The urgent need to recommend an intake of vitamin D that is effective

Prevalence of vitamin d deficiency in a pediatric hospital of eastern India

Vitamin D deficiency is highly prevalent in Indian children of northern, western and southern states. Serum 25 hydroxy cholecalferol (ng/ml) was analyzed in 310 children and adolescents of pediatric hospital of Kolkata, India. Serum calcium (mg/dl), phosphorous (mg/dl) and alkaline phosphatase (IU/L) data was obtained. Median 25(OH)D was 19 ng/ml. 19.2 % of population had serum 25(OH)D < 10 ng/ml (severe deficiency), 52.9 % had <20 ng/ml (deficiency), 24.5 % had 20-29 ng/ml (insufficiency) and 22.6 % had >30 ng/ml (optimum). Deficiency was highest in adolescents (86.1 %), followed by school children (61.0 %), lowest in pre-school children (41.6 %). 25(OH)D concentrations was lowest in winters (P = 0.002) and spring (P = 0.03) compared to summer. There was no correlation with calcium (P = 0.99), phosphorous (P = 0.23) and ALP (P = 0.63). There is high prevalence of vitamin D deficiency in children and adolescents of eastern India. Prevalence was lower in younger subjects. 25(OH)D did not correlate with bone mineral markers.

Prevalence of vitamin D inadequacy in European women aged over 80 years

Inadequate vitamin D status is associated with secondary hyperparathyroidism and increased bone turnover and bone loss, which in turn increases fracture risk. The objective of this study is to assess the prevalence of inadequate vitamin D status in European women aged over 80 years. Assessments of serum 25-hydroxyvitamin D levels (25(OH)D) were performed on 8532 European women with osteoporosis or osteopenia of which 1984 were aged over 80 years. European countries included in the study were: France, Belgium, Denmark, Italy, Poland, Hungary, United Kingdom, Spain and Germany. Two cut-offs of 25(OH)D inadequacy were fixed: <75 nmol/L (30 ng/ml) and <50 nmol/L (20 ng/ml). Mean (SD) age of the patients was 83.4 (2.9) years, body mass index was 25.0 (4.0) kg/m(2) and level of 25(OH)D was 53.3 (26.7) nmol/L (21.4 [10.7] ng/ml). There was a highly significant difference of 25(OH)D level across European countries (p<0.0001). In these women aged over 80 years, the prevalence of 25(OH)D inadequacy was 80.9% and 44.5% when considering cut-offs of 75 and 50 nmol/L, respectively. In the 397 (20.0%) patients taking supplemental vitamin D with or without supplemental calcium, the mean serum 25(OH)D level was significantly higher than in the other patients (65.2 (29.2) nmol/L vs. 50.3 (25.2) nmol/L; P<0.001). This study indicates a high prevalence of vitamin D (25(OH)D) inadequacy in old European women. The prevalence could be even higher in some particular countries.

Calcium and vitamin D in the regulation of energy balance: where do we stand?

There is a pandemic of obesity and associated chronic diseases. Dietary calcium and vitamin D have many extra-skeletal roles in human health. In this review we have summarized the current understanding of their influence on human energy balance by examining the epidemiological, clinical, animal, cellular and molecular evidence. We opine that while calcium and vitamin D are functional nutrients in the battle against obesity, there is a need for prospective human trials to tilt the balance of evidence in favour of these nutrients.

Low 25-hydroxyvitamin D levels in people with a solid tumor cancer diagnosis: the tip of the iceberg?

PURPOSE

Low serum 25-hydroxyvitamin D [25(OH)D] levels have been linked to both cancer incidence and poor prognosis. The frequency of 25(OH)D tests and clinical factors associated with low levels in cancer patients are unknown.

PATIENTS AND METHODS

Electronic medical records from 2006 to 2007 of 39,252 adult solid tumor patients were reviewed. Data included demographics, cancer sites (primary and metastatic), and first serum 25(OH)D level during the study period. Laboratory data, comorbidities, selected medications, and anticancer treatment within the prior 2 months were recorded. Data were compared between (1) those tested and not tested and (2) 25(OH)D levels≤10 ng/ml (deficient), 11-30 ng/ml (insufficient), and ≥31 ng/ml (sufficient). Stepwise logistic regression identified independent predictors of low serum 25(OH)D levels.

RESULTS

The cohort was 86% Caucasian and 48% female with a mean age of 63±14 years (mean±SD). The most prevalent cancer was breast (19%). In total, 2,098 (5%) had a 25(OH)D test. Of those tested, 133 (6%) had levels≤10 ng/ml and 1,311 (62%) 11-30 ng/ml. Tests were more frequent in females and in those with breast, skin, and thyroid cancers (P<0.001). Low 25(OH)D levels were associated (in univariable analyses) with male gender, non-Caucasian race, gastrointestinal tumor primary sites, metastatic disease, benign liver disease, low serum albumin, and elevated liver enzymes. Significant factors in multivariable models for 25(OH)D levels≤10 and ≤30 ng/ml included non-Caucasian race, primary cancer site, and test calendar month. Vitamin D supplements and recent antineoplastic medication were associated with sufficient levels.

CONCLUSIONS

Low (deficient or insufficient) 25(OH)D serum levels were highly prevalent in people with solid tumors. Vitamin D tests were infrequent and paradoxically less often done in high-risk groups. Tests were more frequent in females and in those with breast, skin, and thyroid cancers. Further research should examine role of routine 25(OH)D tests, the clinical consequences of low levels, and therapeutic supplementation in people with cancer.

Associations between serum 25-hydroxyvitamin D concentrations and multiple health conditions, physical performance measures, disability, and all-cause mortality: the Concord Health and Ageing in Men Project

OBJECTIVES

To explore associations between serum 25-hydroxyvitamin D (25(OH)D) levels and a wide range of health conditions, physical performance measures, disability, and mortality in a large epidemiological study to identify an optimum range for 25(OH)D concentrations.

DESIGN

Cross-sectional study, with additional prospective data on falls and mortality.

SETTING

Concord Health and Ageing in Men Project, Sydney, Australia.

PARTICIPANTS

Community-dwelling men aged 70 and older (N = 1,659).

MEASUREMENTS

Serum 25(OH)D levels, general health status, self-reported diseases, physical performance measures, disability (activities of daily living and instrumental activities of daily living) and falls.

RESULTS

Fair, poor, and very poor health; self-reported diabetes mellitus; hyperglycemia; depression; muscle weakness; poor balance; and all-cause mortality were all associated with serum 25(OH)D levels less than 50 nmol/L, even after adjustment for confounding. The findings also suggest that, in older men, for a wide range of health conditions, physical performance measures, disability, falls, and mortality, the optimum range of 25(OH)D is between 50.0 and 74.9 nmol/L, with no additional benefit for 25(OH)D levels of 75.0 nmol/L or greater.

CONCLUSION

Programs aimed at achieving an optimum range of serum 25(OH)D at levels between 50.0 and 74.9 nmol/L may have overall health benefits and such levels are adequate for older men.

Effects of a healthy Nordic diet on plasma 25-hydroxyvitamin D concentration in subjects with metabolic syndrome: a randomized, [corrected] controlled trial (SYSDIET)

PURPOSE

At northern latitudes, vitamin D is not synthesized endogenously during winter, causing low plasma 25-hydroxyvitamin D (25(OH)D) concentrations. Therefore, we evaluated the effects of a healthy Nordic diet based on Nordic nutrition recommendations (NNR) on plasma 25(OH)D and explored its dietary predictors.

METHODS

In a Nordic multi-centre trial, subjects (n = 213) with metabolic syndrome were randomized to a control or a healthy Nordic diet favouring fish (≥300 g/week, including ≥200 g/week fatty fish), whole-grain products, berries, fruits, vegetables, rapeseed oil and low-fat dairy products. Plasma 25(OH)D and parathyroid hormone were analysed before and after 18- to 24-week intervention.

RESULTS

At baseline, 45 % had vitamin D inadequacy (<50 nmol/l), whereas 8 % had deficiency (<25 nmol/l). Dietary vitamin D intake was increased by the healthy Nordic diet (P < 0.001). The healthy Nordic and the control diet reduced the prevalence of vitamin D inadequacy by 42 % (P < 0.001) and 19 % (P = 0.002), respectively, without between-group difference (P = 0.142). Compared with control, plasma 25(OH)D (P = 0.208) and parathyroid hormone (P = 0.207) were not altered by the healthy Nordic diet. Predictors for 25(OH)D were intake of vitamin D, eicosapentaenoic acids (EPA), docosahexaenoic acids (DHA), vitamin D supplement, plasma EPA and plasma DHA. Nevertheless, only vitamin D intake and season predicted the 25(OH)D changes.

