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Open access

Xiaoxia Jia, Yaxin An, Yuechao Xu, Yuxian Yang, Chang Liu, Dong Zhao, and Jing Ke

Background

Obesity is known as a common risk factor for osteoporosis and type 2 diabetes mellitus (T2DM). Perirenal fat, surrounding the kidneys, has been reported to be unique in anatomy and biological functions. This study aimed to explore the relationship between perirenal fat and bone metabolism in patients with T2DM.

Methods

A total of 234 patients with T2DM were recruited from September 2019 to December 2019 in the cross-sectional study. The biochemical parameters and bone turnover markers (BTMs) were determined in all participants. Perirenal fat thickness (PrFT) was performed by ultrasounds via a duplex Doppler apparatus. Associations between PrFT and bone metabolism index were determined via correlation analysis and regression models.

Results

The PrFT was significantly correlated with β-C-terminal telopeptides of type I collagen (β-CTX) (r = −0.14, P < 0.036), parathyroid hormone (iPTH) (r = −0.18, P ≤ 0.006), and 25 hydroxyvitamin D (25-OH-D) (r = −0.14, P = 0.001). Multivariate analysis confirmed that the association of PrFT and β-CTX (β = −0.136, P = 0.042) was independent of other variables.

Conclusion

This study showed a negative and independent association between PrFT and β-CTX in subjects with T2DM, suggesting a possible role of PrFT in bone metabolism. Follow-up studies and further research are necessary to validate the associations and to elucidate the underlying mechanisms.

Open access

Shatha Alharazy, M Denise Robertson, Susan Lanhman-New, Muhammad Imran Naseer, Adeel G. Chaudhary, and Eman Alissa

Background: Measurement of free 25-hydroyvitamin D (25(OH)D) status has been suggested as a more representative marker of vitamin D status than that of total 25(OH)D. Previously, free 25(OH)D could only be calculated indirectly; however, a newly developed direct assay for the measurement of free 25(OH)D is now available. The aim of this study therefore was to investigate directly measured total and free vitamin D levels association with metabolic health in postmenopausal healthy women living in Saudi Arabia.

Methods: A sample of 302 postmenopausal women aged ≥ 50 years (n=302) living in Saudi Arabia were recruited in a cross-section study design. Blood samples were collected from subjects for measurement of serum levels of total 25(OH)D, directly measured free 25(OH)D, metabolic bone parameters, lipid profile, and other biochemical tests.

Results: A positive correlation was found between directly measured free and total 25(OH)D (r=0.64, P<0.0001). Total, but not free 25(OH)D showed significant association with serum intact parathyroid hormone (P=0.004); whilst free 25(OH)D but not total 25(OH)D showed a significant association with total cholesterol and LDL-C (P=0.032 and P=0.045; respectively).

Conclusions: Free 25(OH)D and total 25 (OH)D were found to be consistently correlated; but with different associations to metabolic health parameters. Further research is needed to determine which marker of vitamin D status would be the most appropriate in population studies.

Open access

Laura P B Elbers, Marije Wijnberge, Joost C M Meijers, Dennis C W Poland, Dees P M Brandjes, Eric Fliers, and Victor E A Gerdes

Introduction

Abnormal coagulation tests have been observed in patients with primary hyperparathyroidism (HPT) suggesting a prothrombotic effect of parathyroid hormone (PTH). Vitamin D deficiency (VIDD) is the most frequent cause of secondary HPT. Aim of our study was to investigate the influence of HPT secondary to moderate-to-severe VIDD and vitamin D replacement on the coagulation and fibrinolysis system.

Subjects and methods

Prospective cohort study of patients with vitamin D <25 nmol/L with and without HPT, and a control group of patients on vitamin D suppletion. At baseline and after 2 months of vitamin D suppletion (900,000 IU in 2 months), endocrine and coagulation markers were measured.

Results

59 patients with VIDD of which 34 had secondary HPT and 36 controls were included. After 2 months of suppletion, vitamin D increased by 399% (VIDD with HPT), 442% (all patients with VIDD) and 6% (controls). PTH decreased by 34% (VIDD with HPT, P < 0.01 for decrease), 32% (all VIDD, P < 0.01) and increased by 8% in the controls (P-values: <0.01 for relative changes between VIDD with HPT or all VIDD patients vs controls). Relative changes in PT, aPTT, fibrinogen, Von Willebrand factor, factors VII, VIII and X, thrombin generation, TAFI, clot-lysis time and d-dimer were not different between patients with VIDD with HPT or all VIDD vs controls.

