Epidemiology of vitamin D in health and disease

Association Between Serum Vitamin D Levels and Body Mass Index Status: A Cross-Sectional Study at King Khalid Hospital, Jeddah, Saudi Arabia, From 2019 to 2020

Introduction Low vitamin D levels have been associated more with overweight and obese people in previous studies. One of the possible explanations behind this association is the lipophilic property of vitamin D that causes the vitamin to deposit in adipose tissue and reduces the serum concentration of the vitamin, which still warrants further evaluation. Objective This study estimated the association between serum vitamin D levels and body mass index (BMI) among male patients in Jeddah, Saudi Arabia. Methods This is a cross-sectional study of male patients that was carried out in King Khalid Hospital, Jeddah, Saudi Arabia. Patients were included between October 2019 and November 2020. Results We concluded that almost half of the patients, 1,132 (48.3%), had adequate vitamin D, followed by 773 (33%) with vitamin D inadequacy, and only 288 (12.3%) had vitamin D deficiency. There was a significant relationship between age and vitamin D levels; younger people had lower vitamin D levels compared to older people (p<0.001). It was found that there was no significant relationship between BMI categories and vitamin D levels (p>0.05). Conclusion According to the findings of the current study, there was no discernible relationship between serum vitamin D levels and BMI. However, there was a substantial correlation between age and vitamin D levels, with younger age groups having lower amounts than older individuals. Future studies should adopt a prospective design encompassing multiple centers and preferably include the risk factors for developing vitamin D deficiency, such as sun exposure, dietary habits, comorbidities, etc. Such studies can provide a more accurate assessment of the association between BMI and vitamin D levels.

Study on the relationship between vitamin D level and macrophage typing in patients with type 2 diabetes mellitus

Objective

Population studies have shown that vitamin D (VitD) deficiency is associated with an increased incidence of type 2 diabetes mellitus (T2DM), VitD deficiency is a potential risk factor for T2DM, and the proportion of M1-type macrophages and M2-type macrophages in T2DM patients is imbalanced. Another study reported that VitD can affect the differentiation of macrophages into M1 and M2 types. However, there is no definitive result about the correlation between plasma VitD levels and macrophage typing in patients with T2DM. Whether VitD affects the progression of T2DM by regulating the polarization type of macrophages and the specific regulatory mechanism is not very clear. Therefore, we carried out the following research.

Methods

We first used flow cytometry to detect the proportions of M1 and M2 macrophages in peripheral blood of T2DM patients with different VitD levels. Furthermore, we used ELISA to detect the inflammatory factors affecting macrophage differentiation in patients’ plasma, including IL-6 secreted by M1-type macrophages and TGF-β secreted by M2-type macrophages. Mononuclear cells were separated from human peripheral blood with immunomagnetic beads, cultured in vitro, and treated with different concentrations of VitD, and the ratio of differentiation into M1 and M2 macrophages was detected by flow cytometry.

Results

With the increase of serum 25(OH)D levels in patients with T2DM, the proportion of M1 and M2 macrophages in peripheral blood decreased, that is, the polarized phenotype of macrophages was more inclined to M2 type, while plasma IL-6 gradually decreased, and TGF-β gradually increased. In addition, VitD can promote the differentiation of CD14-positive monocytes cultured in vitro into M2 macrophages.

Conclusions

When the level of VitD in T2DM patients is low, there are more M1-type macrophages in peripheral blood, and when the level of VitD is increased, M2-type macrophages are increased. Changes in related inflammatory factors were also consistent. In vitro culture of monocytes further confirmed that VitD can promote the differentiation of macrophages to M2 type in T2DM patients.

Low serum level of 25-OH vitamin D relates to Th17 and treg changes in colorectal cancer patients

BACKGROUND

Serum 25-hydroxyvitamin D [25(OH)D] level alters in colorectal cancer (CRC) development. Regulatory T (Treg) cells and T- helper type 17 (Th17) cells are involved in immune response. Th17-mediated proinflammatory responses contribute to tumorigenesis, and Treg plays different roles in different periods of CRC. Vitamin D deficiency is associated with significant variations in peripheral immune cells. This study investigated the relationship between Th17 and Treg cells and 25(OH)D level in CRC.

METHODS

Ninety-five CRC patients were included, as well as 80 healthy controls during the same period at the Affiliated Hospital of Jiangnan University. 25(OH)D level was analyzed through electrochemiluminescence (ECLIA). Th17 and Treg levels were evaluated through flow cytometry. Serum levels of interleukin (IL)-10, IL-17, IL-23, and transforming growth factor-β (TGF-β), were analyzed through commercial enzyme-linked immunoassay (ELISA) kits.

RESULTS

25(OH)D levels were downregulated in the serum of CRC patients. Decreased 25(OH)D level contributed to CRC pathogenesis. Decreased 25(OH)D level in CRC correlated with increased Treg and Th17 cell ratios and TGF-β1, IL-10, IL-17, and IL-23 levels in peripheral blood.

CONCLUSION

Decreased 25(OH)D level in the serum of CRC patients had negative correlation with Treg and Th17 ratios and relative cytokines levels.

The Role of CYP3A in Health and Disease

CYP3A is an enzyme subfamily in the cytochrome P450 (CYP) superfamily and includes isoforms CYP3A4, CYP3A5, CYP3A7, and CYP3A43. CYP3A enzymes are indiscriminate toward substrates and are unique in that these enzymes metabolize both endogenous compounds and diverse xenobiotics (including drugs); almost the only common characteristic of these compounds is lipophilicity and a relatively large molecular weight. CYP3A enzymes are widely expressed in human organs and tissues, and consequences of these enzymes' activities play a major role both in normal regulation of physiological levels of endogenous compounds and in various pathological conditions. This review addresses these aspects of regulation of CYP3A enzymes under physiological conditions and their involvement in the initiation and progression of diseases.

Optimization of Automated Sample Preparation for Vitamin D Determination on a Biomek i7 Workstation

Vitamin D belongs to the fat-soluble vitamins and is an integral part of bone metabolism. In the human body, a decreased vitamin D level can be an additional risk factor for diseases like cancer, diabetes, and mental diseases. As a result, an enormous increase in the demand for vitamin D testing has been observed in recent years, increasing the demand for powerful methods for vitamin D determination at the same time.Automation is the key factor in increasing sample throughput. This study compares three fully automated sample preparation methods for the determination of 25(OH)D₂ and 25(OH)D₃ in plasma and serum samples. Starting from a semiautomated reference method, the method is tested manually and subsequently fully automated on the Biomek i7 Workstation by integrating a centrifuge and a positive pressure extractor into the workstation. Alternatively, the centrifugation for the separation of protein aggregates and supernatant is replaced by a filter plate. Finally, the sample throughput is further increased by using phospholipid removal cartridges. The results show that phospholipid removal significantly increases the recovery rates in liquid chromatography-mass spectrometry. With the phospholipid removal cartridges, recovery rates of 97.36% for 25(OH)D₂ and 102.5% for 25(OH)D₃ were achieved, whereas with the automated classic automated preparation method, the recovery rates were 83.31% for 25(OH)D₂ and 86.54% for 25(OH)D₃. In addition to the technical evaluation, the different methods were also examined with regard to their economic efficiency. Finally, the qualitative and quantitative performance of the developed methods is benchmarked with a selected semiautomatic reference method.

In sickness and in health: pivotal role of vitamin D

Within the last several years, frequency of vitamin D testing has multiplied substantially all over the world, since it has been shown to have an important role in many diseases and conditions. Even though liquid chromatography - tandem mass spectrometry (LC-MS/MS) has been identified as "gold standard" method for vitamin D measurement, most laboratories still use immunochemistry methods. Besides analytical problems (hydrophobicity, low circulating concentrations, ability to bind to lipids, albumins and vitamin D binding protein, presence of multiple vitamin D metabolites and variable ratios of 25(OH)D₂ and 25(OH)D₃ in the blood), vitamin D shows great preanalytical variability, since its concentration is drastically influenced by seasonal changes, exposure to sun, type of clothes or sun block creams. Vitamin D is mostly measured in serum or plasma, but new studies are showing importance of measuring vitamin D in pleural effusions, breast milk, urine, synovial fluid and saliva. Besides the main role in calcium homeostasis and bone metabolism, many studies linked vitamin D deficiency with cancer, cardiovascular diseases, diabetes, fertility and many other conditions. However, even though initial observational studies indicated that supplementation with vitamin D might be beneficial in disease development and progression; first results of well-designed randomized controlled prospective studies did not find differences in frequency of cardiovascular events or invasive cancer between patients taking vitamin D supplementation compared to placebo. In the light of these recent findings, validity of excessive vitamin D testing remains an open question.

