Secondary hyperparathyroidism: Predictors and relationship with vitamin D status, bone turnover markers and bone mineral density

INTRODUCTION

Secondary hyperparathyroidism (SHPT) has adverse implications for bone health but is relatively understudied. In this study we examine the prevalence and determinants of SHPT and describe the relationship of SHPT with bone turnover markers and bone mineral density (BMD) in older Irish adults.

METHOD

Eligible participants (n = 4139) were identified from the Trinity-Ulster-Department of Agriculture (TUDA) study, a cohort of Irish adults aged ≥60 years. Exclusion criteria included an estimated glomerular filtration rate (eGFR) <30 ml/min and serum calcium >2.5 mmol/l to remove hyperparathyroidism due to advanced chronic kidney disease (CKD) and primary hyperparathyroidism respectively. The relationship between SHPT and bone turnover markers and BMD (measured by densitometry) was examined in a subsample (n = 1488). Vitamin D deficiency was defined as 25-hydroxyvitamin D [25 (OH)D] <30 nmol/l.

RESULTS

Participants had a mean age of 73.6 ± 7.9 years, 65.1 % were female and 19.4 % were found to be vitamin D deficient. The prevalence of SHPT decreased as vitamin D increased, from 30.6 % in those deficient to 9.8 % in those with 25(OH)D ≥ 50 nmol/l and increased with declining kidney function. In non‑calcium supplement users, principal determinants of SHPT were vitamin D deficiency (OR 4.18, CI 3.05-5.73, p < 0.001), eGFR 30-44 ml/min (OR 3.69, CI 2.44-5.57, p < 0.001), loop diuretic use (OR 3.52, CI 2.59-4.79, p < 0.001) and to a lesser extent body mass index (p = 0.001), eGFR 45-59 ml/min (p < 0.001) and 25(OH)D level 30-49 nmol/l (p = 0.002). Similar findings were observed in calcium supplement users, though proton pump inhibitors were also associated with SHPT (OR 1.55, CI 1.08-2.22, p = 0.018) while vitamin D 30-49 nmol/l was not. In participants with SHPT versus those without, bone turnover markers were higher: bone alkaline phosphatase (p = 0.017) and tartrate-resistant acid phosphatase (p = 0.033), whilst there was lower BMD at the neck of femur (0.880 vs. 0.903 g/cm2, p = 0.033) and total hip (0.968 vs. 0.995 g/cm2, P = 0.017).

DISCUSSION

The results show that up to one in six older Irish adults had SHPT and this was associated with lower BMD and higher concentrations of bone turnover markers. Both vitamin D deficiency and 25(OH)D level 30-49 nmol/l were important predictors of SHPT. Loop diuretics and PPIs may also increase the risk of SHPT, and their use may need to be carefully considered in this population. Further studies examining the potential impact of these factors on bone health in similar populations to our study sample are warranted.

Does preoperative calcium and 1, 25 OH vitamin D supplementation impact postoperative hypocalcemia and length of stay following pediatric thyroidectomy?

OBJECTIVE

To investigate whether perioperative calcium and 1,25 OH vitamin D supplementation (PCDS) influences the rates of postoperative hypocalcemia and length of stay (LOS) following pediatric thyroidectomy.

STUDY DESIGN

Retrospective Cohort Review.

SETTING

Tertiary children's hospital.

METHODS

94 patients who underwent completion or total thyroidectomy with or without concomitant neck dissection from 2010 to 2020 at a single institution were included. Patients with pre-existing hypocalcemia or preoperative vitamin D insufficiency were excluded. Rates of postoperative hypocalcemia and LOS were compared for patients receiving PCDS to those receiving no supplementation.

RESULTS

Thirty percent of patients with PCDS had documented postoperative hypocalcemia compared to 64% of patients without PCDS (p = 0.01). Patients with PCDS had a median LOS of 30 h compared to 36 h (p = 0.002). Multivariable analyses confirmed that patients with PCDS had lower odds of postoperative hypocalcemia (OR: 0.32, CI: 0.11, 0.89) and shorter LOS by 17 h (SE: 8, p = 0.04) after adjustment for confounders.

CONCLUSION

PCDS is associated with significantly lower risk of hypocalcemia and shorter LOS. Standardizing preoperative care for pediatric patients undergoing thyroidectomy may decrease variability and improve outcomes following surgery.

Considerations in the Diagnosis and Treatment of Early Lactation Calcium Disturbances

This article reviews the history of clinical hypocalcemia and the evolving definition of subclinical hypocalcemia, targeting a concept for consideration that not all hypocalcemia is negative. With a goal of presenting bovine practitioners information to assist with individual animal hypocalcemia diagnosis and treatment as well as herd-level monitoring and prevention, we present current methods of direct calcium measurement, therapeutic interventions for clinical hypocalcemia, and postpartum calcium supplementation options and their efficacy. We encourage veterinarians to understand calcium dynamics in the immediate postpartum period and evaluate how individual cow therapy and herd prevention protocols can assist with supporting calcium regulation.

