Vitamin D deficiency: a global perspective

Prevalence of rickets-like bone deformities in rural Gambian children

The aim of this study was to estimate the burden of childhood rickets-like bone deformity in a rural region of West Africa where rickets has been reported in association with a low calcium intake. A population-based survey of children aged 0.5-17.9 years living in the province of West Kiang, The Gambia was conducted in 2007. 6221 children, 92% of those recorded in a recent census, were screened for physical signs of rickets by a trained survey team with clinical referral of suspected cases. Several objective measures were tested as potential screening tools. The prevalence of bone deformity in children <18.0 years was 3.3%. The prevalence was greater in males (M = 4.3%, F = 2.3%, p < 0.001) and in children <5.0 years (5.7%, M = 8.3%, F = 2.9%). Knock-knee was more common (58%) than bow-leg (31%) or windswept deformity (9%). Of the 196 examined clinically, 36 were confirmed to have a deformity outside normal variation (47% knock-knee, 53% bow-leg), resulting in more conservative prevalence estimates of bone deformity: 0.6% for children <18.0 years (M = 0.9%, F = 0.2%), 1.5% for children < 5.0 years (M = 2.3%, F = 0.6%). Three of these children (9% of those with clinically-confirmed deformity, 0.05% of those screened) had active rickets on X-ray at the time of medical examination. This emphasises the difficulties in comparing prevalence estimates of rickets-like bone deformities from population surveys and clinic-based studies. Interpopliteal distance showed promise as an objective screening measure for bow-leg deformity. In conclusion, this population survey in a rural region of West Africa with a low calcium diet has demonstrated a significant burden of rickets-like bone deformity, whether based on physical signs under survey conditions or after clinical examination, especially in boys < 5.0 years.

Lifestyle and Dietary Factors Associated with Serum 25-Hydroxyvitamin D Levels in Korean Young Adults

Inadequate vitamin D status is highly prevalent in the Korean population, especially among young adults. Nonetheless, correlates of suboptimal vitamin D levels in young adults are not well defined. This study aimed to investigate potentially modifiable determinants of vitamin D levels in young adults in Korea. This cross-sectional study was based on health check-up data from 3,450 healthy male and female university students aged 18-29 yr in Seoul between April and May 2013. Serum 25-hydroxyvitamin D [25(OH)D] levels were determined using chemiluminescent immunoassay. Anthropometric data were measured, and lifestyle, dietary, and sociodemographic factors were obtained through self-administered questionnaires. General linear regression was used to assess correlates of serum 25(OH)D levels. The mean serum 25(OH)D level was 11.1 ng/mL, and the prevalence of 25(OH)D levels less than 10 ng/mL was 44.7% (39.5% in men, 50.2% in women). In a final multivariable model, significant positive correlates of serum 25(OH)D were older age, male sex, increased physical activity, sunlight exposure ≥ 30 min/day, eating breakfast regularly, consumption of dairy and fatty fish, and use of vitamin D-containing supplements. In contrast, significant inverse correlates were obesity (body mass index, BMI ≥ 25 kg/m(2)) or underweight (BMI < 18.5 kg/m(2)), abdominal obesity, increased sedentary time, and frequent consumption of instant noodles and sugar-sweetened beverages. In conclusion, many modifiable lifestyle and dietary factors were associated with low serum 25(OH)D levels in Korean young adults. Further studies on potential mechanisms of the correlates and optimal strategies to improve vitamin D status in this vulnerable subpopulation are warranted.

Prevalence of vitamin D inadequacy in athletes: a systematic-review and meta-analysis

BACKGROUND

Vitamin D is essential for maintaining optimal bone health. The prevalence of vitamin D inadequacy in athletes is currently unclear.

OBJECTIVE

The objective of this study is to determine the prevalence of vitamin D inadequacy in athletes.

METHODS

We conducted a systematic review and meta-analysis. Multiple databases were searched and studies assessing serum 25-hydroxyvitamin D [25(OH)D] status in athletes were identified. Serum 25(OH)D is measured to clinically determine vitamin D status. Reviewers independently selected the eligible articles, assessed the methodological quality, and extracted data. Disagreements were resolved by consensus. Weighted proportions of vitamin D inadequacy [serum 25(OH)D <32 ng/mL] were calculated (DerSimonian-Laird random-effects model) and compared using Chi-squared (χ (2)) test. Subgroup analyses were conducted and risk ratios (RRs) with 95 % confidence intervals (CIs) were reported.

RESULTS

Twenty-three studies with 2,313 athletes [mean (standard deviation) age 22.5 (5.0) years, 76 % male] were included. Of 2,313 athletes, 56 % (44-67 %) had vitamin D inadequacy that significantly varied by geographical location (p < 0.001). It was significantly higher in the UK and in the Middle East. The risk significantly increased for winter and spring seasons (RR 1.85; 95 % CI 1.27-2.70), indoor sport activities (RR 1.19; 95 % CI 1.09-1.30), and mixed sport activities (RR 2.54; 95 % CI 1.03-6.26). The risk was slightly higher for >40°N latitude [RR 1.14 (95 % CI 0.91-1.44)] but it increased significantly [RR 1.85 (1.35-2.53)] after excluding the Middle East as an outlier. Seven studies with 359 athletes reported injuries. The prevalence of injuries in athletes was 43 % (95 % CI 20-68) [bone related = 19 % (95 % CI 7-36); muscle and soft-tissue = 37.5 % (95 % CI 11.5-68.5)].