Discussion

Secondary HPT due to VIDD does not have a prothrombotic effect. In contrast with previous reports, PTH does not seem to influence coagulation or fibrinolysis, which is relevant because of the high prevalence of VIDD.

Open access

Huma Qamar, Nandita Perumal, Eszter Papp, Alison D Gernand, Abdullah Al Mahmud, and Daniel E Roth

Intrauterine growth restriction (IUGR) reflects inadequate growth in-utero and is prevalent in low resource settings. This study aimed to assess the association of maternal delivery parathyroid hormone (PTH) – a regulator of bone turnover and calcium homeostasis – with newborn anthropometry, to identify regulators of PTH, and to delineate pathways by which maternal PTH regulates birth size using path analysis. This was a cross-sectional analysis of data from participants (n = 537) enrolled in the Maternal Vitamin D for Infant Growth trial in Dhaka, Bangladesh. Primary exposures were maternal delivery intact PTH (iPTH) or whole PTH (wPTH) and outcomes were gestational age- and sex-standardized z-scores for birth length (LAZ), weight (WAZ), and head circumference (HCAZ). Hypothesized regulators of PTH included calcium and protein intake, vitamin D, magnesium, fibroblast-like growth factor-23 (FGF23), and C-reactive protein. Maternal iPTH was not associated with birth size in linear regression analyses; however, in path analysis models, every SD increase in log(iPTH) was associated with 0.08SD (95% CI: 0.002, 0.162) higher LAZ. In linear regression and path analysis models, wPTH was positively associated with WAZ. Vitamin D suppressed PTH, while FGF23 was positively associated with PTH. In path analysis models, higher magnesium was negatively associated with LAZ; FGF23 was positively associated and protein intake was negatively associated with LAZ, WAZ, and HCAZ. Higher maternal PTH in late pregnancy is unlikely to contribute to IUGR. Future studies should investigate maternal FGF23, magnesium and protein intake as regulators of fetal growth, particularly in settings where food insecurity and IUGR are public health problems.

Open access

Adriana J van Ballegooijen, Marjolein Visser, Marieke B Snijder, Jacqueline M Dekker, Giel Nijpels, Coen D A Stehouwer, Michaela Diamant, and Ingeborg A Brouwer

Objective

A disturbed vitamin D–parathyroid hormone (PTH)–calcium axis may play a role in the pathogenesis of heart failure. Therefore, we investigated whether lower 25-hydroxyvitamin D (25(OH)D) and higher PTH are cross sectionally and after 8 years of follow-up associated with higher B-type natriuretic peptide (BNP) levels in older men and women.

Design and methods

We measured baseline 25(OH)D, PTH, and BNP in 502 subjects in 2000–2001 in the Hoorn Study, a population-based cohort. Follow-up BNP was available in 2007–2009 in 278 subjects. Subjects were categorized according to season- and sex-specific quartiles of 25(OH)D and PTH at baseline. We studied the association of 25(OH)D and PTH quartiles with BNP using linear regression analyses adjusting for confounders. Analyses were stratified by kidney function estimated glomerular filtration rate (eGFR; ≤60 ml/min per 1.73 m2) because of significant interaction.

Results

At baseline, subjects had a mean age of 69.9±6.6 years, mean 25(OH)D level was 52.2±19.5 nmol/l and mean PTH 6.1±2.4 pmol/l. Cross sectionally, 25(OH)D was associated with BNP in subjects with impaired kidney function (eGFR ≤60 ml/min) only. The association attenuated after adjustment for PTH. PTH was cross sectionally associated with BNP, also in subjects with impaired kidney function only: regression coefficient of highest quartile 9.9 pmol/l (95% confidence interval 2.5, 17.4) with a significant trend across quartiles. Neither 25(OH)D nor PTH was associated with BNP in longitudinal analyses.

Conclusion

This study showed overall no strong association between 25(OH)D and BNP. However, PTH was associated with BNP in subjects with impaired kidney function and may point to a potential role in myocardial function.