High-efficiency production of the antimicrobial peptide pediocin PA-1 in metabolically engineered Corynebacterium glutamicum using a microaerobic process at acidic pH and elevated levels of bivalent calcium ions

BACKGROUND

Pediocin PA-1 is a bacteriocin of recognized value with applications in food bio-preservation and the medical sector for the prevention of infection. To date, industrial manufacturing of pediocin PA-1 is limited by high cost and low-performance. The recent establishment of the biotechnological workhorse Corynebacterium glutamicum as recombinant host for pediocin PA-1 synthesis displays a promising starting point towards more efficient production.

RESULTS

Here, we optimized the fermentative production process. Following successful simplification of the production medium, we carefully investigated the impact of dissolved oxygen, pH value, and the presence of bivalent calcium ions on pediocin production. It turned out that the formation of the peptide was strongly supported by an acidic pH of 5.7 and microaerobic conditions at a dissolved oxygen level of 2.5%. Furthermore, elevated levels of CaCl₂ boosted production. The IPTG-inducible producer C. glutamicum CR099 pXMJ19 P_tac pedACD^Cg provided 66 mg L^-1 of pediocin PA-1 in a two-phase batch process using the optimized set-up. In addition, the novel constitutive strain P_tuf pedACD^Cg allowed successful production without the need for IPTG.

CONCLUSIONS

The achieved pediocin titer surpasses previous efforts in various microbes up to almost seven-fold, providing a valuable step to further explore and develop this important bacteriocin. In addition to its high biosynthetic performance C. glutamicum proved to be highly robust under the demanding producing conditions, suggesting its further use as host for bacteriocin production.

Should all pregnant women take calcium supplements in Nepal? GRADE evidence to policy assessment

Background

The WHO recommends oral calcium supplementation (1.5–2.0 g) in pregnant women to reduce the risk of pre-eclampsia living in areas with low dietary calcium intake. Although maternal mortality is high in Nepal and eclampsia causes at least 20% of maternal deaths, implementing WHO recommendations would be a major undertaking.

Objective

This review aimed to assess whether the current evidence supports the blanket supplementation of calcium to prevent pre-eclampsia among pregnant women in Nepal.

Methods

We used a structured approach to appraise the evidence for calcium supplementation in Nepal. We identified what may influence the impact of calcium supplementation in Nepal and conducted a situation analysis in the country covering maternal mortality, pre-eclampsia occurrence, and existing government policy provisions for supplementation. We also consulted with experts and government officials to explore their perspectives and experience on supplementation. We then used AMSTAR (A MeaSurement Tool to Assess Systematic Reviews) to appraise the Cochrane Systematic Review of calcium supplementation. Finally, we used these data in a GRADE (Grading of Recommendations Assessment, Development and Evaluation)–Evidence to Decision framework to reach a policy recommendation.

Results

Our assessment of the Cochrane Review showed that the recommendation made by the WHO is based on weak evidence and trial findings that are not consistent between studies. The Cochrane Review found low certainty of the evidence for benefit (reduction in pre-eclampsia and maternal mortality). Conversely, there is a high certainty of the evidence of undesirable effects (HELLP [haemolysis, elevated liver enzymes and low platelets] syndrome) although this is uncommon. The likely absolute reduction in maternal deaths projected to Nepal was estimated to be low, while the implementation costs were high. Stakeholders also raised several concerns regarding feasibility, acceptability, appropriate dosing, and risk communication.

Conclusions

This review concludes that the blanket supplementation of calcium cannot be recommended in Nepal. A better approach may be to identify high-risk pregnant women and manage their antenatal visits and delivery to prevent mortality from pre-eclampsia.

Effect of calcium supplementation on severe hypocalcemia in patients with secondary hyperparathyroidism after total parathyroidectomy

BACKGROUND

Severe hypocalcemia (SH) is a dreaded complication of total parathyroidectomy (TPTX) without auto-transplantation.

AIM

To compare conventional and preventive calcium supplementation (CS) regimens in terms of SH occurrence after TPTX.

METHODS

This retrospective study included patients who underwent TPTX between January 2015 and May 2018 at the China-Japan Friendship Hospital. From January 2015 to May 2016, conventional CS was performed in patients who underwent TPTX, with calcium amounts adjusted according to postoperative serum calcium levels. From October 2016 to May 2018, preventive CS was performed according to preoperative alkaline phosphatase (ALP) levels. The patients were defined as low-risk (ALP < 500 U/L) and high-risk (ALP > 500 U/L) for SH. All preoperative blood samples were collected in the fasting state on the day before surgery. Postoperative blood samples were obtained at 6-7 AM from the first postoperative day.