CONCLUSION

Despite the limitations of the current evidence, the prevalence of vitamin D inadequacy in athletes is prominent. The risk significantly increases in higher latitudes, in winter and early spring seasons, and for indoor sport activities. Regular investigation of vitamin D status using reliable assays and supplementation is essential to ensure healthy athletes. The prevalence of injuries in athletes is notable but its association with vitamin D status is unclear. A well-designed longitudinal study is needed to answer this possible association.

Vitamin D levels and comorbidities in ambulatory and hospitalized patients in Austria

Vitamin D in its hormonal active form, 1,25-dihydroxyvitamin D (calcitriol), has a major impact on bone turnover by regulating calcium and phosphate homoeostasis. By binding the active vitamin D hormone to the vitamin D receptor (VDR), it acts as a nuclear transcription factor (Bouillon et al., Endocr Rev 29(6):726-776, 2008). The discovery that almost all tissues and cells in the body express the VDR and that several tissues possess the enzymatic capability to convert 25-hydroxyvitamin D (25(OH)-D3; cholecalciferol) to the active form, suggests that vitamin D fulfills various extra-osseous functions (Bouillon et al., Endocr Rev 29(6):726-776, 2008; Holick, N Engl J Med 357(3):266-281, 2007). For example, VDR ensures adequate intestinal calcium absorption by regulating the synthesis of several calcium transport proteins in the duodenum (Bouillon et al., Endocr Rev 29(6):726-776, 2008). Additionally, vitamin D is important for proper muscle function, and some studies suggest it may contribute to prevent type 1 diabetes mellitus, certain autoimmune diseases, hypertension, and several types of cancer (Holick, N Engl J Med 357(3):266-281, 2007).

Mass spectrometric profiling of vitamin D metabolites beyond 25-hydroxyvitamin D

BACKGROUND

The frequency of measurements of vitamin D in the human population has significantly increased over the last decade because vitamin D has now been linked to many diseases, in addition to its established role in bone health. Usually, serum 25-hydroxyvitamin D concentrations are measured to assess the vitamin D status of individuals. Unfortunately, many studies investigating links between vitamin D and disease also use only this single metabolite. Intricate correlations with other vitamin D metabolites or dynamic effects of downstream metabolites may therefore be overlooked. Fortunately, powerful LC-MS/MS approaches have recently become available that can simultaneously quantify the concentrations of multiple vitamin D metabolites. These approaches are challenging, however, because of inherent instrumental problems with detection of vitamin D compounds and the low concentrations of the metabolites in biological fluids.

CONTENT

This review summarizes recent mass spectrometry assays for the quantitative measurement of multiple vitamin D metabolites and their application in clinical research, with a particular focus on the low-abundance downstream metabolic species generated after the initial hydroxylation to 25-hydroxyvitamin D.

SUMMARY

To study the pathobiological effects and function of vitamin D metabolites in disease, in particular in low-abundance species beyond 25-hydroxyvitamin D, we need to know their concentrations. Although detection of these vitamin D species is challenging, a number of recent mass spectrometry assays have successfully demonstrated that LC-MS/MS methods can quantify multiple vitamin D compounds over a wide dynamic range individually or as part of multimetabolite assays.

[Prevalence of vitamin D deficiency and associated factors in women and newborns in the immediate postpartum period]

OBJECTIVE

To assess the prevalence of vitamin D deficiency and its associated factors in women and their newborns in the postpartum period.

METHODS

This cross-sectional study evaluated vitamin D deficiency/insufficiency in 226 women and their newborns in Viçosa (Minas Gerais, BR) between December 2011 and November 2012. Cord blood and venous maternal blood were collected to evaluate the following biochemical parameters: vitamin D, alkaline phosphatase, calcium, phosphorus and parathyroid hormone. Poisson regression analysis, with a confidence interval of 95% was applied to assess vitamin D deficiency and its associated factors. Multiple linear regression analysis was performed to identify factors associated with 25(OH)D deficiency in the newborns and women from the study. The criteria for variable inclusion in the multiple linear regression model was the association with the dependent variable in the simple linear regression analysis, considering p<0.20. Significance level was α<5%.

RESULTS

From 226 women included, 200 (88.5%) were 20 to 44 years old; the median age was 28 years. Deficient/insufficient levels of vitamin D were found in 192 (85%) women and in 182 (80.5%) neonates. The maternal 25(OH)D and alkaline phosphatase levels were independently associated with vitamin D deficiency in infants.

CONCLUSIONS

This study identified a high prevalence of vitamin D deficiency and insufficiency in women and newborns and the association between maternal nutritional status of vitamin D and their infants' vitamin D status.

The Prevalence of Vitamin D Deficiency among Cancer Survivors in a Nationwide Survey of the Korean Population

Background

Recent studies have shown that inadequate vitamin D levels are associated with a poor cancer prognosis, but data regarding actual vitamin D levels in cancer survivors are limited. This study investigated the vitamin D levels and prevalence of vitamin D deficiency among Korean cancer survivors compared with non-cancer controls, and identified the factors associated with vitamin D deficiency.

Methods

Using the Korea National Health and Nutrition Examination Survey (KNHANES), 915 cancer survivors and 29,694 controls without a history of cancer were selected. Serum 25(OH)D levels were measured; vitamin D deficiency was defined as 25(OH)D levels less than 20 ng/mL. Chi-square tests and multiple logistic regression analyses were used to evaluate the prevalence of vitamin D deficiency and associated factors.

