Vitamin D [25(OH)D] metabolites and epimers in obese subject: Interaction and correlations with adverse metabolic health risk factors

BACKGROUND

Although both vitamin D deficiency and obesity are highly prevalent in the UAE, the role of vitamin D metabolites in mediating obesity-related adverse health effects is not clear. We aimed to assess the role of vitamin D metabolites as potential mediators in the association between obesity, inflammation and metabolic risk factors.

METHODS

277 participants who were part of a randomized controlled trial had their assessment that included clinical, anthropometric and physical activity data at baseline and at 6 months. Blood and urine samples were taken for measurements of serum 25(OH)D, 25(OH)D metabolites including 25(OH)D3), 25(OH)D2), 1,25(OH)2D3, 3-Epi-D3), metabolic and inflammatory markers and related biochemical variables. Multiple regression analysis used to assess the role of 25(OH)D metabolites in mediating the effect of increasing body mass index (BMI) on inflammation and metabolic risk factors.

RESULTS

Overall, 277 participants with complete 6 months follow up with a mean (±SD) age of 41 ± 12 and 204 (74%) female were included in the study. Blood pressure, inflammatory, metabolic and lipid profile markers significantly increased in overweight and obese subjects compared to subjects with normal BMI both at baseline and at 6 months (p < 0.05). 25(OH)D revealed significant association with age, gender, HbA1c and type 2 diabetes (p < 0.05). No statistically significant changes in any of 25(OH)D metabolites assessed. Multivariate analysis revealed significant and independent associations between BMI and important inflammatory and metabolic risk factors (p < 0.05). No similar association observed with 25(OH)D metabolites.

CONCLUSION

Although we found significant association between 25(OH)D and prevalence of type 2 diabetes, we found no evidence however to support a role of 25(OH)D metabolites in mediating the effect of BMI on inflammatory or metabolic risk factors.

Association of Dietary Vitamin D Intake, Serum 25(OH)D3, 25(OH)D2 with Cognitive Performance in the Elderly

Background: As life expectancy increases, cognitive performance decline in the elderly has become one of the major global challenges. We aimed to evaluate the association of dietary vitamin D (VD), serum 25-hydroxyvitamin D3 (25(OH)D₃), 25-hydroxyvitamin D2 (25(OH)D₂), and total 25-hydroxyvitamin (25(OH)D) concentration with cognitive performance in older Americans. Methods: The data from the National Health and Nutrition Examination Survey (NHANES), 2011–2014 was used. The cognitive performance was assessed by the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD) Word Learning sub-test, Animal Fluency test, and Digit Symbol Substitution Test (DSST). A binary logistic regression model was applied to evaluate the association between VD and cognitive performance, and restricted cubic spline model was adopted to evaluate the dose–response relationship. Results: While comparing to the lowest dietary VD intake group, the multivariate adjusted odds ratios (ORs) and 95% confidence intervals (CIs) of the highest dietary VD intake group were 0.51 (0.36–0.72) for the Animal Fluency test score and 0.45 (0.31–0.66) for DSST score, respectively; and those of serum total 25(OH)D and 25(OH)D₃ concentration were 0.68 (0.47–0.97) and 0.62 (0.44–0.86) for DSST score. L-shaped relationships were identified for dietary VD intake, serum total 25(OH)D and 25(OH)D₃ concentration with cognition performance. The associations between dietary VD intake, serum total 25(OH)D and cognitive performance were non-significant when stratified by gender. Conclusions: The study indicates that dietary VD intake, serum total 25(OH)D and 25(OH)D₃ concentration were positively associated with cognitive performance. Further studies are needed to clarify the possible effects of dietary VD intake and serum 25(OH)D₂, 25(OH)D₃ on cognitive performance.

25-OHD response to vitamin D supplementation in children: effect of dose but not GC haplotype

OBJECTIVE

GC/DBP effects on response to vitamin D supplementation have not been well-studied. Thus we assessed free and total 25-OHD after vitamin D treatment across the six common GC haplotypes.

DESIGN

This double-blind, randomized study compared two vitamin D3 doses in healthy, urban-dwelling 6-month to 10-year-old children at-risk for vitamin D deficiency. Randomization was stratified by GC haplotype.

METHODS

Children were randomized to receive 2800 or 7000 International Units of vitamin D3 weekly. 25-OHD and 1,25(OH)2D were sampled at baseline and after 1-6 months of supplementation.

RESULTS AND CONCLUSIONS

One hundred ninety-two of 225 enrolled subjects completed the study. After one month, total 25-OHD increased with both doses and were higher with 7000 IU/week (85.5 ± 22.8 nmol/L) compared to 2800 IU/week (76.8 ± 18.0 nmol/L), despite equivalent baseline levels. No further significant increase occurred at 6 months (89.8 ± 35.5 and 74.3 ± 18.3 nmol/L, respectively). Free 25-OHD similarly changed. 25-OHD differed among GC groups at baseline. Although no significant effects of individual GC haplotypes on incremental changes were evident, a trend toward an effect of combined 'at risk' GC alleles on response was evident (P = 0.06). Total 1,25(OH)2D showed modest increases, moreso with the larger dose. In urban-dwelling children at-risk for vitamin D deficiency, 1 month of vitamin D3 2800 IU/week increased 25-OHD across all GC haplotype groups, and somewhat enhanced with 7000 IU/week with no further significant increases after 6 months of supplementation. Free 25-OHD measures offer no monitoring advantage over total 25-OHD.

Vitamin D supplementation for the treatment of COVID-19: a living systematic review

BACKGROUND

The role of vitamin D supplementation as a treatment for COVID-19 has been a subject of considerable discussion. A thorough understanding of the current evidence regarding the effectiveness and safety of vitamin D supplementation for COVID-19 based on randomised controlled trials is required.

OBJECTIVES

To assess whether vitamin D supplementation is effective and safe for the treatment of COVID-19 in comparison to an active comparator, placebo, or standard of care alone, and to maintain the currency of the evidence, using a living systematic review approach.

SEARCH METHODS

We searched the Cochrane COVID-19 Study Register, Web of Science and the WHO COVID-19 Global literature on coronavirus disease to identify completed and ongoing studies without language restrictions to 11 March 2021.

SELECTION CRITERIA

We followed standard Cochrane methodology. We included randomised controlled trials (RCTs) evaluating vitamin D supplementation for people with COVID-19, irrespective of disease severity, age, gender or ethnicity. We excluded studies investigating preventive effects, or studies including populations with other coronavirus diseases (severe acute respiratory syndrome (SARS) or Middle East respiratory syndrome (MERS)).

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methodology. To assess bias in included studies, we used the Cochrane risk of bias tool (ROB 2) for RCTs. We rated the certainty of evidence using the GRADE approach for the following prioritised outcome categories: individuals with moderate or severe COVID-19: all-cause mortality, clinical status, quality of life, adverse events, serious adverse events, and for individuals with asymptomatic or mild disease: all-cause mortality, development of severe clinical COVID-19 symptoms, quality of life, adverse events, serious adverse events.

MAIN RESULTS

We identified three RCTs with 356 participants, of whom 183 received vitamin D. In accordance with the World Health Organization (WHO) clinical progression scale, two studies investigated participants with moderate or severe disease, and one study individuals with mild or asymptomatic disease. The control groups consisted of placebo treatment or standard of care alone. Effectiveness of vitamin D supplementation for people with COVID-19 and moderate to severe disease We included two studies with 313 participants. Due to substantial clinical and methodological diversity of both studies, we were not able to pool data. Vitamin D status was unknown in one study, whereas the other study reported data for vitamin D deficient participants. One study administered multiple doses of oral calcifediol at days 1, 3 and 7,  whereas the other study gave a single high dose of oral cholecalciferol at baseline. We assessed one study with low risk of bias for effectiveness outcomes, and the other with some concerns about randomisation and selective reporting. All-cause mortality at hospital discharge (313 participants) We found two studies reporting data for this outcome. One study reported no deaths when treated with vitamin D out of 50 participants, compared to two deaths out of 26 participants in the control group (Risk ratio (RR) 0.11, 95% confidence interval (CI) 0.01 to 2.13). The other study reported nine deaths out of 119 individuals in the vitamin D group, whereas six participants out of 118 died in the placebo group (RR 1.49, 95% CI 0.55 to 4.04]. We are very uncertain whether vitamin D has an effect on all-cause mortality at hospital discharge (very low-certainty evidence). Clinical status assessed by the need for invasive mechanical ventilation (237 participants) We found one study reporting data for this outcome. Nine out of 119 participants needed invasive mechanical ventilation when treated with vitamin D, compared to 17 out of 118 participants in the placebo group (RR 0.52, 95% CI 0.24 to 1.13). Vitamin D supplementation may decrease need for invasive mechanical ventilation, but the evidence is uncertain (low-certainty evidence). Quality of life We did not find data for quality of life. Safety of vitamin D supplementation for people with COVID-19 and moderate to severe disease We did not include data from one study, because assessment of serious adverse events was not described and we are concerned that data might have been inconsistently measured. This study reported vomiting in one out of 119 participants immediately after vitamin D intake (RR 2.98, 95% CI 0.12 to 72.30). We are very uncertain whether vitamin D supplementation is associated with higher risk for adverse events (very low-certainty). Effectiveness and safety of vitamin D supplementation for people with COVID-19 and asymptomatic or mild disease We found one study including 40 individuals, which did not report our prioritised outcomes, but instead data for viral clearance, inflammatory markers, and vitamin D serum levels. The authors reported no events of hypercalcaemia, but recording and assessment of further adverse events remains unclear. Authors administered oral cholecalciferol in daily doses for at least 14 days, and continued with weekly doses if vitamin D blood levels were > 50 ng/mL.

AUTHORS' CONCLUSIONS

There is currently insufficient evidence to determine the benefits and harms of vitamin D supplementation as a treatment of COVID-19. The evidence for the effectiveness of vitamin D supplementation for the treatment of COVID-19 is very uncertain. Moreover, we found only limited safety information, and were concerned about consistency in measurement and recording of these outcomes. There was substantial clinical and methodological heterogeneity of included studies, mainly because of different supplementation strategies, formulations, vitamin D status of participants, and reported outcomes. There is an urgent need for well-designed and adequately powered randomised controlled trials (RCTs) with an appropriate randomisation procedure, comparability of study arms and preferably double-blinding. We identified 21 ongoing and three completed studies without published results, which indicates that these needs will be addressed and that our findings are subject to change in the future. Due to the living approach of this work, we will update the review periodically.