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.

Ethnic, geographic, and seasonal differences of vitamin D status among adults in south-west China

Background

There are limited data on vitamin D status of Sichuan province, and no investigation has been carried out on the correlations of 25(OH)D and BTMs between healthy Hans and Tibetans of Sichuan province. This study aimed to examine 25(OH)D levels around Sichuan province and to assess differences by ethnicity, age, gender, sunlight exposure, geographic location, and seasons.

Methods

Blood samples from 2317 healthy adults aged of 18 to 75 years and of Han and Tibetan ethnicities were collected in six regions and during four seasons. Serum 25(OH)D₂ and 25(OH)D₃ levels were measured by LC‐MS/MS method. Serum total P1NP and β‐CTX were measured by immunoassay.

Results

Participants aged 18‐40 years showed significantly lower 25(OH)D levels than participants aged 41‐75 years old (P < .0001). The median serum 25(OH)D level for males was significantly higher than that of females (P < .0001). Serum 25(OH)D levels among four seasons and different districts varied significantly (P < .0001). In addition, the 25(OH)D level of Tibetans was significantly lower than that of Hans, while the serum total P1NP and β‐CTX levels of Tibetans were significantly higher than those of Hans (P < .0001).

Conclusion

Adult population was more common to have vitamin D deficiency/insufficiency among Tibetans, females, north regions and in spring and winter.

Low systemic vitamin D as a potential risk factor in primary open-angle glaucoma: a review of current evidence

Currently, intraocular pressure is the only modifiable risk factor for glaucoma; thus, identifying other modifiable determinants may have far-reaching outcomes. There has been increasing interest in vitamin D status and glaucoma pathogenesis as low vitamin D has been identified by some studies as an independent risk factor for glaucoma. Although the exact mechanism of vitamin D in glaucoma remains uncertain, there is sufficient evidence to continue research in this area. There is a potential physiological role for vitamin D as an anti-inflammatory agent in the oxidative stress-driven pathogenesis of primary open-angle glaucoma, and further studies are required to evaluate the temporal and causal relationship. Ocular vitamin D status in the tear, aqueous and vitreous fluid is a prospective gap in research.

Vitamin D and Rehabilitation after Stroke: Status of Art

Stroke is the first cause of disability in the population and post-stroke patients admitted to rehabilitation units often present a malnutrition status which can influence nutritional indices and then vitamin levels. Vitamin D deficiency seems implicated beyond stroke severity and stroke risk, and also affects post-stroke recovery. Some studies on vitamin D levels and outcome in stroke patients are available but very few data on vitamin D levels and outcome after rehabilitation treatment are reported. This literature review shows the possible relationship between vitamin D deficiency and recovery in post-stroke patients undergoing rehabilitation treatment. Moreover, because several studies have reported that single nucleotide polymorphisms and promoter methylation in genes are involved in vitamin D metabolism and might affect circulating vitamin D levels, these aspects are evaluated in the current paper. From the studies evaluated in this review, it emerges that vitamin D deficiency could not only have an important role in the recovery of patients undergoing rehabilitation after a stroke, but that genetic and epigenetic factors related to vitamin D levels could have a crucial role on the rehabilitation outcome of patients after stroke. Therefore, further studies are necessary on stroke patients undergoing rehabilitation treatment, including: (a) the measurement of the 25(OH) vitamin D serum concentrations at admission and post rehabilitation treatment; (b) the identification of the presence/absence of CYP2R1, CYP27B1, CYP24A1 and VDR polymorphisms, and (c) analysis of the methylation levels of these genes pre- and post-rehabilitation treatment.

Fat Soluble Vitamins in Institutionalized Elderly and the Effect of Exercise, Nutrition and Cognitive Training on Their Status-The Vienna Active Aging Study (VAAS): A Randomized Controlled Trial

BACKGROUND

Institutionalized elderly are at higher risk for micronutrient deficiency. In particular, fat soluble micronutrients, which additionally have antioxidative function, are of interest. The purpose of this secondary investigation of the Vienna Active Ageing Study was to assess and evaluate the plasma status of retinol, alpha- and gamma-tocopherol, alpha- and beta-carotene, lutein, zeaxanthin, beta-cryptoxanthin, and lycopene, as well as vitamin D (25(OH)D) in a cohort of institutionalized elderly. We further determined the effect of six months strength training with or without supplementing (antioxidant) vitamins and protein on the plasma status of these ten micronutrients.

METHODS

Three groups (n = 117, age = 83.1 ± 6.1 years)-resistance training (RT), RT combined with protein and vitamin supplementation (RTS), or cognitive training (CT)-performed two guided training sessions per week for six months. Micronutrients were measured with High Performance Liquid Chromatography (HPLC) at baseline and after 6 months of intervention. Physical fitness was assessed by the 6-min-walking, the 30-s chair rise, isokinetic dynamometry, and the handgrip strength tests.

RESULTS

At baseline, the plasma status of retinol was satisfactory, for alpha-tocopherol, beta-carotene, and 25(OH)D, the percentage of individuals with an insufficient status was 33%, 73% and 61%/81% (when using 50 nmol/L or 75 nmol/L as threshold levels for 25(OH)D), respectively. Plasma analyses were supported by intake data. Six months of elastic band resistance training with or without protein-vitamin supplementation had no biological impact on the status of fat soluble micronutrients. Even for vitamin D, which was part of the nutritional supplement (additional 20 µg/d), the plasma status did not increase significantly, however it contributed to a lower percentage of elderly below the threshold levels of 50/75 nmol/L (49%/74%).

CONCLUSIONS

The findings of the study lead to the strong recommendation for regular physical activity and increased consumption of plant-based foods in institutionalized elderly. When supported by blood analysis, supplementing micronutrients in a moderate range should also be considered.

An epidemiology survey of vitamin D deficiency and its influencing factors

BACKGROUND

There is growing evidence that vitamin D is related to the development of a variety of diseases. The current study was performed to investigate the status of serum vitamin D distribution among adult Chinese people and reveal the influence of gender, age, seasonality and residential regions on serum vitamin D levels.

METHOD

This cross-sectional study included 14,302 participants aged from 18 years old to 65 years old from six major cities in China. The basic demographic information and the levels of serum vitamin D (25(OH)D) and vitamin D₃ (25(OH)D₃) were collected from Jan 2, 2014 to Dec 25, 2017.

RESULT

The prevalence of 25(OH)D₃ concentration <30ng/mL reached up to 83%, in which the rate of vitamin D insufficiency (20-29ng/mL) was 32.7%, and vitamin D deficiency (10-19ng/mL) accounted for 41.9%, and vitamin D severe shortage (<10ng/mL) accounted for 8.4%. Women were more likely to have vitamin D₃ deficiency and lower serum vitamin D₃ concentration than men (both p<0.001). The mean concentration of serum 25(OH)D and 25(OH)D₃ in summer and autumn were higher than that in spring and winter (p<0.001), and the mean concentration of serum 25(OH)D in people from Southern China was higher than that in people from other regions (p<0.001). Although the mean concentrations of serum 25(OH)D and 25(OH)D₃ were both increased by age, the percentage of patients with serum 25(OH)D₃ insufficiency was also increased.

CONCLUSION

Serum vitamin D deficiency is very common in adults in China. The level of serum vitamin D may be associated with age, sex, seasonality and residential regions.

