Vitamin D nutritional policy needs a vision for the future

Ameliorative effect of liprotide-encapsulated vitamin D3 on blood glucose, calcium homeostasis, and vitamin D level in a vitamin D and calcium deficient rat model

Vitamin D3, recognized for its higher bioavailability and direct cell utilization, plays a vital role in the human body. Applying β-lactoglobulin with oleic acid (β-Lg-AO) as an encapsulating agent is anticipated to protect and enhance the transport of vitamin D3 to the gastrointestinal system. This study aimed to evaluate effect of liprotide-encapsulated vitamin D3 in a vitamin D-deficient rat on blood glucose, Vitamin D and calcium status. This is pre-post intervention. 24 mice were divided into 4 groups: (K-) normal rats; (K+) rat model of vitamin D and calcium deficiency; (P1) rat model of vitamin D and calcium deficiency with vitamin D3 intervention; (P2) rat model of vitamin D and calcium deficiency with liprotide-encapsulated vitamin D3 intervention. The administered dose of vitamin D3 was 180 IU (2 mL solution). Liprotide-encapsulated vitamin D3 intervention in vitamin D and calcium deficiency rats can significantly increase vitamin D (25 (OH)D) and calcium levels (p < 0.05). The increase in vitamin D (25 (OH)D) level was 53.69 ng/mL, and the increased calcium level was 4.38 mg/dL. Blood glucose levels of vitamin D-calcium deficiency rats decreased significantly (p < 0.05) by 39.87 mg/dL. Vitamin D3 encapsulated liprotide improves vitamin D and calcium in the blood more effectively than vitamin D3 without encapsulation in deficient rats.

Nonlinear correlation between serum vitamin D levels and the incidence of endometrial polyps in infertile women

STUDY QUESTION

Are serum vitamin D levels associated with the incidence of endometrial polyps (EPs) in infertile patients?

SUMMARY ANSWER

Serum 25(OH)D levels were nonlinearly correlated with the incidence of EPs in infertile women.

WHAT IS KNOWN ALREADY

EPs are a common condition that may affect the receptivity of the endometrium in women of reproductive age. Vitamin D regulates cell proliferation and differentiation, apoptosis, angiogenesis, anti-inflammation, and immunomodulation, in addition to its well-known functions in balancing calcium and phosphorus. Previous studies have shown that vitamin D concentrations are associated with reproductive outcomes, and that low vitamin D levels are associated with the incidence of colorectal polyps and nasal polyps. There is little evidence regarding the relationship between EPs and serum vitamin D levels.

STUDY DESIGN, SIZE, DURATION

We conducted a cross-sectional study using data from Guangdong Women and Children Hospital from January 2019 to October 2023, enrolling 3107 patients.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A total of 3107 infertile patients who underwent hysteroscopy were included in this study; 642 patients had endometrial polyps and 2465 had a normal uterine cavity. Hysteroscopy findings included risk of EPs, polyp size, percentage of multiple polyps, and incidence of chronic endometritis (CE). Serum vitamin D were assessed by measuring total 25(OH)D using chemiluminescence. According to international guideline recommendations for vitamin D deficiency, patients were divided into two groups: the <50 nmol/l group and the ≥50 nmol/l group. Univariable and multivariable logistic regression models, stratified analyses, and smooth curve fitting were used to examine the relationship between serum 25(OH)D levels and risk of EPs.

MAIN RESULTS AND THE ROLE OF CHANCE

Of all patients, 23.8% (740/3107) were vitamin D deficient (<50 nmol/l). The incidence of EPs was significantly higher in the 25(OH)D < 50 nmol/l group than in the ≥50 nmol/l group (24.9% vs 19.3%; P = 0.001). However, there were no differences in polyp size, proportion of multiple polyps, and presence of CE between the two groups. After controlling for confounders, 25(OH)D ≥ 50 nmol/l (compared with <50 nmol/l) was negatively associated with risk of EPs (adjusted OR, 0.733; 95% CI, 0.598-0.898). Other variables that had an impact on polyp incidence included BMI, type of infertility, CA125, and CD138-positive plasma cells. In addition, a linear regression model between age and serum 25(OH)D levels showed a positive linear association. Subgroup analyses were performed for different age groups, and the risk of EPs was significantly higher in the 25(OH)D < 50 nmol/l group than in the ≥50 nmol/l group, both in the younger subgroup (23.8% vs 19.1%) and in the older subgroup (28.0% vs 19.9%). The smooth curve fitting model showed a nonlinear correlation between 25(OH)D levels and risk of EPs (nonlinear P-value = 0.020), with an optimal threshold of 51.8 nmol/l for 25(OH)D levels. Moreover, subgroup smooth curve fitting models showed a nonlinear correlation between 25(OH)D levels and polyp risk in patients aged <35 years (nonlinear P-value = 0.010), whereas a linear correlation between 25(OH)D levels and polyp risk was found in patients aged ≥35 years (nonlinear P-value = 0.682).

LIMITATIONS, REASONS FOR CAUTION

Caution should be exercised in interpreting our findings as this is a correlational study and causality cannot be inferred from our results. In addition, because of strict inclusion and exclusion criteria, our results may not be generalizable to unselected populations, including premenopausal women or women of other races.

WIDER IMPLICATIONS OF THE FINDINGS

This study demonstrated for the first time that vitamin D deficiency is an independent risk factor for the incidence of EPs in infertile patients. Identifying modifiable risk factors (e.g. vitamin D deficiency) can help in the development of new strategies for treating polyps or to protect against polyp development. Further clinical intervention trials and laboratory studies are needed to evaluate the effect of vitamin D on the development of EPs and to elucidate the mechanisms.

STUDY FUNDING/COMPETING INTEREST(S)

The study was funded by the National Natural Science Foundation of China (82101718) and Natural Science Foundation of Guangdong Province, China (2022A1515010776). No competing interest was involved in this study.

TRIAL REGISTRATION NUMBER

N/A.

Oral vitamin D supplementation for adults with obesity undergoing bariatric surgery

BACKGROUND

Vitamin D deficiency following bariatric surgery is common and is expected to be associated with a deleterious impact on the skeleton. However, the benefits of vitamin D supplementation and the optimal dose in this population is currently unknown. The available guidelines on the topic are derived from experts' opinions, and are not evidence based.

OBJECTIVES

To compare the effects of different doses of vitamin D supplementation (low dose (less than 600 international units (IU)/day), moderate dose (600 IU/day to 3500 IU/day), high dose (greater than 3500 IU/day)) to each other or to placebo in adults living with obesity undergoing bariatric surgery.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, LILACS, two trial registries, and the reference lists of systematic reviews, articles, and health technology assessment reports without language restrictions. The last search of all databases was 27 June 2023, except Embase, which we searched on 14 August 2015.

SELECTION CRITERIA

We included randomised controlled trials or controlled clinical trials on vitamin D supplementation comparing different doses or comparing vitamin D to placebo in people undergoing bariatric surgery.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Primary outcomes were fractures and adverse events. Secondary outcomes were vitamin D status, all-cause mortality, bone mineral change, secondary hyperparathyroidism, health-related quality of life, and muscle strength. We used GRADE to assess the certainty of the evidence for each outcome in each comparison.

MAIN RESULTS

We identified five trials with 314 participants. We included three trials in the quantitative analysis. Moderate-dose vitamin D compared to placebo One trial compared moderate-dose vitamin D (3200 IU/day) to placebo. Moderate-dose vitamin D, compared to placebo, may improve vitamin D status and may result in little to no difference in the achieved parathyroid hormone level (achieved 25-hydroxyvitamin D level: mean difference (MD) 13.60 ng/mL, 95% confidence interval (CI) 7.94 to 19.26; achieved parathyroid hormone level: -6.60 pg/mL, 95% CI -17.12 to 3.92; 1 study, 79 participants; low-certainty evidence). The trial reported no adverse events in the moderate-dose vitamin D arm, but did not provide any information on adverse events in the placebo arm. There were no data on fractures, all-cause mortality, bone density change, health-related quality of life, and muscle strength. High-dose vitamin D compared to moderate-dose vitamin D Two trials in Roux-en-Y gastric bypass compared moderate-dose (equivalent dose 800 IU/day to 2000 IU/day) to high-dose (equivalent dose 5000 IU/day to 7943 IU/day) vitamin D. The evidence of high-dose vitamin D on adverse events is very uncertain (risk ratio (RR) 5.18, 95% CI 0.23 to 116.56; 2 studies, 81 participants; very low-certainty evidence). High-dose vitamin D may increase 25-hydroxyvitamin D levels compared to a moderate dose at 12 months, but the evidence is very uncertain (MD 15.55 ng/mL, 95% CI 3.50 to 27.61; I2 = 62%; 2 studies, 73 participants; very low-certainty evidence). High-dose vitamin D may have little to no effect on parathyroid hormone levels compared to a moderate dose at 12 months, but the evidence is very uncertain (MD 2.15 pg/mL, 95% CI -21.31 to 17.01; I2 = 0%; 2 studies, 72 participants; very low-certainty evidence). High-dose vitamin D may have little to no effect on mortality and bone mineral density at the lumbar spine, hip, and forearm, but the evidence is very uncertain. There were no data on fractures, health-related quality of life, or muscle strength.

AUTHORS' CONCLUSIONS

No trials reported on fractures and the evidence available on adverse events is scarce. Moderate-dose vitamin D may improve vitamin D status and may result in little to no improvement in parathyroid hormone levels compared with placebo. High-dose vitamin D supplementation (greater than 3500 IU/day) may increase 25-hydroxyvitamin D levels, and may have little to no effect on parathyroid hormone levels, compared to a moderate dose, but the evidence for both is very uncertain. The currently available limited evidence may not have a significant impact on practice. Further studies are needed to explore the impact of vitamin D supplementation on fractures, adverse events, and musculoskeletal parameters in people undergoing bariatric surgery.