RESULTS

A total of 271 patients were included. These patients were 47.7 ± 11.1 years old, and 57.6% were male. Their mean body mass index (BMI) was 22.9 ± 3.8 kg/m². There were no significant differences in sex, age, BMI, preoperative ALP, serum calcium, serum phosphorus, calcium-phosphorus ratio, and intact parathyroid hormone (iPTH) between the two CS groups. Compared with conventional CS, preventive CS led to lower occurrence rates of hypocalcemia within 48 h (46.0% vs 74.5%, P < 0.001) and SH (31.7% vs 64.1%, P < 0.001). Multivariable analysis showed that preoperative iPTH levels [odds ratio (OR) = 1.001, 95% confidence interval (CI): 1.000-1.001, P = 0.009), preoperative ALP amounts (OR = 1.002, 95%CI: 1.001-1.003, P = 0.002), preoperative serum phosphorus levels (OR = 8.729, 95%CI: 1.518-50.216, P = 0.015) and preventive CS (OR = 0.132, 95%CI: 0.067-0.261, P < 0.001) were independently associated with SH. In patients with preoperative ALP ≥ 500 U/L, only preventive CS (OR = 0.147, 95%CI: 0.038-0.562. P = 0.005) was independently associated with SH.

CONCLUSION

This study suggests that preventive CS could reduce the occurrence of SH, indicating its critical value for hypocalcemia after TPTX.

Calcium chloride dihydrate supplementation at ICSI improves fertilization and pregnancy rates in patients with previous low fertilization: a retrospective paired treatment cycle study

PURPOSE

To determine if 5mM calcium chloride dihydrate supplementation of the Polyvinylpyrrolidone (PVP) media at the time of ICSI (ICSI-Ca) improves fertilization, utilization, and clinical pregnancy rates compared to ICSI alone, particularly in patients with a history of low fertilization (< 50%).

METHODS

Retrospective study between 2016 and 2021 at Monash IVF Victoria on a paired cohort of patients (n = 178 patients) where an ICSI cycle was analyzed coupled with the subsequent ICSI-Ca cycle. The paired cohort was further subdivided into a low-fertilization cohort (< 50% fertilization on previous cycles: n = 66 patients) compared to the remaining patients with fertilization ≥ 50% (n = 122). Exclusion criteria included donor cycles, PGT patients, surgical sperm retrieval, women ≥ 45 years old, patients with > 6 cycles, and patients with ≤ 5 inseminated oocytes.

RESULTS

Calcium supplementation significantly increased both fertilization (28.8% ICSI vs 49.7% ICSI-Ca, P < 0.0001) and clinical pregnancy rate (4.9% ICSI vs 25.0% ICSI-Ca: P < 0.05) in the low-fertilization cohort but not in the normal-fertilization cohort. Interestingly, utilization rate significantly increased in the normal-fertilization cohort (32.6% ICSI vs ICSI-Ca: 44.9%, P < 0.01) but not in the low-fertilization cohort, although the number of embryos utilized per patient after ICSI-Ca increased in both groups.

CONCLUSION

Calcium supplementation does not appear to be a detrimental addition to ICSI and may improve IVF outcomes, particularly for patients with a history of low fertilization. Further investigations including prospective case-matched studies or a RCT are required to confirm these findings.

Risk of Hypocalcemia and the Need to Augment Calcium Supplementation After Total Thyroidectomy

Hypocalcemia is the most common complication after total thyroidectomy. The aim of this study was to determine the predictors of postoperative hypocalcemia requiring augmentation of routine calcium supplementation. Prospectively collected data of 61 patients who underwent total thyroidectomy from December 2018 to June 2019 was considered for the study. All patients received calcium and vitamin D supplementation after the surgery. In the postoperative period, serum calcium and parathormone (PTH) levels were monitored. The need of additional oral or intravenous (i.v.) calcium supplementation was evaluated as an outcome measure. This cohort comprised 61 patients with median age of 46 years (range 16-80 years) and 49 (80%) females. Central compartment clearance (CCC) was done in 32 patients. Escalation to increased oral and intravenous calcium was required in 15 patients (24.6%) and 2 patients (3.3%), respectively. Serum parathormone level of 11.5 pg/ml on postoperative day 1 predicted the requirement of additional calcium with a sensitivity of 82.4% and specificity of 77.3%. On univariate analysis, serum PTH (p < 0.001), CCC (p = 0.018), and intraoperative parathyroid gland congestion (p = 0.021) predicted the need for escalation of calcium supplementation. On multivariate analysis, only serum PTH showed a significant impact on the need for augmentation of calcium supplementation (p = 0.003). The need for calcium dose augmentation after total thyroidectomy was significantly associated with CCC, parathyroid gland congestion, and serum PTH levels. Intraoperative identification of parathyroid gland congestion and postoperative serum PTH levels is effective in predicting postoperative hypocalcemia with implications on time and cost.