Open access

Leyre Lorente-Poch, Sílvia Rifà-Terricabras, Juan José Sancho, Danilo Torselli-Valladares, Sofia González-Ortiz, and Antonio Sitges-Serra

Objective:

Permanent hypoparathyroidism is an uncommon disease resulting most frequently from neck surgery. It has been associated with visceral calcifications but few studies have specifically this in patients with post-surgical hypoparathyroidism. The aim of the present study was to assess the prevalence of basal ganglia and carotid artery calcifications in patients with long-term post-thyroidectomy hypoparathyroidism compared with a control population.

Design:

Case–control study.

Methods:

A cross-sectional review comparing 29 consecutive patients with permanent postoperative hypoparathyroidism followed-up in a tertiary reference unit for Endocrine Surgery with a contemporary control group of 501 patients who had an emergency brain CT scan. Clinical variables and prevalence of basal ganglia and carotid artery calcifications were recorded.

Results:

From a cohort of 46 patients diagnosed with permanent hypoparathyroidism, 29 were included in the study. The mean duration of disease was 9.2 ± 7 years. Age, diabetes, hypertension, smoking and dyslipidemia were similarly distributed in case and control groups. The prevalence of carotid artery and basal ganglia calcifications was 4 and 20 times more frequent in patients with permanent hypoparathyroidism, respectively. After propensity score matching of the 28 the female patients, 68 controls were matched for age and presence of cardiovascular factors. Cases showed a four-fold prevalence of basal ganglia calcifications, whereas that of carotid calcifications was similar between cases and controls.

Conclusion:

A high prevalence of basal ganglia calcifications was observed in patients with post-surgical permanent hypoparathyroidism. It remains unclear whether carotid artery calcification may also be increased.

Open access

Daniel Bell, Julia Hale, Cara Go, Ben G Challis, Tilak Das, Brian Fish, and Ruth T Casey

Primary hyperparathyroidism (pHPT) is a common endocrine disorder that can be cured by parathyroidectomy; patients unsuitable for surgery can be treated with cinacalcet. Availability of surgery may be reduced during COVID-19, and cinacalcet can be used as bridging therapy. In this single-centre retrospective analysis, we investigated the utility and safety of cinacalcet in patients with pHPT receiving cinacalcet between March 2019 and July 2020, including pre-parathyroidectomy bridging. We reviewed and summarised the published literature. Cinacalcet dosages were adjusted by endocrinologists to achieve target calcium < 2.70 mmol/L. Eighty-six patients were identified, with the most achieving target calcium (79.1%) with a mean dose of 39.4 mg/day (±17.1 mg/day) for a median duration of 35 weeks (1–178 weeks). Calcium was normalised in a median time of 5 weeks. The majority of patients commenced cinacalcet of 30 mg/day (78 patients) with the remainder at 60 mg/day (8 patients). Forty-seven patients commencing lower dose cinacalcet (30 mg/day) achieved target calcium without requiring 60 mg/day. Baseline PTH was significantly higher in patients requiring higher doses of cinacalcet. 18.6% of patients reported adverse reactions and 4.7% discontinued cinacalcet. Patients treated with cinacalcet pre-parathyroidectomy required a higher dose and fewer achieved target calcium compared to medical treatment with cinacalcet alone. Post-operative calcium was similar to patients who were not given pre-parathyroidectomy cinacalcet. In summary, cinacalcet at an initial dose of 30 mg/day is safe and useful for achieving target calcium in patients with symptomatic or severe hypercalcaemia in pHPT, including those treated for pre-parathyroidectomy. We propose a PTH threshold of >30 pmol/L to initiate at a higher dose of 60 mg/day.

Open access

Maxime Duval, Kalyane Bach-Ngohou, Damien Masson, Camille Guimard, Philippe Le Conte, and David Trewick

Objective

Severe hypocalcemia (Ca <1.9 mmol/L) is often considered an emergency because of a potential risk of cardiac arrest or seizures. However, there is little evidence to support this. The aim of our study was to assess whether severe hypocalcemia was associated with immediately life-threatening cardiac arrhythmias or neurological complications.