Target Values for 25-Hydroxy and 1,25-Dihydroxy Vitamin D Based on Their Associations with Inflammation and Calcium-Phosphate Metabolism

Target values for 25-hydroxy vitamin D and 1,25(OH)2D or 1,25-dihydroxy vitamin D remain a topic of debate among clinicians. We analysed data collected from December 2012 to April 2020 from two cohorts. Cohort A, comprising 455,062 subjects, was used to investigate the relationship between inflammatory indicators (white blood cell [WBC] count and C-reactive protein [CRP]) and 25(OH)D/1,25(OH)2D. Cohort B, including 47,778 subjects, was used to investigate the connection between 25(OH)D/1,25(OH)2D and mineral metabolism markers (phosphate, calcium, and intact parathyroid hormone [iPTH]). Quadratic models fit best for all tested correlations, revealing U-shaped relationships between inflammatory indicators and 25(OH)D and 1,25(OH)2D. Minimal CRP and WBC counts were observed at 1,25(OH)2D levels of 60 pg/mL and at 25(OH)D levels of 32 ng/mL, as well as of 42 ng/mL, respectively. iPTH correlated inversely with both 1,25(OH)2D and 25(OH)D, while phosphate as well as calcium levels positively correlated with both vitamin D forms. Calcium-phosphate product increased sharply when 25(OH)D was more than 50 ng/mL, indicating a possible risk for vascular calcification. Multiple regression analyses confirmed that these correlations were independent of confounders. This study suggests target values for 25(OH)D between 30-50 ng/mL and for 1,25(OH)2D between 50-70 pg/mL, based particularly on their associations with inflammation but also with mineral metabolism markers. These findings contribute to the ongoing discussion around ideal levels of vitamin D but require support from independent studies with data on clinical endpoints.

Impaired Sensitivity to Thyroid Hormones Is Associated With Decreased Vitamin D Levels in the Euthyroid Population

CONTEXT

The relationship between vitamin D and thyroid profiles lacks consensus despite extensive investigations. Whether vitamin D levels correlate with thyroid hormone sensitivity remains largely unexplored.

OBJECTIVE

To explore the relationship between vitamin D levels and thyroid hormone sensitivity among euthyroid individuals.

METHODS

This study involved 6452 euthyroid participants. Clinical parameters, including TSH, free thyroxine, 25-hydroxyvitamin D [25(OH)D], and other relevant indicators were extracted from the National Health and Nutrition Examination Survey 2007-2012. To quantify thyroid hormone sensitivity, we calculated the Thyroid Feedback Quantile-based Index (TFQI), the TSH index (TSHI), and the thyrotropin thyroxine resistance index (TT4RI).

RESULTS

Subjects with impaired thyroid hormone sensitivity have decreased 25(OH)D levels (TFQI, TT4RI: P < 0.05; TSHI: P = .05574) following adjustment of confounding variables. Age-specific analysis found negative correlations between thyroid hormone sensitivity indices and 25(OH)D within the 20 to 60 years subgroup, turning positive in the 60 to 80 years subgroup. In females, thyroid hormone sensitivity indices and vitamin D levels were negatively linked, while in males, vitamin D's relationships with TFQI, TT4RI, and TSHI shifted from negative to positive when 25(OH)D levels exceeded 63.5 nmol/L, 56.7 nmol/L, and 56.7 nmol/L, respectively. Stratification by race revealed U-shaped curvilinear patterns resembling those found in the males. In body mass index (BMI) subanalysis, vitamin D had differing associations with thyroid hormone sensitivity indices: negative in the <25 kg/m2 and ≥30 kg/m2 subgroups and U-shaped in the 25-30 kg/m2 subgroup.

CONCLUSION

Impaired thyroid hormone sensitivity correlates with decreased vitamin D levels among euthyroid subjects, with associations varying by age, sex, race, and BMI.

Vitamin D intake and determinants of vitamin D status during pregnancy in The Norwegian Mother, Father and Child Cohort Study

Background

Norwegian data on vitamin D status among pregnant women indicate a moderate to high prevalence of insufficient vitamin D status (25-hydroxyvitamin D (25OHD) concentrations ≤50  nmol/L). There is a lack of population-based research on vitamin D intake and determinants of 25OHD in pregnant women from northern latitudes. The aims of this study were (1) to evaluate total vitamin D intake from both diet and supplements, (2) to investigate determinants of vitamin D status, and (3) to investigate the predicted response in vitamin D status by total vitamin D intake, in pregnant Norwegian women.

Methods

In total, 2,960 pregnant women from The Norwegian Environmental Biobank, a sub-study within The Norwegian Mother, Father and Child Cohort Study (MoBa), were included. Total vitamin D intake was estimated from a food frequency questionnaire in gestational week 22. Concentrations of plasma 25OHD was analyzed by automated chemiluminescent microparticle immunoassay method in gestational week 18. Candidate determinant variables of 25OHD were chosen using stepwise backward selection and investigated using multivariable linear regression. Predicted 25OHD by total vitamin D intake, overall and stratified by season and pre-pregnancy BMI, was explored using restricted cubic splines in an adjusted linear regression.

Results

Overall, about 61% of the women had a total vitamin D intake below the recommended intake. The main contributors to total vitamin D intake were vitamin D supplements, fish, and fortified margarine. Higher 25OHD concentrations were associated with (in descending order of the beta estimates) summer season, use of solarium, higher vitamin D intake from supplements, origin from high income country, lower pre-pregnancy BMI, higher age, higher vitamin D intake from foods, no smoking during pregnancy, higher education and energy intake. During October-May, a vitamin D intake according to the recommended intake was predicted to reach sufficient 25OHD concentrations >50  nmoL/L.

Conclusion

The findings from this study highlight the importance of the vitamin D intake, as one of few modifiable determinants, to reach sufficient 25OHD concentrations during months when dermal synthesis of vitamin D is absent.

Normal 24-hour Urine Calcium Concentrations after Long-term Daily Oral Intake of Vitamin D in Doses Ranging from 5000 to 50,000 International Units in 14 Adult Hospitalized Psychiatric Patients

Many controversies exist regarding vitamin D₃ supplementation. These include not only diseases that are responsive to vitamin D supplementation, but also the long-term safety of prolonged daily oral vitamin D₃ intake above 4000 to 10,000 International Units (IU). In particular, supplementation levels that do not result in adverse events, and the upper limits of safe serum 25-hydroxyvitamin D (25OHD) concentrations. Adverse reactions reported to occur with excessive vitamin D intake include hypercalcemia, renal failure, calcium crystal formation, undetectable parathyroid hormone concentrations, and hypercalciuria, all of which are reported to be reversible. To address the long-term safety of vitamin D supplementation, we previously reported data from patients in our hospital who have been voluntarily supplemented with vitamin D₃ ranging from 5,000 to 10,000 IU/day since July 2011 as a standard of care for the prevention and treatment of vitamin D deficiency. Historically 90% of patients have agreed to daily supplementation, with most taking 10,000 IU/day. These data indicate no evidence for hypercalcemia, renal failure, calcium crystal formation, nephrolithiasis. or undetectable parathyroid hormone concentrations in patients taking 5,000 or 10,000 IU/day for extended periods of time. As another measure for potential vitamin D toxicity, we retrospectively assessed 24-hour urine calcium excretion in 14 individuals on long-term daily oral vitamin D intake ranging from 5,000 to 50,000 IU/day to further assess the safety of supplementation using these doses. This included patients taking either 5,000 (4), 10,000 (9), or 50,000 (1) IU/day. Time on supplementation ranged from 10 to 102 months. A patient taking 400 IU/day and getting frequent sun exposure was also included. All fifteen 24-hour urine calcium measurements were normal. The current findings complement our experience with over 7000 patients in the past 13 years, indicating that prolonged daily oral intake of vitamin D₃ ranging from 5000 to 10,000 IU/day is safe.

Evaluation of vitamin D levels and biochemical markers in infants diagnosed with laryngomalacia

Background/aim

The pathology of laryngomalacia is still not clear. The aim of this study was to investigate the relationship between vitamin D levels and laryngomalacia, and to evaluate vitamin D levels according to the classification of laryngomalacia.

Materials and methods

This retrospective study was conducted in the Kahramanmaraş Sütçü İmam University Medicine Faculty's Otorhinolaryngology Clinic between June 2014 and January 2021. Laryngomalacia was classified. Laboratory tests for all patients included calcium (Ca), phosphorus (P), parathormone (PTH), blood urea nitrogen (BUN), creatinine (Cre), alanine transaminase (ALT), and 25-hydroxy vitamin D (25-OH-D).

Results

Evaluations were performed for 64 infants with laryngomalacia, including 41 male and 23 female infants with a mean age of 4.6 ± 3.0 months, and a control group of 64 healthy infants with a mean age of 4.5 ± 2.8 months. A statistically significant difference was determined between the laryngomalacia group and the control group with respect to 25-OH-D and PTH levels (p < 0.001). When data were examined according to laryngomalacia types, a statistically significant difference was determined between the groups for 25-OH-D, Ca, P, PTH, and ALT values. The 25-OH-D level was statistically significantly lower in the severe laryngomalacia group than in the mild and control groups (p < 0.001). A statistically significant difference was determined between the moderate and severe laryngomalacia groups and the control group regarding PTH levels (p < 0.001).

Conclusion

Vitamin D deficiency may have a role in the etiology of laryngomalacia, and this view is supported by the finding that there was a decrease in vitamin D levels associated with laryngomalacia classification. In addition, the reduction in PTH levels in infants with laryngomalacia may be explained by the change in Ca metabolism. It would be appropriate for further studies to investigate the response to vitamin D replacement therapy in patients with moderate and severe laryngomalacia.

Vitamin D, a Secosteroid Hormone and Its Multifunctional Receptor, Vitamin D Receptor, in Alzheimer's Type Neurodegeneration

Vitamin D is a secosteroid hormone exerting neurosteroid-like properties. Its well-known nuclear hormone receptor, and recently proposed as a mitochondrial transcription factor, vitamin D receptor, acts for its primary functions. The second receptor is an endoplasmic reticulum protein, protein disulfide isomerase A3 (PDIA3), suggested to act as a rapid response. Vitamin D has effects on various systems, particularly through calcium metabolism. Among them, the nervous system has an important place in the context of our subject. Recent studies have shown that vitamin D and its receptors have numerous effects on the nervous system. Neurodegeneration is a long-term process. Throughout a human life span, so is vitamin D deficiency. Our previous studies and others have suggested that the out-come of long-term vitamin D deficiency (hypovitaminosis D or inefficient utilization of vitamin D), may lead neurons to be vulnerable to aging and neurodegeneration. We suggest that keeping vitamin D levels at adequate levels at all stages of life, considering new approaches such as agonists that can activate vitamin D receptors, and utilizing other derivatives produced in the synthesis process with UVB are crucial when considering vitamin D-based intervention studies. Given most aspects of vitamin D, this review outlines how vitamin D and its receptors work and are involved in neurodegeneration, emphasizing Alzheimer's disease.