The impact of calcium supplementation on methane fermentation and ammonia inhibition of fish processing wastewater

The effect of trace metal supplementation on the methane fermentation of fish processing wastewater (FPW) was studied in both batch and continuous experiments using a self-agitated anaerobic baffled reactor (SA-ABR). In the batch experiments, a single supplementation of Ca²⁺, Co²⁺ and Fe²⁺ was show to have a significant positive impact on the performance of methane fermentation. The continuous experiment results showed that supplementation with 1.5 g-Ca²⁺/L-substrate remarkably enhanced the performance of methane fermentation of the SA-ABR in treating FPW with the optimal organic loading rate achieved at 7.62 g-COD/L/d. During the steady states (stages 2 to 5), the average removal efficiencies of COD, protein, carbohydrate and lipid were 89, 85, 80 and 91%, respectively. The biogas conversion rates were in the range of 0.39 to 0.45 L-biogas/g-COD with a high methane content of 74%. Besides, Ca²⁺ supplementation also improved the resistance of the methane fermentation system to ammonia inhibition.

Moderate/subclinical calcium deficiency attenuates trabecular mass, microarchitecture and bone growth in growing rats

Adequate dietary calcium (Ca) intake is essential for bone accretion, peak bone mass (PBM) attainment, bone quality and strength during the mammalian growth period. Severe Ca deficiency during growing age results in secondary hyperparathyroidism (SHPT) and poor bone quality and strength. However, the impact of moderate Ca deficiency during rats early growth period on bone health and the reversibility with supplementing calcium later in adult life remains unclear. Female Sprague-Dawley (SD) rats (postnatal 28th day, P28) were initiated either with a moderate calcium-deficient diet (MCD, 0.25% w/w Ca) or a control diet (0.8% w/w Ca, control group) till P70. Thereafter, MCD rats were continued either with MCD diet or supplemented with calcium diet (0.8% w/w Ca, calcium supplemented group, CaS) till P150. Another group (control rats) were fed 0.8% w/w Ca containing diet from P28 till P150.

MCD group, as compared to the control group, had significantly reduced serum ionized Ca and procollagen type 1 N-terminal propeptide (P1NP) at P70 while no significant change was observed in serum corrected Ca, inorganic phosphate (P), alkaline phosphatase (ALP), 25-hydroxy vitamin D [25(OH)D], intact parathyroid hormone (iPTH), and urinary C-terminal telopeptide of collagen 1 (CTX-1), Ca, and P. Femoral and tibial metaphysis in MCD rats had significantly reduced linear growth, cortical and trabecular volumetric BMD (vBMD), trabecular microarchitecture (BV/TV%, trabecular thickness, separation and number, structural model index and connectivity density), cortical thickness, and bone stiffness despite the absence of secondary hyperparathyroidism (SHPT). Continued MCD at P70–P150 results in persistence of compromised bone strength while calcium supplementation (CaS group) improved all the parameters related to bone strength and microarchitecture. Our results indicate that uncorrected moderate/subclinical calcium deficiency in growing rats can result in poor bone quality and strength despite the absence of SHPT. This finding could have relevance in children with poor calcium intake in childhood and adolescence.

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Moderate Ca intake impairs bone growth and stiffness in critical growth phase via subclinical Ca deficiency.

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Ca supplementaion reverses the effects subclinical Ca deficiency on bone health.

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Conclusively, moderate Ca intake imposes different effects on the bone at different phases of life.

A narrative review

BACKGROUND

To determine whether routine administration of calcium supplementation is useful in postmenopausal women, while it is associated with an increased risk of cardiovascular complications.

METHODS

A literature search was performed using Medline/PubMed, Scopus and Google Scholar by using relevant keywords.

RESULTS

Calcium supplement exerts a small protective effect against bone loss which disappears after cessation. Antifracture effect of supplemental calcium is limited to older frail women or community-dwelling residents who are vitamin D deficient and have inadequate dietary calcium intake. The results of studies on the association between calcium supplementation and cardiovascular complications are contradictory and do not lead to a decisive conclusion CONCLUSION: Current data do not support routine calcium supplementation to all postmenopausal women for prevention of bone loss or bone fracture.

Changes in vascular calcification and bone mineral density in calcium supplement users from the Canadian Multi-center Osteoporosis Study (CaMOS)

BACKGROUND AND AIMS

Calcium supplements have been associated with increased cardiovascular events. This study investigates the relationship between calcium supplement use and the 5 year progression of abdominal aorta calcification (AAC) in participants from one center of the Canadian Multi-Centre Osteoporosis Study (CaMOS).

METHODS

Participants (n = 296; 217 women and 79 men) had lateral spine X-rays and DEXA bone mineral density (BMD) scans (femoral neck, lumbar spine and total hip) taken at two time points within a 5 year interval. AAC was assessed using the Framingham Method. Calcium supplement use was assessed by a facilitated health history questionnaire and medication inventory.

RESULTS

AAC significantly increased over 5 years, AAC progression was significantly greater in calcium supplement users, as compared to non-users, overall and in females. The amount of calcium was positively correlated to AAC progression. A multi-variable linear regression model was generated for women only, as there were not enough men for multivariable modelling. Calcium supplement use and amount remained significantly associated with AAC progression after adjustment for age, hypertension, diabetes and smoking history. Change in AAC score was not associated with change in BMD T-Score. In univariate analyses of males, calcium supplement use was associated with a significantly greater BMD loss at the lumbar spine, hip, and femoral neck.