CONCLUSION

Consuming a healthy Nordic diet based on NNR increased vitamin D intake but not plasma 25(OH)D concentration. The reason why fish consumption did not improve vitamin D status might be that many fish are farmed and might contain little vitamin D or that frying fish may result in vitamin D extraction. Additional ways to improve vitamin D status in Nordic countries may be needed.

Vitamin D, the immune system and asthma

The effects of vitamin D on bone metabolism and calcium homeostasis have long been recognized. Emerging evidence has implicated vitamin D as a critical regulator of immunity, playing a role in both the innate and cell-mediated immune systems. Vitamin D deficiency has been found to be associated with several immune-mediated diseases, susceptibility to infection and cancer. Recently, there has been increasing interest in the possible link between vitamin D and asthma. Further elucidation of the role of vitamin D in lung development and immune system function may hold profound implications for the prevention and treatment of asthma.

Differential effects of different vitamin D replacement strategies in patients with diabetes

BACKGROUND

The optimal treatment regimen for correcting vitamin D insufficiency in diabetic patients has not been established.

METHODS

Two hundred and forty four adult diabetic patients with vitamin D insufficiency were enrolled to receive: Ergocalciferol (D2) 50,000 IU daily over 10 days (500,000 IU) followed by Calcichew D3 (calcium carbonate/Cholecalciferol) BID (~24,000 IU cholecalciferol/month) (ECC) (n=53); Cholecalciferol (D3) 40,000 IU daily over 10 days (400,000 IU) followed by Calcichew D3 BID (~24,000 IU cholecalciferol/month) (CCC) (n=94) or Cholecalciferol 40,000 IU daily over 10 days (400,000 IU) followed by Cholecalciferol 40,000 IU monthly (CC) (n=97). The 25(OH)D, HbA1c, lipids, blood pressure and eGFR were assessed at baseline and after a mean follow up of 8.0±4.0 months.

RESULTS

Treatment increased 25(OH)D concentrations significantly in ECC (17.4±13.8 vs 29.9±9.6 ng/ml, P<0.0001), CCC (14.2±6.6 vs 30.9±13.1 ng/ml, p<0.0001) and CC (13.5±8.4 vs 33.9±14.4 ng/ml, P<0.0001). The relative increase in 25(OH)D was significantly lower with ECC compared to CC (+14.6±12.2 vs +20.6±15.0, P=0.01) and the majority of subjects in the ECC group (63%) remained vitamin D deficient (25(OH)D <30 ng/ml) compared to CCC (46%) and CC (36%) (P=0.0005).

CONCLUSION

This study demonstrates that relatively aggressive treatment regimens of both vitamin D2 and D3 increase 25(OH)D concentrations in diabetic patients, but the ability to raise 25(OH)D status to 'sufficient' levels is inadequate in a large proportion of individuals.

The high prevalence of vitamin D deficiency and its related maternal factors in pregnant women in Beijing

Maternal vitamin D deficiency has been suggested to influence fetal and neonatal health. Little is known about vitamin D status in Chinese pregnant women. The purpose of this study was to assess the vitamin D status of pregnant women residing in Beijing in winter and evaluate the impact of maternal factors on serum 25-hydroxyvitamin D [25(OH)D] levels. The study was conducted on 125 healthy pregnant women. For each individual, data concerning pre-pregnancy weight, educational status, use of multivitamins and behavioral factors such as daily duration of computer use, walking and sun exposure were obtained. Serum concentrations of 25(OH)D were measured by enzyme-linked immunosorbent assay. The prevalence of vitamin D deficiency (25(OH)D < 50 nmol/L) was 96.8% and almost half (44.8%) of women were severely vitamin D deficiency (25(OH)D < 25 nmol/L). The concentration of 25(OH)D was lower in women with shorter duration of sun exposure (≤ 0.5 h/day, 25.3 ± 8.9 nmol/L) than that in women with longer duration of sun exposure (> 0.5 h/day; 30.3± 9.5 nmol/L; P = 0.003). Thirty six women (28.8%) had sun exposure duration ≥ 1.5h/day. The 25(OH)D concentration in these women was 31.5 ± 9.4 nmol/L which was also much lower than the normal level. Women who reported taking a multivitamin supplement had significantly higher 25(OH)D concentrations (32.3 ± 9.5 nmol/L) when compared with non-users (24.9 ± 8.2 nmol/L; P < 0.001). Pregnant women in Beijing are at very high risk of vitamin D deficiency in winter. Duration of Sun exposure and the use of multivitamin were the most important determinants for vitamin D status. However, neither prolonging the time of sunlight exposure nor multivitamin supplements can effectively prevent pregnant women from vitamin D deficiency. Other measures might have to be taken for pregnant women to improve their vitamin D status in winter.

The association between 25-hydroxyvitamin D and mammographic density in healthy pre- and postmenopausal women regardless of the menstrual cycle phase: a cross-sectional study

Vitamin D deficiency is a known risk factor of breast cancer. An association between vitamin D and breast density has been suggested; however, it remains controversial. The aim of this study was to determine the association between serum 25-hydroxyvitamin D [25(OH)D] level and mammographic density. Subjects in our study included 517 patients who visited the health promotion center of the University Hospital. Mammographic density was classified using the American College of Radiology, Breast Imaging Reporting and Data System. Analysis of variance was performed to clarify the association of serum 25(OH)D level and mammographic density, and odds ratio was calculated by ordinal logistic regression analysis. The mean serum 25(OH)D level was 14.3 ± 7.0 ng/mL in all subjects. In correlation analysis, weak negative correlation was observed between serum 25(OH)D level and mammographic density groups (r = -0.09, P = 0.049). However, ordinal logistic regression analysis showed no statistically significant association between serum 25(OH)D level and mammographic density (odds ratio: 0.75, 95% confidence interval: 0.50-1.13). Results of our study showed that there is no significant association between serum 25(OH)D level and mammographic density. It is thought to be an another mechanism of serum 25(OH)D level on breast cancer risk in addition to breast density.

Decreased bone mineral density and periodontal management

The definition of osteoporosis has evolved beyond low bone mineral density to include impaired bone morphology and matrix properties. As such, the subsequent bone density insufficiencies extend beyond the skeletal risks of fracture and have implications for oral health management patients. As our population ages there is a worldwide increase in the risk of decreased bone mineral density and its subsequent morbidity. This makes age an independent risk factor for fracture and decreased bone mineral density. Multiple examinations and diagnostic tests are currently used in combination to develop an algorithm to assess osteoporotic risk. Oral health care professionals should follow these principles and caution should be used in applying a single independent assessment to determine a patient's osteoporotic or bone metabolism risk. Therapeutic approaches for osteoporosis are often divided into nonpharmacological interventions and pharmacological therapies. The periodontist and other oral health care professionals should have a full understanding of the therapeutic options, benefits and implementation of preventive therapies. Bone turnover is a coupled event of bone formation and bone resorption and it is the imbalance of this homeostasis that results in osteoporosis. Based on this uncoupling of bone resorption and formation, osteoporosis or decreased bone mineral density and osteopenia, may be a risk factor for alveolar bone loss in periodontitis. The role of prevention and maintenance with a history of periodontitis and oesteopenia extends beyond biofilm control and should include management of bone mineral density. The chronic periodontal infection in a patient with osteopenia may place the patient at greatly increased risk for alveolar bone loss, gingival recession and root caries. A key component in the management is the oral health professional's knowledge of the interrelationship between skeletal health and periodontal health.

Dietary vitamin D deficiency in rats from middle to old age leads to elevated tyrosine nitration and proteomics changes in levels of key proteins in brain: implications for low vitamin D-dependent age-related cognitive decline

In addition to the well-known effects of vitamin D (VitD) in maintaining bone health, there is increasing appreciation that this vitamin may serve important roles in other organs and tissues, including the brain. Given that VitD deficiency is especially widespread among the elderly, it is important to understand how the range of serum VitD levels that mimic those found in humans (from low to high) affects the brain during aging from middle age to old age. To address this issue, 27 male F344 rats were split into three groups and fed isocaloric diets containing low (100 IU/kg food), control (1000 IU/kg food), or high (10,000 IU/kg food) VitD beginning at middle age (12 months) and continued for a period of 4-5 months. We compared the effects of these dietary VitD manipulations on oxidative and nitrosative stress measures in posterior brain cortices. The low-VitD group showed global elevation of 3-nitrotyrosine compared to control and high-VitD-treated groups. Further investigation showed that this elevation may involve dysregulation of the nuclear factor κ-light-chain enhancer of activated B cells (NF-κB) pathway and NF-κB-mediated transcription of inducible nitric oxide synthase (iNOS) as indicated by translocation of NF-κB to the nucleus and elevation of iNOS levels. Proteomics techniques were used to provide insight into potential mechanisms underlying these effects. Several brain proteins were found at significantly elevated levels in the low-VitD group compared to the control and high-VitD groups. Three of these proteins, 6-phosphofructokinase, triose phosphate isomerase, and pyruvate kinase, are involved directly in glycolysis. Two others, peroxiredoxin-3 and DJ-1/PARK7, have peroxidase activity and are found in mitochondria. Peptidyl-prolyl cis-trans isomerase A (cyclophilin A) has been shown to have multiple roles, including protein folding, regulation of protein kinases and phosphatases, immunoregulation, cell signaling, and redox status. Together, these results suggest that dietary VitD deficiency contributes to significant nitrosative stress in brain and may promote cognitive decline in middle-aged and elderly adults.