Results

Vitamin D deficiency was observed in 62.7% of cancer survivors and 67.1% of controls. Among cancer survivors, vitamin D deficiency was most prevalent among 19–44 year olds (76.2%) and among managers, professionals, and related workers (79.3%). Multiple logistic regression analysis revealed that younger cancer survivors and those who work indoors were predisposed to vitamin D deficiency.

Conclusion

Vitamin D deficiency was prevalent among both cancer survivors and controls in Korea. The regular evaluation and management of vitamin D levels is needed for both bone health and general health in cancer survivors.

Vitamin D and the risk of atrial fibrillation--the Rotterdam Study

Atrial fibrillation (AF) is the most common chronic arrhythmia and it increases the risk of cardiovascular morbidity and mortality. Still there is not a complete understanding of its etiology and underlying pathways. Vitamin D might regulate renin-angiotensin-aldosterone system and might be involved in inflammation, both implicated in the pathophysiology of AF. The objective of this work was to investigate the association between vitamin D status with the risk of AF in the elderly. This study was conducted within the Rotterdam Study, a community-based cohort of middle-aged and elderly participants in Rotterdam, The Netherlands. We had 3,395 participants who were free of AF diagnosis at the start of our study and who had vitamin D data available. We analyzed the association between serum 25-hydroxivitamin D (25(OH)D) and incidence of AF using Cox regression models. Vitamin D deficiency was defined as serum 25(OH)D concentrations <50 nmol/l, insufficiency between 50 nmol/l and 75 nmol/l, while serum 25(OH)D concentrations equal to and above 75 nmol/l were considered as adequate. After mean follow-up of 12.0 years 263 (7.7%) participants were diagnosed with incident AF. Vitamin D status was not associated with AF in any of the 3 multivariate models tested (model adjusted for socio-demographic factors and life-style factors: HR per 10 unit increment in serum 25(OH)D 0.96, 95% CI: 0.91-1.02; HR for insufficiency: 0.82, 95%CI: 0.60-1.11,and HR for adequate status: 0.76, 95%CI: 0.52-1.12 compared to deficiency). This prospective cohort study does not support the hypothesis that vitamin D status is associated with AF.

Obesity and vitamin D deficiency: a systematic review and meta-analysis

Over the past decade, there have been an increasing number of studies on the association between vitamin D deficiency and anthropometric state. However, we did not identify any meta-analyses of the relationship between obesity and vitamin D deficiency in different age groups. Thus, we evaluated the association between obesity and vitamin D deficiency. We searched for observational studies published up to April 2014 in PubMed/Medline, Web of Science and Scopus databases. We performed a meta-analysis in accordance with the random-effects model to obtain the summary measurement (prevalence ratio, PR). Among the 29,882 articles identified, 23 met the inclusion criteria. The prevalence of vitamin D deficiency was 35% higher in obese subjects compared to the eutrophic group (PR: 1.35; 95% CI: 1.21-1.50) and 24% higher than in the overweight group (PR: 1.24; 95% CI: 1.14-1.34). These results indicate that the prevalence of vitamin D deficiency was more elevated in obese subjects. The vitamin D deficiency was associated with obesity irrespective of age, latitude, cut-offs to define vitamin D deficiency and the Human Development Index of the study location.

Vitamin D status in pre-school children in rural Nepal

OBJECTIVE

Vitamin D plays a major role in Ca and bone metabolism, and its extraskeletal functions are being appraised. Although inadequate vitamin D concentrations have been reported in populations worldwide, too little is known about vitamin D status and its determinants among children in developing countries. We aimed to determine vitamin D status and its determinants in Nepalese children of pre-school age.

DESIGN

A community-based, cross-sectional study.

SETTING

Rural Nepal at latitude 27.39° N.

SUBJECTS

Healthy children (n 280) aged 12-60 months, selected randomly from the records of a vitamin A supplementation programme. Blood samples were collected using the dried blood spot technique and analysed for serum 25-hydroxyvitamin D (s-25(OH)D) concentration using liquid chromatography-tandem mass spectrometry. Ca intake and background variables were assessed with a structured questionnaire.

RESULTS

Hypovitaminosis D, defined as s-25(OH)D concentration less than 50 nmol/l, was found in 91.1% of the children. S-25(OH)D concentration was not related to gender, socio-economic indicators, sun exposure or nutritional status. Currently breast-fed children had higher s-25(OH)D concentrations (36.4 (sd 13.2) nmol/l) than those who were not (28.6 (sd 9.8) nmol/l, P<0.001). Adjustment for sociodemographic factors did not alter the results.

CONCLUSION

There is widespread vitamin D deficiency among pre-school children in a rural area of Nepal. In our sample, sociodemographic factors did not affect the vitamin D status of children, but prolonged breast-feeding was associated with higher s-25(OH)D concentrations. Further research is required to investigate the health consequences of poor vitamin D status for this population.

The relationship between Polycystic ovary syndrome and vitamin D levels

Objective:

The main aim of this study was to determine the association of serum 25-hydroxyvitamin D (25-OH D) levels with hormonal, clinical and metabolic profile in patients with and without Polycystic ovary syndrome (PCOS).