Vitamin D Status in Children With Short Stature: Accurate Determination of Serum Vitamin D Components Using High-Performance Liquid Chromatography-Tandem Mass Spectrometry

OBJECTIVE

Vitamin D is critical for calcium and bone metabolism. Vitamin D insufficiency impairs skeletal mineralization and bone growth rate during childhood, thus affecting height and health. Vitamin D status in children with short stature is sparsely reported. The purpose of the current study was to investigate various vitamin D components by high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) to better explore vitamin D storage of short-stature children in vivo.

METHODS

Serum circulating levels of 25-hydroxyvitamin D2 [25(OH)D2], 25-hydroxyvitamin D3 [25(OH)D3], and 3-epi-25-hydroxyvitamin D3 [3-epi-25(OH)D3, C3-epi] were accurately computed using the LC-MS/MS method. Total 25(OH)D [t-25(OH)D] and ratios of 25(OH)D2/25(OH)D3 and C3-epi/25(OH)D3 were then respectively calculated. Free 25(OH)D [f-25(OH)D] was also measured.

RESULTS

25(OH)D3 and f-25(OH)D levels in short-stature subgroups 2 (school age: 7~12 years old) and 3 (adolescence: 13~18 years old) were significantly lower compared with those of healthy controls. By contrast, C3-epi levels and C3-epi/25(OH)D3 ratios in all the three short-stature subgroups were markedly higher than the corresponding healthy cases. Based on cutoff values developed by Endocrine Society Recommendation (but not suitable for methods 2 and 3), sufficient storage capacities of vitamin D in short-stature subgroups 1, 2, and 3 were 42.8%, 23.8%, and 9.0% as determined by Method 3 [25(OH)D2/3+25(OH)D3], which were lower than those of 57.1%, 28.6%, and 18.2% as determined by Method 1 [25(OH)D2+25(OH)D3+C3-epi] and 45.7%, 28.5%, and 13.6% as determined by Method 2 [25(OH)D2/3+25(OH)D3+C3-epi]. Levels of 25(OH)D2 were found to be weakly negatively correlated with those of 25(OH)D3, and higher 25(OH)D3 levels were positively correlated with higher levels of C3-epi in both short-stature and healthy control cohorts. Furthermore, f-25(OH)D levels were positively associated with 25(OH)D3 and C3-epi levels in children.

CONCLUSIONS

The current LC-MS/MS technique can not only separate 25(OH)D2 from 25(OH)D3 but also distinguish C3-epi from 25(OH)D3. Measurement of t-25(OH)D [25(OH)D2+25(OH)D3] alone may overestimate vitamin D storage in children, and short-stature children had lower vitamin D levels compared with healthy subjects. Ratios of C3-epi/25(OH)D3 and 25(OH)D2/25(OH)D3 might be alternative markers for vitamin D catabolism/storage in short-stature children. Further studies are needed to explore the relationships and physiological roles of various vitamin D metabolites.

Vitamin D supplementation for term breastfed infants to prevent vitamin D deficiency and improve bone health

BACKGROUND

Vitamin D deficiency is common worldwide, contributing to nutritional rickets and osteomalacia which have a major impact on health, growth, and development of infants, children and adolescents. Vitamin D levels are low in breast milk and exclusively breastfed infants are at risk of vitamin D insufficiency or deficiency.

OBJECTIVES

To determine the effect of vitamin D supplementation given to infants, or lactating mothers, on vitamin D deficiency, bone density and growth in healthy term breastfed infants.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to 29 May 2020 supplemented by searches of clinical trials databases, conference proceedings, and citations.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs in breastfeeding mother-infant pairs comparing vitamin D supplementation given to infants or lactating mothers compared to placebo or no intervention, or sunlight, or that compare vitamin D supplementation of infants to supplementation of mothers.

DATA COLLECTION AND ANALYSIS

Two review authors assessed trial eligibility and risk of bias and independently extracted data. We used the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

We included 19 studies with 2837 mother-infant pairs assessing vitamin D given to infants (nine studies), to lactating mothers (eight studies), and to infants versus lactating mothers (six studies). No studies compared vitamin D given to infants versus periods of infant sun exposure. Vitamin D supplementation given to infants: vitamin D at 400 IU/day may increase 25-OH vitamin D levels (MD 22.63 nmol/L, 95% CI 17.05 to 28.21; participants = 334; studies = 6; low-certainty) and may reduce the incidence of vitamin D insufficiency (25-OH vitamin D < 50 nmol/L) (RR 0.57, 95% CI 0.41 to 0.80; participants = 274; studies = 4; low-certainty). However, there was insufficient evidence to determine if vitamin D given to the infant reduces the risk of vitamin D deficiency (25-OH vitamin D < 30 nmol/L) up till six months of age (RR 0.41, 95% CI 0.16 to 1.05; participants = 122; studies = 2), affects bone mineral content (BMC), or the incidence of biochemical or radiological rickets (all very-low certainty). We are uncertain about adverse effects including hypercalcaemia. There were no studies of higher doses of infant vitamin D (> 400 IU/day) compared to placebo. Vitamin D supplementation given to lactating mothers: vitamin D supplementation given to lactating mothers may increase infant 25-OH vitamin D levels (MD 24.60 nmol/L, 95% CI 21.59 to 27.60; participants = 597; studies = 7; low-certainty), may reduce the incidences of vitamin D insufficiency (RR 0.47, 95% CI 0.39 to 0.57; participants = 512; studies = 5; low-certainty), vitamin D deficiency (RR 0.15, 95% CI 0.09 to 0.24; participants = 512; studies = 5; low-certainty) and biochemical rickets (RR 0.06, 95% CI 0.01 to 0.44; participants = 229; studies = 2; low-certainty). The two studies that reported biochemical rickets used maternal dosages of oral D3 60,000 IU/day for 10 days and oral D3 60,000 IU postpartum and at 6, 10, and 14 weeks. However, infant BMC was not reported and there was insufficient evidence to determine if maternal supplementation has an effect on radiological rickets (RR 0.76, 95% CI 0.18 to 3.31; participants = 536; studies = 3; very low-certainty). All studies of maternal supplementation enrolled populations at high risk of vitamin D deficiency. We are uncertain of the effects of maternal supplementation on infant growth and adverse effects including hypercalcaemia. Vitamin D supplementation given to infants compared with supplementation given to lactating mothers: infant vitamin D supplementation compared to lactating mother supplementation may increase infant 25-OH vitamin D levels (MD 14.35 nmol/L, 95% CI 9.64 to 19.06; participants = 269; studies = 4; low-certainty). Infant vitamin D supplementation may reduce the incidence of vitamin D insufficiency (RR 0.61, 95% CI 0.40 to 0.94; participants = 334; studies = 4) and may reduce vitamin D deficiency (RR 0.35, 95% CI 0.17 to 0.72; participants = 334; studies = 4) but the evidence is very uncertain. Infant BMC and radiological rickets were not reported and there was insufficient evidence to determine if maternal supplementation has an effect on infant biochemical rickets. All studies enrolled patient populations at high risk of vitamin D deficiency. Studies compared an infant dose of vitamin D 400 IU/day with varying maternal vitamin D doses from 400 IU/day to > 4000 IU/day. We are uncertain about adverse effects including hypercalcaemia.

AUTHORS' CONCLUSIONS

For breastfed infants, vitamin D supplementation 400 IU/day for up to six months increases 25-OH vitamin D levels and reduces vitamin D insufficiency, but there was insufficient evidence to assess its effect on vitamin D deficiency and bone health. For higher-risk infants who are breastfeeding, maternal vitamin D supplementation reduces vitamin D insufficiency and vitamin D deficiency, but there was insufficient evidence to determine an effect on bone health. In populations at higher risk of vitamin D deficiency, vitamin D supplementation of infants led to greater increases in infant 25-OH vitamin D levels, reductions in vitamin D insufficiency and vitamin D deficiency compared to supplementation of lactating mothers. However, the evidence is very uncertain for markers of bone health. Maternal higher dose supplementation (≥ 4000 IU/day) produced similar infant 25-OH vitamin D levels as infant supplementation of 400 IU/day. The certainty of evidence was graded as low to very low for all outcomes.

Measurement of plasma 25-hydroxyvitamin D2, 25-hydroxyvitamin D3 and 3-epi-25-hydroxyvitamin D3 in population of patients with cardiovascular disease by UPLC-MS/MS method

Vitamin D has a potential role in protecting against cardiovascular disease (CVD). Serum 25-hydroxyvitamin D (25D) is the most widely used indicator of vitamin D status in the human body. 25D is estimated as total of 25-hydroxyvitamin D2 (25D2) and 25-hydroxyvitamin D3 (25D3). However, the presence of 3-epi-25-hydroxyvitamin D3 (3epi25D3) can affect 25D measurement. In this research a novel validated UPLC-MS/MS technique was developed to measure three vitamin D metabolites, 25D2, 25D3 and 3epi25D3 in human plasma. A liquid-liquid extraction using hexane was applied for isolation of the analytes from the samples. A chromatographic separation was achieved in a Kinetex F5 analytical column with isocratic elution (water and methanol with 0.1% methanoic acid, 20:80 v/v). Mass spectrometry detection of the metabolites was performed in a triple-quadruple tandem mass spectrometer under positive ion mode. Concentrations of the analytes were estimated in plasma samples of 54 patients. Validation parameters of the UPLC-MS/MS method, including linearity, precision, accuracy, and stability, fulfilled the requirements for bioanalytical assays. The deficient concentration of 25D (<20 ng/mL) was stated in over 60% of patients. 3epi25D3 was present in 78% of samples and its relative amount ranged from 0 to 54.1% of 25D concentration. The analysis of 25D2, 25D3 and 3epi25D3 by the validated UPLC-MS/MS method in plasma of patients with CVD permitted the classification of the patients with insufficient levels of 25D. 3epi25D3 might be relevant in the classification of vitamin D status.

Vitamin D Status Impacts Genital Mucosal Immunity and Markers of HIV-1 Susceptibility in Women

While vitamin D insufficiency is known to impact a multitude of health outcomes, including HIV-1, little is known about the role of vitamin D-mediated immune regulation in the female reproductive tract (FRT). We performed a pilot clinical study of 20 women with circulating 25(OH)D levels <62.5 nmol/L. Participants were randomized into either weekly or daily high-dose oral vitamin D supplementation groups. In addition to serum vitamin D levels, genital mucosal endpoints, including soluble mediators, immune cell populations, gene expression, and ex vivo HIV-1 infection, were assessed. While systemic vitamin D levels showed a significant increase following supplementation, these changes translated into modest effects on the cervicovaginal factors studied. Paradoxically, post-supplementation vitamin D levels were decreased in cervicovaginal fluids. Given the strong correlation between vitamin D status and HIV-1 infection and the widespread nature of vitamin D deficiency, further understanding of the role of vitamin D immunoregulation in the female reproductive tract is important.