The effects of vitamin D₂ or D₃ supplementation on glycaemic control and related metabolic parameters in people at risk of type 2 diabetes: protocol of a randomised double-blind placebo-controlled trial

BACKGROUND

The global prevalence of type 2 diabetes is increasing. Effective strategies to address this public health challenge are currently lacking. A number of epidemiological studies have reported associations between low concentrations of 25-hydroxy vitamin D and the incidence of diabetes, but a causal link has not been established. We investigate the effect of vitamin D supplementation on the metabolic status of individuals at increased risk of developing type 2 diabetes.

METHODS/DESIGN

In a randomised double-blind placebo-controlled trial individuals identified as having a high risk of type 2 diabetes (non-diabetic hyperglycaemia or positive diabetes risk score) are randomised into one of three groups and given 4 doses of either placebo, or 100,000 IU Vitamin D₂ (ergocalciferol) or 100,000 IU Vitamin D₃ (cholecalciferol) at monthly intervals. The primary outcome measure is the change in glycated haemoglobin level between baseline and 4 months. Secondary outcome measures include blood pressure, lipid levels, apolipoproteins, highly sensitive C-reactive protein, parathyroid hormone (PTH) and safety of supplementation. and C-reactive protein. The trial is being conducted at two sites (London and Cambridge, U.K.) and a total of 342 participants are being recruited.

DISCUSSION

Trial data examining whether supplementation of vitamin D improves glycaemic status and other metabolic parameters in people at risk of developing type 2 diabetes are sparse. This trial will evaluate the causal role of vitamin D in hyperglycaemia and risk of type 2 diabetes. Specific features of this trial include recruitment of participants from different ethnic groups, investigation of the relative effectiveness and safety of vitamin D₂ and D₃ and an evidence based approach to determination of the dose of supplementation.

TRIAL REGISTRATION

EudraCT2009-011264-11; ISRCTN86515510.

25-Hydroxyvitamin D in the range of 20 to 100 ng/mL and incidence of kidney stones

OBJECTIVES

Increasing 25-hydroxyvitamin D serum levels can prevent a wide range of diseases. There is a concern about increasing kidney stone risk with vitamin D supplementation. We used GrassrootsHealth data to examine the relationship between vitamin D status and kidney stone incidence.

METHODS

The study included 2012 participants followed prospectively for a median of 19 months. Thirteen individuals self-reported kidney stones during the study period. Multivariate logistic regression was applied to assess the association between vitamin D status and kidney stones.

RESULTS

We found no statistically significant association between serum 25-hydroxyvitamin D and kidney stones (P = .42). Body mass index was significantly associated with kidney stone risk (odds ratio = 3.5; 95% confidence interval = 1.1, 11.3).

CONCLUSIONS

We concluded that a serum 25-hydroxyvitamin D level of 20 to 100 nanograms per milliliter has no significant association with kidney stone incidence.

The effect of vitamin D on nonspecific low back pain

BACKGROUND

Nonspecific low back pain is known as one of the most common reasons for chronic low back pain (CLBP) that burdens healthcare systems with high costs. According to a hypothesis, CLBP has been associated with vitamin D3 deficiency, the goal of this study is to evaluate the effect of vitamin D3 administration on improvements in CLBP.

MATERIALS AND METHODS

This double blind randomized clinical trial included 53 patients aged between 18-40 years with nonspecific CLBP. Pain was measured using the pain visual analogue scale score (VAS), and serum 25-OH-vitamin D level was measured using an enzyme-linked immunosorbent assay kit. The patients were randomly divided into two groups based on sex and weight. Pearl of vitamin D(3) (50 000 IU) or placebo was administered orally every week for 8 weeks. Data were analyzed via SPSS 17th edition software using two-tailed paired t-test and chi-square test.

RESULTS

There were 26 and 27 patients in drug and placebo groups respectively. Out of 53 subjects, 75.47% were female. There was no statistically significant difference in the mean age, sex, and mean weight between the two groups. The mean serum 25-OH-vitamin D level was 18.86 ± 9.24 nmol/L on the first visit. After 8 weeks of intervention, the mean serum 25-OH-vitamin D level changed from 17.88 ± 9.04 to 27.52 ± 9.04 (P = 0.043) and from 19.81 ± 9.60 to 18.91 ± 7.84 (P = 0.248) in drug and placebo groups, respectively. The mean VAS score for pain decreased from 5.42 ± 1.65 to 3.03 ± 3.14 (P = 0.001) and from 6.42 ± 1.62 to 3.11 ± 3.08 (P = 0.001) among drug and placebo groups, respectively. The mean changes in chronic pain were 2.38 ± 2.62, 95% confidence interval (CI) = 1.32-3.44 in the drug group and 3.33 ± 3.67, 95%CI = 0.61-2.55 in the placebo group. No significant statistical difference between the two groups was observed.

CONCLUSION

According to our results, both vitamin D(3) and placebo treatments improved CLBP and there was no significant difference between vitamin D(3) and placebo groups.

[Vitamin D and breast cancer: physiopathology, biological and clinical implications]

There is a recent increase in interest of vitamin D and breast cancer, facing the number of publications on the subject. This increase have several reasons, on the one hand, vitamin D deficiency is more and more prevalent and, on the other hand, there are new data that highlights the extra-bone effects of vitamin D, especially in breast cancer, the vitamin D is involved in the breast cancer risk factor, the prognosis, and the interaction with breast cancer treatments. This combination between vitamin D deficiency and breast cancer is extremely usual, and combined with all cancer clinical parameters: the incidence, the tumour biology, the clinical presentation, the prognosis, and the antineoplastic treatment tolerance. This vitamin D deficiency is increased after adjuvant cancer treatments. And yet, this problem increases bone metabolism disruptions in breast cancer patients, inducing osteoporotic risk at long time, even though this population is curable. This problem is therefore serious in the adjuvant breast cancer treatment. Unfortunately, in this population, the current recommendations are clearly insufficient, and the current randomized clinical trial results would contribute to define the best way to correct the vitamin D deficiency, quickly and secure.

Vitamin D supplementation reduces the risk of acute otitis media in otitis-prone children

BACKGROUND

The aim of this study was to evaluate whether a deficit in vitamin D (VD) is associated with an increased risk of recurrent acute otitis media (AOM) and whether VD supplementation is effective in reducing the number of AOM episodes in otitis-prone children.

METHODS

A total of 116 children with a history of recurrent AOM (≥3 episodes in preceding 6 months or ≥4 episodes in preceding 12 months) were prospectively and blindly randomized to receive oral VD 1000 IU/d or placebo for 4 months. Episodes of AOM were monitored for 6 months.

RESULTS

Fifty-eight children received placebo and 58 with similar characteristics were treated with VD. The number of children experiencing ≥1 AOM episode during the study period was significantly lower in the treatment group (26 versus 38; P = 0.03). There was a marked difference in the number of children who developed uncomplicated AOM (P < 0.001), but no difference in the number of children with ≥1 episode of spontaneous otorrhea. The likelihood of AOM was significantly reduced in the patients whose serum VD concentrations were ≥30 ng/mL.

CONCLUSIONS

VD hypovitaminosis is common in children with recurrent AOM and associated with an increase in the occurrence of AOM when serum 25(OH)D levels are <30 ng/mL. The administration of VD in a dosage of 1000 IU/d restores serum values of ≥30 ng/mL in most cases and is associated with a significant reduction in the risk of uncomplicated AOM.

Vitamin D3 supplementation scheme in HIV-infected patients based upon pharmacokinetic modelling of 25-hydroxycholecalciferol

AIMS

Vitamin D deficiency is prevalent in HIV-infected patients and has been associated with osteopenia and HIV disease progression. Our aims were to investigate the pharmacokinetics of 25-hydroxycholecalciferol [25(OH)D], the effect of antiretroviral treatment (ARV) and others factors that may influence the pharmacokinetics, and to determine a vitamin D3 dosing scheme to reach the 30 ng ml(-1) threshold (defined as 25(OH)D sufficiency).