Materials and Methods:

Forty-eight normal-weight (body mass index (BMI) of 19-24.99 kg/m²) women with PCOS, 36 overweight (BMI of 25-29.9 kg/m²) women with PCOS and 56 normal-weight controls participated in the study. Blood samples were collected in the early follicular phase (between day 2 and day 5 of the menstrual cycle) at 9:00 am after an overnight fast. Circulating concentrations of 25-OH D, luteinizing hormone (LH), follicle stimulating hormone (FSH), prolactin, TSH, free testosterone, dehydroepiandrosterone sulphate (DHEA-SO4), 17-hydroxyprogesterone, sex hormone-binding globulin (SHBG), fasting insulin, fasting glucose, and lipid profile were assessed.

Results:

Normal weight (BMI 19-24.99 kg/m²) and overweight (BMI 25-29.99 kg/m²) women with PCOS were compared with normal-weight controls and lower 25-OH D levels were found in both PCOS groups (p<0.05 and p<0.01, respectively 25-OH D significantly negatively correlated with waist circumference (WC), waist-to-hip ratio (WHR), free testosterone and modified Ferriman-Gallwey scores, however, there was a positive correlation between 25-OH D and SHBG levels (p<0.05).

Conclusion:

Our findings suggest that PCOS is associated with hypovitaminosis D.

Ethnic differences in urinary calcium and phosphate excretion between Gambian and British older adults

Ethnic differences in renal calcium and phosphate excretion exist, which may depend on differences in their dietary intakes and regulatory factors. We report highly significant differences in urinary calcium and phosphate excretion between white British and Gambian adults after statistical adjustment for mineral intakes, indicating an independent effect of ethnicity.

INTRODUCTION

Populations vary in their risk of age-related osteoporosis. There are racial or ethnic differences in the metabolism of the bone-forming minerals calcium (Ca) and phosphate (P), with a lower renal Ca and P excretion in African-Americans compared to white counterparts, even at similar intakes and rates of absorption. Also, Africans in The Gambia have a lower Ca excretion compared to white British subjects, groups known to differ in their dietary Ca intake. Here, we report on differences in urinary Ca and P excretion between Gambian and white British adults while allowing for known predictors, including dietary intakes.

METHODS

Participants were healthy white British (n = 60) and Gambian (n = 61) men and women aged 60-75 years. Fasting blood and 2-h urine samples were collected. Markers of Ca and P metabolism were analysed. Dietary intake was assessed with country-specific methods.

RESULTS

White British older adults had higher creatinine-corrected urinary Ca and P excretion (uCa/uCr, uP/uCr) and lower tubular maximum of Ca and P compared to Gambian counterparts. The predictors of urinary Ca and P differed between groups. Multiple regression analysis showed that dietary Ca and Ca/P were predictors of uCa/uCr and uP/uCr, respectively. Ethnicity remained a significant predictor of uCa/uCr and uP/uCr after adjustment for diet and other factors.

CONCLUSIONS

Gambian older adults have higher renal Ca conservation than British counterparts. Dietary mineral intakes were predictors of the differences in urinary Ca and P excretion, but ethnicity remained a highly significant predictor after statistical adjustment. This suggests that ethnicity has an independent effect on renal Ca and P handling.

Vitamin D₃supplementation in Batswana children and adults with HIV: a pilot double blind randomized controlled trial

Objectives

Since vitamin D insufficiency is common worldwide in people with HIV, we explored safety and efficacy of high dose cholecalciferol (D₃) in Botswana, and evaluated potential modifiers of serum 25 hydroxy vitamin D change (Δ25D).

Design

Prospective randomized double-blind 12-week pilot trial of subjects ages 5.0–50.9 years.

Methods

Sixty subjects randomized within five age groups to either 4000 or 7000IU per day of D₃ and evaluated for vitamin D, parathyroid hormone, HIV, safety and growth status. Efficacy was defined as serum 25 hydroxy vitamin D (25D) ≥32ng/mL, and safety as no simultaneous elevation of serum calcium and 25D. Also assessed were HIV plasma viral RNA viral load (VL), CD4%, anti-retroviral therapy (ART) regime, and height-adjusted (HAZ), weight-adjusted (WAZ) and Body Mass Index (BMIZ) Z scores.

Results

Subjects were 50% male, age (mean±SD) 19.5±11.8 years, CD4% 31.8±10.4, with baseline VL log₁₀ range of <1.4 to 3.8 and VL detectable (>1.4) in 22%. From baseline to 12 weeks, 25D increased from 36±9ng/ml to 56±18ng/ml (p<0.0001) and 68% and 90% had 25D ≥32ng/ml, respectively (p = 0.02). Δ25D was similar by dose. No subjects had simultaneously increased serum calcium and 25D. WAZ and BMIZ improved by 12 weeks (p<0.04). HAZ and CD4% increased and VL decreased in the 7000IU/d group (p<0.04). Younger (5–13y) and older (30–50y) subjects had greater Δ25D than those 14–29y (26±17 and 28±12 vs. 11±11ng/ml, respectively, p≤0.001). Δ25D was higher with efavirenz or nevirapine compared to protease inhibitor based treatment (22±12, 27±17, vs. 13±10, respectively, p≤0.03).

Conclusions

In a pilot study in Botswana, 12-week high dose D₃ supplementation was safe and improved vitamin D, growth and HIV status; age and ART regimen were significant effect modifiers.