1,25-Dihydroxyvitamin D3 enhances glucose-stimulated insulin secretion in mouse and human islets: a role for transcriptional regulation of voltage-gated calcium channels by the vitamin D receptor

AIM

Vitamin D deficiency in rodents negatively affects glucose-stimulated insulin secretion (GSIS) and human epidemiological studies connect poor vitamin D status with type 2 diabetes. Previous studies performed primarily in rat islets have shown that vitamin D can enhance GSIS. However the molecular pathways linking vitamin D and insulin secretion are currently unknown. Therefore, experiments were undertaken to elucidate the transcriptional role(s) of the vitamin D receptor (VDR) in islet function.

METHODS

Human and mouse islets were cultured with vehicle or 1,25-dihydroxyvitamin-D₃ (1,25D₃) and then subjected to GSIS assays. Insulin expression, insulin content, glucose uptake and glucose-stimulated calcium influx were tested. Microarray analysis was performed. In silico analysis was used to identify VDR response elements (VDRE) within target genes and their activity was tested using reporter assays.

RESULTS

Vdr mRNA is abundant in islets and Vdr expression is glucose-responsive. Preincubation of mouse and human islets with 1,25D₃ enhances GSIS and increases glucose-stimulated calcium influx. Microarray analysis identified the R-type voltage-gated calcium channel (VGCC) gene, Cacna1e, which is highly upregulated by 1,25D₃ in human and mouse islets and contains a conserved VDRE in intron 7. Results from GSIS assays suggest that 1,25D₃ might upregulate a variant of R-type VGCC that is resistant to chemical inhibition.

CONCLUSION

These results suggest that the role of 1,25D₃ in regulating calcium influx acts through the R-Type VGCC during GSIS, thereby modulating the capacity of beta cells to secrete insulin.

Association of Vitamin D Status with Body Mass Index in Adolescents in Ukraine

Background and aims: Vitamin D status in many health managements have been researched extensively, but its dependence with obesity still remains controversial. This article is devoted to examination of blood cholecalciferol levels in Ukrainian population with establishment the association of cholecalciferol levels and body mass index (BMI). Materials and methods: For this observed investigation, data were collected during the summer 2017, over a period of one week from three township areas in Carpathian region, Ukraine from 304 adults aged 19-78 years. Measured variables contained 25(OH)D level, weight and weight applied to check BMI degree. The average level of vitamin D among adolescents presented 23.1 ± 8.2 ng/ml. Female gender was associated with lower vitamin D concentrations (22.9 ± 9.3 ng/ml vs. 26.2 ± 8.5 ng/ml for men). Among the participants, 74.4% had a BMNI of 25 kg/m2 and over, and in 27.3% of them the number was 30 kg/m2 and over. Results: Violation of vitamin D status was detected in 90.5% persons. 1.8% people had been identified as severe 25(OH)D deficiency. Measurement of cholecalciferol demonstrated meaningful connection between its level and BMI only in persons with BMI 25-29.9 kg/m2. Average vitamin D concentrations in persons with BMI over30 kg/m2 did not vary to a significant range from data in persons with normal body weight. Conclusions: Vitamin D status among the adolescents in Ukraine is far from optimum. Our results confirm reliable association between cholecalciferol level and BMI in persons with overweight. Interchange between conservation of vitamin D and BMI needs additional surveys.

10 years of 25-hydroxyvitamin-D testing by LC-MS/MS-trends in vitamin-D deficiency and sufficiency

In early 2000's vitamin-D deficiency was shown to be prevalent in several countries including the United States (US). Studies exploring the role of vitamin-D metabolism in diverse disease pathways generated an increased demand for vitamin-D supplementation and an immense public interest in measurement of vitamin-D metabolite levels. In this report, we review the role of vitamin-D metabolism in disease processes, clinical utility of measuring vitamin-D metabolites including 25-hydroxyvitamin-D (25(OH)D), 1,25-dihydroxyvitamin-D and 24,25-dihydroxyvitamin-D and discuss vitamin-D assay methodologies including immunoassays and liquid chromatography mass spectrometry (LC-MS/MS) assays. We also provide examples of vitamin-D toxicity and insight into the trends in serum 25(OH)D levels in the US population based on 10 years of data from on serum 25(OH)D values from ~5,000,000 patients who were tested at the Mayo Medical Laboratories between February 2007-February 2017.

Mendelian randomisation study of the relationship between vitamin D and risk of glioma

To examine for a causal relationship between vitamin D and glioma risk we performed an analysis of genetic variants associated with serum 25-hydroxyvitamin D (25(OH)D) levels using Mendelian randomisation (MR), an approach unaffected by biases from confounding. Two-sample MR was undertaken using genome-wide association study data. Single nucleotide polymorphisms (SNPs) associated with 25(OH)D levels were used as instrumental variables (IVs). We calculated MR estimates for the odds ratio (OR) for 25(OH)D levels with glioma using SNP-glioma estimates from 12,488 cases and 18,169 controls, using inverse-variance weighted (IVW) and maximum likelihood estimation (MLE) methods. A non-significant association between 25(OH)D levels and glioma risk was shown using both the IVW (OR = 1.21, 95% confidence interval [CI] = 0.90–1.62, P = 0.201) and MLE (OR = 1.20, 95% CI = 0.98–1.48, P = 0.083) methods. In an exploratory analysis of tumour subtype, an inverse relationship between 25(OH)D levels and glioblastoma (GBM) risk was identified using the MLE method (OR = 0.62, 95% CI = 0.43–0.89, P = 0.010), but not the IVW method (OR = 0.62, 95% CI = 0.37–1.04, P = 0.070). No statistically significant association was shown between 25(OH)D levels and non-GBM glioma. Our results do not provide evidence for a causal relationship between 25(OH)D levels and all forms of glioma risk. More evidence is required to explore the relationship between 25(OH)D levels and risk of GBM.

Vitamin D and Ageing

One hundred years has passed since the discovery of vitamin D as the active component of cod-liver oil which cured the bone disease rickets. Since then our knowledge of vitamin D has expanded tremendously and has included recognition of the importance of UV radiation as a source of the vitamin as well as the discovery of the vitamin as a nutrient, a pro-hormone and a potent steroid hormone with a major role in calcium and bone metabolism. In the last 25 years or so, the discovery of the vitamin D receptor in over 30 different body tissues together with the existence of the alpha-1-hydroxylase enzyme in these tissues provided evidence of a pleiotropic role of vitamin D outside its classical role in the skeleton. These important discoveries have provided the basis for the increasing interest in vitamin D in the context of nutritional requirements for health including the prevention of chronic diseases of ageing. The recent publication of the Dietary Reference Intake report on vitamin D and calcium by the North American Institute of Medicine (IOM) is the most comprehensive report to date on the basis for setting nutritional requirements for vitamin D. This chapter will summarize the nutritional aspects of vitamin D and discuss the changes in vitamin D metabolism and requirements with ageing. It will summarize key evidence on the relationship between vitamin D status and some of the main ageing related health outcomes including bone, muscle and cognitive health as well as survival focusing on the published literature in very-old adults (those >= 85 years of age).

Vitamin D levels and susceptibility to asthma, elevated immunoglobulin E levels, and atopic dermatitis: A Mendelian randomization study

BACKGROUND

Low circulating vitamin D levels have been associated with risk of asthma, atopic dermatitis, and elevated total immunoglobulin E (IgE). These epidemiological associations, if true, would have public health importance, since vitamin D insufficiency is common and correctable.