METHODS

This monocentric retrospective study included 422 HIV-infected patients aged 16 to 85 years. A total of 723 25(OH)D concentrations were available for pharmacokinetic evaluation and a population pharmacokinetic model was developed with MONOLIX 3.2.

RESULTS

Median 25(OH)D at baseline was 16 ng ml(-1) (interquartile range 11-23 ng ml(-1)) for the total population, 17% of patient had concentrations below 10 ng ml(-1), 68% between 10 and 30 ng ml(-1) and 15% above 30 ng ml(-1). 25(OH)D pharmacokinetics were best described by a one compartment model with an additional endogenous production. The effects of season and skin phototype were significant on production rate. The endogenous production was 20% lower in non-white skin phototype patients and was decreased by 16% during autumn, winter and spring. No significant differences in 25(OH)D concentrations were related to antiretroviral drugs (ARV). To obtain concentrations between 30 and 80 ng ml(-1), the dosing recommendation was 100,000 IU every month.

CONCLUSIONS

Season and skin phototype had an influence on the endogenous production of 25(OH)D. However no effect of ARV was found. A dosing scheme to reach sufficient 25(OH)D concentrations is proposed.

Genetic variation in the vitamin D receptor, plasma 25-hydroxyvitamin D, and biomarkers of cardiometabolic disease in Caucasian young adults

BACKGROUND/AIMS

Vitamin D regulates gene transcription by binding to the vitamin D receptor (VDR), potentially affecting cardiometabolic disease risk. However, studies of 25-hydroxyvitamin D [25(OH)D] and cardiometabolic disease are inconsistent. Inconsistencies may result from unaccounted for interactions between VDR genetic variants and 25(OH)D. We examined the effect of 25(OH)D on the association between VDR variants and cardiometabolic disease biomarkers.

METHODS

The relationship between 25(OH)D, 24 VDR variants, and 10 cardiometabolic biomarkers was examined in 488 Caucasians aged 20-29 years. Covariate-adjusted general linear models were used to examine the interaction effect of 25(OH)D × VDR on each biomarker. When interactions were significant (p < 0.05), relationships were further examined with analysis of covariance, stratified by tertiles of 25(OH)D and adjusted for multiple comparisons.

RESULTS

In the lowest tertile of 25(OH)D, major allele homozygotes for rs3819545 had higher insulin and HOMA-IR than minor allele carriers (p ≤ 0.002). Fasting insulin and HOMA-IR were lower in the highest than the lowest tertile of 25(OH)D among major allele homozygotes (p < 0.0001), but minor allele carriers had similar levels regardless of vitamin D status.

CONCLUSIONS

We identified 25(OH)D-dependent associations between rs3819545 and glycemic dysregulation biomarkers. Major allele homozygotes with low vitamin D status may be at increased risk of insulin resistance.

Vitamin D supplementation in older people (VDOP): Study protocol for a randomised controlled intervention trial with monthly oral dosing with 12,000 IU, 24,000 IU or 48,000 IU of vitamin D₃

The randomised, double blind intervention trial ‘Optimising Vitamin D Status in Older People’ (VDOP) will test the effect of three oral dosages of vitamin D given for one year on bone mineral density (BMD) and biochemical markers of vitamin D metabolism, bone turnover and safety in older people. VDOP is funded by Arthritis Research UK, supported through Newcastle University and MRC Human Nutrition Research and sponsored by the Newcastle upon Tyne Hospitals NHS Foundation Trust.^a

Association between vitamin D insufficiency and adverse pregnancy outcome: global comparisons

Background

Vitamin D insufficiency has been associated with a number of adverse pregnancy outcomes, and has been recognized as a public health concern.

Aim

The objective of this study was to determine the impact of vitamin D deficiency on maternal complications like gestational diabetes mellitus (GDM), anemia, iron deficiency, and preeclampsia among pregnant women.

Subjects and methods

This was a cohort study undertaken at antenatal clinics at the Women’s Hospital of Hamad Medical Corporation in Doha. A total of 2,487 Arab pregnant women above 24 weeks’ gestation with any maternal complication were approached, and 1,873 women (75.3%) consented to participate in the study. Data on sociodemographic and clinical characteristics by interview and biochemistry parameters were retrieved from medical records. Multivariate logistic regression analysis was performed to determine the associated risk factors.

Results

Of the studied pregnant women, nearly half of them had vitamin D deficiency (48.4%). Younger women below 30 years old (43.2%, P = 0.032), housewives (65.3%, P = 0.008), and those on low monthly household incomes (QR5,000–9,999) (49.2%, P = 0.03) were significantly more likely to have lower vitamin D compared with those who had sufficient vitamin D levels. Exposure to sunlight (63.4%, P = 0.05), daily physical activity (64.4%, P = 0.05), and vitamin D supplement intake (89.7%, P < 0.001) were significantly lower in deficient pregnant women. In the study sample of pregnant women, 13.9% had GDM, 11.5% had anemia, 8.6% had iron deficiency, and 6.9% had preeclampsia. Severe vitamin D deficiency was significantly higher in pregnant women with GDM (16.5% vs 11%), anemia (17.1% vs 11%), iron deficiency (18.5% vs 11.2%), and preeclampsia (19.8% vs 11.4%) when compared to the uncomplicated group. Socioeconomic status was low in pregnant women with complications like GDM, anemia, iron deficiency, and pre-eclampsia. Pregnancy complications like GDM (52.7%), anemia (53.2%), iron deficiency (55.6%), and preeclampsia (51.9%) were higher in Qataris. Also, GDM (66.2%), anemia (66.2%), iron deficiency (68.5%), and preeclampsia (58.1%) were observed more commonly among housewives compared to working women. Obesity was significantly more common in pregnant women with GDM (41.5%) and preeclampsia (41.1%).

Conclusion

The study findings revealed that maternal vitamin D deficiency in pregnancy is significantly associated with elevated risk for GDM, anemia, and preeclampsia. The risk of vitamin D deficiency was higher in Qataris, housewives and those with low monthly household income.

SEANUTS: the nutritional status and dietary intakes of 0.5–12-year-old Thai children

In the present study, we investigated nutritional status and health-related factors in a multistage cluster sample of 3119 Thai urban and rural children aged 0·5–12·9 years. In a subsample, blood samples were collected for the measurement of Hb, transferrin receptor, vitamin A and vitamin D concentrations. The prevalence of stunting and underweight was higher in rural children than in urban children, whereas the wasting rate was similar in both rural and urban areas. Among children aged 3·0–5·9 years, the prevalence of overweight was significantly higher in urban areas than in rural areas and so was the obesity rate in children aged 6·0–12·9 years. Protein intakes of all age groups were relatively high in both the areas. Intakes of Ca, Fe, Zn and vitamin C were significantly higher in urban areas than in rural areas. The prevalence of anaemia in rural areas was twice as high as that in urban areas, particularly in infants and young children. However, the prevalence of Fe-deficiency anaemia was similar in both urban and rural areas. While the prevalence of vitamin A deficiency (by serum retinol cut-off < 0·7 μmol/l) seemed to be very low, vitamin A insufficiency (by serum retinol cut-off < 1·05 μmol/l) was more prevalent (29·4–31·7 %) in both the areas. The prevalence of vitamin D insufficiency ranged between 27·7 and 45·6 % among the children. The present study indicates that the double burden of malnutrition is still a major public health problem in Thailand. Further studies need to explore the associated risk factors for these nutrient deficiencies. Effective strategies and actions are needed to tackle the nutritional problems in Thai children.

Effect of supplementation with vitamin D2-enhanced mushrooms on vitamin D status in healthy adults

Vitamin D deficiency is emerging worldwide and many studies now suggest its role in the development of several chronic diseases. Due to the low level of vitamin D naturally occurring in food there is a need for supplementation and use of vitamin D-enhanced products. The aim of the present study was to determine if daily consumption of vitamin D2-enhanced mushrooms increased vitamin D status in free-living healthy adults or affected markers of the metabolic syndrome. A total of ninety volunteers (aged 40-65 years) were randomly assigned to one of two 4-week studies: mushroom study (15 µg vitamin D2 or placebo mushroom powder) and capsule study (15 µg vitamin D3 or placebo capsules). Consumption of vitamin D2-enhanced mushrooms increased serum 25-hydroxyvitamin D2 (25(OH)D2) by 128 % from baseline (3·9 (sd 1·9) nmol/l; P < 0·05). Serum 25(OH)D3 increased significantly in the vitamin D3 capsule group (a 55 % increase from a baseline of 44.0 (sd 17·1) nmol/l; P < 0·05). Vitamin D status (25(OH)D) was affected only in the vitamin D3 group. Plasminogen activator inhibitor-1 was lowered by vitamin D2 intake. Vitamin D2 from enhanced mushrooms was bioavailable and increased serum 25(OH)D2 concentration with no significant effect on 25(OH)D3 or total 25(OH)D.