Trial Registration

ClinicalTrials.gov NCT02189902

Regulation of the vitamin D receptor gene by environment, genetics and epigenetics

The vitamin D receptor (VDR) plays a pivotal role as a mediator of 1α,25(OH)2D signalling. Besides its role in calcium homeostasis, ligand- bound VDR supports immunity and cell cycle control. While VDR regulates numerous genes across the genome, much remains to be learned about the regulation of the VDR gene itself. Hindered VDR expression and function have a broad impact, contributing to diverse diseases, including cancer, multiple sclerosis, type 1 diabetes and tuberculosis. A better understanding of the three main factors regulating the VDR, namely environment, genetics and epigenetics, may facilitate the development of improved strategies for treatment and prevention of diseases associated with impaired VDR function. This review aims to illuminate the complex interaction and contributions of the three levels of VDR gene regulation to endorse consideration of all three regulatory factors when studying gene regulation.

Is high prevalence of Vitamin D deficiency evidence for autism disorder?: In a highly endogamous population

Aim:

To determine the association between Vitamin D and autism, and the difference in level of Vitamin D in autism children and control.

Design:

Case–control study conducted between June 2011 and May 2013, among autism at the Hamad Medical Corporation and controls at the School Health Clinics and Primary Health Care Clinics

Subjects and Methods:

A total of 254 cases and 254 controls. The Autism Diagnostic Observation Schedule-Generic is a semi-structured, standardized assessment of social interaction, communication, play and imaginative use of materials for individuals suspected of having autism spectrum disorders. Data on clinical manifestations and laboratory, family history, body mass index (BMI) and clinical biochemistry variables including serum 25-hydroxy Vitamin D, calcium, phosphorus and magnesium were obtained. Univariate and multivariate statistical analyzes were performed.

Results:

Of the total number of 508 children surveyed, 254 of autism and 254 of healthy children were contacted. The mean age (± standard deviation, in years) for autism versus control children was 5.51 ± 1.58 versus 5.76 ± 1.56. There were statistically significant differences between autism and healthy children control subjects with respect to educational level of mother (P = 0.016); occupation of mother (P = 0.005); BMI (P < 0.001); consanguinity (P = 0.015); exposure to sun (P = 0.002) and walking time per day <60 min (P < 0.001). The mean value of Vitamin D in autism children was much lower than the normal value, and there was a significant difference found in the mean values of Vitamin D between autism (18.39 ± 8.2 with median 18) and versus control children (21.59 ± 8.4) (P < 0.0001) and with median 21 (P = 0.004). Besides mean values of calcium, phosphorous, magnesium, glucose, potassium and alkaline phosphate were statistically significant higher in control healthy children compared to autism children (P < 0.001). Multivariate logistic regression analysis revealed that the mean serum Vitamin D level, calcium, consanguinity, BMI, physical activity, child order, and ferritin, were considered as the main factors associated with autism. Of total 254 of autism children, 14.2% had severe Vitamin D deficiency (<10 ng/ml), 43.7% had moderate insufficient levels (between 10 and 20 ng/ml), 28.3% had mild insufficient levels (between 20 and 30 ng/ml), and only 13.8% of autism had sufficient levels (>30 ng/ml). Similarly, of the total 254 of healthy children 8.3% had severe Vitamin D deficiency (<10 ng/ml), 37% had moderate insufficient levels (between 10 and 20 ng/ml), 37.4% had mild insufficient levels (between 20 and 30 ng/ml), and only 17.3% had sufficient levels (>30 ng/ml). Furthermore, there was statistically significant differences between autism and control subjects with respect to the serum level of Vitamin D (P = 0.023).

Conclusion:

The present study revealed that Vitamin D deficiency was higher in autism children compared to healthy children and supplementing infants with Vitamin D might be a safe and more effective strategy for reducing the risk of autism.

Factors associated with 25-hydroxyvitamin D levels in patients with liver cirrhosis

INTRODUCTION

Lower 25-hydroxyvitamin D [25(OH)D] levels have been observed in cirrhotic patients and have been related to disease severity. However, most previous studies included patients with very advanced disease, lacking an adequate control for other variables that could interfere with vitamin D levels. We sought to investigate the prevalence of hypovitaminosis D and the factors related to its occurrence.

MATERIAL AND METHODS

This cross-sectional study included 133 cirrhotic patients and 30 healthy controls. Bivariate and multivariate analyses were performed to determine factors associated with 25(OH)D levels below the lower tertile. Thirty patients who had been recently hospitalized were compared in two time points.

RESULTS

Mean 25(OH)D levels were 32.34 ± 11.38 in controls and 27.03 ± 6.22 ng/mL in patients (P = 0.018). 25(OH)D levels were < 30 ng/mL in 69.9% and < 20 ng/mL in 14.3% of the sample. Levels of 25(OH)D below the lower tertile (< 24 ng/mL) were independently associated with higher triceps skinfold and non-Caucasian race. Parathyroid hormone above the reference value (65 pg/mL) was found in 24.6% of patients without association with 25(OH)D or severity of liver disease. Significantly lower levels of 25(OH)D were found at the time of acute decompensation of cirrhosis.

CONCLUSIONS

In conclusion, hypovitaminosis D was prevalent in cirrhotics and it was associated with adiposity and non-Caucasian race in stable patients with relatively well preserved liver function. However, significantly lower levels were observed during admission for acute decompensation suggesting an impact of systemic inflammation or liver dysfunction on 25(OH)D levels.