METHODS AND FINDINGS

We aimed to test whether genetically lowered vitamin D levels were associated with risk of asthma, atopic dermatitis, or elevated serum IgE levels, using Mendelian randomization (MR) methodology to control bias owing to confounding and reverse causation. The study employed data from the UK Biobank resource and from the SUNLIGHT, GABRIEL and EAGLE eczema consortia. Using four single-nucleotide polymorphisms (SNPs) strongly associated with 25-hydroxyvitamin D (25OHD) levels in 33,996 individuals, we conducted MR studies to estimate the effect of lowered 25OHD on the risk of asthma (n = 146,761), childhood onset asthma (n = 15,008), atopic dermatitis (n = 40,835), and elevated IgE level (n = 12,853) and tested MR assumptions in sensitivity analyses. None of the four 25OHD-lowering alleles were associated with asthma, atopic dermatitis, or elevated IgE levels (p ≥ 0.2). The MR odds ratio per standard deviation decrease in log-transformed 25OHD was 1.03 (95% confidence interval [CI] 0.90-1.19, p = 0.63) for asthma, 0.95 (95% CI 0.69-1.31, p = 0.76) for childhood-onset asthma, and 1.12 (95% CI 0.92-1.37, p = 0.27) for atopic dermatitis, and the effect size on log-transformed IgE levels was -0.40 (95% CI -1.65 to 0.85, p = 0.54). These results persisted in sensitivity analyses assessing population stratification and pleiotropy and vitamin D synthesis and metabolism pathways. The main limitations of this study are that the findings do not exclude an association between the studied outcomes and 1,25-dihydoxyvitamin D, the active form of vitamin D, the study was underpowered to detect effects smaller than an OR of 1.33 for childhood asthma, and the analyses were restricted to white populations of European ancestry. This research has been conducted using the UK Biobank Resource and data from the SUNLIGHT, GABRIEL and EAGLE Eczema consortia.

CONCLUSIONS

In this study, we found no evidence that genetically determined reduction in 25OHD levels conferred an increased risk of asthma, atopic dermatitis, or elevated total serum IgE, suggesting that efforts to increase vitamin D are unlikely to reduce risks of atopic disease.

The role of tachysterol in vitamin D photosynthesis – a non-adiabatic molecular dynamics study

To investigate the role of tachysterol in the regulation of vitamin D photosynthesis, we studied its absorption properties and photodynamics by ab initio methods and non-adiabatic molecular dynamics.

PILL Series. Vitamin D deficiency

Vitamin D deficiency is common and may contribute to osteopenia, osteoporosis and falls risk in the elderly. Screening for vitamin D deficiency is important in high-risk patients, especially for patients who suffered minimal trauma fractures. Vitamin D deficiency should be treated according to the severity of the deficiency. In high-risk adults, follow-up serum 25-hydroxyvitamin D concentration should be measured 3-4 months after initiating maintenance therapy to confirm that the target level has been achieved. All patients should maintain a calcium intake of at least 1,000 mg for women aged ≤ 50 years and men ≤ 70 years, and 1,300 mg for women > 50 years and men > 70 years.

Lifestyle and Other Factors Explain One-Half of the Variability in the Serum 25-Hydroxyvitamin D Response to Cholecalciferol Supplementation in Healthy Adults

BACKGROUND

Many factors have been associated with serum 25-hydroxyvitamin D [25(OH)D] concentrations in observational studies, with variable consistency. However, less information is available on factors affecting the magnitude of changes in serum 25(OH)D resulting from vitamin D supplementation.

OBJECTIVE

This study aimed to identify factors associated with the serum 25(OH)D response to supplementation with 1000 IU cholecalciferol/d during the first year of a large, multicenter, randomized, placebo-controlled colorectal adenoma chemoprevention trial.

METHODS

Eligible older adults who were not vitamin D-deficient [serum 25(OH)D ≥12 ng/mL] were randomly assigned in a modified 2 × 2 factorial design to 1 of 4 groups: daily 1000 IU cholecalciferol, 1200 mg Ca as carbonate, both, or placebo. Women could elect 2-group (calcium ± cholecalciferol) random assignment. In secondary analyses, we used multivariable models to assess factors associated with serum 25(OH)D concentrations in all enrollees (n = 2753) and with relative changes in serum 25(OH)D after 1 y cholecalciferol supplementation among those randomly assigned (n = 2187).

RESULTS

In multivariable models, 8 factors accounted for 50% of the variability of proportional change in serum 25(OH)D after cholecalciferol supplementation. Larger increases were associated with being female (34.5% compared with 20.5%; P < 0.001) and with lower baseline serum 25(OH)D (P < 0.0001), optimal adherence to study pill intake (P = 0.0002), wearing long pants and sleeves during sun exposure (P = 0.0002), moderate activity level (P = 0.01), use of extra vitamin D-containing supplements during the trial (P = 0.03), and seasons of blood draw (P ≤ 0.002). Several genetic polymorphisms were associated with baseline serum 25(OH)D and/or serum response, but these did not substantially increase the models' R² values. Other factors, including body mass index, were associated with serum 25(OH)D at baseline but not with its response to supplemental cholecalciferol.

CONCLUSIONS

The factors that most affected changes in serum 25(OH)D concentrations in response to cholecalciferol supplementation included sex, baseline serum 25(OH)D, supplement intake adherence, skin-covering clothes, physical activity, and season. Genetic factors did not play a major role. This trial was registered at www.clinicaltrials.gov as NCT00153816.

Vitamin D status, hypertension and body mass index in an urban black community in Mangaung, South Africa

Background

A strong relationship exists between hypertension and body weight. Research has linked both higher blood pressure and body weight with lower vitamin D status.

Objective

This study assessed the vitamin D status of a low-income, urban, black community in South Africa, to examine whether serum levels of 25-hydroxy vitamin D [25(OH)D] are associated with hypertension and body mass index (BMI).

Methods

Data collected from 339 adults (25–64 years) from the Assuring Health for All in the Free State (AHA-FS) study were analysed. Variables measured include serum 25(OH)D, blood pressure, weight and height to determine BMI, and HIV status.

Results

Mean 25(OH)D level was 38.4 ± 11.2 ng/mL for the group; 43.5 ± 11.8 ng/mL and 37.0 ± 10.6 ng/mL for males and females, respectively. Approximately 40% of the participants were HIV-positive and 63.4% hypertensive. Based on BMI, 11.8% were underweight, 33.0% normal weight, 23.0% overweight and 32.1% obese. HIV status showed no correlation with 25(OH)D levels when controlling for BMI. Poor inverse relationships were found between BMI and 25(OH)D (p = 0.01), and between mean arterial blood pressure and 25(OH)D (p = 0.05). When controlling for BMI, no correlation was found between 25(OH)D and the prevalence of hypertension or mean arterial blood pressure.

Conclusion

Approximately 96% of participants had an adequate vitamin D status, which could be attributed to latitude, sunny conditions and expected high levels of sun exposure because of living conditions. Results confirmed a poor inverse relationship between vitamin D status and hypertension, which seems to be dependent on BMI.

Vitamin D and functional arterial parameters in postmenopausal women with metabolic syndrome

PURPOSE

Our cross sectional study aimed to identify the relation between vitamin D level and functional arterial parameters in postmenopausal women with metabolic syndrome.

MATERIAL AND METHODS

100 postmenopausal women at age 50-65 with diagnosed metabolic syndrome were included in this study. Laboratory tests were performed to determine lipid profile, serum glucose, creatinine, C-reactive protein, serum levels of 25(OH) D, ionized calcium and urine albumin/creatinine ratio. Also non-invasive assessment of arterial function (arterial stiffness, flow-mediated dilatation and carotid artery ultrasound examinations) was performed.

RESULTS

The mean vitamin D blood concentration was 47.4±16.9nmol/l. The prevalence of modest insufficiency and deficiency of vitamin D was 62%. Vitamin D concentration in samples assembled from January to March was significantly lower than concentration levels from September to November. No significant relationship was observed between vitamin D and endothelial function, arterial stiffness, carotid intima-media thickness. Week negative correlation was stated between mean arterial pressure and 25(OH) D concentration (p=0.04). A positive correlation was found between high density lipoprotein cholesterol and vitamin 25(OH) D (r=0.3, p<0.05). No significant difference between 25(OH) D and other lipoproteins, calcium ions, glucose, albumin/creatinine ratio and C-reactive protein blood concentrations were found.

CONCLUSIONS

The prevalence of vitamin D deficiency in postmenopausal women with metabolic syndrome is high. No relation was found between vitamin D levels and parameters that indicate atherosclerotic vascular lesions. Nevertheless our study revealed the relation between concentrations of vitamin D and mean blood pressure and high density lipoprotein cholesterol.