Determinants of serum levels of vitamin D: a study of life-style, menopausal status, dietary intake, serum calcium, and PTH

Background

Low blood levels of vitamin D (25-hydroxy D3, 25OHD3) in women have been associated with an increased risk of several diseases. A large part of the population may have suboptimal 25OHD3 levels but high-risk groups are not well known. The aim of the present study was to identify determinants for serum levels of 25OHD3 in women, i.e. factors such as lifestyle, menopausal status, diet and selected biochemical variables.

Methods

The study was based on women from the Malmö Diet and Cancer Study (MDCS), a prospective, population-based cohort study in Malmö, Sweden. In a previous case–control study on breast cancer, 25OHD3 concentrations had been measured in 727 women. In these, quartiles of serum 25OHD3 were compared with regard to age at baseline, BMI (Body Max Index), menopausal status, use of oral contraceptives or menopausal hormone therapy (MHT) , life-style (e.g. smoking and alcohol consumption), socio-demographic factors, season, biochemical variables (i.e. calcium, PTH, albumin, creatinine, and phosphate), and dietary intake of vitamin D and calcium. In order to test differences in mean vitamin D concentrations between different categories of the studied factors, an ANOVA test was used followed by a t-test. The relation between different factors and 25OHD3 was further investigated using multiple linear regression analysis and a logistic regression analysis.

Results

We found a positive association between serum levels of 25OHD3 and age, oral contraceptive use, moderate alcohol consumption, blood collection during summer/ autumn, creatinine, phosphate, calcium, and a high intake of vitamin D. Low vitamin D levels were associated with obesity, being born outside Sweden and high PTH levels.

Conclusions

The present population-based study found a positive association between serum levels of 25OHD3 and to several socio-demographic, life-style and biochemical factors. The study may have implications e. g. for dietary recommendations. However, the analysis is a cross-sectional and it is difficult to suggest Lifestyle changes as cause- effect relationships are difficult to assess.

Vitamin D status and dietary intake in a Swedish COPD population

INTRODUCTION

Emerging evidence indicates that patients with chronic obstructive pulmonary disease (COPD) have a poorer vitamin D status than the general population, possibly affecting several comorbidities. In northern latitudes, these problems could be even more accentuated in wintertime because of the low ultraviolet B radiation.

OBJECTIVES

To examine the dietary intake of vitamin D and the levels of 25-hydroxyvitamin D (25-OH-D) in a COPD population compared with a reference group in Swedish settings.

METHODS

Ninety-eight COPD patients (forced expiratory volume in 1 s/vital capacity ratio < 0.65) recruited from the outpatient clinics at the university hospitals in Gothenburg and Uppsala, Sweden were included in this cross-sectional study. The reference group (149 individuals) was randomly selected from the Swedish National Registry. The serum concentrations of 25-OH-D, intact parathyroid hormone, creatinine and calcium were measured. A trained dietitian conducted a dietary history interview to evaluate food intake of vitamin D, prescribed drugs and supplements containing vitamin D.

RESULTS AND CONCLUSIONS

The mean serum concentration of 25-OH-D was significantly higher in the reference group (57.6 ± 23 nmol/L) compared with the COPD group (51.5 ± 22 nmol/L) (P = 0.039). The dietary intake was predominantly below the recommendations in both groups. Mean total daily intake of vitamin D and mean daily supplementation of vitamin D was significantly higher in the COPD group (P = 0.012 and P = 0.030, respectively). Low intake of vitamin D and low serum levels of 25-OH-D are common in both COPD patients and an elderly Swedish population. Monitoring vitamin D status and possibly routinely treating COPD patients with vitamin D and calcium should be considered to minimise the risk of severe vitamin D deficiency among COPD patients.

DALI: Vitamin D and lifestyle intervention for gestational diabetes mellitus (GDM) prevention: an European multicentre, randomised trial - study protocol

Background

Gestational diabetes mellitus (GDM) is an increasing problem world-wide. Lifestyle interventions and/or vitamin D supplementation might help prevent GDM in some women.

Methods/design

Pregnant women at risk of GDM (BMI≥29 (kg/m²)) from 9 European countries will be invited to participate and consent obtained before 19+6 weeks of gestation. After giving informed consent, women without GDM will be included (based on IADPSG criteria: fasting glucose<5.1mmol; 1 hour glucose <10.0 mmol; 2 hour glucose <8.5 mmol) and randomized to one of the 8 intervention arms using a 2×(2×2) factorial design: (1) healthy eating (HE), 2) physical activity (PA), 3) HE+PA, 4) control, 5) HE+PA+vitamin D, 6) HE+PA+placebo, 7) vitamin D alone, 8) placebo alone), pre-stratified for each site. In total, 880 women will be included with 110 women allocated to each arm. Between entry and 35 weeks of gestation, women allocated to a lifestyle intervention will receive 5 face-to-face, and 4 telephone coaching sessions, based on the principles of motivational interviewing. The lifestyle intervention includes a discussion about the risks of GDM, a weight gain target <5kg and either 7 healthy eating ‘messages’ and/or 5 physical activity ‘messages’ depending on randomization. Fidelity is monitored by the use of a personal digital assistance (PDA) system. Participants randomized to the vitamin D intervention receive either 1600 IU vitamin D or placebo for daily intake until delivery. Data is collected at baseline measurement, at 24–28 weeks, 35–37 weeks of gestation and after delivery. Primary outcome measures are gestational weight gain, fasting glucose and insulin sensitivity, with a range of obstetric secondary outcome measures including birth weight.

Discussion

DALI is a unique Europe-wide randomised controlled trial, which will gain insight into preventive measures against the development of GDM in overweight and obese women.

Trial registration

ISRCTN70595832

A novel method to calculate solar UV exposure relevant to vitamin D production in humans

We present a novel method to calculate vitamin D3 -weighted exposure by integrating the incident solar spectral radiance over all relevant parts of the human body. Earlier investigations are based on the irradiance on surfaces, whereas our calculated exposure of a voxel model of a human takes into account the complex geometry of the radiation field. Assuming that sufficient vitamin D3 (1000 international units) can be produced within the human body in one minute for a completely uncovered body in vertical posture in summer at midlatitudes (e.g. Rome, June 21, noon, UV index of 10), we calculate the exposure times needed in other situations or seasons to gain enough vitamin D3 . Our calculations show that the UV index is not a good indicator for the exposure which depends on the orientation of the body (e.g. vertical (standing) or horizontal (lying down) posture). Without clothing the exposure is dominated by diffuse sky radiation and it is nearly irrelevant how the body in vertical posture is oriented toward the sun. At the winter solstice (December 21, noon, cloudy) at least in central Europe sufficient vitamin D3 cannot be obtained with realistic clothing, even if the exposure were extended to all daylight hours.

Associations between vitamin D and self-reported respiratory disease in older people from a nationally representative population survey

OBJECTIVES

To investigate the association between serum 25-hydroxy vitamin D (25(OH)D) concentrations and respiratory diseases in older people.

DESIGN

Cross-sectional, nationally representative sample.

SETTING

Community.

PARTICIPANTS

Two thousand seventy noninstitutionalized adults aged 65 and older taking part in the Health Survey for England 2005.

MEASUREMENTS

Serum 25(OH)D levels, self-reported long-term respiratory tract diseases, and covariates (age, sex, social class, season of examination, use of vitamin supplements, and physical health status).

RESULTS

Participants with severe deficiency (25(OH)D < 35 nmol/L) had more than twice the risk of respiratory disease than those in the highest quartile of 25(OH)D status (>64 nmol/L), and those with moderate deficiency (second quartile: 25(OH)D 35-48.9 nmol/L) had 1.75 times greater odds of respiratory diseases, even after adjustment with covariates. Adjusted analysis showed that those in the third quartile (25(OH)D 49.0 to 63.9 nmol/L) also had a greater risk of respiratory disease (odds ratio = 1.63, 95% confidence interval = 1.04-2.57).

CONCLUSION

Low serum 25(OH)D concentrations are associated with respiratory disease. Ensuring adequate 25(OH)D levels is of public health importance for older populations living in northern latitudes and may be an effective way to prevent concurrent respiratory infections and related complications in older people. Further studies are required to investigate whether vitamin D supplementation may reduce the incidence and exacerbations of respiratory disease.

