affects osteopenia in postmenopausal patients with primary hyperparathyroidism

Prevalence of Vitamin D Inadequacy in Urolithiasis Patients

Introduction

The role of vitamin D in kidney stone disease is unclear. Current evidence and existing studies are inconsistent and inconclusive. The objective of this study is to assess the prevalence of vitamin D (VD) inadequacy (VDI) and metabolic abnormalities in urolithiasis patients presenting to a tertiary care center.

Materials and methods

This is a prospective case-control study of 200 patients divided into two groups - Group 1: 100 urolithiasis patients (case group), and Group 2: 100 non-urolithiasis patients (control group) - which was conducted from January 2016 to January 2017. Demographic, clinical data, parathyroid level, serum 25-hydroxy VD [25(OH)D], and metabolic stone work-up were recorded and analyzed. 

Results

Patient demographics were comparable in both groups. The prevalence of vitamin D inadequacy in urolithiasis patients was 95% as compared to 57% in the control group. The mean value ± SD of serum vitamin D in urolithiasis patients (16.5 ± 8.6 ng/mL) was significantly lower than in non-urolithiasis patients (28.7 ± 8.3 ng/mL) (p = <0.0001). Thirty-seven percent of the patients were recurrent stone formers. Hyperparathyroidism was observed in 77% of the patients and 71% of them were secondary to VDI.

Conclusion

Urolithiasis patients were found to have an increased prevalence of deficient VD related to secondary hyperparathyroidism.

All 25-hydroxyvitamin D-deficient Indian postmenopausal women do not have secondary hyperparathyroidism

This study shows a high 25-hydroxyvitamin D deficiency among postmenopausal women accompanying secondary hyperparathyroidism. However, a sizable number of subjects did not have secondary hyperparathyroidism despite having low 25-hydroxyvitamin D levels. This condition arises a research question in clinical practice needed to be addressed in the future.

PURPOSE

The present study was attempted to determine the prevalence of secondary hyperparathyroidism and also to analyze the mean value (cutoff) of 25-hydroxyvitamin D from where the PTH begins to rise in Indian postmenopausal women.

METHODS

A cross-sectional study including 334 postmenopausal women attending the outpatient department (MOPD) of Lok Nayak Hospital, New Delhi, between July 2008 and June 2010. Institutional ethical approval was obtained for this study. The apparently healthy postmenopausal women and attendees of the patients were included in the study. Post-thyroidectomy, thyroid illness, pregnant women, subjects taking drugs that can affect bone mineral metabolism, such as glucocorticoids, antitubercular therapy, antiepileptic, and 25-hydroxyvitamin D supplement were excluded from the study. BMD parameters such as PTH and 25(OH)D were measured by using commercial kits from DiaSorin, USA, and blood chemistry was evaluated by standard methods from the central facility of the center. Dietary calcium was analyzed by applying a food frequency questionnaire by a trained dietician.

RESULTS

Mean (SD) age of the subjects was 56.4 ± 7.7 years. The mean BMI was 24.7 ± 5.5 kg/m². The baseline biochemical investigations such as total bilirubin, liver function test (LFT), kidney function test (KFT), calcium, phosphorous, total protein, and serum albumin were in reference range except alkaline phosphatase (ALP). The mean values of 25(OH)D and PTH were 12.95 ± 8.08 ng/ml and 91.60 ± 75.56 pg/ml respectively. The 24-h dietary calcium intake was 487.06 ± 239.36 mg/24 h. 25-hydroxyvitamin D deficiency was found in 277 subjects (82.93%) and was inversely related to PTH. Forty-three subjects had 25-hydroxyvitamin D levels between 20 and 29 ng/ml (12.87%), and only 14 subjects (4.19%) had optimum 25-hydroxyvitamin D levels. Secondary hyperparathyroidism was found in 235 (70.35%) subjects; however, it was not found in 30%.

CONCLUSIONS

Majority of postmenopausal women of India had 25-hydroxyvitamin D deficiency with raised PTH levels. The cutoff point of 25-hydroxyvitamin D at which PTH began to rise was found at 25 ng/ml which seems similar to that of the Caucasians.