Vitamin D and Inflammation: Potential Implications for Severity of Covid-19

Background Recent research has indicated that vitamin D may have immune supporting properties through modulation of both the adaptive and innate immune system through cytokines and regulation of cell signalling pathways. We hypothesize that vitamin D status may influence the severity of responses to Covid-19 and that the prevalence of vitamin D deficiency in Europe will be closely aligned to Covid-19 mortality. Methods We conducted a literature search on PubMed (no language restriction) of vitamin D status (for older adults) in countries/areas of Europe affected by Covid-19 infection. Countries were selected by severity of infection (high and low) and were limited to national surveys or where not available, to geographic areas within the country affected by infection. Covid-19 infection and mortality data was gathered from the World Health Organisation. Results Counter-intuitively, lower latitude and typically 'sunny' countries such as Spain and Italy (particularly Northern Italy), had low mean concentrations of 25(OH)D and high rates of vitamin D deficiency. These countries have also been experiencing the highest infection and death rates in Europe. The northern latitude countries (Norway, Finland, Sweden) which receive less UVB sunlight than Southern Europe, actually had much higher mean 25(OH)D concentrations, low levels of deficiency and for Norway and Finland, lower infection and death rates. The correlation between 25(OH)D concentration and mortality rate reached conventional significance (P=0.046) by Spearman's Rank Correlation. Conclusions Optimising vitamin D status to recommendations by national and international public health agencies will certainly have benefits for bone health and potential benefits for Covid-19. There is a strong plausible biological hypothesis and evolving epidemiological data supporting a role for vitamin D in Covid-19.

Variation in plasma 25-hydroxyvitamin D2 and D3 in normal pregnancy with gestational age, sampling season, and complications: A longitudinal cohort study

Introduction

Low levels of vitamin D in pregnancy have been associated with the risk of a variety of pregnancy outcomes. Few studies have investigated vitamin D concentrations throughout pregnancy in healthy women, and most guidelines recommend high vitamin D levels. In the present study, we investigated 25-hydroxyvitamin D concentrations in healthy Caucasian Danish women in relation to season, gestational age and possible vitamin D-linked complications.

Materials and methods

Eight hundred and one healthy Caucasian Danish women with an expected normal pregnancy were recruited among 2147 women attending first trimester screening. Seven blood samplings were planned throughout the pregnancy and delivery period. The 25-hydroxyvitamin D2 (25(OH)D2) and 25-hydroxyvitamin D3 (25(OH)D3) concentrations were measured by LC-MS/MS and total 25-hydroxyvitamin D (25(OH)D) were calculated.

Results

A total of 3304 samples from 694 women were available for 25(OH)D measurements. The mean (25^th-75^th percentiles) concentrations of 25(OH)D, 25(OH)D3, and 25(OH)D2 were 54.6 (38.8–68.6) nmol/L, 52.2 (36.4–66.4) nmol/L, and 2.4 (2.2–2.2) nmol/L, respectively. Season was the strongest predictor of 25(OH)D concentration, with the lowest values observed in winter and spring, where only 42% and 41% of samples, respectively, were above 50 nmol/L. Nearly all women had values below the suggested optimal level of 75 nmol/L, independent of season. 25(OH)D peaked at gestational weeks 21–34. Plasma 25(OH)D2 levels were low in all seasons. Women with complications during pregnancy had higher 25(OH)D (estimated difference 9.8 nmol/L, standard error 2.7, p<0.001) than did women without complications, and women giving birth vaginally had lower 25(OH)D than did those delivering via elective (10.0 nmol/L, standard error 2.1, p<0.001) or emergency cesarean section (6.8 nmol/L, standard error 2.2, p<0.001).

Conclusion

The 25(OH)D concentrations vary with both season and gestational age. Healthy women had lower 25(OH)D concentrations than recommended, without an association with an increased risk of pregnancy complications. Guidelines for vitamin D in pregnancy may require revision.

A novel caged Cookson-type reagent toward a practical vitamin D derivatization method for mass spectrometric analyses

RATIONALE

25-Hydroxylated vitamin D is the best marker for vitamin D (VD). Due to its low ionization efficiency, a Cookson-type reagent, 1,2,4-triazoline-3,5-dione (TAD), is used to improve the detection/quantification of VD metabolites by liquid chromatography/tandem mass spectrometry (LC/MS/MS). However, the high reactivity of TAD makes its solution stability low and inconvenient for practical use. We here describe the development of a novel caged Cookson-type reagent, and we assess its performances in the quantitative and differential detection of four VD metabolites in serum using LC/MS/MS.

METHODS

Caged 4-(4'-dimethylaminophenyl)-1,2,4-triazoline-3,5-dione (DAPTAD) analogues were prepared from 4-(4'-dimethylaminophenyl)-1,2,4-triazolidine-3,5-dione. Their stability and reactivity were examined. The optimized caged DAPTAD (14-(4-(dimethylamino)phenyl)-9-phenyl-9,10-dihydro-9,10-[1,2]epitriazoloanthracene-13,15-dione, DAP-PA) was used for LC/MS/MS analyses of VD metabolites.

RESULTS

The solution stability of DAP-PA in ethyl acetate dramatically improved compared with that of the non-caged one. We measured the thermal retro-Diels-Alder reaction enabling the release of DAPTAD and found that the derivatization reaction was temperature-dependent. We also determined the detection limit and the lower limit of quantifications for four VD metabolites with DAPTAD derivatization.

CONCLUSIONS

DAP-PA was stable enough for mid- to long-term storage in solution. This advantage shall contribute to the detection and quantification of VD in clinical laboratories, and as such to the broader use of clinical mass spectrometry.

Characterizing neonatal vitamin D deficiency in the modern era: A maternal-neonatal birth cohort from Southern Europe

Absence of adequate maternal vitamin D supplementation and decreased maternal ultraviolet exposure during pregnancy are key determinants for the manifestation of neonatal hypovitaminosis D at birth. These parameters may vary, according to country-specific dietary patterns, health policies and sunshine exposure. We aimed to investigate differences in calcium metabolism and anthropometric profiles according to neonatal vitamin D status at birth, in a sunny region of Northern Greece. A secondary aim was to identify maternal parameters as risk factors for developing neonatal vitamin D deficiency at birth. A total of 129 mother-neonate pairs were included in the study and classified into three groups, according to neonatal 25-hydroxy-D [25(OH)D)] concentrations at birth [deficiency (<30 nmol/l), insufficiency (30-50 nmol/l) and sufficiency (>50 nmol/l)]. Neonatal biochemical and anthropometric profiles and maternal demographic, social, dietary and biochemical profiles were comparatively evaluated between the three groups. Univariate and multivariate logistic regression was performed to identify independent associations of maternal factors with neonatal vitamin D status. Vitamin D deficient-neonates manifested higher parathyroid hormone (7.20 ± 2.60 vs 5.50 ± 1.50 pg/ml, p = 0.01) and lower corrected calcium (10.70 ± 0.70 vs 11.30 ± 1.30 mg/dl, p = 0.02) concentrations compared with vitamin d-insufficient neonates. Mothers of vitamin D deficient and insufficient neonates had a lower total of 25(OH)D (31.7 ± 19.2 and 36.5 ± 22.3 vs 53.3 ± 39.0 nmol/l, p < 0.01) and 25(OH)D₃ (27.4 ± 17.5 and 33.3 ± 19.9 vs 47.3 ± 36.7 nmol/l, p < 0.01 and p = 0.04, respectively) concentrations respectively, compared with those of vitamin D-sufficient neonates. Maternal use of alcohol during pregnancy was associated with a 5.57-fold higher risk for neonatal vitamin D deficiency at birth (OR 5.57, 95 % CI1.17-26.56, p = 0.03). Newborns with vitamin D deficiency presented a 6.89-fold higher risk of having been given birth by vitamin D deficient mothers (OR 6.89, 95 % CI 3.09-15.38, p < 0.01). In conclusion, neonatal vitamin D deficiency is associated with maternal 25(OH)D concentrations at birth and maternal alcohol use. Further studies are required to replicate these findings in other regions and populations.

Differential Effects of Oral Boluses of Vitamin D2 vs Vitamin D3 on Vitamin D Metabolism: A Randomized Controlled Trial

CONTEXT

Vitamin D2 and vitamin D3 have been hypothesized to exert differential effects on vitamin D metabolism.

OBJECTIVE

To compare the influence of administering vitamin D2 vs vitamin D3 on metabolism of vitamin D3.

METHODS

We measured baseline and 4-month serum concentrations of vitamin D3, 25-hydroxyvitamin D3 [25(OH)D3], 25-hydroxyvitamin D2, 24R,25-dihydroxyvitamin D3 [24R,25(OH)2D3], 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3], and 4β,25-dihydroxyvitamin D3 [4β,25(OH)2D3] in 52 adults randomized to receive a total of four oral bolus doses of 2.5 mg vitamin D2 (n = 28) or vitamin D3 (n = 24) over four months. Metabolite-to-parent compound ratios were calculated to estimate hydroxylase activity. Pairwise before vs after comparisons were made to evaluate effects of vitamin D2 and vitamin D3 on metabolism of vitamin D. Mean postsupplementation metabolite-to-parent ratios were then compared between groups.

RESULTS

Vitamin D2 was less effective than vitamin D3 in elevating total serum 25(OH)D concentration. Vitamin D2 suppressed mean four-month serum concentrations of 25(OH)D3, 24R,25(OH)2D3, 1α,25(OH)2D3, and 4β,25(OH)2D3 and mean ratios of 25(OH)D3 to D3 and 1α,25(OH)2D3 to 25(OH)D3, while increasing the mean ratio of 24R,25(OH)2D3 to 25(OH)D3. Vitamin D3 increased mean four-month serum concentrations of 25(OH)D3, 24R,25(OH)2D3, 1α,25(OH)2D3, and 4β,25(OH)2D3 and the mean ratio of 24R,25(OH)2D3 to 25(OH)D3. Participants receiving vitamin D2 had lower mean postsupplementation ratios of 25(OH)D3 to vitamin D3 and 1α,25(OH)2D3 to 25(OH)D3 than those receiving vitamin D3. Mean postsupplementation ratios of 24R,25(OH)2D3 to 25(OH)D3 and 4β,25(OH)2D3 to 25(OH)D3 did not differ between groups.