CONCLUSIONS

Older female calcium supplement users had significantly higher AAC progression over 5 years, but did not have any significant BMD preservation. These results suggest that vascular calcification may contribute to the cardiovascular events observed in calcium supplement users.

Investigation of the preventive effect of calcium on inflammation-mediated choroidal neovascularization

AIMS

Age-related macular degeneration (AMD) is a leading cause of irreversible blindness in elderly people. The pathogenesis of neovascular AMD is known but is closely related to inflammation and choroidal neovascularization (CNV). The aim of this study was to investigate the anti-inflammatory and anti-angiogenic effects of calcium on neovascular AMD.

MAIN METHODS

Human retinal pigment epithelial cells (ARPE-19) were used to identify protein markers of inflammation induced by differentiated macrophages. Choroidal neovascularization (CNV) mouse model was established by rupturing the Bruch's membrane using laser photocoagulation in C57BL/6 mice. Mice were divided into the following groups: untreated control and calcium supplemented. The expression levels of toll-like receptor isotype (TLR) 4, nuclear factor kappa B (NF-κB), hypoxia-inducible factor-1α (Hif-1α), and vascular endothelial growth factor (VEGF) were investigated to check whether calcium supplementation results in suppression of inflammation and has an anti-angiogenic effect. CNV was evaluated by immunofluorescence staining on choroidal flat mounts.

KEY FINDING

The inflammation-induced expression of TLR4, NF-κB, and Hif-1α was decreased in ARPE-19 cells after calcium supplementation. Inhibition of the transcriptional activation of ARPE-19 cells by Hif-1α suppression resulted in decreased VEGF expression. In the laser-induced CNV mouse model, calcium supplementation inhibited inflammatory mediators and neovascularization in the retinal tissue.

SIGNIFICANCE

Supplementation with calcium seems to constrain inveterate symptoms of neovascular AMD by inhibiting inflammation and angiogenesis in the laser-induced CNV mouse model.

Predicting transient hypocalcemia in patients with unplanned parathyroidectomy after thyroidectomy

OBJECTIVE

To assess the utility of rapid parathyroid hormone (PTH) values in predicting transient post-operative hypocalcemia in patients with unplanned parathyroidectomy during total or completion thyroidectomy.

METHODS

All patients who underwent total or completion thyroidectomy between January 2010 and January 2015 were reviewed. Incidences of post-operative hypocalcemia were compared in patients with and without unplanned parathyroidectomy. Unplanned parathyroidectomy was defined as intra-operative incidental or intentional parathyroidectomy. Logistic regression assessed for predictors of hypocalcemia and optimum amount of calcium supplementation.

RESULTS

Thirty-eight (13.6%) patients had evidence of incidental parathyroidectomy and 39/280 (13.9%) patients had parathyroid autotransplantation intra-operatively. Central neck dissection and malignancy were identified as risk factors for unplanned parathyroidectomy (p = 0.001, p = 0.060). Patients with unplanned parathyroidectomy were more likely to have hypocalcemia (p = 0.002) and hypoparathyroidism (p < 0.0005). PTH value was the only significant predictor of hypocalcemia in these patients. In patients with a post-operative PTH of ≤15, initial calcium supplementation ≥ 1000 mg decreased the risk of hypocalcemia (p < 0.05).

CONCLUSION

Post-operative PTH value predicts hypocalcemia in patients undergoing total and completion thyroidectomy with unplanned parathyroidectomy. In patients with a post-operative PTH < 15, initial calcium supplementation with ≥1000 mg of elemental calcium is recommended.

Supplemental calcium intake in the aging individual: implications on skeletal and cardiovascular health

Adequate calcium intake during childhood is necessary to achieve optimal peak bone mass and this has the potential by increasing bone reserves, to modulate the rate of age-associated bone loss. However, data regarding the efficacy of calcium obtained either through the diet or in the form of medicinal supplementation, for prevention of bone loss and osteoporotic fractures in the elderly is conflicting. Calcium alone is unlikely to be of benefit for this purpose though the co-administration of calcium and vitamin D may have modest fracture risk benefits. Supplemental calcium with or without vitamin D has recently come into the spotlight after the publication of the findings from a controversial randomized controlled trial that associated calcium supplementation with an increased risk of myocardial infarction. Since then, multiple studies have explored this potential link. The data remains conflicting and the potential mechanistic link if any exists, remains elusive. This review examines the relationship between supplemental calcium intake and skeletal and cardiovascular health in the aging individual through an appraisal of studies done on the subject in the last three decades. It also briefly details some of the studies evaluating fractional absorption of calcium in the elderly and the rationale behind the current recommended dietary allowances of calcium.