Severe acute malnutrition and infection

Severe acute malnutrition (SAM) is associated with increased severity of common infectious diseases, and death amongst children with SAM is almost always as a result of infection. The diagnosis and management of infection are often different in malnourished versus well-nourished children. The objectives of this brief are to outline the evidence underpinning important practical questions relating to the management of infectious diseases in children with SAM and to highlight research gaps. Overall, the evidence base for many aspects covered in this brief is very poor. The brief addresses antimicrobials; antipyretics; tuberculosis; HIV; malaria; pneumonia; diarrhoea; sepsis; measles; urinary tract infection; nosocomial Infections; soil transmitted helminths; skin infections and pharmacology in the context of SAM. The brief is structured into sets of clinical questions, which we hope will maximise the relevance to contemporary practice.

Vitamin D insufficiency and insulin resistance in obese adolescents

Obese adolescents represent a particularly vulnerable group for vitamin D deficiency which appears to have negative consequences on insulin resistance and glucose homeostasis. Poor vitamin D status is also associated with future risk of type 2 diabetes and metabolic syndrome in the obese. The biological mechanisms by which vitamin D influences glycemic control in obesity are not well understood, but are thought to involve enhancement of peripheral/hepatic uptake of glucose, attenuation of inflammation and/or regulation of insulin synthesis/secretion by pancreatic β cells. Related to the latter, recent data suggest that the active form of vitamin, 1,25-dihydroxyvitamin D, does not impact insulin release in healthy pancreatic islets; instead they require an environmental stressor such as inflammation or vitamin D deficiency to see an effect. To date, a number of observational studies exploring the relationship between the vitamin D status of obese adolescents and markers of glucose homeostasis have been published. Most, although not all, show significant associations between circulating 25-hydroxyvitamn D concentrations and insulin sensitivity/resistance indices. In interpreting the collective findings of these reports, significant considerations surface including the effects of pubertal status, vitamin D status, influence of parathyroid hormone status and the presence of nonalcoholic fatty liver disease. The few published clinical trials using vitamin D supplementation to improve insulin resistance and impaired glucose tolerance in obese adolescents have yielded beneficial effects. However, there is a need for more randomized controlled trials. Future investigations should involve larger sample sizes of obese adolescents with documented vitamin D deficiency, and careful selection of the dose, dosing regimen and achievement of target 25-hydroxyvitamn D serum concentrations. These trials should also include clamp-derived measures of in vivo sensitivity and β-cell function to more fully characterize the effects of vitamin D replenishment on insulin resistance.

Nutritional and Physical Activity Interventions to Improve Immunity

Physical activity and nutrition are important in a healthy lifestyle with potential benefits to immunity often overlooked. Infection of the upper respiratory tract, and the associated symptoms, are the most frequent presentations to general practitioners and may have significant economic and social impact. In this review, we consider the role of physical activity and nutrition in improving immunity. Evidence suggests that regular moderate activity is particularly beneficial for immune enhancement and reducing the risk of infection. We also discuss some nutritional strategies. Unfortunately, the evidence for many is weak. Avoiding nutritional deficiencies seems the most pragmatic recommendation. This can be achieved with a balanced diet. Including a variety of fruits and vegetables may help ensure adequate intake of essential nutrients with little risk of excess intake of any single nutrient. Supplementation with individual nutrients is generally not recommended. Multinutrients may be beneficial for those with a preexisting deficiency but not if normal dietary intake is sufficient. Further benefit may be gained from some supplements including probiotics, bovine colostrum, and some plant-derived products (Echinacea, black elderberry, and some polyphenols) but only in specific situations/contexts. Individuals should consider their personal needs, use caution, and avoid the indiscriminate use of supplements.

Vitamin D deficiency in adolescents

The prevalence of severe vitamin D deficiency (VDD) in adolescents is variable but considerably high in many countries, especially in Middle-east and Southeast Asia. Different factors attribute to this deficiency including lack of sunlight exposure due to cultural dress codes and veiling or due to pigmented skin, and less time spent outdoors, because of hot weather, and lower vitamin D intake. A potent adaptation process significantly modifies the clinical presentation and therefore clinical presentations may be subtle and go unnoticed, thus making true prevalence studies difficult. Adolescents with severe VDD may present with vague manifestations including pain in weight-bearing joints, back, thighs and/or calves, difficulty in walking and/or climbing stairs, or running and muscle cramps. Adaptation includes increased parathormone (PTH) and deceased insulin-like growth factor-I (IGF-I) secretion. PTH enhances the tubular reabsorption of Ca and stimulates the kidneys to produce 1, 25-(OH) 2D3 that increases intestinal calcium absorption and dissolves the mineralized collagen matrix in bone, causing osteopenia and osteoporosis to provide enough Ca to prevent hypocalcaemia. Decreased insulin like growth factor-I (IGF-I) delays bone growth to economize calcium consumption. Radiological changes are not uncommon and include osteoporosis/osteopenia affecting long bones as well as vertebrae and ribs, bone cysts, decalcification of the metaphysis of the long bones and pseudo fractures. In severe cases pathological fractures and deformities may occur. Vitamin D treatment of adolescents with VDD differs considerably in different studies and proved to be effective in treating all clinical, biochemical, and radiological manifestations. Different treatment regiments for VDD have been discussed and presented in this mini-review for practical use. Adequate vitamin D replacement after treating VDD, improving calcium intake (milk and dairy products), encouraging adequate exposure to the sun and possible enrichment of the stable food with vitamin D in areas with high prevalence of VDD are important measures to prevent the harmful consequences of VDD.