CONCLUSIONS

Bolus-dose vitamin D2 is less effective than bolus-dose vitamin D3 in elevating total serum 25(OH)D concentration. Administration of vitamin D2 reduces 25-hydroxylation of vitamin D3 and 1-α hydroxylation of 25(OH)D3, while increasing 24R-hydroxylation of 25(OH)D3.

Multiple Sclerosis Patients Show Lower Bioavailable 25(OH)D and 1,25(OH)2D, but No Difference in Ratio of 25(OH)D/24,25(OH)2D and FGF23 Concentrations

Vitamin D (VitD) insufficiency is common in multiple sclerosis (MS). VitD has possible anti-inflammatory effects on the immune system. The ratio between VitD metabolites in MS patients and the severity of the disease are suggested to be related. However, the exact effect of the bone-derived hormone fibroblast-growth-factor-23 (FGF23) and VitD binding protein (VDBP) on this ratio is not fully elucidated yet. Therefore, the aim is to study differences in total, free, and bioavailable VD metabolites and FGF23 between MS patients and healthy controls (HCs). FGF23, vitD (25(OH)D), active vitD (1,25(OH)₂D), inactive 24,25(OH)D, and VDBP were measured in 91 MS patients and 92 HCs. Bioavailable and free concentrations were calculated. No difference in FGF23 (p = 0.65) and 25(OH)D/24.25(OH)₂D ratio (p = 0.21) between MS patients and HCs was observed. Bioavailable 25(OH)D and bioavailable 1.25(OH)₂D were lower (p < 0.01), while VDBP concentrations were higher in MS patients (p = 0.02) compared with HCs, specifically in male MS patients (p = 0.01). In conclusion, FGF23 and 25(OH)D/24.25(OH)₂D did not differ between MS patients and HCs, yet bioavailable VitD concentrations are of potential clinical relevance in MS patients. The possible immunomodulating role of VDBP and gender-related differences in the VD-FGF23 axis in MS need further study.

The interaction between prepregnancy BMI and gestational vitamin D deficiency on the risk of gestational diabetes mellitus subtypes with elevated fasting blood glucose

BACKGROUND & AIMS

To investigate the association of VitD with GDM, and examine the potential modifying effect of prepregnancy BMI in Chinese pregnant women.

METHODS

3318 pregnant women underwent oral glucose tolerance test (OGTT) were selected from Zhoushan Pregnant Women Cohort. Plasma VitD levels were measured in the first (T1) and/or second trimester (T2). Multiple linear and logistic regression models were used for evaluating the association of VitD with GDM.

RESULTS

Prepregnancy BMI was positively associated with all three time-point glucose of OGTT. 25(OH)D level in T1 (β = -0.003) and T2 (β = -0.004), and its change from T1 to T2 (β = -0.004) were significantly and inversely associated with fasting blood glucose (FBG) of OGTT, but not 1-h and 2-h postload blood glucose of OGTT, respectively. The negative associations of VitD and FBG were stronger among overweight/obese women. VitD deficiency (25(OH)D < 20 ng/ml) in T2 was associated with an increased risk of GDM with increased FBG, GDM subtype 1 (OR: 2.10) and subtype 3 (OR: 2.19). Moreover, prepregnancy BMI modified this effect on GDM subtype 1 (BMI < 24: OR = 1.42; BMI ≥ 24: OR = 9.61, P for interaction = 0.002). Lower VitD increment from T1 to T2 was associated with a higher risk for GDM among overweight/obese women. Additionally, GDM prevalence fluctuated with the season, i.e. lower in summer/fall and higher in winter/spring.

CONCLUSIONS

Maternal VitD deficiency was associated with a higher risk of GDM subtype with increased FBG, and the risk is much greater among overweight/obesity women. The lower the VitD increment during pregnancy, the greater the risk of GDM, especially in overweight/obesity women. Furthermore, seasonal variation of GDM may be exhibited as a critical confounder in the association of VitD and GDM.

The association between anxiety and depression with 25(OH)D and thyroid stimulating hormone levels

OBJECTIVE

To evaluate the relationships between the serum levels of these parameters and mood disorders, including depression and anxiety.

METHODS

One hundred and fifty patients (77 with anxiety and 73 with depression), aged 18 to 79 years old, who were referred to the Neuro Psychiatry Clinic of Uskudar University in Istanbul, Turkey were included in this study from June 2018 to December 2018. According to the Beck Anxiety Inventory and Beck Depression Inventory II results, the anxiety patients met the mild and moderate anxiety criteria and the depression patients met the moderate and severe depression criteria, respectively. Venous blood samples were collected after overnight fasting, and the 25(OH)D and thyroid stimulating hormone (TSH) levels were measured.

RESULTS

The data showed a significantly higher TSH level in the females when compared to their male counterparts in the severe depression subgroup (p=0.011).

CONCLUSION

A serum TSH evaluation may be considered as a useful biochemical marker for more efficient depression management.

The association between anxiety and depression with 25(OH)D and thyroid stimulating hormone levels

Objectives:

To evaluate the relationships between the serum levels of these parameters and mood disorders, including depression and anxiety.

Methods:

One hundred and fifty patients (77 with anxiety and 73 with depression), aged 18 to 79 years old, who were referred to the Neuro Psychiatry Clinic of Uskudar University in Istanbul, Turkey were included in this study from June 2018 to December 2018. According to the Beck Anxiety Inventory and Beck Depression Inventory II results, the anxiety patients met the mild and moderate anxiety criteria and the depression patients met the moderate and severe depression criteria, respectively. Venous blood samples were collected after overnight fasting, and the 25(OH)D and thyroid stimulating hormone (TSH) levels were measured.

Results:

The data showed a significantly higher TSH level in the females when compared to their male counterparts in the severe depression subgroup (p = 0.011).

Conclusion:

A serum TSH evaluation may be considered as a useful biochemical marker for more efficient depression management.

Vitamin D status during pregnancy and the risk of gestational diabetes mellitus: A longitudinal study in a multiracial cohort

AIM

To prospectively and longitudinally investigate vitamin D status during early to mid-pregnancy in relation to gestational diabetes mellitus (GDM) risk.

METHODS

In a nested case-control study of 107 GDM cases and 214 controls within the Fetal Growth Studies-Singleton Cohort, plasma levels of 25-hydroxyvitamin D2 and D3 (25(OH)D) and vitamin D binding protein were measured at gestational weeks 10 to 14, 15 to 26, 23 to 31, and 33 to 39; we further calculated total, free, and bioavailable 25(OH)D. Conditional logistic regression models and linear mixed-effects models were used.

RESULTS

We observed a threshold effect for the relation of vitamin D biomarkers with GDM risk. Vitamin D deficiency (<50 nmol/L) at 10 to 14 gestational weeks was associated with a 2.82-fold increased risk for GDM [odds ratio (OR) = 2.82, 95% confidence interval (CI): 1.15-6.93]. Women with persistent vitamin D deficiency at 10 to 14 and 15 to 26 weeks of gestation had a 4.46-fold elevated risk for GDM compared with women persistently non-deficient (OR = 4.46, 95% CI: 1.15-17.3).

CONCLUSIONS

Maternal vitamin D deficiency as early as the first trimester of pregnancy was associated with an elevated risk of GDM. The association was stronger for women who were persistently deficient through the second trimester. Assessment of vitamin D status in early pregnancy may be clinically important and valuable for improving risk stratification and developing effective interventions for the primary prevention of GDM.

Free versus total serum 25-hydroxyvitamin D in a murine model of colitis

Inflammatory bowel diseases (IBD) such as ulcerative colitis and Crohn's disease have been linked to vitamin D-deficiency. Using a dextran sodium sulphate (DSS)-induced model of IBD we have shown previously that mice raised on vitamin D-deficient diets from weaning have lower serum 25-hydroxyvitamin D (25OHD) levels and develop more severe colitis compared to vitamin D-sufficient counterparts. We have also shown in vitro that immune responses to 25OHD may depend on 'free' rather than total serum concentrations of 25OHD. To investigate the possible effects of free versus total 25OHD on anti-inflammatory immune responses in vivo we have studied DSS-induced colitis in wild type C57BL/6 mice raised from weaning on diets containing vitamin D2 (D2) or vitamin D3 (D3) only (both 1000 IU/kg feed). 25OHD2 has lower binding affinity for the vitamin D binding protein than 25OHD3 which results in higher levels of free 25OHD2 relative to free 25OHD3 in mice raised on a D2-only diet. Total serum 25OHD concentrations, measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS), showed that D2 mice had significantly lower levels of 25OHD than D3 mice (6.85 ± 2.61 nmol/L vs. 49.16 ± 13.8 nmol/L for D2 and D3 respectively). Despite this, direct ELISA measurement showed no difference in free serum 25OHD levels between D2 and D3 mice (13.62 ± 2.26 pmol/L vs. 14.11 ± 2.24 pmol/L for D2 and D3 respectively). Analysis of DSS-induced colitis also showed no difference in weight loss or disease progression between D2 and D3 mice. These data indicate that despite D2-fed mice being vitamin D-deficient based on serum total 25OHD concentrations, these mice showed no evidence of increased inflammatory colitis disease relative to vitamin D-sufficient D3 mice. We therefore propose that free, rather than total serum 25OHD, may be a better marker of immune responses to vitamin D in vivo.

Rapid liquid chromatography-tandem mass spectrometry method for determination of 24,25(OH)2D and 25OHD with efficient separation of 3-epi analogs

This study establishes and validates a rapid method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) without derivatization steps to simultaneously measure of 24,25(OH)₂D₂, 24,25(OH)₂D₃, 25OHD₂, and 25OHD₃, while efficiently separating the 3-epi analogs. Samples were prepared by precipitation and liquid-liquid extraction. The linearity, precision, accuracy, recovery and matrix effect of the method were thoroughly evaluated according to the Clinical & Laboratory Standards Institute guidelines. Additionally, the four vitamin D metabolites in the serum of 38 apparently healthy Chinese volunteers were evaluated. The total analysis time was 8.0 min, with efficient separation of 3-epi 24,25(OH)₂D₃ and 3-epi 25OHD₃, without interference from isomers such as 23,25(OH)₂D₃ or 1,25(OH)₂D₂, 1,25(OH)₂D₃. Good reproducibility was obtained for all four metabolites with within-run coefficient variations (CVs) of 4.07%-6.55%, 4.26%-7.84%, 2.46%-7.21%, and 4.90%-6.87% for 25OHD₃, 25OHD₂, 24,25(OH)₂D₃, and 24,25(OH)₂D₂, respectively, and the total CVs were 4.29%-6.64%, 6.14%-7.84%, 4.33%-7.21%, 5.82%-9.90%, respectively. The limit of quantification was 0.625 ng/mL for 25OHD₃ and 25OHD₂, and 0.5 ng/mL for 24,25(OH)₂D₃ and 24,25(OH)₂D₂. The relative bias of the LC-MS/MS method compared to the certified results of SRM 972a for 25OHD₃, 25OHD₂ and 24,25(OH)₂D₃ was -2.21% to 1.01%, 3.38% to 6.73%, and -7.72% to -3.9%, respectively. The mean±SD values for 25OHD, 24,25(OH)₂D and 25OHD/24,25(OH)₂D in the volunteers were 13.5±4.4 ng/mL(range:7.6-27.5 ng/mL), 0.84±0.42 ng/mL (range:0.26-2.1 ng/mL), and 18±7(range:8-37), respectively. Thus, a simple, precise LC-MS/MS method for appropriate retention and separation of vitamin D metabolites and their epi analogs was developed.