Primary hyperparathyroidism

In this Review, we describe the pathogenesis, diagnosis and management of primary hyperparathyroidism (PHPT), with a focus on recent advances in the field. PHPT is a common endocrine disorder that is characterized by hypercalcaemia and elevated or inappropriately normal serum levels of parathyroid hormone. Most often, the presentation of PHPT is asymptomatic in regions of the world where serum levels of calcium are routinely measured. In addition to mild hypercalcaemia, PHPT can manifest with osteoporosis and hypercalciuria as well as with vertebral fractures and nephrolithiasis, both of which can be asymptomatic. Other clinical forms of PHPT, such as classical disease and normocalcaemic PHPT, are less common. Parathyroidectomy, the only curative treatment for PHPT, is recommended in patients with symptoms and those with asymptomatic disease who are at risk of progression or have subclinical evidence of end-organ sequelae. Parathyroidectomy results in an increase in BMD and a reduction in nephrolithiasis. Various medical therapies can increase BMD or reduce serum levels of calcium, but no single drug can do both. More data are needed regarding the neuropsychological manifestations of PHPT and the pathogenetic mechanisms leading to sporadic PHPT, as well as on risk factors for complications of the disorder. Future work that advances our knowledge in these areas will improve the management of the disorder.

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.

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.

Vitamin d status in patients operated for primary hyperparathyroidism: comparison of patients from southern and northern europe

Aim. The interaction between vitamin D deficiency and primary hyperparathyroidism (PHPT) is not fully understood. The aim of this study was to investigate whether patients with PHPT from Spain and Sweden differed in vitamin D status and PHPT disease activity before and after surgery. Methods. We compared two cohorts of postmenopausal women from Spain (n = 126) and Sweden (n = 128) that had first-time surgery for sporadic, uniglandular PHPT. Biochemical variables reflecting bone metabolism and disease activity, including levels of 25-hydroxy vitamin D3 (25(OH)D) and bone mineral density, BMD, were measured pre- and one year postoperatively. Results. Median preoperative 25(OH)D levels were lower, and adenoma weight, PTH, and urinary calcium levels were higher in the Spanish cohort. The Spanish patients had higher preoperative levels of PTH (13.5 versus 11.0 pmol/L, P < 0.001), urinary calcium (7.3 versus 4.1 mmol/L, P < 0.001), and heavier adenomas (620 versus 500 g, P < 0.001). The mean increase in BMD was higher in patients from Spain and in patients with vitamin D deficiency one year after surgery. Conclusion. Postmenopasual women with PHPT from Spain had a more advanced disease and lower vitamin 25(OH)D levels. Improvement in bone density one year after surgery was higher in patients with preoperative vitamin D deficiency.

Role of parathyroid hormone in bone fragility of postmenopausal women with vitamin D insufficiency

Vitamin D insufficiency is related to an increase in PTH, which might be critical for an increase in bone fragility. However, the role of endogenous PTH in vitamin D insufficiency-induced fracture risk remains unclear. The present study was performed to examine the relationships among vitamin D insufficiency, bone fragility, and PTH in 202 Japanese postmenopausal women. Serum 25-hydroxyvitamin D (25[OH]D) levels were measured. The percentages of subjects with 25(OH)D levels below 10, 15, and 20 ng/ml were 5.0, 41.0, and 80.7%, respectively. Serum 25(OH)D levels were negatively related to age and serum levels of Cr and PTH; they were positively related to bone mineral density (BMD). In multiple regression analysis, BMD was significantly related to 25(OH)D levels when adjusted for age, body mass index (BMI), and serum levels of Cr and PTH. Multiple logistic regression analysis showed that lower 25(OH)D levels were significantly related to prevalent fracture risk when adjusted for age, BMI, serum levels of Cr and PTH, as well as femoral neck BMD. The proportion of subjects with prevalent fractures was significantly higher in the group with lower PTH and lower 25(OH)D than in the group with lower PTH and higher 25(OH)D or higher PTH and higher 25(OH)D. In conclusion, vitamin D insufficiency was found to be related to prevalent fracture risk independently of PTH. Functional hypoparathyroidism, rather than functional hyperparathyroidism, might be a risk factor for bone fragility in vitamin D insufficiency.

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.