Vitamin D and vitamin B12 deficiencies are common in patients with midgut carcinoid (SI-NET)

BACKGROUND/OBJECTIVES

Patients with small intestinal neuroendocrine tumours (SI-NET) often have diarrhoea from hormonal overproduction, surgery and medical treatment, leading to malabsorption of bile salts, fats, vitamin B12 and fat-souble vitamins. This could lead to malnutrition.

SUBJECTS/METHODS

We assessed nutritional status in 50 consecutive out patients with disseminated SI-NET, 25 patients in each cohort. The first cohort was descriptive and the second cohort supplemented with vitamin D, B12 and calcium. Vitamin D deficiency was defined as <50 nmol/l. All patients were assessed by clinical chemistry and dual-energy X-ray absorptiometry (DXA) and interviewed about weight changes, appetite, gastrointestinal disorders, sunhabits and the use of supplements.

RESULTS

In the first cohort, 29% of the patients were severely and 17% moderately vitamin D deficient. In patients without prior substitution, 32% had subnormal vitamin B12 levels. Seventy-six percent had low bone density. In the second cohort with vitamin and mineral supplementation, none had severe vitamin D deficiency, but 28% had moderate deficiency. No patient had subnormal vitamin B12 levels. Sixty percent had low bone density. The serum levels of vitamin D and B12 were higher and parathyroid hormone (PTH) lower in the second cohort compared with the first cohort (P⩽0,022). Vitamin D and PTH were negatively correlated, r=-30, P=⩽0.036.

CONCLUSIONS

Low serum levels of vitamin D and vitamin B12, and low bone density are common in patients with disseminated SI-NET. Supplementation of vitamin D, B12 and calcium resulted in higher serum levels of vitamins, lower PTH levels and diminished severe vitamin D deficiency and is thus recommended as standard care.

Serum 25-hydroxyvitamin D concentration and its determinants in the very old: the Newcastle 85+ Study

SUMMARY

Data on vitamin D status in very old adults are lacking. The aim of this study was to assess 25-hydroxyvitamin D [25(OH)D] concentrations and its predictors in 775 adults aged 85 years old living in North-East England. Low 25(OH)D was alarmingly high during winter/spring months, but its biological significance is unknown.

INTRODUCTION

Despite recent concerns about the high prevalence of vitamin D deficiency in much of the British adult and paediatric population, there is a dearth of data on vitamin D status and its predictors in very old adults. The objective of the present study was to describe vitamin D status and its associated factors in a broadly representative sample of very old men and women aged 85 years living in the North East of England (55° N).

METHODS

Serum concentrations of 25-hydroxyvitamin D [25(OH)D] were analysed in 775 participants in the baseline phase of the Newcastle 85+ cohort study. Season of blood sampling, dietary, health, lifestyle and anthropometric data were collected and included as potential predictors of vitamin D status in ordinal regression models.

RESULTS

Median serum 25(OH)D concentrations were 27, 45, 43 and 33 nmol/L during spring, summer, autumn and winter, respectively. The prevalence of vitamin D deficiency according to North American Institute of Medicine guidelines [serum 25(OH)D <30 nmol/L] varied significantly with season with the highest prevalence observed in spring (51%) and the lowest prevalence observed in autumn (23%; P < 0.001). Reported median (inter-quartile range) dietary intakes of vitamin D were very low at 2.9 (1.2-3.3) μg/day. In multivariate ordinal regression models, non-users of either prescribed or non-prescribed vitamin D preparations and winter and spring blood sampling were associated with lower 25(OH)D concentrations. Dietary vitamin D intake, disability score and disease count were not independently associated with vitamin D status in the cohort.

CONCLUSION

There is an alarming high prevalence of vitamin D deficiency (<30 nmol/L) in 85-year-olds living in North East England at all times of the year but particularly during winter and spring. Use of vitamin D containing preparations (both supplements and medications) appeared to be the strongest predictor of 25(OH)D concentrations in these very old adults.

Quantification of 1,25-Dihydroxyvitamin D2 and D3 in Serum Using Liquid Chromatography-Tandem Mass Spectrometry

1,25-Dihydroxyvitamin D is the active form of vitamin D and plays a critical role in the maintenance of calcium and phosphorous metabolism of the human body. Measurement of 1,25-dihydroxyvitamin D in serum can aid in clinical diagnosis and/or management of renal disease, sarcoidosis, and rare inherited diseases. We present here an effective and accurate method for measuring 1,25-dihydroxyvitamin D3 and 1,25-dihydroxyvitamin D2 by high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) after immunoaffinity extraction. The MS/MS is operated in multiple reaction mode with positive electrospray. Quantification is based on peak area ratios of the analytes to respective deuterated internal standards. This method offered a linear range from 4.0 to 160.0 pg/mL with analytical recovery of 89.9-115.5 % for both 1,25-dihydroxyvitamin D3 and 1,25-dihydroxyvitamin D2.

Vitamin D and health: the need for more randomized controlled trials

The importance of vitamin D for calcium absorption and bone health is undisputed. In addition, vitamin D may also be important for more than the skeleton as low serum levels of 25-hydroxyvitamin D (25(OH)D) have been associated with a number of diseases like cardiovascular disease, diabetes, cancer and infections. This is mainly based on observational studies and proof of causal relations from randomized controlled trials (RCTs) are lacking. At present several large RCTs including from 2152 to 25,000 subjects and with cardiovascular disease and cancer as endpoints are ongoing. Results are expected within 3-5 years, and hopefully these studies will give us a definite answer on need for vitamin D supplementation. However, since vitamin D deficiency (serum 25(OH)D <50nmol/L) has not been an inclusion criterion in these studies, there is a risk of a null effect. If so, one has to establish the effects of vitamin D in truly vitamin D deficient subjects, studies that in retrospect obviously should have been the starting point for RCTs on vitamin D and health. This article is part of a Special Issue entitled '17th Vitamin D Workshop'.

Vitamin D is significantly associated with total testosterone and sex hormone-binding globulin in Malaysian men

OBJECTIVE

Cross-sectional studies in the Caucasian population have shown a significant relationship between vitamin D and testosterone levels, but data in the Asian population are limited. This study aimed to determine the association between vitamin D and testosterone levels in Malaysian men.

METHODS

Chinese and Malay men (n = 382) aged 20 years or above residing in the Klang Valley, Malaysia were recruited. Their fasting blood was collected for serum testosterone, sex hormone-binding globulin (SHBG) and 25-hydroxyvitamin D (25(OH)D) assays. Relationship between 25(OH)D and testosterone levels was analyzed using multiple regression analysis. Testosterone and SHBG levels among subjects with different vitamin D status were compared using univariate analysis. Confounders such as age, ethnicity and body mass index (BMI) were adjusted.

RESULTS

25(OH)D was significantly and positively associated with total testosterone and SHBG levels before and after adjustment for age and ethnicity (p < 0.05). Only association with SHBG remained significant after further adjustment for BMI (p < 0.05). Total testosterone and SHBG values displayed an increasing trend from subjects with vitamin D deficiency to those with optimal level (p < 0.05). The trend was attenuated after adjustment for BMI (p > 0.05).

CONCLUSION

25(OH)D is significantly associated with total testosterone and SHBG in Malaysian men but this association is BMI-dependent.

Vitamin D deficiency is associated with increased fecal incontinence symptoms

INTRODUCTION AND HYPOTHESIS

Vitamin D is an important micronutrient in muscle function. We hypothesize that vitamin D deficiency may contribute to fecal incontinence (FI) symptoms by affecting the anal continence mechanism. Our goal was to characterize the association of vitamin D deficiency as a variable affecting FI symptoms and its impact on health-related quality of life (HR-QoL).

METHODS

This case-control study assessed women seen at a tertiary-care referral center. Participants were identified as having had a serum vitamin D level obtained within a year of their visit: cases were women presenting for care for FI symptoms; controls were women without any pelvic floor symptoms presenting to the same clinical site for general gynecologic care. Cases completed the Modified Manchester Health Questionnaire (MMHQ) and the Fecal Incontinence Severity Index to measure symptom severity and burden on QoL.