Vitamin D: a potentially important secosteroid for coping with COVID-19

COVID-19 is a disease that has caused a high number of deaths in the world, and despite being controlled, it requires attention and the search for new quick and economical therapeutic strategies. In this sense, vitamin D stands out, an immunomodulator that has shown beneficial effects in decreasing the risk and severity of acute respiratory tract infections, including COVID-19. Therefore, this review presents a number of experimental, observational and clinical studies on the importance of vitamin D against viral infections with an emphasis on COVID-19, highlighting the relationship between vitamin D, Renin-Angiotensin System and cytokine storms with decreased inflammatory lesions in patients with COVID-19. In addition, aspects of pathophysiology, metabolism, risk factors, sources and recommendations of vitamin D are described. We conclude that vitamin D plays a protective role against inflammatory lesions and can decrease the risk of infections and the severity of COVID-19. Therefore, it is essential to maintain adequate levels of vitamin D to avoid complications related to its deficiency.

Safety Data in Patients with Autoimmune Diseases during Treatment with High Doses of Vitamin D3 According to the “Coimbra Protocol”

Background: In 2013, the group of Cicero Coimbra, Brazil, reported the clinical efficacy of high doses of vitamin D3 in patients suffering from autoimmune skin disorders (“Coimbra protocol”, CP). However, hypercalcemia and the subsequent impaired renal function may be major concerns raised against this protocol. Methods: We report for the first time for a broad spectrum of autoimmune diseases in 319 patients (mean age (±SD) 43.3 ± 14.6 years, 65.5% female, 34.5% male) safety data for high doses of orally applied vitamin D3 (treatment period: up to 3.5 years) accompanied by a strict low-calcium diet and regular daily fluid intake of at least 2.5 L. Results: Mean vitamin D3 dose was 35,291 ± 21,791 IU per day. The measurement of more than 6100 single relevant laboratory parameters showed all mean values (±SD) within the normal range for total serum calcium (2.4 ± 0.1 mmol/L), serum creatinine (0.8 ± 0.2 mg/dL), serum creatinine associated estimated GFR (92.5 ± 17.3 mL/min), serum cystatin C (0.88 ± 0.19 mg/L), serum TSH (1.8 ± 1 mIU/L), and for 24 h urinary calcium secretion (6.9 ± 3.3 mmol/24 h). We found a very weak relationship between the dosage of oral vitamin D3 and the subsequent calcium levels, both in serum and in urinary excretion over 24 h, respectively. Conclusions: Our data show the reliable safety of the CP in autoimmune patients under appropriate supervision by experienced physicians.

Safety of High-Dose Vitamin D Supplementation Among Children Aged 0 to 6 Years: A Systematic Review and Meta-analysis

IMPORTANCE

Several health benefits of vitamin D have been suggested; however, the safety of high-dose supplementation in early childhood is not well described.

OBJECTIVE

To systematically assess the risk of adverse events after high-dose supplementation with vitamin D reported in published randomized clinical trials.

DATA SOURCES

PubMed and ClinicalTrials.gov were searched through August 24, 2021.

STUDY SELECTION

Randomized clinical trials of high-dose vitamin D supplementation in children aged 0 to 6 years, defined as greater than 1000 IU/d for infants (aged 0-1 year) and greater than 2000 IU/d for children aged 1 to 6 years.

DATA EXTRACTION AND SYNTHESIS

Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline, 2 reviewers independently extracted the data from the eligible studies. Summary risk ratio (RR), 95% CI, and P values were derived from random-effects meta-analysis.

MAIN OUTCOMES AND MEASURES

Adverse events, serious adverse events (SAEs), and/or levels of 25-hydroxyvitamin D, calcium, alkaline phosphatase, phosphate, parathyroid hormone, and/or the ratio of urine calcium to creatinine levels.

RESULTS

A total of 32 randomized clinical trials with 8400 unique participants were included. Different clinical outcomes of children receiving high-dose vitamin D supplements ranging from 1200 to 10 000 IU/d and bolus doses from 30 000 IU/week to a single dose of 600 000 IU were evaluated. Eight studies with 4612 participants were eligible for meta-analysis using a control group receiving either low-dose vitamin D supplementation (≤400 IU/d) or placebo when investigating the risk of SAEs such as hospitalization or death. No overall increased risk of SAEs in the high-dose vitamin D vs control groups was found (RR, 1.01 [95% CI, 0.73-1.39]; P = .89, I2 = 0%). In addition, risk of hypercalcemia (n = 726) was not increased (RR, 1.18 [95% CI, 0.72-1.93]; P = .51). Clinical adverse events potentially related to the vitamin D supplementation reported in the studies were rare.

CONCLUSIONS AND RELEVANCE

This meta-analysis and systematic review found that high-dose vitamin D supplementation was not associated with an increased risk of SAEs in children aged 0 to 6 years, and that clinical adverse events potentially related to the supplementation were rare. These findings suggest that vitamin D supplementation in the dose ranges of 1200 to 10 000 IU/d and bolus doses to 600 000 IU to young children may be well tolerated.

Association between serum vitamin D level and uterine fibroid in premenopausal women in Indian population

We aim to evaluate the association between serum 25-hydroxyvitamin D₃ levels and total number, volume and location of uterine fibroids (UFs) in premenopausal women in North Indian population. This case control study was undertaken in 310 women between 18 years and 45 years of age. Cases comprised of 102 women with fibroid lesion and the control group included 208 women with normal uterine morphology on ultrasonography. Blood samples were taken for measuring 25-hydroxyvitamin D₃ levels. The mean serum 25-hydroxyvitamin D₃ level in the study and control group was 14.52 ± 7.89 ng/mL and 26.6 ± 14.36 ng/mL respectively (p < 0.05). There was significant inverse correlation between serum 25-hydroxyvitamin D₃ levels and total volume of fibroids (p = 0.000) while none between 25-hydroxyvitamin D₃ levels with location, number of fibroids. 25-hydroxyvitamin D₃ deficiency was more common in the study group (54.90%) compared to healthy controls (6.7%) while sufficiency was more common among controls (67.8% vs. 27.45) (p < 0.05). Women with deficient 25-hydroxyvitamin D₃ levels have an odds of 18.36 for developing uterine fibroid. Women with low parity, those belonging to higher socioeconomic status and having less than 1-hour sun exposure per day were independently found to have high risk for development of UFs. Vitamin D may have a role in growth of UFs. Women not able to get adequate sun exposure due to indoor working conditions may need evaluation and supplementation as prophylaxis for development of fibroid.

Vitamin D: A Critical Regulator of Intestinal Physiology

Calcium is required for the functioning of numerous biological processes and is essential for skeletal health. The major source of new calcium is from the diet. The central role of vitamin D in the maintenance of calcium homeostasis is to increase the absorption of ingested calcium from the intestine. The critical importance of vitamin D in this process is noted in the causal link between vitamin D deficiency and rickets, as well as in studies using genetically modified mice including mice deficient in the vitamin D receptor (Vdr null mice) or in the cytochrome P‐450 enzyme, 25‐hydroxyvitamin D₃‐1α‐ hydroxylase (CYP27B1) that converts 25‐hydroxyvitamin D₃ to the hormonally active form of vitamin D, 1,25‐dihydroxyvitamin D₃ [1,25(OH)₂D₃] (Cyp27b1 null mice). When these mice are fed diets with high calcium and lactose, rickets is prevented. The studies using mouse models provide supporting evidence indicating that the major physiological function of 1,25(OH)₂D₃/VDR is intestinal calcium absorption. This review summarizes what is known about mechanisms involved in vitamin D‐regulated intestinal calcium absorption. Recent studies suggest that vitamin D does not affect a single entity, but that a complex network of calcium‐regulating components is involved in the process of 1,25(OH)₂D₃‐mediated active intestinal calcium absorption. In addition, numerous 1,25(OH)₂D₃ actions in the intestine have been described independent of calcium absorption. Although the translatability to humans requires further definition, an overview is presented that provides compelling evidence from the laboratory of 1,25(OH)₂D₃ intestinal effects, which include the regulation of adhesion molecules to enhance barrier function, the regulation of intestinal stem cell function, cellular homeostasis of other divalent cations, the regulation of drug metabolizing enzymes, and anti‐inflammatory effects. © 2021 The Author. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Vitamin D and Its Role in Oral Diseases Development. Scoping Review

Vitamin D is a fat-soluble secosteroid that plays a significant role in the whole body, including the maxillofacial region. The discovery of its receptors in many cells and organs made it possible to reveal the participation of vitamin D not only in the regulation of calcium phosphate metabolism, but also in immune processes, in providing anti-inflammatory and antimicrobial effects, slowing down cell proliferation and stimulating differentiation. In this literature review, we demonstrate the association between low vitamin D levels and the development of recurrent aphthous stomatitis, the course and response to treatment of squamous cell carcinoma of the oral cavity, the severity of periodontal diseases, and the processes of osseointegration and bone remodeling during dental implantation and guided tissue regeneration. The aim of our article was to demonstate a possible connection between vitamin D level and the oral diseases that can be presented at an oral surgery appointment, which will help clinicians to reduce the risk of early dental implant failure, ensure favorable outcomes of augmentative operations, as well as decrease the destructive effects of severe periodontitis and other conditions throug knowledge and timely lab tests and endocrinologist prescriptions.