Children With Vitamin D Deficiency: Is A Wrist X-Ray Necessary?

BACKGROUND

Rickets is failure in mineralization of growing bone and cartilage due to extreme vitamin D deficiency (VDD). The study aimed to identify rickets among vitamin D deficient children and determine any relationship between clinical findings and paraclinical evidence.

METHODS

This study was conducted in two stages. In the first stage, blood was drawn from 406 children aged 30-72 months for measurement of 25(OH)D level. Of these children, 108 had 25(OH)D levels of <20 ng/dL and were evaluated physically for signs and symptoms scores (0-1) of VDD and rickets. Biochemical analysis and radiography of the child's left wrist and hand was performed.

RESULTS

Of the 119 children (29.67%) with 25(OH)D levels of <20 ng/dL, 42 (10.3%) had vitamin D levels of ≤15 ng/dL. There was no correlation between serum 25(OH)D level and levels of calcium (Ca) (r = -0.16), alkaline phosphatase (ALP) (r = -0.12), P (r = 0.13), and parathyroid hormone (PTH) (r = -0.15,) in children with VDD. The mean of signs and symptoms scores had no significant difference between children with (1.59 ± 0.8) and without (1.73 ± 1.01) VDD (P = 0.3). None of the children with VDD had radiographic evidence of rickets. Radiographic data showed that 69.2% (72), 10.6% (11), and 20.2% (21) of the children had delayed, normal, and advanced bone age, respectively.

CONCLUSION

Abnormal radiological findings of rickets were not found on wrist X-rays. Thus, this investigation is not necessary within the range of vitamin D levels described in the current study.

Long-term treatment with metformin in type 2 diabetes and vitamin D levels: A post-hoc analysis of a randomized placebo-controlled trial

AIMS

To study the effects of metformin, as compared to placebo, on serum levels of vitamin D (25-hydroxyvitamin D [25(OH)D]) in patients with advanced type 2 diabetes.

MATERIALS AND METHODS

In the HOME trial, a randomized placebo-controlled trial, 390 insulin-treated patients with type 2 diabetes were treated with 850 mg metformin or placebo thrice daily for 52 months. In a post-hoc analysis, we examined changes in the combined levels of 25(OH)D₂ and 25(OH)D₃ at 4 and 16 months during the study.

RESULTS

Mean combined 25(OH)D at baseline was 68.2 nmoL/L (95% confidence interval [CI]: 65.5-71.1). In mixed model analysis, metformin, as compared to placebo, had no effect on 25(OH)D levels during 16 months (coefficient: 1.002 per month, multiplicative model; 95% CI: 0.998-1.006, P = .30). Metformin was associated with a small increase of 25(OH)D₂ (coefficient: 1.012 per month; 95% CI: 1.003-1.021, P = .008). However, 25(OH)D₂ is only a very small fraction (3%) of 25(OH)D. Seasonal variation had the biggest impact on 25(OH)D levels. Vitamin B12 levels were not associated with the levels of 25(OH)D.

CONCLUSION

Metformin had no effect on serum 25(OH)D during 16 months in the setting of a clinical randomized controlled trial in patients with type 2 diabetes. Our results show that metformin doesn't lead to vitamin D deficiency.

Interactions between Vitamin D Status, Calcium Intake and Parathyroid Hormone Concentrations in Healthy White-Skinned Pregnant Women at Northern Latitude

Adverse effects of low vitamin D status and calcium intakes in pregnancy may be mediated through functional effects on the calcium metabolic system. Little explored in pregnancy, we aimed to examine the relative importance of serum 25-hydroxyvitamin D (25(OH)D) and calcium intake on parathyroid hormone (PTH) concentrations in healthy white-skinned pregnant women. This cross-sectional analysis included 142 participants (14 ± 2 weeks' gestation) at baseline of a vitamin D intervention trial at 51.9 °N. Serum 25(OH)D, PTH, and albumin-corrected calcium were quantified biochemically. Total vitamin D and calcium intakes (diet and supplements) were estimated using a validated food frequency questionnaire. The mean ± SD vitamin D intake was 10.7 ± 5.2 μg/day. With a mean ± SD serum 25(OH)D of 54.9 ± 22.6 nmol/L, 44% of women were <50 nmol/L and 13% <30 nmol/L. Calcium intakes (mean ± SD) were 1182 ± 488 mg/day and 23% of participants consumed <800 mg/day. The mean ± SD serum albumin-adjusted calcium was 2.2 ± 0.1 mmol/L and geometric mean (95% CI) PTH was 9.2 (8.4, 10.2) pg/mL. PTH was inversely correlated with serum 25(OH)D (r = -0.311, p < 0.001), but not with calcium intake or serum calcium (r = -0.087 and 0.057, respectively, both p > 0.05). Analysis of variance showed that while serum 25(OH)D (dichotomised at 50 nmol/L) had a significant effect on PTH (p = 0.025), calcium intake (<800, 800⁻1000, ≥1000 mg/day) had no effect (p = 0.822). There was no 25(OH)D-calcium intake interaction effect on PTH (p = 0.941). In this group of white-skinned women with largely sufficient calcium intakes, serum 25(OH)D was important for maintaining normal PTH concentration.

Decreased Levels of Circulating Carboxylated Osteocalcin in Children with Low Energy Fractures: A Pilot Study

OBJECTIVE

In the past decades, an increased interest in the roles of vitamin D and K has become evident, in particular in relation to bone health and prevention of bone fractures. The aim of the current study was to evaluate vitamin D and K status in children with low-energy fractures and in children without fractures.

METHODS

The study group of 20 children (14 boys, 6 girls) aged 5 to 15 years old, with radiologically confirmed low-energy fractures was compared with the control group of 19 healthy children (9 boys, 10 girls), aged 7 to 17 years old, without fractures. Total vitamin D (25(OH)D3 plus 25(OH)D2), calcium, BALP (bone alkaline phosphatase), NTx (N-terminal telopeptide), and uncarboxylated (ucOC) and carboxylated osteocalcin (cOC) serum concentrations were evaluated. Ratio of serum uncarboxylated osteocalcin to serum carboxylated osteocalcin ucOC:cOC (UCR) was used as an indicator of bone vitamin K status. Logistic regression models were created to establish UCR influence for odds ratio of low-energy fractures in both groups.

RESULTS

There were no statistically significant differences in the serum calcium, NTx, BALP, or total vitamin D levels between the two groups. There was, however, a statistically significant difference in the UCR ratio. The median UCR in the fracture group was 0.471 compared with the control group value of 0.245 (p < 0.0001). In the logistic regression analysis, odds ratio of low-energy fractures for UCR was calculated, with an increased risk of fractures by some 78.3 times.

CONCLUSIONS

In this pilot study, better vitamin K status expressed as the ratio of ucOC:cOC-UCR—is positively and statistically significantly correlated with lower rate of low-energy fracture incidence.

Vitamin D Status and Immune Health Outcomes in a Cross-Sectional Study and a Randomized Trial of Healthy Young Children

In young children, the relationship between vitamin D and biomarkers of immune function is not well elucidated. The objective was to investigate relationships between vitamin D and immune function in young children. Data were from a cross-sectional study (study 1) of healthy children 1.8⁻5.9 years (n = 457) and a 12 weeks trial using vitamin D fortified foods (study 2) in healthy 1.8⁻8.7 years old (n = 77) in Montreal, Canada. Vitamin D status and ex vivo immune function were assessed. In study 1 (male: n = 242; 53%), plasma IL-6, TNFα and CRP were significantly higher (p < 0.05) in children with 25-hydroxyvitamin D (25(OH)D) ≥ 75 nmol/L compared to.

Occult urolithiasis in asymptomatic primary hyperparathyroidism

OBJECTIVE

Recent international guidelines suggest renal imaging to detect occult urolithiasis in all patients with asymptomatic primary hyperparathyroidism (PHPT), but data regarding their prevalence and associated risk factors are limited. We evaluated the prevalence and risk factors for occult urolithiasis.

METHODS

Cross-sectional analysis of 96 asymptomatic PHPT patients from a university hospital in the United States with and without occult nephrolithiasis.

RESULTS

Occult urolithiasis was identified in 21% of patients. Stone formers had 47% higher 24-hour urinary calcium excretion (p = 0.002). Although available in only a subset of patients (n = 28), activated vitamin D [1,25(OH)₂D] was 29% higher (p = 0.02) in stone formers. There was no difference in demographics, BMI, calcium or vitamin D intake, other biochemistries, renal function, BMD, or fractures. Receiver operating characteristic curves indicated that urinary calcium excretion and 1,25(OH)₂D had an area under the curve of 0.724 (p = 0.003) and 0.750 (p = 0.04), respectively. A urinary calcium threshold of >211mg/day provided a sensitivity of 84.2% and a specificity of 55.3% while a 1,25(OH)₂D threshold of >91pg/mL provided a sensitivity and specificity of 62.5% and 90.0% respectively for the presence of stones.

CONCLUSION

Occult urolithiasis is present in about one-fifth of patients with asymptomatic PHPT and is associated with higher urinary calcium and 1,25(OH)₂D. Given that most patients will not have occult urolithiasis, targeted imaging in those most likely to have occult stones rather than screening all asymptomatic PHPT patients may be useful. The higher sensitivity of urinary calcium versus 1,25(OH)₂D suggests screening those with higher urinary calcium may be an appropriate approach.