Serum 25-hydroxyvitamin D concentrations and depressive symptoms among young adult men and women

There has been an increased interest in the role of vitamin D in depression; however, there have been few studies conducted in younger population groups. Our aim was to investigate the association between vitamin D status and depressive symptoms in a non-clinical young adult sample living in Dunedin, New Zealand. A cross-sectional sample of 615 young adults completed a questionnaire including demographics and the Centre for Epidemiological Studies Depression Scale (CES-D). Height, weight and a blood sample for 25-hydroxyvitamin D [25(OH)D] was obtained. Serum 25(OH)D was used to predict depression scores, adjusting for potential confounders including time spent outdoors for 13 consecutive days, BMI, age, sex and ethnicity. Prevalence of low vitamin D was high even in this age group, and serum 25(OH)D was negatively associated with depression symptoms before and after adjustment. When investigating the relationship between the presence versus absence of depressive symptoms and quartiles of 25(OH)D, participants in the lowest quartile were more likely to report depressive symptoms compared with those in the highest quartile. Although our findings suggest that vitamin D is a predictor of depression symptomatology, even when controlling for time spent outdoors, a randomised controlled trial in this young adult target group is needed to confirm the association.

Calcium and vitamin D metabolism in children in developing countries

Low dietary calcium intakes and poor vitamin D status are common findings in children living in developing countries. Despite many of the countries lying within the tropics and subtropics, overcrowding, atmospheric pollution, a lack of vitamin D-fortified foods, and social customs that limit skin exposure to sunlight are major factors in the development of vitamin D deficiency. Low dietary calcium intakes are typically observed as a consequence of a diet limited in dairy products and high in phytates and oxalates which reduce calcium bioavailability. Calcium intakes of many children are a third to a half of the recommended intakes for children living in developed countries, yet the consequences of these low intakes are poorly understood as there is limited research in this area. It appears that the body adapts very adequately to these low intakes through reducing renal calcium excretion and increasing fractional intestinal absorption. However, severe deficiencies of either calcium or vitamin D can result in nutritional rickets, and low dietary calcium intakes in association with vitamin D insufficiency act synergistically to exacerbate the development of rickets. Calcium supplementation in children from developing countries slightly increases bone mass, but the benefit is usually lost on withdrawal of the supplement. It is suggested that the major effect of calcium supplementation is on reducing the bone remodelling space rather than structurally increasing bone size or volumetric bone density. Limited evidence from one study raises concerns about the use of calcium supplements in children on habitually low calcium intakes as the previously supplemented group went through puberty earlier and had a final height several centimetres shorter than the controls.

Evidence of differential effects of vitamin d receptor variants on epithelial ovarian cancer risk by predicted vitamin d status

INTRODUCTION

Experimental studies suggest vitamin D inhibits ovarian carcinogenesis. Yet, epidemiologic studies of ovarian cancer risk and lifestyle correlates of vitamin D status, plasma 25-hydroxyvitamin D [25(OH)D], or vitamin D receptor (VDR) variants have been inconsistent.

OBJECTIVE

To evaluate VDR genetic associations by high vs. low predicted 25(OH)D, scores derived from known determinants of plasma 25(OH)D. To assess ovarian cancer associations with variants identified in genome-wide association studies (GWAS) of plasma 25(OH)D.

METHODS

We genotyped up to seven VDR and eight 25(OH)D GWAS variants in the Nurses' Health Studies (562 cases, 1,553 controls) and New England Case-Control study (1,821 cases, 1,870 controls). We estimated haplotype scores using expectation-maximization-based algorithms. We used unconditional logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CI). We combined study results using DerSimonian and Laird meta-analysis.

RESULTS

Ovarian cancer risk increased per A allele of rs7975232 (VDR; OR = 1.12, 95% CI = 1.01-1.25) among all women. When stratified by predicted 25(OH)D, ovarian cancer was associated with rs731236 (VDR; per C allele OR = 1.31) and rs7975232 (OR = 1.38) among women with high predicted 25(OH)D, but not among women with low levels (P ≤ 0.009). We also observed heterogeneity by predicted 25(OH)D for the ovarian cancer association with VDR 3' end haplotypes (P = 0.009). Of 25(OH)D-associated GWAS loci, rs7041 was associated with reduced ovarian cancer risk (per T allele OR = 0.92, 95% CI = 0.85-0.99), which did not differ by predicted 25(OH)D status.

CONCLUSION

Our study suggests an influence of VDR 3' end variants on ovarian cancer risk may be observed in women with high predicted 25(OH)D, which remained even after taking multiple comparisons into consideration. Future studies are needed to confirm our results and explore further the relation between vitamin D exposure, genetic variants, and ovarian cancer risk.

Clinical aspects of paediatric visceral leishmaniasis in North-west Ethiopia

OBJECTIVE

Visceral leishmaniasis (VL) in north-west Ethiopia is causing an overwhelming case load among adult migrant workers that masked the disease burden in children. This study describes the clinical profile and explores comorbidities in paediatric VL patients.