Impact of bone mineral density in reducing fracture risk in patients receiving alendronate plus alfacalcidol therapy

BACKGROUD

Changes in bone mineral density (BMD) are a potential surrogate marker for fracture endpoints in clinical trials. However little is known whether the increase in BMD in response to combination treatment with alendronate plus alfacalcidol is associated with fracture risk reduction. We aimed to evaluate the impact of BMD on fracture risk in osteoporosis patients, using the data from the randomized clinical trial comparing alendronate plus alfacalcidol with alendronate alone.

METHODS

We selected 412 patients with two or more prevalent vertebral fractures and who had BMD measurements at baseline and after 6, 12, and/or 24 months out of 2022 patients from the database of the Japanese Osteoporosis Intervention Trial. Patients in this subset who received combination treatment with alendronate plus alfacalcidol had shown a lower risk of fracture than patients treated with alendronate alone. We used Poisson regression model analysis to calculate the proportion of treatment effect (PTE) that was attributable to BMD increases in patients receiving combination treatment.

RESULTS

The highest PTE attributable to changes in BMD was 1.2% in patients with a BMD increase of 3% or more in the lumbar spine. For BMD measurements of the radius, the highest PTE was 2.8% with a BMD increase of 0% or more. For BMD measurements of the metacarpal bone, the highest PTE was 1.2% with a BMD increase of 3% or more. In patients with a BMD greater than or equal to 70% of the young adult mean in the lumbar spine, the PTE attributable to BMD was 0.2%. In patients with a BMD greater than or equal to 70% of the young adult mean in the radius, the PTE attributable to BMD was 0.3%.

CONCLUSIONS

The additional effects of alfacalcidol in reducing fracture risk do not likely result from increased BMD; other mechanisms remain a possibility.

Potential Role of Natural Products to Combat Radiotherapy and Their Future Perspectives

Cancer is the second leading cause of death in the world. Chemotherapy and radiotherapy (RT) are the common cancer treatments. In addition to these limitations, the development of adverse effects from chemotherapy and RT reduces the quality of life for cancer patients. Cellular radiosensitivity, or the ability to resist and overcome cell damage caused by ionizing radiation (IR), is directly related to cancer cells' response to RT. Therefore, radiobiological research is emphasizing chemical compounds 'radiosensitization of cancer cells so that they are more reactive in the IR spectrum. Recent years researchers have seen an increase in interest in natural products that have antitumor effects with minimal side effects. Natural products, on the other hand, are easy to recover and therefore less expensive. There have been several scientific studies done based on these compounds that have tested their ability in vitro and in vivo to induce tumor radiosensitization. The role of natural products in RT, as well as their usefulness and potential applications, is the goal of this current review.

Effect of oral contraceptives on total and bioavailable 25-hydroxyvitamin D

Studies show an increase in circulating levels of 25-hydroxyvitamin D [25(OH)D] in women using combined oral contraceptives (COCs). 25(OH)D is a quantitatively important metabolite and widely used clinical marker of vitamin D status and is regulated by vitamin D binding protein (VDBP). However, studies have not identified the type of formulations used by the women, and there are no data on the effect of progestins on 25(OH)D levels. Our study objective was to compare the effects of two COC formulations [ethinyl estradiol (EE)/norethindrone acetate (NETA) vs. EE/levonorgestrel (LNG)] as well as LNG alone on total and bioavailable (free plus albumin-bound) 25(OH)D levels in serum samples collected at baseline, mid treatment, and end of treatment. Total 25(OH)D and VDBP were measured by immunoassay, and bioavailable 25(OH)D was calculated. The results show that with the EE/NETA formulation, total and bioavailable 25(OH)D and VDBP levels increased non-significantly by 7.4 %, 14.9 %, and 10 %, respectively, from baseline to end of treatment. In contrast, the corresponding changes with EE/LNG showed an increase of 4.4 % in total 25(OH)D but a significant decrease of 18.2 % in bioavailable 25(OH)D and increase of 19.1 % in VDBP. When LNG was administered alone, no significant changes were observed in total and bioavailable 25(OH)D or VDBP levels during the course of treatment. Our findings show considerably different effects on total and bioavailable 25(OH)D levels, as well as VDBP levels, with different oral contraceptive formulations. LNG may have a suppressive effect on VDBP, similar to its well-known androgenic effect on SHBG. Further studies are needed to determine the effect of hormonal contraceptive formulations on vitamin D status and its potential impact on women's health.

Antimicrobial Peptides and Physical Activity: A Great Hope against COVID 19

Antimicrobial peptides (AMPs), α- and β-defensins, possess antiviral properties. These AMPs achieve viral inhibition through different mechanisms of action. For example, they can: (i) bind directly to virions; (ii) bind to and modulate host cell-surface receptors, disrupting intracellular signaling; (iii) function as chemokines to augment and alter adaptive immune responses. Given their antiviral properties and the fact that the development of an effective coronavirus disease 2019 (COVID-19) treatment is an urgent public health priority, they and their derivatives are being explored as potential therapies against COVID-19. These explorations using various strategies, range from their direct interaction with the virus to using them as vaccine adjuvants. However, AMPs do not work in isolation, specifically in their role as potent immune modulators, where they interact with toll-like receptors (TLRs) and chemokine receptors. Both of these receptors have been shown to play roles in COVID-19 pathogenesis. In addition, it is known that a healthy lifestyle accompanied by controlled physical activity can represent a natural weapon against COVID-19. In competitive athletes, an increase in serum defensins has been shown to function as self-protection from the attack of microorganisms, consequently a controlled physical activity could act as a support to any therapies in fighting COVID-19. Therefore, including information on all these players' interactions would produce a complete picture of AMP-based therapies' response.

Association of Vitamin D Receptor Gene Polymorphisms with Serum Vitamin D Levels in a Greek Rural Population (Velestino Study)

BACKGROUND/AIM

An alarming increase in vitamin D deficiency even in sunny regions highlights the need for a better understanding of the genetic background of the vitamin D endocrine system and the molecular mechanisms of gene polymorphisms of the vitamin D receptor (VDR). In this study, the serum levels of 25(OH)D3 were correlated with common VDR polymorphisms (ApaI, BsmI, FokI, and TaqI) in 98 subjects of a Greek homogeneous rural population.

METHODS

25(OH)D3 concentration was measured by ultra-HPLC, and the VDR gene polymorphisms were identified by quantitative real-time PCR followed by amplicon high-resolution melting analysis.

RESULTS

Subjects carrying either the B BsmI (OR: 0.52, 95% CI: 0.27-0.99) or t TaqI (OR: 2.06, 95%: 1.06-3.99) allele presented twice the risk for developing vitamin D deficiency compared to the reference allele. Moreover, subjects carrying 1, 2, or all 3 of these genotypes (BB/Bb, Tt/tt, and FF) demonstrated 2-fold (OR: 2.04, 95% CI: 0.42-9.92), 3.6-fold (OR: 3.62, 95% CI: 1.07-12.2), and 7-fold (OR: 6.92, 95% CI: 1.68-28.5) increased risk for low 25(OH)D3 levels, respectively.

CONCLUSIONS

Our findings reveal a cumulative effect of specific VDR gene polymorphisms that may regulate vitamin D concentrations explaining, in part, the paradox of vitamin D deficiency in sunny regions, with important implications for precision medicine.

Oral and Topical Vitamin D, Sunshine, and UVB Phototherapy Safely Control Psoriasis in Patients with Normal Pretreatment Serum 25-Hydroxyvitamin D Concentrations: A Literature Review and Discussion of Health Implications

Vitamin D, sunshine and UVB phototherapy were first reported in the early 1900s to control psoriasis, cure rickets and cure tuberculosis (TB). Vitamin D also controlled asthma and rheumatoid arthritis with intakes ranging from 60,000 to 600,000 International Units (IU)/day. In the 1980s, interest in treating psoriasis with vitamin D rekindled. Since 1985 four different oral forms of vitamin D (D2, D3, 1-hydroxyvitaminD3 (1(OH)D3) and 1,25-dihydroxyvitaminD3 (calcitriol)) and several topical formulations have been reported safe and effective treatments for psoriasis-as has UVB phototherapy and sunshine. In this review we show that many pre-treatment serum 25(OH)D concentrations fall within the current range of normal, while many post-treatment concentrations fall outside the upper limit of this normal (100 ng/mL). Yet, psoriasis patients showed significant clinical improvement without complications using these treatments. Current estimates of vitamin D sufficiency appear to underestimate serum 25(OH)D concentrations required for optimal health in psoriasis patients, while concentrations associated with adverse events appear to be much higher than current estimates of safe serum 25(OH)D concentrations. Based on these observations, the therapeutic index for vitamin D needs to be reexamined in the treatment of psoriasis and other diseases strongly linked to vitamin D deficiency, including COVID-19 infections, which may also improve safely with sufficient vitamin D intake or UVB exposure.

Vitamin D and Kidney Diseases: A Narrative Review

Vitamin D (Vit. D) is among the most important elements of the human body that play pivotal roles in health and disease. It belongs to the fat-soluble secosteroid family, which is provided by either foods or direct exposure to sunlight that converts 7-hydroxycholesterol to the Vit. D precursor. An alternative step is bio-activation, which delivers an active form of Vit. D (Vit. D3), which participates in various noticeable functions including calcium regulation, bone remodeling, fertility, glucose control, and detoxification. The most recent literature is carefully reviewed (2049 articles) and the relative information was collected and discussed meticulously. Inclusion criteria were the articles that mentioned the relationship between Vit. D, adipokine, and kidney disease and exclusion criteria were nonrelevant articles. Vit. D plays several roles in the normal function of the kidney and metabolism. It has been revealed that Vit. D has a crucial impact on kidney disease and that its deficiency leads to kidney dysfunction and further renal disorder. Apart from the direct relationship of Vit. D with kidney disease, the association of adipocytes and adipokines with Vit. D and kidney function has also been studied. The noticeable role of Vit. D in kidney disease is investigated in various studies. It has been found that Vit. D has a pivotal role in kidney function and metabolism. Further study can reveal the better-detailed information about the exact relation of Vit. D and kidney disorders. The aim of the review was to provide a better insight into the exact role of Vit. D and adipokine in the kidney disease.