Contribution of vitamin D insufficiency to the pathogenesis of multiple sclerosis

The contribution of vitamin D insufficiency to the pathogenesis of multiple sclerosis (MS) is reviewed. Among the multiple recently discovered actions of vitamin D, an immunomodulatory role has been documented in experimental autoimmune encephalomyelitis and in humans. This action in the peripheral immune system is currently the main known mechanism through which vitamin D might influence MS, but other types of actions could be involved within the central nervous system. Furthermore, vitamin D insufficiency is widespread in temperate countries and in patients with MS at the earliest stages of the disease, suggesting that the deleterious effects related to vitamin D insufficiency may be exerted in these patients. In fact, many genetic and environmental risk factors appear to interact and contribute to MS. In genetics, several human leukocyte antigen (HLA) alleles (more particularly HLA-DRB1*1501) could favour the disease whereas some others could be protective. Some of the genes involved in vitamin D metabolism (e.g. CYP27B1) also play a significant role. Furthermore, three environmental risk factors have been identified: past Epstein-Barr virus infection, vitamin D insufficiency and cigarette smoking. Interactions between genetic and environmental risk or protective factors may occur during the mother's pregnancy and could continue during childhood and adolescence and until the disease is triggered in adulthood, therefore possibly modulating the MS risk throughout the first decades of life. Furthermore, some clinical findings already strongly suggest that vitamin D status influences the relapse rate and radiological lesions in patients with MS, although the results of adequately powered randomized clinical trials using vitamin D supplementation have not yet been reported. While awaiting these incontrovertible results, which might be long in coming, patients with MS who are currently in vitamin D insufficiency should be supplemented, at least for their general health status, using moderate doses of the vitamin.

Relationships between serum 25-hydroxyvitamin D and quantitative ultrasound bone mineral density in 0-6 year old children

The relationship between serum 25-hydroxyvitamin D and quantitative ultrasound bone mineral density in young children remains unclear. In addition, consensus has not been reached with regard to the concentration of 25(OH)D to define vitamin D deficiency for infants and children. In the present study, 203 children 0-6 years old were recruited in Shanghai, China. The concentrations of serum 25(OH)D, weight, length, and quantitative ultrasound bone mineral density (BMD) of left mid-tibia were determined. Low BMD was defined as <20th percentile of given age and sex. Low 25(OH)D was defined as 25(OH)D<20 ng/ml. The results showed that median serum 25(OH)D level was 19.0 ng/ml, and 58.6% had a serum 25(OH)D below 20 ng/ml. After adjusting for potential confounders, a linear relationship between serum 25(OH)D and BMD was observed. Serum 25(OH)D was positively associated with BMD (ß=323.3, 95% CI=201.0-445.7, p<0.001), and low 25(OH)D (<20 ng/ml) had a high risk for low BMD (OR=5.5, 95% CI=2.5-12). In addition, there is a nonlinear relationship between 25(OH)D and low BMD, and a threshold for 25(OH)D of 20 ng/ml existed for low BMD. The prevalence of low BMD was 47.1% in the group of 25(OH)D<20 ng/ml, much higher than 16.7% in the group of 25(OH)D ≥ 20 ng/ml (p<0.05). The results suggested that quantitative ultrasound BMD could be an indicator for vitamin D status in young children, and also provided further evidence to define vitamin D deficiency for infants and children.

Severe and uncontrolled adult asthma is associated with vitamin D insufficiency and deficiency

BACKGROUND

Vitamin D has effects on the innate and adaptive immune system. In asthmatic children low vitamin D levels are associated with poor asthma control, reduced lung function, increased medication intake, and exacerbations. Little is known about vitamin D in adult asthma patients or its association with asthma severity and control.

METHODS

Clinical parameters of asthma control and 25-hydroxyvitamin D (25(OH)D) serum concentrations were evaluated in 280 adult asthma patients (mean ± SD: 45.0 ± 13.8 yrs., 40% male, FEV1 74.9 ± 23.4%, 55% severe, 51% uncontrolled).

RESULTS

25(OH)D concentrations in adult asthmatics were low (25.6 ±11.8 ng/ml) and vitamin D insufficiency or deficiency (vitamin D <30 ng/ml) was common (67%). 25(OH)D levels were related to asthma severity (intermittent: 31.1 ± 13.0 ng/ml, mild: 27.3 ± 11.9 ng/ml, moderate: 26.5 ± 12.0 ng/ml, severe: 24.0 ± 11.8 ng/ml, p = 0.046) and control (controlled: 29.5 ± 12.5 ng/ml, partly controlled 25.9 ± 10.8 ng/ml, uncontrolled: 24.2 ± 11.8 ng/ml, p = 0.030). The frequency of vitamin D insufficiency or deficiency was significantly higher in patients with severe or uncontrolled asthma and was associated with a lower FEV1 (vitamin D <30 vs. ≥30 ng/ml 2.3 ± 0.9 L vs. 2.7 ± 1.0 L, p = 0.006), higher levels of exhaled NO (45 ± 46 ppb vs. 31 ± 37 ppb, p = 0.023), a higher BMI (28.3 ± 6.2 vs. 25.1 ± 3.9, p < 0.001), and sputum eosinophilia (5.1 ± 11.8% vs. 0.5 ± 1.0%, p = 0.005). The use of oral corticosteroids or sputum eosinophilia was associated with a 20% or 40% higher risk of vitamin D insufficiency or deficiency.

CONCLUSIONS

25(OH)D levels below 30 ng/ml are common in adult asthma and most pronounced in patients with severe and/or uncontrolled asthma, supporting the hypothesis that improving suboptimal vitamin D status might be effective in prevention and treatment of asthma.

Vitamin d, calcium, and dairy intakes and stress fractures among female adolescents

OBJECTIVE To identify whether calcium, vitamin D, and/or dairy intakes are prospectively associated with stress fracture risk among female adolescents. DESIGN Prospective cohort study. SETTING Adolescent girls living throughout the United States. PARTICIPANTS A total of 6712 girls aged 9 to 15 years at baseline in the Growing Up Today Study, an ongoing prospective cohort study. MAIN EXPOSURES Dairy, calcium, and vitamin D intakes assessed by food frequency questionnaire every 12 to 24 months between 1996 and 2001. MAIN OUTCOME MEASURE Incident stress fracture that occurred between 1997 and 2004 as reported by mothers of the participants in 2004. Cox proportional hazards models were used to examine associations. RESULTS During 7 years of follow-up, 3.9% of the girls developed a stress fracture. Dairy and calcium intakes were unrelated to risk of developing a stress fracture. However, vitamin D intake was inversely related to stress fracture risk. The multivariable-adjusted hazard ratio of stress fracture for the highest vs the lowest quintile of vitamin D intake was 0.49 (95% CI, 0.24-1.01; Ptrend = .07). We conducted a stratified analysis to estimate the association between vitamin D intake and stress fracture risk among girls participating in at least 1 h/d of high-impact activity, among whom 90.0% of the stress fractures occurred, and found that higher vitamin D intake predicted significantly lower risk of stress fracture (Ptrend = .04). CONCLUSIONS Vitamin D intake is associated with lower stress fracture risk among adolescent girls who engage in high levels of high-impact activity. Neither calcium intake nor dairy intake was prospectively associated with stress fracture risk.

Prevention and treatment of vitamin D deficiency

Vitamin D insufficiency and deficiency are widespread in many countries. We review the evidence pertaining to its prevention and treatment. Deficiency may be adequately treated with many different therapeutic regimens of either cholecalciferol or ergocalciferol, owing to the high therapeutic index of both compounds. Nevertheless, the current evidence suggests that regular dosing with oral cholecalciferol (e.g., 60,000 IU weekly) may have slight advantages over other regimens when replenishing vitamin D stores following deficiency. For long-term supplementation, smaller regular doses, such as cholecalciferol 1,000 IU daily, or 10,000 IU weekly, are suitable. Giving reliable and specific advice about appropriate sunlight exposure remains difficult because of differing interindividual skin pigmentation and variable sunlight UVB content at different latitudes, at different times of year, and in different terrestrial environments.

Contributions of sunlight and diet to vitamin D status

Vitamin D is made in the skin using ultraviolet radiation of specific low wavelength, 290-315 nm (UVB). For many parts of the world there is a period when there is insufficient intensity of UVB to make vitamin D, which is reflected by a clear seasonal variation in vitamin D status. Sun avoidance practices, melanin in pigmented skin, and sun protection creams (sunscreen), if used properly, can dramatically reduce vitamin D synthesis. Few foods naturally contain vitamin D, although some countries fortify foods with vitamin D. Regulatory mechanisms in the skin mean there is no danger of vitamin D toxicity through sunlight synthesis. Although oral vitamin D is potentially toxic with high-dose supplements, there is a wide safety margin. Long-term safety data covering a range of potential adverse outcomes are limited.