The association between daily 500 mg calcium supplementation and lower pregnancy-induced hypertension risk in Bangladesh

BACKGROUND

Evidence suggests that daily supplementation of 1500 to 2000 mg of calcium during pregnancy reduces pregnancy-induced hypertension (PIH). However, the evidence on the efficacy of low-dose calcium supplementation on PIH is limited. This paper assesses the longitudinal correlation between low-dose calcium intake (500 mg daily) and change in blood pressure during pregnancy among a homogeneous population in terms of hypertension and pre-eclampsia.

METHODS

The study followed a retrospective cohort study design, and was carried out among 11,387 pregnant women from 10 rural upazilas (sub-districts) of Bangladesh where maternal nutrition initiative (MNI), implemented by Building Resources Across Communities (BRAC), was ongoing. The modified Poisson regression model was used to estimate the association (risk ratio) between consumption of calcium tablets and PIH.

RESULTS

The present research found that women who consumed 500 mg/d calcium tablets for more than 6 months during their pregnancy had a 45% lower risk of developing hypertension compared to those who consumed less calcium (RR = 0.55, 95% CI = 0.33-0.93).

CONCLUSIONS

Daily supplementation of 500 mg oral calcium during pregnancy for at least 180 tablets is associated with a considerably reduced risk of PIH, but this study is unable to confirm whether this association is causal. The causal relationship needs to be confirmed through a large scale randomized controlled trial.

Applying international guidelines for calcium supplementation to prevent pre-eclampsia: simulation of recommended dosages suggests risk of excess intake in Ethiopia

OBJECTIVE

To simulate impact of Ca supplementation on estimated total Ca intakes among women in a population with low dietary Ca intakes, using WHO recommendations: 1·5-2·0 g elemental Ca/d during pregnancy to prevent pre-eclampsia.

DESIGN

Single cross-sectional 24 h dietary recall data were adjusted using IMAPP software to simulate proportions of women who would meet or exceed the Estimated Average Requirement (EAR) and Tolerable Upper Intake Level (UL) assuming full or partial adherence to WHO guidelines.

SETTING

Nationally and regionally representative data, Ethiopia's 'lean' season 2011.

SUBJECTS

Women 15-45 years (n 7908, of whom 492 pregnant).

RESULTS

National mean usual Ca intake was 501 (sd 244) mg/d. Approximately 89, 91 and 96 % of all women, pregnant women and 15-18 years, respectively, had dietary Ca intakes below the EAR. Simulating 100 % adherence to 1·0, 1·5 and 2·0 g/d estimated nearly all women (>99 %) would meet the EAR, regardless of dosage. Nationally, supplementation with 1·5 and 2·0 g/d would result in intake exceeding the UL in 3·7 and 43·2 % of women, respectively, while at 1·0 g/d those exceeding the UL would be <1 % (0·74 %) except in one region (4·95 %).

CONCLUSIONS

Most Ethiopian women consume insufficient Ca, increasing risk of pre-eclampsia. Providing Ca supplements of 1·5-2·0 g/d could result in high proportions of women exceeding the UL, while universal consumption of 1·0 g/d would meet requirements with minimal risk of excess. Appropriately tested screening tools could identify and reduce risk to high Ca consumers. Research on minimum effective Ca supplementation to prevent pre-eclampsia is also needed to determine whether lower doses could be recommended.

The role of calcium supplementation in healthy musculoskeletal ageing : An expert consensus meeting of the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) and the International Foundation for Osteoporosis (IOF)

The place of calcium supplementation, with or without concomitant vitamin D supplementation, has been much debated in terms of both efficacy and safety. There have been numerous trials and meta-analyses of supplementation for fracture reduction, and associations with risk of myocardial infarction have been suggested in recent years. In this report, the product of an expert consensus meeting of the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) and the International Foundation for Osteoporosis (IOF), we review the evidence for the value of calcium supplementation, with or without vitamin D supplementation, for healthy musculoskeletal ageing. We conclude that (1) calcium and vitamin D supplementation leads to a modest reduction in fracture risk, although population-level intervention has not been shown to be an effective public health strategy; (2) supplementation with calcium alone for fracture reduction is not supported by the literature; (3) side effects of calcium supplementation include renal stones and gastrointestinal symptoms; (4) vitamin D supplementation, rather than calcium supplementation, may reduce falls risk; and (5) assertions of increased cardiovascular risk consequent to calcium supplementation are not convincingly supported by current evidence. In conclusion, we recommend, on the basis of the current evidence, that calcium supplementation, with concomitant vitamin D supplementation, is supported for patients at high risk of calcium and vitamin D insufficiency, and in those who are receiving treatment for osteoporosis.

Usefulness of pre- and post-operative calcium and Vitamin D supplementation in prevention of hypocalcemia after total thyroidectomy: A randomized controlled trial

BACKGROUND

Total thyroidectomy (TT) is a commonly performed surgery and postoperative hypocalcemia is a major detriment to early discharge. The aim of this randomized controlled trial was to ascertain the usefulness of routine pre- and post-operative calcium and Vitamin D supplementation in prevention of hypocalcemia after TT.