Intake of 25-Hydroxyvitamin D3 May Reduce the Severity of Upper Respiratory Tract Infection: Post hoc Analysis of a Randomized, Double-Blind, Placebo-Controlled, Parallel Group Comparison Study

To evaluate the effects of 25-hydroxyvitamin D₃ (25OHD) on symptoms at the onset of the upper respiratory tract infection (URTI) in subjects with insufficient or deficient serum 25-hydroxyvitamin D levels, we conducted a post hoc analysis of data from a randomized, placebo-controlled study; the subjects received 10 μg of 25OHD per day or a placebo for 16 weeks. The Wisconsin Upper Respiratory Symptom Survey-21 was used to determine URTI. The study endpoints included WURSS-21 scores, number of URTI events, and proportion of medication (antibiotics, antipyretic analgesics) usage. We found that the physical symptom scores for "Runny nose," "Sneezing," and "Head congestion" were significantly lower in the 25OHD group than in the placebo group; for all items except "Breathe easily, "the quality of life" scores were significantly improved in the 25OHD group. There was no significant difference in the number of URTI events or the proportion of medication use between the groups. Collectively, the findings of this study indicate that a sufficient 25OHD intake can reduce physical symptoms at the onset of upper respiratory tract infection, particularly nasal symptoms, and may improve the quality of life at the time of onset.

Is it reasonable to ignore vitamin D status for musculoskeletal health?

Severe vitamin D deficiency—25-hydroxyvitamin D (25OHD) concentrations below around 25–30 nmol/L—may lead to growth plate disorganization and mineralization abnormalities in children (rickets) and mineralization defects throughout the skeleton (osteomalacia) and proximal muscle weakness. Both problems are reversed with vitamin D treatment. Apart from this musculoskeletal dysfunction at very low vitamin D levels, there is apparent inconsistency in the available data about whether concentrations of 25OHD below around 50 nmol/L cause muscle function impairment and increase the risk of fracture. This narrative review provides evidence to support the contention that improving vitamin D status, up to around 50 nmol/L, plays a small causal role in optimizing bone and muscle function as well as reducing overall mortality.

Vitamin D deficiency as the risk of respiratory tract infections in the institutionalized elderly: A prospective 1-year cohort study

BACKGROUND & AIMS

Respiratory tract infections (RTIs) are one of the major causes of morbidity and mortality in the elderly. Since vitamin D is known to play important roles in immunity, and its deficiency has been reported to be prevalent in the elderly, we have studied the relationship between serum 25-hydroxyvitamin D [25(OH)D] level, which is the most reliable marker for vitamin D status, and the incidence of RTIs in the institutionalized elderly by a prospective observational study.

METHODS

From 208 Japanese subjects aged 60 and older fulfilling the inclusion criteria, 148 subjects remained after propensity score matching. Data were obtained from the medical records including their age, gender, histories of co-morbidities and medications, the incidence of acute RTIs including pneumonia. Measurement of serum 25(OH)D level and assessment of nutrients intake including vitamin D were done at baseline. Cox's proportional hazard analysis was performed to assess the significant predictors for RTIs during the follow-up period.

RESULTS

The median observation duration was 354.2 days, and the incidence of RTIs was 75.8 person-years. Subjects with RTIs had significantly lower serum 25(OH)D concentration, and a higher prevalence of vitamin D deficiency (25(OH)D < 10 ng/mL). Cox's proportional hazard analysis revealed that vitamin D deficiency was a significant predictor for RTIs.

CONCLUSIONS

Our results suggested that vitamin D deficiency was a significant predictor for an increased incidence of RTIs in institutionalized elderly, and the necessity of vitamin D supplementation for the prevention of RTIs was considered.

Vitamin D toxicity in a pediatric toxicological referral center; a cross-sectional study from Iran

Background

Vitamin D is an essential element for body health with its supplements generally administered to prevent vitamin D deficiency. Since these supplements are available in domestic settings, vitamin D toxicity may happen in children.

Methods

All children younger than 12 years who presented to the pediatric emergency department of Loghman Hakim Hospital, Tehran, Iran with history of ingestion of more than 1500 IU/day of vitamin D supplements were enrolled. Patients’ demographic data, on-presentation signs and symptoms, laboratory findings, treatments given, and outcome were evaluated.

Result

Fifteen patients presented during the study period. Their mean age was 46.53 ± 10.14 months and 12 (80%) were girls. All of them had unintentionally ingested vitamin D. Mean ingested dose was 406700.7 ± 227400.1 IU. In eight patients (53.3%), 25 hydroxy vitamin D level was more than 100 ng/mL. One patient experienced hypercalcemia while all of them were asymptomatic and discharged without complications. There was no significant difference between patients with and without high levels of 25 OH vitamin D regarding lab tests, toxicity course, and outcome.

Conclusions

It seems that acute vitamin D toxicity is a benign condition in our pediatric population which may be due to high prevalence of vitamin D deficiency in Iran.

Vitamin D Status and Vitamin D-Dependent Apoptosis in Obesity

The role of vitamin D in obesity appears to be linked to vitamin D insufficient/deficient status. However, mechanistic understanding of the role of vitamin D in obesity is lacking. We have shown earlier that the vitamin D hormonal form, 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃), induces cell death by apoptosis in mature adipocytes. This effect of the hormone is mediated by the cellular Ca²⁺ signaling pathway: a sustained increase of intracellular (cytosolic) Ca²⁺ concentration followed by activation of Ca²⁺-dependent initiators and effectors of apoptosis. In recent animal studies, we demonstrated that low vitamin D status is observed in diet-induced obesity (DIO). High intake of vitamin D₃ in DIO decreased the weight of white adipose tissue and improved biomarkers related to adiposity and Ca²⁺ regulation. The anti-obesity effect of vitamin D (1,25(OH)₂D₃) in DIO was determined by the induction of Ca²⁺-mediated apoptosis in mature adipocytes executed by Ca²⁺-dependent apoptotic proteases (calpains and caspases). Thus, a high intake of vitamin D in obesity increases vitamin D nutritional status and normalizes vitamin D hormonal status that is accompanied by the reduction of adiposity. Overall, our findings imply that vitamin D may contribute to the prevention of obesity and obesity-related diseases and that the mechanism of the anti-obesity effect of 1,25(OH)₂D₃ includes induction of Ca²⁺-mediated apoptosis in adipocytes.

The Vitamin D Assessment (ViDA) study - Design and main findings

Accumulating evidence from observational studies indicates that vitamin D status is inversely associated with a many non-skeletal diseases. This has initiated the conduct of several large clinical trials to determine if high dose vitamin D supplementation (≥ 2000 IU/day or monthly equivalent) prevents non-skeletal disease including cardiovascular disease, cancer and mortality. One of these trials is the Vitamin D Assessment (ViDA) Study which recruited 5110 participants, aged 50-84 years, mostly from primary care practices in Auckland, New Zealand. The intervention was a capsule that contained either 100,000 IU vitamin D3 or placebo, two of which were taken by each participant soon after randomization, and then monthly up to 31 July 2015 (median follow-up 3.3 years). Information on study outcomes came from self-completed questionnaires and health data collected routinely by the Ministry of Health. There was no effect of vitamin D on the main outcomes: cardiovascular disease, acute respiratory infections, non-vertebral fractures, falls and all cancer. In contrast, vitamin D increased persistence with taking statins among participants on long term statin therapy. Beneficial effects were seen also for lung function among ever smokers (especially if vitamin D deficient), and in participants with low 25-hydroxyvitamin D levels for bone mineral density and arterial function. The findings support future research being carried out mainly in people who are vitamin D deficient, although there are practical and ethical issues in recruiting such people into future vitamin D supplementation trials.

Serum vitamin D levels among children aged 0-12 years in the First Affiliated Hospital of Harbin Medical University, China

Background

Vitamin D deficiency (VDD) and vitamin D insufficiency (VDI) are highly prevalent in the world, but the vitamin D status of children in northeast China is seldom investigated. The aim of this study was to clarify the prevalence of VDD and VDI among children in the First Affiliated Hospital of Harbin Medical University in Heilongjiang province in China.

Methods

We collected data from 9795 children who were outpatients aged 0-12 years who visited the First Affiliated Hospital of Harbin Medical University from September 2014 to August 2016. Serum 25-hydroxy vitamin D [25(OH)D] levels were determined by chemiluminescent immunoassay and categorized as <20, 20-30 and >30 ng/mL.

Results

The highest mean level of serum 25(OH)D was found at the 1-3 years stage (31.14 ng/mL) and the lowest at 6-12 years stage (18.58 ng/mL). The mean serum 25(OH)D level among school girls (17.86 ng/mL) was lower than that of boys (19.12 ng/mL). The prevalence of vitamin D sufficiency during 2014 was only 17.2%, but increased to ~45% in 2016.

Conclusions

The prevalence of VDD and insufficiency among children in the First Affiliated Hospital of Harbin Medical University is high, especially among children aged 6-12 years.

Calcifediol Decreases Interleukin-6 Secretion by Cultured Human Trophoblasts From GDM Pregnancies

Gestational diabetes mellitus (GDM) is often characterized by low maternal calcifediol (25OHD) and high inflammation levels. This study aimed to determine whether placental protein expressions of CYP27B1, vitamin D receptor (VDR), and CYP24A1 are impaired in GDM and to investigate the effect of a 25OHD treatment on IL-6 secretion by GDM trophoblasts compared with normoglycemic (NG) trophoblasts. Placental tissue samples were harvested to determine protein expression of CYP27B1, VDR, and CYP24A1 by immunoblots. Isolated trophoblasts were stimulated with 25OHD concentrations (25 to 2000 nM) once a day for 3 days and IL-6 secretion was quantified (ELISA). We recruited 17 NG women, 19 women with GDM treated with diet and exercise alone (GDM-d) and 9 women with GDM who necessitated insulin therapy (GDM-i). Protein expressions of CYP27B1 and VDR were significantly higher in placental tissue from GDM-d women compared with NG women (both P = 0.02), whereas no differences were detected between GDM-i and NG placental tissues. In cultured trophoblasts (two groups; n = 5 NG and n = 5 GDM-d), exposure to increasing 25OHD concentrations significantly decreased IL-6 secretion in the GDM-d group only (P = 0.006). After treatment with 25OHD (2000 nM), IL-6 secretion was lower in the GDM-d group compared with the NG group (P = 0.03). Our results suggest an upregulation of the VDR-1,25(OH)2D complex bioavailability in GDM-d placentas, possibly reflecting a compensatory mechanism aiming to ensure that vitamin D can exert its genomic and nongenomic effects in the target cells of the placental-fetal unit. Our findings support an anti-inflammatory effect of vitamin D at the feto-maternal interface in GDM-d pregnancies.