The use of synthetic and natural vitamin D sources in pig diets to improve meat quality and vitamin D content

This study investigated the effects of synthetic and natural sources of vitamin D biofortification in pig diets on pork vitamin D activity and pork quality. One hundred and twenty pigs (60 male, 60 female) were assigned to one of four dietary treatments for a 55 d feeding period. The dietary treatments were (1)50 μg vitamin D₃/kg of feed; (2)50 μg of 25-hydroxvitamin D₃/kg of feed (25-OH-D₃); (3)50 μg vitamin D₂/kg of feed; (4)50 μg vitamin D₂-enriched mushrooms/kg of feed (Mushroom D₂). The pigs offered the 25-OH-D₃ diet exhibited the highest (P < 0.001) serum total 25-hydroxyvitamin D concentration and subsequently exhibited the highest (P < 0.05) Longissimus thoracis (LT) total vitamin D activity. Mushroom D₂ and 25-OH-D₃ supplementation increased pork antioxidant status. The vitamin D₂-enriched mushrooms improved (P < 0.05) pig performance, carcass weight and LT colour. In conclusion, 25-OH-D₃ is the most successful source for increasing pork vitamin D activity, while Mushroom D₂ may be a new avenue to improve animal performance and pork quality.

Obesity, Bariatric Surgery, and Vitamin D

The high prevalence of obesity is a worldwide problem associated with multiple comorbidities, including cardiovascular diseases. Vitamin D deficiency with secondary hyperparathyroidism is common in obese individuals and can be aggravated after bariatric surgery. Moreover, there is no consensus on the optimal supplementation dose of vitamin D in postbariatric surgical patients. We present new data on the variability of 25(OH)D response to supplementation in postmenopausal obese women. It is important to recognize and treat vitamin D deficiency before bariatric surgery to avoid postoperative complications, such as metabolic bone disease with associated high fracture risk. The objective of this article is to discuss the bone metabolism consequences of vitamin D deficiency after bariatric surgery.

Circulating concentrations of vitamin D in relation to pancreatic cancer risk in European populations

Evidence from in vivo, in vitro and ecological studies are suggestive of a protective effect of vitamin D against pancreatic cancer (PC). However, this has not been confirmed by analytical epidemiological studies. We aimed to examine the association between pre-diagnostic circulating vitamin D concentrations and PC incidence in European populations. We conducted a pooled nested case-control study within the European Prospective Investigation into Cancer and Nutrition (EPIC) and the Nord-Trøndelag Health Study's second survey (HUNT2) cohorts. In total, 738 primary incident PC cases (EPIC n = 626; HUNT2 n = 112; median follow-up = 6.9 years) were matched to 738 controls. Vitamin D [25(OH)D2 and 25(OH)D3 combined] concentrations were determined using isotope-dilution liquid chromatography-tandem mass spectrometry. Conditional logistic regression models with adjustments for body mass index and smoking habits were used to estimate incidence rate ratios (IRRs) and 95% confidence intervals (95%CI). Compared with a reference category of >50 to 75 nmol/L vitamin D, the IRRs (95% CIs) were 0.71 (0.42-1.20); 0.94 (0.72-1.22); 1.12 (0.82-1.53) and 1.26 (0.79-2.01) for clinically pre-defined categories of ≤25; >25 to 50; >75 to 100; and >100 nmol/L vitamin D, respectively (p for trend = 0.09). Corresponding analyses by quintiles of season-standardized vitamin D concentrations also did not reveal associations with PC risk (p for trend = 0.23). Although these findings among participants from the largest combination of European cohort studies to date show increasing effect estimates of PC risk with increasing pre-diagnostic concentrations of vitamin D, they are not statistically significant.

Biomarkers of cardiometabolic health and nutritional status in individuals with positive celiac disease serology

BACKGROUND

Celiac disease (CD) is an autoimmune disorder characterized by damage to the intestinal mucosa and nutrient malabsorption in severe cases. However, it remains unclear whether nutrient deficiencies and other adverse health effects are prevalent in individuals with positive CD serology identified through screening studies.

OBJECTIVE

The objective was to determine whether biomarkers of cardiometabolic health and nutritional status differ between those with positive and negative CD serology identified in a screening study of Canadian adults.

METHODS

Participants ( n=2832) were from the Toronto Nutrigenomics and Health Study and the Toronto Healthy Diet Study. Individuals were screened for CD-specific anti-tissue transglutaminase autoantibodies. Lipid profiles as well as concentrations of six carotenoids (α-carotene, β-carotene, β-cryptoxanthin, lutein, lycopene, and zeaxanthin), three tocopherols (α-tocopherol, δ-tocopherol, and γ-tocopherol), retinol, ascorbic acid, and 25-hydroxyvitamin D were cross-sectionally compared between those with positive and negative CD serology using general linear mixed models.

RESULTS

Individuals with positive CD serology ( n=23) had significantly lower levels of HDL-cholesterol ( p=0.008) and apolipoprotein-AI ( p=0.02), a higher ratio of total cholesterol to HDL-cholesterol ( p=0.006), and a higher apolipoprotein-B/AI ratio ( p=0.03) than those with negative CD serology. Positive CD serology was also associated with significantly lower concentrations of retinol ( p=0.006) in fully adjusted models. Those with positive CD serology had lower serum 25-hydroxyvitamin D in unadjusted models ( p=0.01), but not in fully adjusted models ( p=0.08).

CONCLUSIONS

Individuals with undiagnosed CD may have unfavorable lipid profiles and be at elevated risk for inadequacy of certain fat-soluble vitamins, but not widespread nutrient deficiencies.

Vitamin D assays in clinical laboratory: Past, present and future challenges

Vitamin D status is usually assessed by measuring the serum 25-hydroxyvitamin D (25(OH)D) concentration. There has been a dramatic increase in 25-OHD requests over recent years prompting many laboratories to consider the use of automated immunoassays. In this presentation, we will discuss and compare the two major techniques that are used for measuring of vitamin D (the binding assay and chemical assay techniques). Chemiluminescence immunoassays (CLIA), radioimmunoassy (RIA), and binding protein assay are belonging to the binding assay, while the chemical assay includes high performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Significant differences in the 25(OH)D determination were observed between various assays. Standardization and harmonization of 25(OH)D measurements are therefore urgently needed. The widespread introduction of well standardized assays in clinical laboratories is the challenge in the next years.

Development of Standard Reference Material (SRM) 2973 Vitamin D Metabolites in Frozen Human Serum (High Level)

The National Institute of Standards and Technology (NIST), in collaboration with the National Institutes of Health Office of Dietary Supplements and the Vitamin D Standardization Program, has recently issued a new serum-matrix Standard Reference Material (SRM): 2973 Vitamin D Metabolites in Frozen Human Serum (High Level). SRM 2973 was designed to provide a serum material with a total 25-hydroxyvitamin D [25(OH)D] concentration near 100 nmol/L to complement the existing serum-based SRMs with values assigned for total 25(OH)D between 20 and 80 nmol/L. Values were assigned for 25-hydroxyvitamin D2 [25(OH)D2], 25-hydroxyvitamin D3 [25(OH)D3], 3-epi-25(OH)D3, and total 25(OH)D [the sum of 25(OH)D2 + 25(OH)D3] using the NIST isotope dilution LC with tandem MS (MS/MS) reference measurement procedure (RMP) and related methods. SRM 2973 has a certified value of 98.4 ± 2.1 nmol/L for 25(OH)D3 and reference values of 1.59 ± 0.05 nmol/L for 25(OH)D2 and 5.23 ± 0.20 nmol/L for 3-epi-25(OH)D3. In addition, a candidate RMP for 24R,25-dihydroxyvitamin D3 [24R,25(OH)2D3] based on LC-MS/MS was used to assign values to SRM 2973 and the existing SRM 972a Vitamin D Metabolites in Frozen Human Serum. Reference values for 24R,25(OH)2D3 were assigned to SRM 2973 (7.51 ± 0.26 nmol/L) and the four levels of SRM 972a: Level 1 (6.38 ± 0.23 nmol/L), Level 2 (3.39 ± 0.12 nmol/L), Level 3 (3.88 ± 0.013 nmol/L), and Level 4 (6.32 ± 0.22 nmol/L). The development of SRM 2973 [with a higher concentration of 25(OH)D3] and the addition of values for 24R,25(OH)2D3 assigned to both SRM 972a and SRM 2973 provide laboratories involved in vitamin D measurements with improved QA tools.

Pilot study of parathyroid glands in adult and pediatric subjects exposed to ionizing radiation after the ChNPP accident, methodology of parathyroid diagnostic ultrasound

OBJECTIVE

Estimation of the parathyroid hyperplasia prevalence after the ChNPP accident in adults exposed to ion izing radiation and their descendants using the diagnostic ultrasound and its methodology elaboration.

MATERIALS AND METHODS

The pilot prospective study of the prevalence of parathyroid hyperplasia among the Chornobyl Nuclear Power Plant (ChNPP) accident adult survivors (n=686) and their descendants (54 children) was performed using diagnostic ultrasound examination of thyroid and parathyroids. Among the study subjects there were 339 ChNPP accident clean up workers (ACUW), 32 persons were evacuated from the 30 km exclusion zone and 224 ones were included to the control group. Diagnostic ultrasound of thyroid and parathyroids was performed according to the standard method. Additionally, in children with parathyroid hyperplasia an additional assay of 25 hydroxyvitamin D levels in serum was performed. In calculating the statistical significance, its level p < 0.05 was considered statistically significant.

RESULTS

Parathyroids are a few small but critically important endocrine glands that synthesize parathyroid hormone, regulating mainly phosphoric calcium metabolism. Insufficient (hypoparathyroidism) or excessive (hyperparathy roidism) function of parathyroids is harmful to the patients affecting the state of nervous and cardiovascular sys tem. Parathyroidss can accumulate isotopes of cesium, strontium and radioactive iodine. The available data testify to an increased incidence of clinically significant hyperplasia of parthyroids (more than 9 mm in adults and more than 5 mm in children) among persons exposed toionizng radiation as a result of the accident at the ChNPP (28.64%) and their descendants (23.8-70.6%). First of all are concerned those adults who live in contaminated areas in comparison with the control group (24.15% in not irradiated). Evacuees from the 30 km exclusion zone being the category of people who were exposed to the absorbed iodine isotopes in the first days of the Chernobyl accident are the another risk group. These data demonstrate sensitivity of parathyroidss to the impact of incorpo rated isotopes (iodine, cesium and strontium), which in the long term exposure create conditions for structural and functional changes in regulation of phosphorous calcium metabolism being the basis for a significant prevalence of osteopenia and osteoporosis in irradiated individuals and their descendants. A number of further studies are required to clarify the findings and to disclose the hormonal mechanisms of radiation effects on parathyroids.