MATERIALS AND METHODS

Sixty consecutive patients who underwent total or near TT from February 2013 to August 2014 were included in the study. They were randomly divided into two groups - Group 1 received oral calcium (500 mg every 6 h) and Vitamin D (calcitriol 0.25 mcg every 6 h) 7 days before and 7 days after the surgery; and Group 2 did not receive supplementation. Symptoms and signs of hypocalcemia were monitored. Calcium profile was measured pre- and post-operatively at 6, 12, 24, 48, 72 h, and on 30^th day. Hypocalcemia after surgery was either symptomatic or laboratory documented. Serum calcium level ≤ 8.5 mg/dl was considered as laboratory hypocalcemia.

RESULTS

Twelve patients from Group 2, and 3 patients from Group 1 developed symptomatic hypocalcemia (P < 0.01). Laboratory hypocalcemia within postoperative 24 h was comparable between two groups, but more patients of Group 2 compared to Group 1 developed hypocalcemia at 48 h (6 and 13, respectively; P = 0.04) and at 72 h after surgery (5 and 14, respectively; P = 0.01). Twenty-four hours postoperative serum calcium level was significantly associated with grade of goiter, preoperative calcium, and nature of thyroid disease (benign or malignant). On multiple linear regression analysis, preoperative serum calcium was only independent variable significantly associated with development of 24 h post-TT hypocalcemia.

CONCLUSION

Routine pre- and post-TT calcium and Vitamin D supplementation can significantly reduce postoperative hypocalcemia.

Effect of Milk Powder Supplementation with Different Calcium Contents on Bone Mineral Density of Postmenopausal Women in Northern China: A Randomized Controlled Double-Blind Trial

The objective of this study is to examine the effect of milk powder supplementation with different calcium contents on bone mineral density (BMD) in postmenopausal Chinese women, and to determine a more appropriate dose of calcium supplementation. A 2-year, randomized controlled double-blind trial. Postmenopausal women (n = 210) aged 50-65 years were recruited and assigned randomly into three calcium supplementation groups. All participants received milk powder supplementation with different calcium contents (300, 600, and 900 mg per day for groups A, B, and C, respectively) and all groups received 800 IU of vitamin D per day. During the follow-up period, BMD of the left hip and lumbar spine (as the main indicator) was measured using dual-energy X-ray absorptiometry at the baseline, 1 and 2 years. Both three BMD measures and the changes of BMD over 2 years were used to analyze. Before adjusting for covariates, BMD in group A of the lumbar spine and groups A and B of greater trochanter decreased significantly from the baseline over time but increased significantly in the rest groups of the lumbar spine and greater trochanter and in three groups of Ward's triangle. There were significant differences across the three groups for changes of BMD in the greater trochanter and Ward's triangle. When adjusting for covariates, there were significant decreases with time in group A of the spine (P = 0.001), groups A and B of greater trochanter (P = 0.0002 and P = 0.04, respectively) and increases in groups B and C of Ward's triangle (P = 0.03 and P = 0.004, respectively). BMD change in the greater trochanter was significantly different among three groups. For healthy postmenopausal women, high calcium milk powder supplementation was better in retarding bone loss than medium and low calcium in the greater trochanter. Considering the dietary calcium intake of postmenopausal women in north of China, a dose of 900 mg/day is considered as the most appropriate calcium supplementation for greater trochanter but not for other sites.

Methylation analysis in fatty-acid-related genes reveals their plasticity associated with conjugated linoleic acid and calcium supplementation in adult mice

PURPOSE

DNA methylation is one of the most extensively studied mechanisms within epigenetics, and it is suggested that diet-induced changes in methylation status could be involved in energy metabolism regulation. Conjugated linoleic acid (CLA) and calcium supplementation counteract body weight gain, particularly under a high-fat (HF) diet, in adult mice. The aim was to determine whether the modulation of DNA methylation pattern in target genes and tissues could be an underlying mechanism of action.

METHODS

Mice (C57BL/6J) were divided into five groups according to diet and treatment: normal fat as the control group (12 % kJ content as fat), HF group (43 % kJ content as fat), HF + CLA (6 mg CLA/day), HF + calcium (12 g/kg of calcium) and HF with both compounds. Gene expression and methylation degree of CpG sites in promoter sequences of genes involved in fatty acid metabolism, including adiponectin (Adipoq), stearoyl-CoA desaturase (Scd1) and fatty acid synthase (Fasn), were determined by bisulphite sequencing in liver and epididymal white adipose tissue.

RESULTS

Results showed that the methylation profile of promoters was significantly altered by dietary supplementation in a gene- and tissue-specific manner, whereas only slight changes were observed in the HF group. Furthermore, changes in specific CpG sites were also associated with an overall healthier metabolic profile, in particular for calcium-receiving groups.

CONCLUSIONS

Both CLA and calcium were able to modify the methylation pattern of genes involved in energy balance in adulthood, which opens a novel area for increasing efficiency in body weight management strategies.