The Protective Role of Calbindin-D9k on Endoplasmic Reticulum Stress-Induced Beta Cell Death

Intracellular calcium ion content is tightly regulated for the maintenance of cellular functions and cell survival. Calbindin-D_9k (CaBP-9k) is responsible for regulating the distribution of cytosolic free-calcium ions. In this study, we aimed to investigate the effect of CaBP-9k on cell survival in pancreatic beta cells. Six-month-old wildtype CaBP-9k, CaBP-28k, and CaBP-9k/28k knockout (KO) mice were used to compare the pathological phenotypes of calcium-binding protein-deleted mice. Subsequently, the endoplasmic reticulum (ER) stress reducer tauroursodeoxycholic acid (TUDCA) was administered to wildtype and CaBP-9k KO mice. In vitro assessment of the role of CaBP-9k was performed following CaBP-9k overexpression and treatment with the ER stress inducer thapsigargin. Six-month-old CaBP-9k KO mice showed reduced islet volume and up-regulation of cell death markers resulting from ER stress, which led to pancreatic beta cell death. TUDCA treatment recovered islet volume, serum insulin level, and abdominal fat storage by CaBP-9k ablation. CaBP-9k overexpression elevated insulin secretion and recovered thapsigargin-induced ER stress in the INS-1E cell line. The results of this study show that CaBP-9k can protect pancreatic beta cell survival from ER stress and contribute to glucose homeostasis, which can reduce the risk of type 1 diabetes and provide the molecular basis for calcium supplementation to diabetic patients.

Scope and limitations of nuclear magnetic resonance techniques for characterisation and quantitation of vitamin D in complex mixtures

BACKGROUND

The accurate determination of vitamin D in skin is of considerable importance in evaluating penetration of skin health products through the different layers of the skin.

OBJECTIVE

We report on the characterisation and quantitation of vitamin D in an idealised sample and in complex mixtures which mimic that of a typical skin cream, using qNMR, 2D NMR and DOSY techniques.

METHODS

The characterisation and quantitation conditions were acquired over several heterogeneous samples, allowing for analysis of how the dynamic range and complexity of the different sample mixtures affect the limits of detection (LOD) and limits of quantitation (LOQ) of vitamin D. NMR is of particular value to this task as it is non-destructive, uses a primary ratio method for quantification, and tolerates a wide variety of hydrophilic and hydrophobic components within a given matrix.

RESULTS

In this investigation, we have attained a trueness level <10%, repeatability values of <1% and brought the limit of quantitation down to 100 nmol/L (≈limit of baseline range of vitamin D₂ and D₃ per litre seen in vivo), commenting on the limitations observed, such as peak overlap and sensitivity limits.

CONCLUSIONS

Pure shift optimised sequences allow us to reduce peak overlapping, allowing further characterisation of individual compounds and the separation of complex mixtures using NMR.

Daily oral dosing of vitamin D3 using 5000 TO 50,000 international units a day in long-term hospitalized patients: Insights from a seven year experience

Vitamin D3 is a secosteroid hormone produced in the skin in amounts estimated up to 25,000 international units (IUs) a day by the action of UVB radiation on 7-dehydrocholesterol. Vitamin D deficiency is common due to both lack of adequate sun exposure to the skin, and because vitamin D is present in very few food sources. Deficiency is strongly linked to increased risk for a multitude of diseases, several of which have historically been shown to improve dramatically with either adequate UVB exposure to the skin, or to oral or topical supplementation with vitamin D. These diseases include asthma, psoriasis, rheumatoid arthritis, rickets and tuberculosis. All patients in our hospital have been routinely screened on admission for vitamin D deficiency since July 2011, and offered supplementation to either correct or prevent deficiency. During this time, we have admitted over 4700 patients, the vast majority of whom agreed to supplementation with either 5000 or 10,000 IUs/day. Due to disease concerns, a few agreed to larger amounts, ranging from 20,000 to 50,000 IUs/day. There have been no cases of vitamin D3 induced hypercalcemia or any adverse events attributable to vitamin D3 supplementation in any patient. Three patients with psoriasis showed marked clinical improvement in their skin using 20,000 to 50,000 IUs/day. Analysis of 777 recently tested patients (new and long-term) not on D3 revealed 28.7% with 25-hydroxyvitaminD3 (25OHD3) blood levels < 20 ng/ml, 64.1% < 30 ng/ml, a mean 25OHD3 level of 27.1 ng/ml, with a range from 4.9 to 74.8 ng/ml. Analysis of 418 inpatients on D3 long enough to develop 25OHD3 blood levels > 74.4 ng/ml showed a mean 25OHD3 level of 118.9 ng/ml, with a range from 74.4 to 384.8 ng/ml. The average serum calcium level in these 2 groups was 9.5 (no D3) vs 9.6 (D3), with ranges of 8.4 to 10.7 (no D3) vs 8.6 to 10.7 mg/dl (D3), after excluding patients with other causes of hypercalcemia. The average intact parathyroid hormone levels were 24.2 pg/ml (D3) vs. 30.2 pg/ml (no D3). In summary, long-term supplementation with vitamin D3 in doses ranging from 5000 to 50,000 IUs/day appears to be safe.

Congenital laryngomalacia: Is it an inflammatory disease? The role of vitamin D

OBJECTIVES/HYPOTHESIS

Laryngomalacia is the most common cause of stridor in infants. The exact pathophysiology is still not well understood. Our objective was to investigate whether laryngomalacia is an inflammatory disease, focusing on the possible role of vitamin D.

STUDY DESIGN

Case-control study.

METHODS

Sixty Egyptian infants and 60 mothers were included in this study. They were divided into four equal groups (n = 30 for each): infants with laryngomalacia (LM-infants), control infants (C-infants), mothers of the infants with laryngomalacia (LM-mothers), and mothers of the control infants (C-mothers). Laryngoscopy was performed and serum 25-hydroxyvitamin D (25[OH]-vitamin-D) and interleukin 6 (IL-6) were estimated.

RESULTS

Significant increase of serum IL-6 associated with a significant decrease in serum 25(OH)-vitamin D was observed in the LM-infants compared to the C-infants (P < .001 for both). LM-mothers had significantly lower 25(OH)-vitamin D status compared to C-mothers (P < .001).

CONCLUSIONS

Deficiency of 25(OH)-vitamin D in LM-infants may result in dysregulation of the immune responses with elevation of a proinflammatory cytokine (IL-6). Laryngomalacia could be an inflammatory disease due to 25(OH)-vitamin D deficiency as evidenced by the high level of IL-6. This finding may open the door to the appropriate prevention, diagnosis, and treatment, especially for moderate to severe laryngomalacia.

LEVEL OF EVIDENCE

3b Laryngoscope, 130:448-453, 2020.

Low serum 25-hydroxyvitamin D increases cognitive impairment in elderly people

It has been reported that many elderly people have low serum levels of 25-hydroxyvitamin D [25(OH)D] and that serum 25(OH)D levels may have a relationship with cognitive function. The aim of this study was to examine the relationship between serum 25(OH)D levels and cognitive function in a Japanese population. This cross-sectional study was performed as a part of the Project in Sado for Total Health (PROST). The PROST study evaluated cognitive state and serum vitamin D level from June 2011 to November 2013 for 740 patients (431 men and 309 women). The Mini-Mental State Examination-Japanese version (MMSE-J) and serum 25(OH)D level measurements were used as assessment tools. Cognitive impairment was defined using MMSE-J ≤ 23 as a cutoff. Multiple logistic regression analyses were performed to calculate the odds ratios (ORs) for low MMSE-J scores. The average subject age was 68.1 years, the average MMSE- J score was 25.9, and the average 25(OH)D level was 24.6 ng/mL. Significant ORs for cognitive impairment were observed for both high age and low serum 25(OH)D. The adjusted OR for the lowest versus highest serum 25(OH)D quartiles was 2.70 (95% confidence interval 1.38-5.28, P = 0.0110). Low serum 25(OH)D levels were independently associated with a higher prevalence of cognitive impairment.

Vitamin D basis of Alzheimer's disease: from genetics to biomarkers

Alzheimer's disease (AD) is a progressive neurodegenerative disorder seen mostly in the elderly population. While to date AD research has focused on either neurochemical disruptions, genetic studies, or the pathological hallmarks, little has been done to establish a novel approach that would encompass all three aspects, one that would overcome the current barriers in AD research and determine the cause of AD and, eventually, discover a treatment. Meanwhile, there have been strong indications in recent years that vitamin D, a secosteroid hormone, and its receptors are fundamentally involved in neurodegenerative mechanisms. Observational studies have pointed to vitamin D deficiency as a genetic risk factor for AD, Parkinson's disease (PD), vascular dementia, and multiple sclerosis (MS), as well as other neurological disorders, brought about by alterations in genes involved in metabolism, transportation, and actions of vitamin D. Molecular studies have demonstrated that vitamin D treatments prevent amyloid production while also increasing its clearance from the brain in AD. Finally, recent vitamin D intervention studies have reported significant improvement in cognitive performance in subjects with senile dementia, mild cognitive impairment, and AD. This review aims to describe how a vitamin D research strategy, fully integrating all aspects of present-day AD research, would elucidate the genetic, molecular, and biochemical background of the disease.