A randomized trial of vitamin D supplementation in 2 community health center networks in South Carolina

OBJECTIVE

We sought to determine whether 4000 IU/d (vs 2000 IU/d) of vitamin D during pregnancy is safe and improves maternal/neonatal 25-hydroxyvitamin D [25(OH)D] in a dose-dependent manner.

STUDY DESIGN

A total of 257 pregnant women 12-16 weeks' gestation were enrolled. Randomization to 2000 vs 4000 IU/d followed 1-month run-in at 2000 IU/d. Participants were monitored for hypercalciuria, hypercalcemia, and 25(OH)D status.

RESULTS

Maternal 25(OH)D (n = 161) increased from 22.7 ng/mL (SD 9.7) at baseline to 36.2 ng/mL (SD 15) and 37.9 ng/mL (SD 13.5) in the 2000 and 4000 IU groups, respectively. While maternal 25(OH)D change from baseline did not differ between groups, 25(OH)D monthly increase differed between groups (P < .01). No supplementation-related adverse events occurred. Mean cord blood 25(OH)D was 22.1 ± 10.3 ng/mL in 2000 IU and 27.0 ± 13.3 ng/mL in 4000 IU groups (P = .024). After controlling for race and study site, preterm birth and labor were inversely associated with predelivery and mean 25(OH)D, but not baseline 25(OH)D.

CONCLUSION

Maternal supplementation with vitamin D 2000 and 4000 IU/d during pregnancy improved maternal/neonatal vitamin D status. Evidence of risk reduction in infection, preterm labor, and preterm birth was suggestive, requiring additional studies powered for these endpoints.

A prospective study of serum 25-hydroxyvitamin d levels and mortality among African Americans and non-African Americans

The beneficial biologic effects attributed to vitamin D suggest a potential to influence overall mortality. Evidence addressing this hypothesis is limited, especially for African Americans who have a high prevalence of vitamin D insufficiency. The authors conducted a nested case-control study within the prospective Southern Community Cohort Study to relate baseline serum levels of 25-hydroxyvitamin D (25(OH)D) with subsequent mortality. Cases were 1,852 participants who enrolled from 2002 to 2009 and died >12 months postenrollment. Controls (n = 1,852) were matched on race, sex, age, enrollment site, and blood collection date. The odds ratios for quartile 1 (<10.18 ng/mL) versus quartile 4 (>21.64 ng/mL) levels of 25(OH)D were 1.60 (95% confidence interval (CI): 1.20, 2.14) for African Americans and 2.11 (95% CI: 1.39, 3.21) for non-African Americans. The effects were strongest for circulatory disease death, where quartile 1 versus quartile 4 odds ratios were 2.53 (95% CI: 1.44, 4.46) and 3.25 (95% CI: 1.33, 7.93) for African Americans and non-African Americans, respectively. The estimated odds of total mortality were minimized in the 25(OH)D range of 35-40 ng/mL. These findings provide support for the hypothesis that vitamin D status may have an important influence on mortality for both African Americans and non-African Americans.

Drug-vitamin D interactions: a systematic review of the literature

Extensive media coverage of the potential health benefits of vitamin D supplementation has translated into substantial increases in supplement sales over recent years. Yet, the potential for drug-vitamin D interactions is rarely considered. This systematic review of the literature was conducted to evaluate the extent to which drugs affect vitamin D status or supplementation alters drug effectiveness or toxicity in humans. Electronic databases were used to identify eligible peer-reviewed studies published through September 1, 2010. Study characteristics and findings were abstracted, and quality was assessed for each study. A total of 109 unique reports met the inclusion criteria. The majority of eligible studies were classified as class C (nonrandomized trials, case-control studies, or time series) or D (cross-sectional, trend, case report/series, or before-and-after studies). Only 2 class C and 3 class D studies were of positive quality. Insufficient evidence was available to determine whether lipase inhibitors, antimicrobial agents, antiepileptic drugs, highly active antiretroviral agents, or H2 receptor antagonists alter serum 25(OH)D concentrations. Atorvastatin appears to increase 25(OH)D concentrations, whereas concurrent vitamin D supplementation decreases concentrations of atorvastatin. Use of thiazide diuretics in combination with calcium and vitamin D supplements may cause hypercalcemia in the elderly or those with compromised renal function or hyperparathyroidism. Larger studies with stronger study designs are needed to clarify potential drug-vitamin D interactions, especially for drugs metabolized by cytochrome P450 3A4 (CYP3A4). Healthcare providers should be aware of the potential for drug-vitamin D interactions.

Vitamin D, effects on brain development, adult brain function and the links between low levels of vitamin D and neuropsychiatric disease

Increasingly vitamin D deficiency is being associated with a number of psychiatric conditions. In particular for disorders with a developmental basis, such as autistic spectrum disorder and schizophrenia the neurobiological plausibility of this association is strengthened by the preclinical data indicating vitamin D deficiency in early life affects neuronal differentiation, axonal connectivity, dopamine ontogeny and brain structure and function. More recently epidemiological associations have been made between low vitamin D and psychiatric disorders not typically associated with abnormalities in brain development such as depression and Alzheimer's disease. Once again the preclinical findings revealing that vitamin D can regulate catecholamine levels and protect against specific Alzheimer-like pathology increase the plausibility of this link. In this review we have attempted to integrate this clinical epidemiology with potential vitamin D-mediated basic mechanisms. Throughout the review we have highlighted areas where we think future research should focus.

Supplementation with 1000 IU vitamin D/d leads to parathyroid hormone suppression, but not increased fractional calcium absorption, in 4-8-y-old children: a double-blind randomized controlled trial

BACKGROUND

The effects of vitamin D supplementation in healthy prepubertal children on physiologic outcomes have not been investigated.

OBJECTIVE

The objective was to evaluate the effects of supplementation with 1000 IU vitamin D(3)/d on calcium absorption.

DESIGN

In a double-blind, placebo-controlled trial, we randomly assigned 64 children to 1000 IU vitamin D(3)/d (n = 32) or placebo (n = 32) for 8 wk. Stable isotopes were used to assess calcium absorption. The main outcome measure was calcium absorption before and after supplementation.

RESULTS

All of the data are shown as means ± SDs. At baseline, vitamin D intake was 221 ± 79 IU/d and calcium intake was 830 ± 197 mg/d. Baseline serum 25-hydroxyvitamin D [25(OH)D] was not significantly correlated with fractional or total calcium absorption. After 8 wk, with baseline values used as a covariate, no differences were seen in fractional or total calcium absorption based on supplementation group (P = 0.75 and 0.36, respectively). Supplemented children had a significant increase in 25(OH)D concentrations (from 27.7 ± 7.4 to 36.0 ± 10.3 ng/mL; P < 0.0001) and a decrease in parathyroid hormone (from 21.4 ± 10.4 to 12.9 ± 7.1 pg/mL; P < 0.001); no significant changes in the placebo group were observed. No adverse side effects were noted in either group.

CONCLUSIONS

Vitamin D(3) supplementation at 1000 IU/d increases 25(OH)D and decreases parathyroid hormone in children with average vitamin D intakes below the dietary recommendations of the Institute of Medicine. However, no significant effects of this change on calcium absorption occurred. This trial was registered at clinicaltrials.gov as NCT 00868738.

Variation in vitamin D supplementation among adults in a multi-race/ethnic health plan population, 2008

Background

Vitamin D may have a role in many chronic conditions in addition to bone health. Nutritional surveys among Americans have reported high levels of vitamin D insufficiency, especially among Blacks and Latinos. Our study examined variation in vitamin D supplementation practices in an adult health plan population by age, gender, and race-ethnicity.

Methods

Self-report data from a 2008 general health survey in a large Northern California health plan were used to characterize number and types of sources of vitamin D supplementation (multivitamin, calcium with D, singular D) among women and men aged 25-85, overall, by race-ethnicity, and for obese, diabetic, and hypertensive subgroups.

Results

In this population, 40% of women and 54% of men ≤ 50, and 24% of women and 53% of men aged 51-85 get no vitamin D from dietary supplements. Higher vitamin D supplementation among women > 50 is associated with higher reported intake of calcium with D. Black and Latina women aged 25-85 and Filipinas in the ≤ 50 age group were significantly less likely than non-Hispanic Whites to get vitamin D from supplements, whereas vitamin D supplementation practices among Chinese women did not significantly differ from non-Hispanic Whites. Among men, Latinos aged 25-85 and Black and Chinese ≤ 50 were significantly less likely than non-Hispanic Whites to get vitamin D from supplements. Similar race-ethnic differences in vitamin D supplementation patterns were observed for people in the obese, diabetic, and hypertensive groups.