RESULTS

Among the 31 cases and 81 controls, no demographic or medical differences existed. Women with FI had lower vitamin D levels (mean 29.2 ± 12.3 cases vs. 35 ± 14.1 ng/ml controls p = 0.04). The odds of vitamin D deficiency were higher in women with FI compared with controls [odds ratio (OR) 2.77, 95 % confidence interval (CI) 1.08-7.09]. Among cases, women with vitamin D deficiency (35 %) had higher MMHQ scores, indicating greater FI symptom burden [51.3 ± 29.3 (vitamin D deficient) vs. 30 ± 19.5 (vitamin D sufficiency), p = 0.02]. No differences were noted for FI severity, p = 0.07.

CONCLUSIONS

Vitamin D deficiency is prevalent in women with fecal incontinence and may contribute to patient symptom burden.

Vitamin D deficiency in Crohn's disease and healthy controls: a prospective case-control study in the Netherlands

BACKGROUND AND AIMS

Vitamin D deficiency has been observed in a wide range of medical conditions including Crohn's disease (CD). We aimed to assess whether CD patients have lower vitamin D levels than healthy controls, and to determine risk factors for vitamin D deficiency.

METHODS

25(OH)D was measured by chemiluminescent immunoassay in serum obtained from 101 CD patients and 41 controls. Demographics, sunlight exposure, dietary vitamin D intake, comorbidities and medication were recorded using validated questionnaires. In CD patients the Harvey-Bradshaw index, Montreal classification and surgical resections were also evaluated. 25(OH)D levels of > 75 nmol/L, between 50 and 75 nmol/L and < 50 nmol/L were considered as normal, suboptimal and deficient, respectively.

RESULTS

Vitamin D levels were rather low but comparable among CD patients and controls (mean 25(OH)D 51.6 nmol/L(± 26.6) in CD, and 60.8 nmol/L(± 27.6) in controls. Multivariate regression analysis revealed BMI, sun protection behaviour, non-Caucasian ethnicity, no use of tanning beds, and no holidays in the last year as significantly associated with serum 25(OH)D levels in CD patients (R=0.62). In the control group no statistically significant factors were identified that had an impact on 25(OH)D serum levels.

CONCLUSIONS

Vitamin D deficiency is common in CD patients, but also in healthy controls. Appropriate vitamin D screening should be advised in patients with CD. Moreover, the positive effect of sunlight on the vitamin D status should be discussed with CD patients, but this should be balanced against the potential risk of developing melanomas, especially in patients using thiopurines.

Is vitamin D deficiency a cause of increased morbidity and mortality at older age or simply an indicator of poor health?

To assess whether vitamin D deficiency is a cause of increased morbidity and mortality or simply an indicator of poor health, we assessed (1) the cross-sectional and longitudinal association of vitamin D deficiency with self-rated health (SRH) and frailty and (2) the association of vitamin D deficiency with mortality, with and without control for SRH and frailty. Analyses were performed in 9,579 participants of the German, population-based ESTHER cohort (age-range at baseline: 50-74 years), with follow-ups after 2, 5 and 8 years (mortality: 12 years). During follow-up, 129 subjects newly reported poor SRH, 510 developed frailty and 1,450 died. In cross-sectional analyses, subjects with vitamin D deficiency had higher odds of a poor SRH and frailty but no association with SRH or frailty was observed in longitudinal analyses. The association of vitamin D deficiency with all-cause and several cause-specific mortalities was strong and unaltered by time-dependent adjustment for classic mortality risk factors, SRH and frailty. In conclusion, vitamin D deficiency may not cause frailty or poor general health but may nevertheless be a prognostic marker for mortality, independent of the individual's morbidity.

Vitamin D supplementation for prevention of mortality in adults

BACKGROUND

Available evidence on the effects of vitamin D on mortality has been inconclusive. In a recent systematic review, we found evidence that vitamin D3 may decrease mortality in mostly elderly women. The present systematic review updates and reassesses the benefits and harms of vitamin D supplementation used in primary and secondary prophylaxis of mortality.

OBJECTIVES

To assess the beneficial and harmful effects of vitamin D supplementation for prevention of mortality in healthy adults and adults in a stable phase of disease.

SEARCH METHODS

We searched The Cochrane Library, MEDLINE, EMBASE, LILACS, the Science Citation Index-Expanded and Conference Proceedings Citation Index-Science (all up to February 2012). We checked references of included trials and pharmaceutical companies for unidentified relevant trials.

SELECTION CRITERIA

Randomised trials that compared any type of vitamin D in any dose with any duration and route of administration versus placebo or no intervention in adult participants. Participants could have been recruited from the general population or from patients diagnosed with a disease in a stable phase. Vitamin D could have been administered as supplemental vitamin D (vitamin D3 (cholecalciferol) or vitamin D2 (ergocalciferol)) or as an active form of vitamin D (1α-hydroxyvitamin D (alfacalcidol) or 1,25-dihydroxyvitamin D (calcitriol)).

DATA COLLECTION AND ANALYSIS

Six review authors extracted data independently. Random-effects and fixed-effect meta-analyses were conducted. For dichotomous outcomes, we calculated the risk ratios (RRs). To account for trials with zero events, we performed meta-analyses of dichotomous data using risk differences (RDs) and empirical continuity corrections. We used published data and data obtained by contacting trial authors.To minimise the risk of systematic error, we assessed the risk of bias of the included trials. Trial sequential analyses controlled the risk of random errors possibly caused by cumulative meta-analyses.

MAIN RESULTS

We identified 159 randomised clinical trials. Ninety-four trials reported no mortality, and nine trials reported mortality but did not report in which intervention group the mortality occurred. Accordingly, 56 randomised trials with 95,286 participants provided usable data on mortality. The age of participants ranged from 18 to 107 years. Most trials included women older than 70 years. The mean proportion of women was 77%. Forty-eight of the trials randomly assigned 94,491 healthy participants. Of these, four trials included healthy volunteers, nine trials included postmenopausal women and 35 trials included older people living on their own or in institutional care. The remaining eight trials randomly assigned 795 participants with neurological, cardiovascular, respiratory or rheumatoid diseases. Vitamin D was administered for a weighted mean of 4.4 years. More than half of the trials had a low risk of bias. All trials were conducted in high-income countries. Forty-five trials (80%) reported the baseline vitamin D status of participants based on serum 25-hydroxyvitamin D levels. Participants in 19 trials had vitamin D adequacy (at or above 20 ng/mL). Participants in the remaining 26 trials had vitamin D insufficiency (less than 20 ng/mL).Vitamin D decreased mortality in all 56 trials analysed together (5,920/47,472 (12.5%) vs 6,077/47,814 (12.7%); RR 0.97 (95% confidence interval (CI) 0.94 to 0.99); P = 0.02; I(2) = 0%). More than 8% of participants dropped out. 'Worst-best case' and 'best-worst case' scenario analyses demonstrated that vitamin D could be associated with a dramatic increase or decrease in mortality. When different forms of vitamin D were assessed in separate analyses, only vitamin D3 decreased mortality (4,153/37,817 (11.0%) vs 4,340/38,110 (11.4%); RR 0.94 (95% CI 0.91 to 0.98); P = 0.002; I(2) = 0%; 75,927 participants; 38 trials). Vitamin D2, alfacalcidol and calcitriol did not significantly affect mortality. A subgroup analysis of trials at high risk of bias suggested that vitamin D2 may even increase mortality, but this finding could be due to random errors. Trial sequential analysis supported our finding regarding vitamin D3, with the cumulative Z-score breaking the trial sequential monitoring boundary for benefit, corresponding to 150 people treated over five years to prevent one additional death. We did not observe any statistically significant differences in the effect of vitamin D on mortality in subgroup analyses of trials at low risk of bias compared with trials at high risk of bias; of trials using placebo compared with trials using no intervention in the control group; of trials with no risk of industry bias compared with trials with risk of industry bias; of trials assessing primary prevention compared with trials assessing secondary prevention; of trials including participants with vitamin D level below 20 ng/mL at entry compared with trials including participants with vitamin D levels equal to or greater than 20 ng/mL at entry; of trials including ambulatory participants compared with trials including institutionalised participants; of trials using concomitant calcium supplementation compared with trials without calcium; of trials using a dose below 800 IU per day compared with trials using doses above 800 IU per day; and of trials including only women compared with trials including both sexes or only men. Vitamin D3 statistically significantly decreased cancer mortality (RR 0.88 (95% CI 0.78 to 0.98); P = 0.02; I(2) = 0%; 44,492 participants; 4 trials). Vitamin D3 combined with calcium increased the risk of nephrolithiasis (RR 1.17 (95% CI 1.02 to 1.34); P = 0.02; I(2) = 0%; 42,876 participants; 4 trials). Alfacalcidol and calcitriol increased the risk of hypercalcaemia (RR 3.18 (95% CI 1.17 to 8.68); P = 0.02; I(2) = 17%; 710 participants; 3 trials).