Is Vitamin D3 Transdermal Formulation Feasible? An Ex Vivo Skin Retention and Permeation

Vitamin D₃ supplementation is important to prevent and treat hypovitaminosis that is a worldwide public health issue. Most types of supplementation are by oral route or fortification foods. The alternative route must be investigated, as transdermal route, for people with fat malabsorption or other diseases that impair the absorption of vitamin D₃. This study focused on verifying the feasibleness of vitamin D₃ skin retention and permeation with the presence of chemical penetration enhancers (soybean lecithin, isopropyl palmitate, propylene glycol, ethoxydiglycol, and cereal alcohol) at different pharmaceutical forms (gel and cream) through a human skin. The integrity of skin was evaluated by transepidermal water loss (TEWL) during the skin retention and permeation test. The combination of chemical penetration enhancers presented in cream did not compromise the skin, different from the gel that association of cereal alcohol and propylene glycol compromised the skin in 24 h. Gel formulation showed vitamin D₃ detection at stratum corneum in 4 h and at epidermis and dermis in 24 h. Vitamin D₃ demonstrated an affinity with the vehicle in the cream formulation and was detected at the skin surface. No active was found at receptor fluid for both formulations. In conclusion, the vitamin D₃ did not indicate feasibleness for transdermal use probably due to its physical-chemical characteristics such as high lipophilicity since it was not permeated through a human skin. Nevertheless, the transdermal route should be continuously investigated with less lipophilic derivates of vitamin D₃ and with different combination of penetration enhancers.

Calcium homeostasis in diabetes mellitus

Diabetes mellitus (DM) is becoming a lifestyle-related pandemic disease. Diabetic patients frequently develop electrolyte disorders, especially diabetic ketoacidosis or nonketotic hyperglycemic hyperosmolar syndrome. Such patients show characteristic potassium, magnesium, phosphate, and calcium depletion. In this review, we discuss a homeostatic mechanism that links calcium and DM. We also provide a synthesis of the evidence in favor or against this linking mechanism by presenting recent clinical indications, mainly from veterinary research. There are consistent results supporting the use of calcium and vitamin D supplementation to reduce the risk of DM. Clinical trials support a marginal reduction in circulating lipids, and some meta-analyses support an increase in insulin sensitivity, following vitamin D supplementation. This review provides an overview of the calcium and vitamin D disturbances occurring in DM and describes the underlying mechanisms. Such elucidation will help indicate potential pathophysiology-based precautionary and therapeutic approaches and contribute to lowering the incidence of DM.

Prognostic Significance of Serum Vitamin D Levels in Egyptian Females with Breast Cancer

Objective:

To determine the frequency and prognostic significance of vitamin D deficiency in Egyptian women with breast cancer (BC).

Methods:

This prospective study included 50 women with primary invasive, non-metastatic BC. The serum level of 25-hydroxy vitamin D [25(OH)D was measured by ELISA at diagnosis, before any cancer treatment. Vitamin D deficiency was defined as 25(OH) D<20 ng/mL. Patients were followed up for a median of 30 months (range: 18-48).

Results:

The median level of 25(OH)D was 29.0 ng/mL (range: 10.0-55.0 ng/mL). Fifteen patients (30%) had vitamin D deficiency, which was positively associated with larger tumor size (p < 0.001), higher grade (p = 0.014), advanced stage (p = 0.001), lymph node positivity (p = 0.012), and HER2/neureceptor expression (p = 0.002). It was also linked with worse overall survival (OS) and disease free survival (DFS) (p = 0.026, and p = 0.004, respectively). On multivariate analysis, DFS was independently affected by vitamin D deficiency with an HR of 2.8 (95%CI: 1.6-7.0, p = 0.022) and advanced stage, i.e. stage II had worse survival compared to stage I with an HR of 4.8 (95%CI:1.1-21.7, p = 0.042).

Conclusion:

Vitamin D deficiency had a negative effect on overall and disease-free survival in our breast cancer cases, being related to tumor size, stage, grade, nodal status and HER2/neu receptor expression.

Serum Concentrations of 25-Hydroxyvitamin D and Depression in a General Middle-Aged to Elderly Population in Finland

OBJECTIVES

Low concentrations of serum 25-hydroxyvitamin D [25(OH)D] have been postulated to associate with an increased prevalence of depression. As there are a limited number of publications on this issue, we examined the association between serum 25(OH)D and depression in a general middle-aged or older population.

DESIGN

A population-based cross-sectional study.

SETTING AND PARTICIPANTS

A total of 1602 men and women from the population-based Kuopio Ischaemic Heart Disease Risk Factor Study (KIHD) in Eastern Finland, aged 53-73 y in 1998-2001, were analysed.

MEASUREMENTS

Depressive symptoms were assessed with the DSM-III depression scale, and those individuals who had scores over 4 (range 0-12) or had reported undergoing current antidepressant therapy, were considered as suffering from depression. Associations were estimated in serum 25(OH)D tertiles using logistic regression.

RESULTS

Among the participants, 183 subjects (11.4%) were considered to have depression. The mean age of the subjects was 62.6 years (SD 6.4, range 53.4-73.8 years). The mean serum 25(OH)D concentration was 43.8 nmol/L (SD 17.7, range 8.5-112.8 nmol/L), concentrations <50 nmol/L were observed in 65.0% of the subjects, and only 5.0% displayed concentrations ≥75 nmol/L. After multivariable adjustments, the odds ratios for having depression in the tertiles (from highest to the lowest) of serum 25(OH)D were 1, 1.35 (95 % CI: 0.87, 2.09) and 1.64 (95 % CI: 1.03, 2.59), P for trend=0.036.

CONCLUSION

These findings indicate that a lower concentration of serum 25(OH)D is associated with a higher prevalence of depression in an elderly general population.

Intake of 25-Hydroxyvitamin D3 Reduces Duration and Severity of Upper Respiratory Tract Infection: A Randomized, Double-Blind, Placebo-Controlled, Parallel Group Comparison Study

OBJECTIVES

This study aimed to assess the effect of 25-hydroxyvitamin D3 (25OHD) which is a hydroxide of vitamin D3 ingestion on upper respiratory tract infection (URTI).

DESIGN AND SETTING

A prospective, randomized, double-blind, placebo-controlled study was performed from December 2015 to September 2016 in the Nihonbashi Egawa Clinic, Kei Medical Office TOC Building Medical Clinic, and Medical Corporation Kaiseikai Kita-Shinyokohama Medical Clinic, in Japan.

PARTICIPANTS

Four hundred twenty eight participants aged 45-74 years were screened by their serum 25-hydoroxyvitamin D concentration.

INTERVENTION

The participants were randomized to either 25OHD (10 μg/day) or placebo capsule, daily, for 16 consecutive weeks.

MEASUREMENTS

The primary outcome measure was the incidence proportion of URTI, and the secondary outcome measures were the physical severity score, the quality-of-life (QOL) score, the duration of URTI, and the incidence proportion of new URTI events every four weeks. Data were collected using cold diary Wisconsin Upper Respiratory Symptom Survey-21 (WURSS-21) during the intervention.

RESULTS

Of 428 participants screened, 252 with serum 25-hydroxyvitamn D levels were deficient or insufficient (75 nmol/L or less) were enrolled in this study. Of these, 105 placebo and 110 25OHD group subjects completed the study. For the incidence proportion of URTI, no effect of 25OHD intake was observed. On the other hand, the duration of URTI was shorter in the 25OHD (P = 0.061) compared to placebo. For the incidence proportion of URTI every four weeks, the incidence of new URTI was decreased in both groups over the time of intake. However, when the 25OHD and the placebo were compared, a decrease in the incidence proportion of URTI was seen earlier in the 25OHD. When the total physical severity score and the total QOL score during the study were assessed, they both were significantly improved in the 25OHD compared to placebo.

CONCLUSIONS

The intake of 25OHD may reduce the duration of URTI, the physical severity, and the QOL when suffering from URTI.

Low vitamin D status in relation to cardiovascular disease and mortality in Swedish women - Effect of extended follow-up

BACKGROUND AND AIMS

The impact of vitamin D concentrations on subsequent cardiovascular disease (CVD) and overall mortality has been generally examined for periods under two decades. The magnitude of the association may depend on follow-up length. We aimed to investigate the relationship between baseline vitamin D and risk of total CVD, stroke and all-cause mortality over three decades of follow-up. Secondly, we aimed to assess how follow-up affects the associations.

METHODS AND RESULTS

Concentrations of 25-hydroxyvitamin D (25D) were measured in a population-based sample of 1227 middle-aged women using serum collected at baseline and categorized into low (lowest 25D quartile) vs high 25D status (upper three 25D quartiles). Hazard ratio (HR) of the endpoints was estimated for low 25D. The impact of follow-up was examined in intermediary analyses where follow-up was interrupted up to four times, each time decreasing it by five years. There were 596 cardiovascular events and 635 participants died. During the first 17 years, the low 25D group experienced a 29% higher CVD risk and 3.3-fold higher stroke risk after accounting for confounders. Longer follow-up diminished significantly these risks and 25D status had no contribution at 32 years. For mortality, the decline over time was less dramatic, with HR = 1.96 (1.25; 3.08) at 17 years and HR = 1.42 (1.17; 1.72) at 37 years.

CONCLUSION

Low 25D status increased the risk for all endpoints, but a lengthy follow-up diminished these risks towards the null. The impact of follow-up depends on the outcome. Future studies of 25D and disease should use repeated 25D assessments.