CONCLUSIONS

Parathyroid glands are radiosensitive and susceptible to effects of strontium, cesium and iodine iso topes, which cause parathyroid irradiation and subsequent structural and functional changes, being a prerequisite for development of osteopenia and osteoporosis in the ChNPP accident survivors and their descendants. High inci dence of parathyroid hypertrophy is found in the inhabitants of the radiation contaminated territories (long term irradiation by cesium isotopes), as well as in evacuated from the 30 km exclusion zone (irradiation by iodine iso topes in the early days of the accident).

The vitamin D receptor functional variant rs2228570 (C>T) does not associate with type 2 diabetes mellitus

AIM

Vitamin D acts through the binding to the vitamin D receptor (VDR). Several polymorphisms in VDR gene have been studied. Among these, the rs2228570 C>T (FokI) variant has been demonstrated to be functional, leading to a protein with a different size and activity. So far, genetic studies on the association between VDR gene rs2228570 single nucleotide polymorphism (SNP) and type 2 diabetes mellitus (T2DM) showed contradictory results. Thus, we performed an association study in a large cohort of adult Italian subjects with T2DM and in nondiabetic controls.

MATERIALS AND METHODS

For this study, 1713 subjects, 883 T2DM patients and 830 controls, were genotyped for the polymorphism. All participants without a diagnosis of diabetes underwent oral glucose tolerance test (OGTT), with measurement of glucose and insulin levels. Indices of insulin resistance (Homeostatic model assessment of insulin resistance, insulin sensitivity index), secretion (homeostatic model assessment for beta-cell, corrected insulin response at 30 minutes) and disposition index were calculated.

RESULTS

Genotype distributions and allele frequencies did not show difference between T2DM subjects and controls. We did not find significant differences among the three genotypes regarding gender, age, BMI, waist, hip, waist-to-hip ratio, and blood pressure. There were also no significant differences in lipid parameters, aspartate aminotransferase, and alanine aminotransferase levels. We tested for association with OGTT-derived data and surrogate indices of insulin resistance and secretion. We did not find significant differences among the genotypes in any of above-mentioned parameters. Furthermore, vitamin D levels were measured in a subgroup of subjects. We did not find significant differences among the genotypes.

CONCLUSIONS

Our study does not provide evidence for the association of the rs2228570 polymorphism with T2DM in a Caucasian population.

Role of the National Institute of Standards and Technology (NIST) in Support of the Vitamin D Initiative of the National Institutes of Health, Office of Dietary Supplements

Since 2005, the National Institute of Standards and Technology (NIST) has collaborated with the National Institutes of Health (NIH), Office of Dietary Supplements (ODS) to improve the quality of measurements related to human nutritional markers of vitamin D status. In support of the NIH-ODS Vitamin D Initiative, including the Vitamin D Standardization Program (VDSP), NIST efforts have focused on (1) development of validated analytical methods, including reference measurement procedures (RMPs); (2) development of Standard Reference Materials (SRMs); (3) value assignment of critical study samples using NIST RMPs; and (4) development and coordination of laboratory measurement QA programs. As a result of this collaboration, NIST has developed RMPs for 25-hydroxyvitamin D2 [25(OH)D2], 25(OH)D3, and 24R,25-dihydroxyvitamin D3 [24R,25(OH)2D3]; disseminated serum-based SRMs with values assigned for 25(OH)D2, 25(OH)D3, 3-epi-25(OH)D3, and 24R,25(OH)2D3; assigned values for critical samples for VDSP studies, including an extensive interlaboratory comparison and reference material commutability study; provided an accuracy basis for the Vitamin D External Quality Assurance Scheme; coordinated the first accuracy-based measurement QA program for the determination of 25(OH)D2, 25(OH)D3, and 3-epi-25(OH)D3 in human serum/plasma; and developed methods and SRMs for the determination of vitamin D and 25(OH)D in food and supplement matrix SRMs. The details of these activities and their benefit and impact to the NIH-ODS Vitamin D Initiative are described.

Vitamin D Sufficiency of Canadian Children Did Not Improve Following the 2010 Revision of the Dietary Guidelines That Recommend Higher Intake of Vitamin D: An Analysis of the Canadian Health Measures Survey

In 2010, the dietary guidelines for vitamin D for Canadians and Americans aged 1–70 years were revised upward. It is unknown whether the vitamin D status of Canadian children improved after 2010. We compared the prevalence of vitamin D sufficiency (25-hydroxy vitamin D (25(OH)D) concentration of ≥50 nmol/L), 25(OH)D concentration and the frequency of consuming vitamin D-rich foods among children aged 6–18 years-old using data from the nationally representative 2007/2009 and 2012/2013 Canadian Health Measures Surveys. Associations of sociodemographic, anthropometric, seasonal, and regional variables with achieving vitamin D sufficiency, 25(OH)D concentration, and consumption of vitamin D-rich foods were assessed using multiple logistic and linear regression models. 79% and 68% of children in 2007/2009 and 2012/2013 respectively, were vitamin D sufficient. The main dietary source of vitamin D was milk. Between 2007/2009 and 2012/2013, the frequency of milk and fish consumption declined, but egg and red meat consumption was unchanged. Age, income, weight status, season and ethnicity were associated with 25(OH)D concentration and vitamin D sufficiency. Vitamin D status declined after the upward revision of dietary guidelines for vitamin D, consequently, dietary intake was inadequate to meet sufficiency. Public health initiatives to promote vitamin D-rich foods and supplementation for Canadian children are needed.

Concordance of vitamin D peripheral levels in infertile couples' partners

A large number of evidence supports the role of vitamin D insufficiency in both women and men infertility. However, no studies have evaluated the rate of concordance of vitamin D status between the partners. This finding might open new scenarios in the interpretation of the available data linking vitamin D insufficiency and infertility. In the present cross-sectional study, 103 consecutive infertile couples were recruited between April and May 2014. Both partners concomitantly provided a serum sample for the assessment of 25-hydroxy-vitamin D [25-(OH)-D]. Vitamin D insufficiency was defined as serum 25-(OH)-D <20 ng/ml. One hundred-fifty subjects (73 women and 77 males) were 25-(OH)-D insufficient, corresponding to a rate of 73%. Overall, concordance was observed in 73 couples (71%), thus higher than the expected 61% (0.732 + 0.272) based on chance (p = 0.007). The Pearson coefficient of correlation R2 between the partners of the couples was 0.52 (p < 0.001). No statistically significant differences emerged when evaluating the rate of 25-(OH)-D insufficiency according to the causes of infertility. Serum 25-(OH)-D correlates within the partners of infertile couples. Further evidence is warranted to determine the clinical relevance and possible clinical applications of this finding.

Does Vitamin D Status Correlate with Cardiometabolic Risk Factors in Adults with Growth Hormone Deficiency?

Apart from being individually associated with cardiometabolic health, 25(OH)D and IGF-1 interplay with a positive correlation between them, which raises questions about the role of vitamin D for the adverse cardiovascular (CV) risk profile in hyposomatotropism. Thus, we aimed to investigate vitamin D status in GH deficiency (GHD) and the association between 25(OH)D and metabolic syndrome (MetS), its components, and other surrogate markers of CV risk. A total of 129 GHD adults (childhood-onset GHD, 41.9%) underwent blood testing (glucose, insulin, lipid profile, uric acid); blood pressure, anthropometric and bioelectrical-impedance measurements. Other CV risk markers were examined in a subsample of the initial population - hsCRP, adiponectin, and asymmetric dimethylarginine (n=88); carotid intima-media thickness (n=44). Total serum 25(OH)D, measured by electro-chemiluminescence binding assay, was used for vitamin D status assessment (adequate,≥30 ng/ml; insufficient, 20-29.9 ng/ml; deficient,<20 ng/ml). Data demonstrated high prevalence of hypovitaminosis D in GHD (deficiency 79.1%; insufficiency 14.7%), with lower 25(OH)D among adult-onset GHD subjects (14.0±7.2 vs. 16.8±8.0 ng/ml, p=0.039) and patients with MetS (11.8±4.5 vs. 16.3±8.1 ng/ml, p<0.0001). 25(OH)D correlated negatively and weakly with BMI, waist circumference, percent body fat, visceral fat area, and systolic BP. Regardless of whether vitamin D is a cause or a consequence of these metabolic abnormalities, 25(OH)D testing in hyposomatotropism is advisable. Normalization of vitamin D status is not proven to improve CV outcomes in general population, but it might have favorable effects in GHD, as its benefits might be restricted to patients with both low 25(OH)D and certain risk factors.

[Hypovitaminosis D in Children with Hashimoto’s Thyroiditis]

BACKGROUND

Vitamin D deficiency or insufficiency may play a role in the pathogenesis of certain autoimmune diseases.

AIM

To measure vitamin D levels in children with Hashimoto’s thyroiditis (HT) (either with subclinical or marked hypothyroidism) and in healthy controls.

MATERIAL AND METHODS

We included 68 children with HT aged 12 ± 4 years (39 females) from a pediatric outpatient clinic and 68 healthy children aged 10 ± 4 years (37 females). Calcium metabolism parameters, thyroid function tests and anti-thyroid peroxidase (anti-TPO), anti-thyroglobulin (anti-TG) and 25 hydroxy vitamin D (25OHD) levels were measured.

RESULTS

Patients were older than controls but well matched by gender distribution. Mean 25OHD levels were significantly lower in HT patients than controls (16.8 ± 9.3 and 24.1 ± 9.4 ng/mL respectively, P < 0.01). Frequency of vitamin D deficiency was 76 and 35% in HT patients and controls, respectively (P < 0.001).

CONCLUSIONS

Vitamin D deficiency is more common in children with HT than healthy controls.

Development of an Improved Standard Reference Material for Vitamin D Metabolites in Human Serum

The National Institute of Standards and Technology (NIST) has developed Standard Reference Material (SRM) 972a Vitamin D Metabolites in Frozen Human Serum as a replacement for SRM 972, which is no longer available. SRM 972a was developed in collaboration with the National Institutes of Health's Office of Dietary Supplements. In contrast to the previous reference material, three of the four levels of SRM 972a are composed of unmodified human serum. This SRM has certified and reference values for the following 25-hydroxyvitamin D [25(OH)D] species: 25(OH)D2, 25(OH)D3, and 3-epi-25(OH)D3. The value assignment and certification process included three isotope-dilution mass spectrometry approaches, with measurements performed at NIST and at the Centers for Disease Control and Prevention (CDC). The value assignment methods employed have been modified from those utilized for the previous SRM, and all three approaches now incorporate chromatographic resolution of the stereoisomers, 25(OH)D3 and 3-epi-25(OH)D3.