Methods

A retrospective observational study was carried out over a 2-year period in the Adult Emergency Department (ED) of Nantes University Hospital. All patients who had a protein-corrected calcium concentration measure were eligible for inclusion. Patients with multiple myeloma were excluded. The primary outcome was the number of life-threatening cardiac arrhythmias and/or neurological complications during the stay in the ED.

Results

A total of 41,823 patients had protein-corrected calcium (pcCa) concentrations measured, 155 had severe hypocalcemia, 22 were excluded because of myeloma leaving 133 for analysis. Median pcCa concentration was 1.73 mmol/L (1.57–1.84). Seventeen (12.8%) patients presented a life-threatening condition, 14 (10.5%) neurological and 3 (2.2%) cardiac during ED stay. However, these complications could be explained by the presence of underlying co-morbidities and or electrolyte disturbances other than hypocalcemia. Overall, 24 (18%) patients died in hospital. Vitamin D deficiency, chronic kidney disease and hypoparathyroidism were the most frequently found causes of hypocalcemia.

Conclusion

Thirteen percent of patients with severe hypocalcemia presented a life-threatening cardiac or neurological complication on the ED. However, a perfectly valid alternative cause could account for these complications. Further research is warranted to define the precise role of hypocalcemia.

Open access

Rolf Jorde and Guri Grimnes

Objective

In addition to its skeletal effects, vitamin D may also be important for health in general. It is uncertain what level of serum 25-hydroxyvitamin D (25(OH)D), marker of vitamin D status, is sufficient for these effects. With decreasing serum 25(OH)D levels there is an increase in serum PTH. The point at which this occurs has been considered as a threshold for vitamin D sufficiency. The thresholds found have varied widely and have mainly been based on observational studies. However, to truly establish a threshold for vitamin D effects, this has to be based on randomized controlled trials (RCTs).

Methods

The study included 2803 subjects from a general health survey, the Tromsø study, and pooled individual person data from five vitamin D intervention studies (n = 1544). Serum parathyroid hormone (PTH) and change in PTH after vitamin D supplementation were related to serum 25(OH)D levels in steps of 25 nmol/L (<24, 25–49, 50–74, 75–99, and >99 nmol/L).

Results

In the Tromsø study, in the females there was a gradual decrease in serum PTH with increasing serum 25(OH)D with no apparent plateau, whereas in the males the decrease in PTH in subjects with serum 25(OH)D >74 nmol/l was marginal. In pooled RCTs, there was a significant reduction in serum PTH by vitamin D supplementation regardless of baseline serum 25(OH)D level.

Conclusions

The use of the serum PTH–25(OH)D relation from observational studies to determine a threshold for vitamin D sufficiency is highly questionable.

Open access

Marianne C Astor, Kristian Løvås, Anette S B Wolff, Bjørn Nedrebø, Eirik Bratland, Jon Steen-Johnsen, and Eystein S Husebye

Primary hypomagnesemia with secondary hypocalcemia (HSH) is an autosomal recessive disorder characterized by neuromuscular symptoms in infancy due to extremely low levels of serum magnesium and moderate to severe hypocalcemia. Homozygous mutations in the magnesium transporter gene transient receptor potential cation channel member 6 (TRPM6) cause the disease. HSH can be misdiagnosed as primary hypoparathyroidism. The aim of this study was to describe the genetic, clinical and biochemical features of patients clinically diagnosed with HSH in a Norwegian cohort. Five patients in four families with clinical features of HSH were identified, including one during a national survey of hypoparathyroidism. The clinical history of the patients and their families were reviewed and gene analyses of TRPM6 performed. Four of five patients presented with generalized seizures in infancy and extremely low levels of serum magnesium accompanied by moderate hypocalcemia. Two of the patients had an older sibling who died in infancy. Four novel mutations and one large deletion in TRPM6 were identified. In one patient two linked homozygous mutations were located in exon 22 (p.F978L) and exon 23 (p.G1042V). Two families had an identical mutation in exon 25 (p.E1155X). The fourth patient had a missense mutation in exon 4 (p.H61N) combined with a large deletion in the C-terminal end of the gene. HSH is a potentially lethal condition that can be misdiagnosed as primary hypoparathyroidism. The diagnosis is easily made if serum magnesium is measured. When treated appropriately with high doses of oral magnesium supplementation, severe hypomagnesemia is uncommon and the long-term prognosis seems to be good.