AUTHORS' CONCLUSIONS

Vitamin D3 seemed to decrease mortality in elderly people living independently or in institutional care. Vitamin D2, alfacalcidol and calcitriol had no statistically significant beneficial effects on mortality. Vitamin D3 combined with calcium increased nephrolithiasis. Both alfacalcidol and calcitriol increased hypercalcaemia. Because of risks of attrition bias originating from substantial dropout of participants and of outcome reporting bias due to a number of trials not reporting on mortality, as well as a number of other weaknesses in our evidence, further placebo-controlled randomised trials seem warranted.

Vitamin D2-enriched button mushroom (Agaricus bisporus) improves memory in both wild type and APPswe/PS1dE9 transgenic mice

Vitamin D deficiency is widespread, affecting over 30% of adult Australians, and increasing up to 80% for at-risk groups including the elderly (age>65). The role for Vitamin D in development of the central nervous system is supported by the association between Vitamin D deficiency and incidence of neurological and psychiatric disorders including Alzheimer's disease (AD). A reported positive relationship between Vitamin D status and cognitive performance suggests that restoring Vitamin D status might provide a cognitive benefit to those with Vitamin D deficiency. Mushrooms are a rich source of ergosterol, which can be converted to Vitamin D2 by treatment with UV light, presenting a new and convenient dietary source of Vitamin D2. We hypothesised that Vitamin D2-enriched mushrooms (VDM) could prevent the cognitive and pathological abnormalities associated with dementia. Two month old wild type (B6C3) and AD transgenic (APPSwe/PS1dE9) mice were fed a diet either deficient in Vitamin D2 or a diet which was supplemented with VDM, containing 1±0.2 µg/kg (∼54 IU/kg) vitamin D2, for 7 months. Effects of the dietary intervention on memory were assessed pre- and post-feeding. Brain sections were evaluated for amyloid β (Aβ) plaque loads and inflammation biomarkers using immuno-histochemical methods. Plasma vitamin D metabolites, Aβ40, Aβ42, calcium, protein and cholesterol were measured using biochemical assays. Compared with mice on the control diet, VDM-fed wild type and AD transgenic mice displayed improved learning and memory, had significantly reduced amyloid plaque load and glial fibrillary acidic protein, and elevated interleukin-10 in the brain. The results suggest that VDM might provide a dietary source of Vitamin D2 and other bioactives for preventing memory-impairment in dementia. This study supports the need for a randomised clinical trial to determine whether or not VDM consumption can benefit cognitive performance in the wider population.

Vitamin D and bone health outcomes in older age

The aim of this review is to summarise the evidence linking vitamin D to bone health outcomes in older adults. A plethora of scientific evidence globally suggests that large proportions of people have vitamin D deficiency and are not meeting recommended intakes. Older adults are at particular risk of the consequences of vitamin D deficiency owing to a combination of physiological and behavioural factors. Epidemiological studies show that low vitamin D status is associated with a variety of negative skeletal consequences in older adults including osteomalacia, reduced bone mineral density, impaired Ca absorption and secondary hyperparathyroidism. There seems to be inconsistent evidence for a protective role of vitamin D supplementation alone on bone mass. However, it is generally accepted that vitamin D (17·5 μg/d) in combination with Ca (1200 mg/d) reduces bone loss among older white subjects. Evidence for a benefit of vitamin D supplementation alone on reducing fracture risk is varied. According to a recent Agency for Healthcare Research and Quality review in the USA the evidence base shows mixed results for a beneficial effect of vitamin D on decreasing overall fracture risk. Limitations such as poor compliance with treatment, incomplete assessment of vitamin D status and large drop-out rates however, have been highlighted within some studies. In conclusion, it is generally accepted that vitamin D in combination with Ca reduces the risk of non-vertebral fractures particularly those in institutional care. The lack of data on vitamin D and bone health outcomes in certain population groups such as diverse racial groups warrants attention.

Highly selective isolation and separation of 25-hydroxyvitamin D and 3-epi-25-hydroxyvitamin D metabolites from serum

Background: Increasing health concerns related to vitamin D deficiency including Alzheimer’s and immune diseases, along with various cancers, have heightened awareness of the nutrient. As the associated health concerns grow, so does the need for fast and accurate analytical testing for diagnostics and treatment. Established immunoassay methods have been challenged for accuracy caused largely by endogenous interferences. This has driven the interest in more specific LC–MS/MS methodology where specificity is gained through chromatographic and MS resolution. Results: Herein, a pentafluorophenyl stationary phase is shown to provide superior selectivity for the separation of the closely related 25-hydroxyvitamin D3 and 3-epi-25-hydroxyvitamin D3 as compared with many methods reported in the literature. To increase robustness and reliability, a novel protein precipitation/phospholipid removal device is also utilized. The novel approach was applied to human samples with a comparison with established clinical LC–MS/MS services for measuring 25-hydroxyvitamin D in adults and for infants (<1 year old). Conclusion: The data showed a good correlation between the routine service for adults and infant patient samples and illustrated the need to resolve the epimers. The unique selectivity of the pentafluorophenyl phase combined with the selective protein depletion and phospholipid enable a fast, accurate and robust analysis of 25-hydroxyvitamin D and related forms, which are otherwise unattainable with commonly used sample preparation and reversed-phase HPLC approaches.

Juvenile onset systemic lupus erythematosus: a possible role for vitamin D in disease status and bone health

Purpose: In juvenile onset systemic lupus erythematosus (JoSLE), evidence for the association between vitamin D status, lupus activity, and bone health is very limited and not conclusive. The aim of this study was, therefore, to assess in JoSLE patients the possible relevance of vitamin D deficiency in disease and bone parameters. Methods: Fifty-seven JoSLE patients were initially compared to 37 age, race and body mass index (BMI) -matched healthy controls. The serum concentration of 25 hydroxyvitamin D (25OHD) was determined by radioimmunoassay. Patients with 25OHD deficiency (≤20 ng/mL) were compared to those with levels >20 ng/mL. Disease activity was evaluated by SLE Disease Activity Index (SLEDAI). Bone mineral density (BMD) and body composition (BC) were measured using dual-energy X-ray absorptiometry (DXA). Results: 25OHD levels were similar in patients and controls (21.44 ± 7.91 vs 22.54 ± 8.25 ng/mL, p = 0.519), regardless of supplementation (65% of patients and none in controls). Thirty-one patients with 25OHD deficiency (≤20 ng/mL) were further compared to the 26 JoSLE patients with levels >20 ng/mL. These two groups were well-balanced regarding vitamin D confounding variables: age ( p = 0.100), ethnicity ( p = 1.000), BMI ( p = 0.911), season (p = 0.502 ), frequency of vitamin D supplementation ( p = 0.587), creatinine ( p = 0.751), renal involvement ( p = 0.597 ), fat mass ( p = 0.764), lean mass ( p = 0.549), previous/current use of glucocorticoids(GC) ( p = 1.0), immunosuppressors ( p = 0.765), and mean current daily dose of GC ( p = 0.345). Patients with vitamin D deficiency had higher SLEDAI (3.35 ± 4.35 vs 1.00 ± 2.48, p = 0.018), lower C4 levels (12.79 ± 6.78 vs 18.38 ± 12.24 mg/dL, p = 0.038), lower spine BMD (0.798 ± 0.148 vs 0.880 ± 0.127 g/cm2, p = 0.037 ) and whole body BMD (0.962 ± 0.109 vs 1.027 ± 0.098 g/cm2, p = 0.024). Conclusion: JoSLE vitamin D deficiency, in spite of conventional vitamin D supplementation, affects bone and disease activity status independent of therapy and fat mass reinforcing the recommendation to achieve adequate levels.