Vitamin D Status, Muscle Strength and Physical Performance Decline in Very Old Adults: A Prospective Study

Mixed reports exist about the role of 25-hydroxyvitamin D (25(OH)D) in muscle ageing and there are few prospective studies involving the very old (aged ≥ 85) who are at highest risk of low 25(OH)D, loss of muscle mass and strength, and physical performance decline. In the Newcastle 85+ Study (n = 845), we aimed to determine the association between 25(OH)D season-specific quartiles (hereafter SQ1–SQ4), grip strength (GS) and physical performance decline (Timed Up-and-Go Test, TUG) over 5 years using mixed models. In the time-only models with linear and quadratic slopes, SQ1 and SQ4 of 25(OH)D were associated with weaker GS initially in men (SQ1: β (SE) = −2.56 (0.96); SQ4: −2.16 (1.06)) and women (SQ1: −1.10 (0.52); SQ4: −1.28 (0.50)) (all p ≤ 0.04). In the fully adjusted models, only men in SQ1 had a significant annual decline in GS of 1.41 kg which accelerated over time (−0.40 (0.1)), (both p ≤ 0.003) compared with those in combined middle quartiles. Only women in SQ1 and SQ4 of 25(OH)D had worse TUG times initially, but the rate of TUG decline was not affected. Low baseline 25(OH)D may contribute to muscle strength decline in the very old and particularly in men.

Distal lower limb strength is reduced in subjects with impaired glucose tolerance and is related to elevated intramuscular fat level and vitamin D deficiency

AIM

To quantify muscle strength and size in subjects with impaired glucose tolerance (IGT) in relation to intramuscular non-contractile tissue, the severity of neuropathy and vitamin D level.

METHODS

A total of 20 subjects with impaired glucose tolerance and 20 control subjects underwent assessment of strength and size of knee extensor, flexor and ankle plantar and dorsi-flexor muscles, as well as quantification of intramuscular non-contractile tissue and detailed assessment of neuropathy and serum 25-hydroxy vitamin D levels.

RESULTS

In subjects with impaired glucose tolerance, proximal knee extensor strength (P = 0.17) and volume (P = 0.77), and knee flexor volume (P = 0.97) did not differ from those in control subjects. Ankle plantar flexor strength was significantly lower (P = 0.04) in the subjects with impaired glucose tolerance, with no difference in ankle plantar flexor (P = 0.62) or dorsiflexor volume (P = 0.06) between groups. Intramuscular non-contractile tissue level was significantly higher in the ankle plantar flexors and dorsiflexors (P = 0.03) of subjects with impaired glucose tolerance compared with control subjects, and it correlated with the severity of neuropathy. Ankle plantar flexor muscle strength correlated significantly with corneal nerve fibre density (r = 0.53; P = 0.01), a sensitive measure of small fibre neuropathy, and was significantly lower in subjects with vitamin D deficiency (P = 0.02).

CONCLUSIONS

People with impaired glucose tolerance have a significant reduction in distal but not proximal leg muscle strength, which is not associated with muscle atrophy, but with increased distal intramuscular non-contractile tissue, small fibre neuropathy and vitamin D deficiency.

High and low vitamin D level is associated with cardiovascular autonomic neuropathy in people with Type 1 and Type 2 diabetes

AIM

To investigate the possible association between vitamin D deficiency and cardiovascular autonomic neuropathy in people with diabetes.

METHODS

A total of 113 people with Type 1 or Type 2 diabetes [mean (interquartile range) diabetes duration 22.0 (12-31) years, mean (sd) age 56.2 (13.0) years, 58% men] underwent vitamin D (D2 and D3) assessment, and were screened for cardiovascular autonomic neuropathy using three cardiovascular reflex tests [heart rate response to deep breathing (E/I ratio), to standing (30/15 ratio) and to the Valsalva manoeuvre] and assessment of 5-min resting heart rate and heart rate variability indices.

RESULTS

We found an inverse U-shaped association between serum vitamin D level and E/I ratio, 30/15 ratio and three heart rate variability indices (P < 0.05). Vitamin D level was non-linearly associated with cardiovascular autonomic neuropathy diagnosis (P < 0.05 adjusted for age and sex). Linear regression models showed that an increase in vitamin D level from 25 to 50 nmol/l was associated with an increase of 3.9% (95% CI 0.1;7.9) in E/I ratio and 4.8% (95% CI 4.7;9.3) in 30/15 ratio. Conversely, an increase from 125 to 150 nmol/l in vitamin D level was associated with a decrease of 2.6% (95% CI -5.8;0.1) and 4.1% (95% CI -5.8;-0.5) in the respective outcome measures.

CONCLUSIONS

High and low vitamin D levels were associated with cardiovascular autonomic neuropathy in people with diabetes. Future studies should explore this association and the efficacy of treating dysvitaminosis D to prevent cardiovascular autonomic neuropathy.

Improvement in Neuropathy Specific Quality of Life in Patients with Diabetes after Vitamin D Supplementation

OBJECTIVE

To assess the effect of vitamin D supplementation on neuropathy specific quality of life (NeuroQoL) in patients with painful diabetic neuropathy.

METHODS

This prospective, open label study was conducted between June 2012 and April 2013. Patients with symptomatic diabetic neuropathy were given a single dose of 600,000 IU intramuscular vitamin D, and NeuroQol was assessed at baseline and at five follow-up visits every 4 weeks.

RESULTS

Of 143 participants, 41.3% were vitamin D deficient (vitamin D < 20 ng/ml). Treatment with vitamin D resulted in a significant increase in 25(OH)D (P < 0.0001) and a significant improvement in the NeuroQoL subscale score for emotional distress (P = 0.04), with no significant change in the other NeuroQoL domains of painful symptoms and paresthesia, loss of temperature and touch sensation, unsteadiness, limitation in daily activities, and interpersonal problems. There was a significant reduction in patient perception about foot problems on QoL of "quite a lot" (P < 0.05) and "very much" (P < 0.0001) with a significant reduction in the baseline response of having a "poor" QoL from 5.2% to 0.7% (P < 0.0001) and an increase in the response of an "excellent QoL" from 1.5% to 7.4% (P < 0.0001).

CONCLUSION

Vitamin D is effective in improving quality of life in patients with painful diabetic neuropathy.

A Rapid and Simple Liquid-Chromatography-Tandem Mass Spectrometry Method for Measuring 25-Hydroxyvitamin D2 and 25-Hydroxyvitamin D3 in Human Serum: Comparison with Two Automated Immunoassays

BACKGROUND

Total 25-hydroxyvitamin D (25(OH)D) is well-known to be a reliable biomarker of human vitamin D status, with the recognition of widespread vitamin D insufficiency in general populations. The aims of this study are to validate a fast and simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for quantifying 25(OH)D₂ and 25(OH)D₃ in serum and to compare two automated immunoassays with the LC-MS/MS method.

METHODS

Samples were prepared by protein precipitation with ethanol including 25(OH)D₃-d₆, followed by a liquid-liquid extraction with hexane. The analytes were separated within a total run time of 3 min. Accuracy was evaluated with standard reference materials (SRM) 972a. Using 150 samples, the LC-MS/MS method was compared with the LIAISON^® assay and ADVIA Centaur^® assay.

RESULTS

The LC-MS/MS method had a limit of quantitation of 1 ng/mL for the 25(OH)D₂ and 25(OH)D₃ with linear responses between 1 and 100 ng/mL. Intra- and inter-assay precision were <8.8% and <13.2%, respectively. It also showed a smallest mean difference (+0.9%) for the SRM level 1 to 3, compared to the two immunoassays. Compared to the LC-MS/MS, the mean biases of the RIAISON and ADVIA were +2.4 and +7.9 ng/mL, respectively. Also, the agreement of the LC-MS/MS with the RIAISON was better than that with the ADVIA.

CONCLUSION

This study suggests that the LC-MS/MS method traceable to the SRM can be reliably applied in routine quantification of 25(OH)D₂ and 25(OH)D₃.

Comparison of two methods for measuring 25-OH vitamin D in the follow-up of patients after bilio-pancreatic diversion bariatric surgery

OBJECTIVE

Our objective was to compare the ECLIA from Roche versus the LC-MS/MS method for quantitation of serum 25-hydroxy-vitamin D in patients who have undergone bariatric surgery.

DESIGN AND METHODS

Cross-sectional and correlational studies were performed on three different groups for the 25-OH-D levels quantitated by both methods. The control group of apparently healthy subjects was randomly selected in a clinical chemistry laboratory. Test groups were patients who had undergone bilio-pancreatic diversion (BPD) and were supplemented either with vitamin D₂ or with vitamin D₃. The number of samples per group was established according to the CLSI recommendation protocol (EPO9-A2-IR).

RESULTS

The agreement of LC-MS/MS with the Roche method was acceptable in the apparently healthy subjects group and in the post-BPD D₃-supplemented group with an average bias of -1.7% and -9.2%, respectively. However, this agreement was unacceptable in the post-BPD D₂-supplemented group with an average bias of -45.3%. The LC-MS/MS enabled us to detect four patients who had excess vitamin D or poisoning with vitamin D for which it was necessary to stop the supplementation with vitamin D in the D₂ -supplemented group.

CONCLUSION

Despite the apparent good agreement between the Roche method and LC-MS/MS in the healthy subjects group and in the post-DBP D₃-supplemented patient group, a considerable bias seems to exist, particularly in the presence of D₂. The LC-MS/MS method is therefore the most accurate method to follow the vitamin D₂ -supplemented bariatric population.

[Serum levels of vitamin D in systemic lupus erythematosus patients (SLE) and their relationship with disease activity: longitudinal study]

OBJECTIVE

To determine changes over time of serum levels of 25-hydroxy vitamin D (25(OH)D) in Mexican patients with SLE and their relationship with disease activity.

MATERIALS AND METHODS

Longitudinal and observational study. Women with SLE were included. Serum levels of 25(OH)D were measured at baseline and after two years; the disease activity was measured with MEX-SLEDAI. Patients with initial suboptimal levels of 25(OH)D received supplements or increased doses of calcitriol.

RESULTS

105 women with SLE were included, mean age 49.4 ± 11 years. Serum levels of 25(OH)D were higher at two years (baseline 20 ± 6.8 vs. follow-up 22.7 ± 7.7; p = < 0.001). There were no differences between disease activity scores at baseline and two years (baseline 1.7 ± 1.9 vs. follow-up 1.1 ± 1.7; p = 0.7). Serum levels of 25(OH)D did not correlate with disease activity during the follow up, p = 0.7. No correlation was found between changes in MEX-SLEDAI scores and serum levels of 25(OH)D, p = 0.87.

CONCLUSION

Mexican women with SLE had increased serum levels of 25(OH)D. No correlation between serum levels of 25(OH)D and disease activity was found.