Conclusions

Our survey results suggest that in 2008, a large percentage of women and an even larger percentage of men in a large Northern California health plan get no vitamin D from dietary supplements, and that Blacks and Latinos and obese adults, who are at higher risk of vitamin D deficiency, are also the least likely to get any vitamin D from dietary supplements.

Vitamin D deficiency: a new risk factor for type 2 diabetes?

Recent compelling evidence suggests a role of vitamin D deficiency in the pathogenesis of insulin resistance and insulin secretion derangements, with a consequent possible interference with type 2 diabetes mellitus. The mechanism of this link is incompletely understood. In fact, vitamin D deficiency is usually detected in obesity in which insulin resistance is also a common finding. The coexistence of insulin resistance and vitamin D deficiency has generated several hypotheses. Some cross-sectional and prospective studies have suggested that vitamin D deficiency may play a role in worsening insulin resistance; others have identified obesity as a risk factor predisposing individuals to exhibit both vitamin D deficiency and insulin resistance. The available data from intervention studies are largely confounded, and inadequate considerations of seasonal effects on 25(OH)D concentrations are also a common design flaw in many studies. On the contrary, there is strong evidence that obesity might cause both vitamin D deficiency and insulin resistance, leaving open the possibility that vitamin D and diabetes are not related at all. Although it might seem premature to draw firm conclusions on the role of vitamin D supplementation in reducing insulin resistance and preventing type 2 diabetes, this manuscript will review the circumstances leading to vitamin D deficiency and how such a deficiency can eventually independently affect insulin sensitivity.

Vitamin D and asthma in children

Vitamin D deficiency and insufficiency are increasingly being recognized in the general population, and have been largely attributed to lifestyle changes (reduced exposure to sunshine due to working indoors or the use of protective clothing and sunscreen; changes in diet) over the last few decades. The musculoskeletal consequences of severe vitamin D deficiency are well established, however, a number of other disorders have now been linked to vitamin D insufficiency, including asthma. There is growing appreciation of the likely importance of vitamin D as a pleiotrophic mediator that contributes to pulmonary health. Children with asthma appear to be at increased risk of vitamin D insufficiency. Epidemiologic data suggest that low serum vitamin D in children with asthma is associated with more symptoms, exacerbations, reduced lung function, increased medication usage and severe disease. In vitro studies have demonstrated that vitamin D enhances steroid responsiveness in adult asthmatics. Vitamin D may play an important role in pulmonary health by inhibiting inflammation, in part through maintaining regulatory T cells, and direct induction of innate antimicrobial mechanisms. More research is required to fully understand the role of vitamin D in the maintenance of airway homeostasis and address the diagnostic and therapeutic implications vitamin D may have in the future of asthma management. This review summarises the current understanding and uncertainties regarding the effect of vitamin D deficiency and insufficiency in children with asthma.

Association of vitamin D receptor gene polymorphisms with susceptibility to asthma in Tunisian children: A case control study

BACKGROUND

Vitamin D and its nuclear receptor (VDR) are linked to asthma in a genetic and immunologic basis. Polymorphisms in the VDR gene may alter the actions of vitamin D and then influence the development and the severity of asthma.

AIMS

We aimed at elucidating the genetic association of VDR gene polymorphisms with susceptibility to asthma in Tunisian children and with serum vitamin D levels.

METHODS

The study included 155 patients recruited from Abderrahmen MAMI hospital in Tunisia and two hundred twenty five healthy individuals matched with patients in age and sex for comparison. VDR genotypes were determined by PCR-RFLP method using endonuclease FokI, BsmI, TaqI and ApaI and vitamin D was assessed with a radioimmunoassay kit.

RESULTS

The distribution of genotype frequencies differed significantly between asthmatics and controls (FokI: P=0.04; BsmI: P=0.006; TaqI: P=0.006). Haplotype analyses revealed a significant association between bAt and bat haplotypes and asthma (P=0.00076, P=0.016). When patients were stratified according to atopic status and stage of severity, no significant association was detected with VDR variants. No association was found between VDR SNPs and serum 25-hydroxyvitamin D levels.

CONCLUSION

Our study shows a relation between VDR gene polymorphisms and susceptibility to asthma in children.

Vitamin D: an overview of its role in skeletal muscle physiology in children and adolescents

Many children may have insufficient serum concentrations of vitamin D, which could prevent optimal muscle development and function. Vitamin D deficiency in animal models results in negative effects on muscle fiber structure and calcium/phosphorus handling, suggesting an integral role of vitamin D in skeletal muscle function. While there is a dearth of data in humans, the available evidence demonstrates a positive association between vitamin D status and muscle function. This review focuses on the important role of vitamin D in muscle function in children and adolescents who live in North American regions where exposure to ultraviolet B radiation is limited and who are thus at increased risk for vitamin D insufficiency. The effects of vitamin D on muscle cell proliferation and differentiation, muscle fiber structure, and calcium and phosphorus handling are discussed. Moreover, the roles of vitamin D and the vitamin D receptor and their genomic and nongenomic actions in muscle function are explored in depth. Future research should aim to establish a vitamin D status consistent with optimal musculoskeletal development and function in young children.

Comparison of narrowband ultraviolet B exposure and oral vitamin D substitution on serum 25-hydroxyvitamin D concentration

BACKGROUND

A short course of narrowband ultraviolet B (NB-UVB) exposures increases the serum 25-hydroxyvitamin D [25(OH)D] concentration in patients with psoriasis and healthy subjects.

OBJECTIVES

To compare the effects of NB-UVB and oral vitamin D substitution in healthy subjects in winter.

METHODS

Healthy adult hospital employees and medical students were screened for serum 25(OH)D concentration. Those with 25(OH)D below 75 nmol L(-1) were randomly given either 12 NB-UVB exposures or 20 μg of oral cholecalciferol daily for 4 weeks. The NB-UVB exposures were given with a Waldmann UV 7001 cabin and the mean cumulative dose was 48·4 standard erythema doses. Serum 25(OH)D was measured before and after the treatments by radioimmunoassay.

RESULTS

The baseline serum 25(OH)D concentrations were 52·9 ± 10·4 (mean ± SD) in the 33 NB-UVB-treated and 53·5 ± 12·7 nmol L(-1) in the 30 oral cholecalciferol-treated subjects. The mean increase in serum 25(OH)D was 41·0 nmol L(-1) [95% confidence interval (CI) 34·8-47·2; P < 0·001] in the NB-UVB group and 20·2 nmol L(-1) (95% CI 14·6-26·0; P < 0·001) in the cholecalciferol group. The difference between the two treatments was significant at 2 weeks (P = 0·033) and at 4 weeks (P < 0·001). One month after the treatments the 25(OH)D concentrations had increased further.

CONCLUSIONS

The present study shows that 12 NB-UVB exposures given during 4 weeks increase serum 25(OH)D concentration significantly more than 20 μg of oral cholecalciferol daily. A short NB-UVB course is an effective way to improve vitamin D balance in winter and the response is still evident 2 months after the course.

Associations between 25-hydroxyvitamin D and weight gain in elderly women

BACKGROUND

25-Hydroxyvitamin D [25(OH)D] levels are lower in obese individuals. Determining whether low vitamin D status can predispose weight gain requires a longitudinal study.

METHODS

From a community-based multicenter U.S. prospective cohort of 9704 (Study of Osteoporotic Fractures [SOF]), 4659 women aged ≥65 with baseline 25(OH)D measurement were followed for 4.5 years. They were weighed at baseline and follow-up visits, and a subset (n=1054) had 25(OH)D levels remeasured at follow-up.

RESULTS

Women with 25(OH)D levels ≥30 ng/mL had lower baseline weight (141.6 pounds) compared to women with 25(OH)D levels <30 ng/mL (148.6 pounds) (p<0.001). Overall, 25(OH)D status was not associated with weight change over 4.5 years, although there was a significant interaction between 25(OH)D status and weight change category (loss, gain, stable) (p<0.0001). In women who gained ≥5% weight, those with baseline 25(OH)D levels ≥30 ng/mL gained 16.4 pounds (12.2% of baseline weight) over 4.5 years compared to 18.5 pounds (13.9% of baseline weight) in women with levels <30 ng/mL (p=0.04). In women who lost ≥5% weight or remained stable (<5% weight change), there was no association between 25(OH)D status at baseline and weight change. Among women who gained weight and had 25(OH)D measured at both visits, having sustained or developing 25(OH)D levels ≥30 ng/mL was associated with less weight gain between visits (14.81 vs. 16.34 pounds, p=0.04).

CONCLUSIONS

Higher 25(OH)D levels are associated with lower weight gains, suggesting low vitamin D status may predispose to fat accumulation.