Racial differences in the association between gestational diabetes mellitus and risk of type 2 diabetes

BACKGROUND

It is recognized that a history of gestational diabetes mellitus (GDM) predicts incident type 2 diabetes in women. However, it is unclear if there is a racial disparity between the association of GDM and type 2 diabetes.

METHODS

We studied 1,142 women with a history of GDM and 18,856 women without a history of GDM aged 13-50 years with their first record of pregnancy in Louisiana State University Hospital-Based Longitudinal Study database between 1990 and 2009. History of GDM was used to predict incident type 2 diabetes.

RESULTS

During a mean follow-up of 8.6 years, 1,394 women developed type 2 diabetes. The multivariable adjusted hazard ratio (HR) of type 2 diabetes was 6.52 (95% confidence interval [CI] 5.73-7.43) among women with GDM compared to women without GDM. Stratification by age, race, and body mass index (BMI) gave similar results. Compared with African American and white women without a history of GDM, the relative risk for type 2 diabetes was higher in African American women than in white women with a history of GDM. Compared with non-GDM women compartments, GDM women after delivery for <1, 1.0-3.9, 4.0-5.9, 6.0-7.9, 8-9.9, and ≥10.0 years had 4.00, 5.44, 4.26, 3.16, 4.49, and 4.17 times higher risk of having type 2 diabetes, respectively.

CONCLUSIONS

A history of GDM is a strong predictor of subsequent type 2 diabetes among Louisiana women, especially among African American women.

Diet, genetics, and disease: a focus on the middle East and north Africa region

The Middle East and North Africa (MENA) region suffers a drastic change from a traditional diet to an industrialized diet. This has led to an unparalleled increase in the prevalence of chronic diseases. This review discusses the role of nutritional genomics, or the dietary signature, in these dietary and disease changes in the MENA. The diet-genetics-disease relation is discussed in detail. Selected disease categories in the MENA are discussed starting with a review of their epidemiology in the different MENA countries, followed by an examination of the known genetic factors that have been reported in the disease discussed, whether inside or outside the MENA. Several diet-genetics-disease relationships in the MENA may be contributing to the increased prevalence of civilization disorders of metabolism and micronutrient deficiencies. Future research in the field of nutritional genomics in the MENA is needed to better define these relationships.

Vitamin D status: a review with implications for the pelvic floor

Vitamin D is a micronutrient vital in calcium homeostasis and musculoskeletal function. Vitamin D insufficiency is a common variant of vitamin D deficiency that shows clinical signs of rickets and osteomalacia. The clinical significance of vitamin D insufficiency is being explored in several medical conditions. However, the most robust work suggests a role in musculoskeletal disease. The pelvic floor is a unique part of the body and the function of which is dependent on interrelationships between muscle, nerve, connective tissue, and bone. Pelvic floor disorders result when these relationships are disrupted. This paper reviews current knowledge regarding vitamin D nutritional status, the importance of vitamin D in muscle function, and how insufficient or deficient vitamin D levels may play a role in the function of the female pelvic floor.

Vitamin D status in women with pelvic floor disorder symptoms

INTRODUCTION AND HYPOTHESIS

Our aim was to characterize the relationship between 25-hydroxyvitamin D [25(OH)D] status with pelvic floor symptom distress and impact on quality of life.

METHODS

A retrospective chart review was performed in women with a 25(OH)D level drawn within 1 year of their gynecology/urogynecology visit. Validated questionnaires including the Colorectal-Anal Distress Inventory (CRADI)-8 and Incontinence Impact Questionnaire (IIQ-7) were used. Multivariate analyses characterized pelvic floor disorder (PFD) symptom differences among women by vitamin D status.

RESULTS

We studied 394 women. Mean ± standard deviation (SD) 25(OH)D levels were higher in women without than with PFD symptoms (35.0 ± 14.1 and 29.3 ± 11.5 ng/ml, respectively (p < 0.001)]. The prevalence of vitamin D insufficiency was 51% (136/268). CRADI-8 and IIQ-7 scores were higher among women with vitamin D insufficiency (p = 0.03 and p = 0.001, respectively). Higher IIQ-7 scores were independently associated with vitamin D insufficiency (p < 0.001).

CONCLUSIONS

Insufficient vitamin D is associated with increased colorectal symptom distress and greater impact of urinary incontinence on quality of life.

Unravelling the details of vitamin D photosynthesis by non-adiabatic molecular dynamics simulations

We investigate the photodynamics of vitamin D derivatives by a fully analytical implementation of the linear response time-dependent density functional theory surface hopping method (LR-TDDFT-SH). Our study elucidates the dynamics of the processes involved in vitamin D formation at the molecular level and with femtosecond resolution. We explain the major experimental findings and provide new insights that cannot directly be obtained from experiments: firstly, we investigate the dynamics of the photoinduced ring-opening of provitamin D (Pro) and cyclohexadiene (CHD) and the subsequent rotational isomerization. In agreement with recent experiments and CC2 calculations, only the bright S(1) state is involved in the ring-opening reaction. Our calculations confirm the experimentally reported 5 : 1 ratio between the excited state lifetimes of Pro and CHD. The longer lifetimes of Pro are attributed to steric constraints of the steroid skeleton and to temperature effects, both emerging directly from our simulations. For CHD and Pro, we present an explanation of the biexponential decay recently reported by Sension and coworkers [Tang et al., J. Phys. Chem., 2011, 134, 104503]: our calculations suggest that the fast and slow components arise from a reactive and an unreactive reaction pathway, respectively. Secondly, we assess the wavelength dependent photochemistry of previtamin D (Pre). Using replica exchange molecular dynamics we sample the Pre conformers present at thermal equilibrium. Based on this ensemble we explain the conformation dependent absorption and the essential features of Pre photochemistry. Consistent with the experiments, we find ring-closure to occur mostly after excitation of the cZc conformers and at lower energies, whereas Z/E isomerization of the central double bond preferably occurs after excitation at higher energies. For the isomerization we provide the first theoretical evidence of the proposed hula-twist mechanism. Our results show that LR-TDDFT-SH is a highly valuable tool for studying the photochemistry of moderately large systems, even though challenges remain in the vicinity of conical intersections.

Nutrient intake variability and number of days needed to assess intake in preschool children

The duration of the period of time during which diet should be recorded for sufficiently accurate results on the usual intake of an individual is an especially challenging issue in prospective studies among children. We set out to describe nutrient intake variability in preschoolers and to determine the number of record days required (D) to estimate intake of energy and thirty-two nutrients. The diet and the use of dietary supplements were assessed with three consecutive daily food records including one weekend day in 1639 children participating in the population-based birth cohort of the Type 1 Diabetes Prediction and Prevention Project (DIPP) in Finland. Variance ratios and D stratified by sex and age groups were calculated for 455 (1-year-old), 471 (3-year-old) and 713 (6-year-old) children (born between 1998 and 2003). Within:between variance ratios and D increase with increasing age, and are slightly higher for girls. Vitamin A, cholesterol, n-3 and n-6 fatty acids, β-carotene and folate intakes require the most replicates. Including supplemental intake has an impact on the variance estimates according to the proportion of supplement users. In the DIPP Nutrition Study with 3 d food records, the correlation coefficients between observed and true intakes of energy and thirty-two nutrients averaged 0·91 in 1-year-old children, 0·79 in 3-year-old children and 0·74 in 6-year-old children. For providing accurate nutrient intake estimates, three replicates of food records are reasonable in 1-year-old children but must be questioned for several nutrients in 3- and 6-year-old children. The accuracy of ranking boys is greater than that for girls.