Calcium supplementation modulates gut microbiota in a prebiotic manner in dietary obese mice

SCOPE

Dietary calcium has been inversely associated with body fat and energy balance. The main scope of this study has been to assess the potential contribution of gut microbiota on energy regulation mediated by calcium.

METHODS AND RESULTS

Gut microbiota in C57BL/6J mice receiving calcium supplementation under a high-fat (HF) diet were analysed by PCR and their relationships with host metabolic parameters were determined. Calcium conferred a prebiotic-like effect on gut microbiota, and animals presented lower plasmatic endotoxin levels, increased expression of angiopoietin-like 4 in intestine and lower hepatic lipid content, although increased expression of stress markers in adipose tissue and of inflammation in liver was also found. To determine whether slimming effects could be transferred to obese mice, a faecal microbial transplant (FMT) was carried out, showing that host bacteria grown under a HF diet could not be superseded by those from calcium-fed animals. Therefore, FMT was not able to transfer the beneficial effects of calcium.

CONCLUSION

In conclusion, calcium modulated gut microbiota in a prebiotic manner, establishing a host cross-talk and promoting a healthier metabolic profile. However, lack of effectiveness of FMT suggests the need of further appropriate dietary factors in addition to the bacteria per se.

Calcium supplementation improves clinical outcome in intensive care unit patients: a propensity score matched analysis of a large clinical database MIMIC-II

Observational studies have linked hypocalcemia with adverse clinical outcome in critically ill patients. However, calcium supplementation has never been formally investigated for its beneficial effect in critically ill patients. To investigate whether calcium supplementation can improve 28-day survival in adult critically ill patients. Secondary analysis of a large clinical database consisting over 30,000 critical ill patients was performed. Multivariable analysis was performed to examine the independent association of calcium supplementation and 28-day morality. Furthermore, propensity score matching technique was employed to investigate the role of calcium supplementation in improving survival.

INTERVENTION

none. Primary outcome was the 28-day mortality. 90-day mortality was used as secondary outcome. A total of 32,551 adult patients, including 28,062 survivors and 4489 non-survivors (28-day mortality rate: 13.8 %) were included. Calcium supplementation was independently associated with improved 28-day mortality after adjusting for confounding variables (hazard ratio: 0.51; 95 % CI 0.47-0.56). Propensity score matching was performed and the after-matching cohort showed well balanced covariates. The results showed that calcium supplementation was associated with improved 28- and 90-day mortality (p < 0.05 for both Log-rank test). In adult critically ill patients, calcium supplementation during their ICU stay improved 28-day survival. This finding supports the use of calcium supplementation in critically ill patients.

Calcium supplementation increases circulating cholesterol by reducing its catabolism via GPER and TRPC1-dependent pathway in estrogen deficient women

BACKGROUND

Limited studies have addressed the effects of calcium supplementation (CaS) on serum total cholesterol (TC) in postmenopausal women and the results are inconclusive. Moreover, the potential mechanisms through which CaS regulates cholesterol metabolism in the absence of estrogen are still sealed for the limitation of human being study.

METHODS

Cross-sectional survey, animal and in vitro experiments were conducted to investigate the effect of CaS on endogenous cholesterol metabolism in estrogen deficiency and identify its potential mechanisms. Ovariectomized rats were used to mimic estrogen deficiency. In vitro, HepG2 cell line was exposed to estradiol and/or calcium treatment.

RESULTS

We demonstrated that CaS significantly increased serum TC and the risk of hypercholesterolemia and myocardial infarction in postmenopausal women. Increased serum TC in estrogen deficiency was caused mainly by decreased cholesterol catabolism rather than increased synthesis. This was mediated by reduced 7α-hydroxylase resulting from increased liver intracellular Ca(2+) concentrations, reduced intracellular basal cAMP and subsequent up-regulation of SREBP-1c and SHP expression. Estrogen had a protective role in preventing CaS-induced TC increase by activating the G-protein coupled estrogen receptor, which mediated the estrogen effect through the transient receptor potential canonical 1 cation channel.

CONCLUSIONS

CaS increases endogenous serum TC via decreasing hepatic cholesterol catabolism in estrogen deficiency. G-protein coupled estrogen receptor is shown to be a key target in mediating CaS-induced TC increase. CaS should be monitored for the prevention of serum TC increase during menopause.

Hypocalcemic cardiomyopathy presenting as cardiogenic shock

Hypocalcemia is a less known but treatable cause for dilated cardiomyopathy, leading to severe heart failure in children. Cardiogenic shock related to hypocalcemic cardiomyopathy is a rare event. We describe 5 infants presenting with cardiogenic shock over 3 years, who were found to have severe hypocalcemia as a sole cause of myocardial dysfunction. The patients responded to calcium and vitamin D supplementation promptly and left ventricular systolic function normalized within months of treatment. In any case of cardiogenic shock, hypocalcemia should be included in the differential diagnosis and must be investigated.