Results of daily oral dosing with up to 60,000 international units (iu) of vitamin D3 for 2 to 6 years in 3 adult males

In the 1930's and 1940's, vitamin D was reported to be an effective treatment for a number of diseases, including asthma, psoriasis, rheumatoid arthritis, rickets and tuberculosis. High doses were used, 60,000 to 300,000 IU a day for asthma, and 200,000 to 600,000 IU a day for rheumatoid arthritis. Toxicity from hypercalcemia occurred after prolonged oral dosing with these supraphysiologic doses. Assays for measuring vitamin D in the blood were not available, and blood levels of vitamin D associated with hypercalcemia were unknown. A 2011 report on vitamin D toxicity showed that hypercalcemia resolved when 25-hydroxyvitamin D (25OHD) blood levels dropped below 400ng/ml in 2 patients with blood levels ranging from 645ng/ml to 1220ng/ml after accidental ingestion of massive doses of vitamin D. We now know that vitamin D is made in the skin in amounts ranging up to 25,000 IU a day with exposure to UVB radiation. There is little data on the safety and blood levels of 25OHD and calcium after prolonged daily intake of amounts of vitamin D in this range. In this report, one subject took increasing daily doses of vitamin D3 for 6 years starting in April 2009: 6500 IU for 6 months; increasing to 10,000 IU for 13 months; 20,000 IU for 24 months; 40,000 IU for 12 months; 50,000 IU for 10 months, and 60,000 IU since October 2014. 25OHD blood levels were 28, 81, 204, 216, 225, 166, and 218ng/ml. Subject 2 began 10,000 IU in Nov 2011, increased to 20,000 IU in Feb 2014, 25,000 IU in June 2014, and 30,000 IU in Oct 2014, and then decreased to 20,000 IU in June 2015. 25OHD blood levels were 96.6, 161.1 and 106.9ng/ml. He reported marked clinical improvement in his asthma. Subject 3 started on daily 10,000 IU in Sept 2013, increasing to 20,000 IU on Nov 2013. 25OHD blood levels were 31.4, 102, 164, 148, and 143ng/ml. No one developed hypercalcemia or any adverse events. The major finding of this case series is prolonged daily dosing of vitamin D3 with doses of 10,000 to 60,000 IU was safely tolerated.

Vitamin D supplementation in cutaneous malignant melanoma outcome (ViDMe): a randomized controlled trial

BACKGROUND

Previous studies have investigated the protective effect of vitamin D serum levels, at diagnosis and during the follow-up period after treatment, on melanoma outcome. In the present study we assess whether vitamin D supplementation, in the follow-up period after diagnosis and surgical resection of the primary tumor, has a protective effect on relapse of cutaneous malignant melanoma and whether this protective effect correlates with vitamin D levels in serum and Vitamin D Receptor immunoreactivity in the primary tumor.

METHODS/DESIGN

This study is a multicenter randomized double blind placebo- controlled phase III trial. Patients between the age of 18 and 80 years diagnosed and treated surgically for a melanoma stage IB-III are eligible for randomization in a 1:1 ratio to active treatment or placebo. The study drug is taken each month and consists of either 100,000 International Unit cholecalciferol or arachidis oleum raffinatum used as a placebo. The primary endpoint is relapse free survival. The secondary endpoints are 25 hydroxyvitamin D3 serum levels at diagnosis and at 6 month intervals, melanoma subtype, melanoma site and stage of melanoma at diagnosis according to the 2009 American Joint Committee on Cancer melanoma staging and classification. At randomization a bloodsample is taken for DNA analysis. The study is approved by the local Ethics Committees.

DISCUSSION

If we can confirm our hypothesis that vitamin D supplementation after removal of the tumor has a protective effect on relapse of cutaneous malignant melanoma we may reduce the burden of CMM at several levels. Patients, diagnosed with melanoma may have a better clinical outcome and improved quality of life. There will be a decrease in health care costs related to treatment of metastatic disease and there will be a decrease in loss of professional years, which will markedly reduce the economic burden of the disease.

TRIAL REGISTRATION

Clinical Trial.gov, NCT01748448 , 05/12/2012.

The relationship between serum vitamin D levels and sleep quality in fixed day indoor field workers in the electronics manufacturing industry in Korea

Background

Although recent studies have investigated the influence of vitamin D on sleep patterns, there is a lack of research on the relationship between vitamin D and sleep patterns in Korean workers. This study focused on the relationship between serum vitamin D levels and sleep in fixed day indoor field workers in the electronics manufacturing industry in Korea.

Methods

The 1472 subjects who were included in this study were selected from fixed day workers in the electronics manufacturing industry who had received a worker’s special health examination at a hospital in Changwon, South Gyeongsang Province between January 2015 and December 2015. Nighttime workers and those who showed symptoms of depression were excluded from this study. The sociodemographic and lifestyle variables of the participants were investigated, including age, sex, marital status, level of education, body mass index, smoking habits, alcohol consumption habits, and regular exercise. Work-related factors were evaluated, such as employee tenure and occupational stress. Serum 25-hydroxyvitamin D was measured as an indicator of vitamin D levels, and quality of sleep was evaluated using the Pittsburgh Sleep Quality Index (PSQI) translated into Korean.

Results

The subjects had a mean serum vitamin D level of 13.70 ± 5.93 ng/mL. Vitamin D deficiency, defined as a serum vitamin D level of <10 ng/mL, was found in 24.8% of males and significantly more frequently in females (47.6%). Poor sleep quality was reported by 19.8% of participants with serum vitamin D levels ≥10 ng/mL and by 21.7% of those with serum vitamin D levels <10 ng/mL, which was a significant difference (P = .007). Multiple logistic regression analysis adjusting for significant variables found that poor sleep quality was more likely in those with vitamin D deficiency than those with higher serum vitamin D levels (odds ratio = 1.36; 95% CI, 1.01–1.82). A comparison of serum vitamin D levels and PSQI components showed that the mean scores for subjective sleep quality, sleep latency, and sleep duration were significantly higher in the vitamin D-deficient participants, indicating that the vitamin D-deficient participants had poorer sleep quality.

Conclusions

This study investigated serum vitamin D levels in fixed day indoor field workers in the manufacturing industry in Korea and analyzed the relationship of vitamin D deficiency with sleep quality. A significant correlation was found between serum vitamin D deficiency and poor sleep quality. Based on the results of this study, sleep disorder management for workers can be improved by providing regular examinations checking their serum vitamin D levels and supplying vitamin D to workers with serum vitamin D deficiency to enhance their quality of sleep.

Higher prevalence of vitamin D deficiency in German pregnant women compared to non-pregnant women

PURPOSE

Adequate vitamin D status is crucial for normal development of the fetus and for maternal health. As data on vitamin D status (25-hydroxyvitamin D, 25(OH)D) in German women of different states of pregnancy were not available, this study compared the vitamin D status of German women in all trimesters of pregnancy with that of non-pregnant women.

METHODS

The study sample of 858 women (18-45 years) was recruited from April 2013 to March 2015 as a part of the cross-sectional Germany-wide VitaMinFemin study. Serum 25(OH)D levels were determined using chemiluminescence immunoassay.

RESULTS

A total of 78.1% of the pregnant women and 53.9% of the non-pregnant women had a vitamin D status <50.0 nmol/L (p < 0.001). In pregnant women, the multivariate binary analysis showed that winter [odds ratio (OR) 13.5], longitude of residence between 6.3°E and 8.9°E (OR 2.0) or 9.0°E and 10.9°E (OR 2.3) and third trimester (OR 2.3) were associated with a higher risk of vitamin D status <25.0 nmol/L, whereas increasing age per one year (OR 0.9) with a lower risk. Compared with non-pregnant women, pregnant women were 3.7 times more likely to have a vitamin D status <25.0 nmol/L.

CONCLUSION

A low vitamin D status is prevalent among German pregnant women and should be improved to supply mother and fetus adequately.

Harmonization Study Between LC-MS/MS and Diasorin RIA for Measurement of 25-Hydroxyvitamin D Concentrations in a Large Population Survey

BACKGROUND

Population-based research on vitamin D has increased dramatically in recent years. Such studies are typically reliant on assay procedures to measure reliable and comparable levels of 25-hydroxyvitamin D [25(OH)D] concentrations.

METHODS

Concentrations of 25(OH)D3 and 25(OH)D2 were measured using LC-MS/MS in 5,915 participants (aged 31 years) of Northern Finland Birth Cohort 1966. Blood samples were assayed in batches over a course of 18 months. As anomalies were present in the measurements, 200 samples were reassayed using Diasorin RIA. Agreement between measurements was assessed by Passing-Bablok regression and limits of agreement (LoA). To harmonize LC-MS/MS with Diasorin RIA measurements, formulae were derived from the LoA.

RESULTS

Concentrations measured by LC-MS/MS were much higher than those measured by Diasorin RIA, with a mean difference of 12.9 ng/ml. Constant variation was evident between batch measurements after log transformation. Statistical formula was applied separately for each batch of LC-MS/MS measurements, enabling us to remove both the constant and proportional bias that was evident prior to the transformation.

CONCLUSION

Despite the introduction of schemes/programs to improve accuracy of assays to measure 25(OH)D, significant differences can still happen. In these instances, methods to harmonize measurements based on a relatively small number of replicates can be successfully applied to establish confidence and to enable between-study comparisons.

Breastfeeding woman are at higher risk of vitamin D deficiency than non-breastfeeding women - insights from the German VitaMinFemin study

BACKGROUND

Despite increased awareness of the adverse health effects of vitamin D deficiency, only a few studies have evaluated the vitamin D status (25-hydroxyvitamin D [25(OHD)]) of breastfeeding women and up to now, no information exits for German breastfeeding women. Therefore, the aim of study was to determine the vitamin D status of breastfeeding women compared to non-pregnant and non-breastfeeding (NPNB) women.

METHODS

This cross-sectional study investigated 124 breastfeeding women and 124 age and season matched NPNB women from the German "Vitamin and mineral status among German women" study. The study participants were recruited from April 2013 to March 2015 and did not take vitamin D supplements. Serum 25(OH)D was analyzed by chemiluminescent immunoassay.

RESULTS

Vitamin D deficiency (<25.0 nmol/L) was prevalent in 26.6% of the breastfeeding women. The majority of women (49.2%) showed 25(OH)D concentration between 25.0 and 49.9 nmol/L. In multiple binary logistic regression analysis, breastfeeding women had a 4.0-fold higher odds ratio (OR) (95% confidence interval [CI] 1.8, 8.7) for vitamin D deficiency than NPNB women. For breastfeeding women, the risk of vitamin D deficiency was higher in the winter and spring months (OR: 2.6, 95% CI 1.1, 6.3) and increased with lower longitude per one unit (OR 0.7, 95% CI 0.6, 0.9).

CONCLUSION

Breastfeeding women in Germany had a higher risk of deficient vitamin D levels than NPNB women. In further studies, the optimal vitamin D status for breastfeeding women should be investigated and also the required vitamin D doses to ensure this vitamin D status.

TRIAL REGISTRATION

German Clinical Trial Register (identification number: DRKS00004789).