METHODS

A prospective study at two hospitals in this region (Gondar and Humera) was conducted in a year period, 2011-2012. The clinical manifestations and comorbidities such as malnutrition, intestinal parasitosis and vitamin D deficiency and HIV infection were assessed, and treatment outcomes noted.

RESULTS

A total of 122 children with VL were detected during the study period with median age of 8.5 years (IQR 5-12 years); 23% were under 5 years. Eighty-five (69.7%) cases were male. The clinical manifestations were similar to the adult patients. High rates of malnutrition, intestinal parasitosis (47.5%) and hypovitaminosis D (56.4%) were detected. The proportion of stunting and wasting was 63% and 22.2% in children aged under five years, and 50.5% and 75.9% in 5-year and older children, respectively, using WHO standard growth curves. Only one child had HIV infection. In 95% of the cases, sodium stibogluconate (20 mg/kg/day for 30 days) was used for treatment. The treatment success rate at end of therapy was 98.3%, but the definitive outcome at 6 months could not be determined because of a high loss to follow-up (80.2%).

CONCLUSION

While HIV co-infection was rare, malnutrition, intestinal parasitosis and vitamin D deficiency were frequent indicating the need for further research on their role in the pathophysiology. Meanwhile, systematic assessment and management of malnutrition and intestinal parasitosis in VL programmes is recommended.

Correction of Low Vitamin D Improves Fatigue: Effect of Correction of Low Vitamin D in Fatigue Study (EViDiF Study)

Background:

Fatigue is a common presenting complaint of patients in the primary care offices. Low levels of vitamin D have been associated with fatigue in cancer patients. Normalization of vitamin D level improves their fatigue. Whether low vitamin D plays a role in fatigue in medically stable patients is not known.

Aims:

This prospective non-randomized therapeutic study observed the prevalence of low vitamin D in fatigue and the effect of normalization of vitamin D on fatigue.

Material and Methods:

One hundred and seventy four adult patients, who presented in our primary care office with fatigue and stable chronic medical conditions,completed fatigue assessment questionnaires. Patients with low vitamin D levels received ergocalciferol therapy for 5 weeks. Scores of pre- and post-treatment fatigue assessment questionnaires were compared.

Results:

Prevalence of low vitamin D was 77.2% in patients who presented with fatigue. After normalization of vitamin D levels fatigue symptom scores improved significantly (P < 0.001) in all five subscale categories of fatigue assessment questionnaires.

Conclusion:

The prevalence of low vitamin D is high in patients who present with fatigue and stable chronic medical conditions, if any. Normalization of vitamin D levels with ergocalciferol therapy significantly improves the severity of their fatigue symptoms.

Incidence of Vitamin D Insufficiency in Coastal South-Eastern US Patient Population With Cardiovascular Disease

Background

Vitamin D insufficiency is increasingly gaining prominence as an associated cardiovascular disease (CVD) risk factor, often thought to be an issue in colder climates and higher altitudes. The intent of this study was to ascertain vitamin D levels in the southern Alabama gulf-coast region that has a high number of sunny days along with an annual average elevated UV ray index.

Methods

An observational retrospective study of 204 patients with established CVD treated at the University of South Alabama’s Heart Center from January 2007 through January 2013 was undertaken. One-way ANOVA analyses were performed to determine any significant difference in the mean 25-hydroxyvitamin D (25(OH)D) serum based on gender and also based on race/ethnicity. Further, odds ratio (OR) was computed to ascertain if there was a relationship between vitamin D insufficiency and elevated body mass index (BMI).

Results

Out of 204 patients, 53.4% (n = 109) were found to have vitamin D insufficiency (25(OH)D = 20.1 ng/mL), while 46.6% (n = 95) were within the normal range (25(OH)D = 37.8 ng/mL). The mean 25(OH)D of the entire group was 28.3, indicating a general trend of vitamin D insufficiency for patients treated at the cardiology clinics.

Conclusion

This study established the prevalence of vitamin D insufficiency in the hot and high UV ray index climate of the coastal south-eastern United States. Also, it revealed the relationship of increased BMI with low 25(OH)D serum level. More extensive studies should be conducted in similar climates to further assess vitamin D insufficiency.

25(OH)D2 half-life is shorter than 25(OH)D3 half-life and is influenced by DBP concentration and genotype

CONTEXT

There is uncertainty over the equivalence of vitamins D2 and D3 to maintain plasma 25-hydroxyvitamin D (25(OH)D).

OBJECTIVE

The objective of the study was to compare the plasma half-lives of 25(OH)D2 and 25(OH)D3 in two distinct populations with different dietary calcium intake and 25(OH)D status.

PARTICIPANTS

Healthy men (aged 24 and 39 y), resident in The Gambia (n = 18) or the United Kingdom (n = 18) participated in the study.

INTERVENTIONS

The intervention included an oral tracer dose of deuterated-25(OH)D2 and deuterated-25(OH)D3 (both 40 nmol). Blood samples were collected over 33 days.

MAIN OUTCOME MEASURES

25(OH)D2 and 25(OH)D3 plasma half-lives, concentrations of 25(OH)D, and vitamin D binding protein (DBP) and DBP genotypes were measured.

RESULTS

25(OH)D2 half-life [mean (SD)] [13.9 (2.6) d] was shorter than 25(OH)D3 half-life [15.1 (3.1) d; P = .001] for countries combined, and in Gambians [12.8 (2.3) d vs 14.7 (3.5) d; P < .001], but not in the United Kingdom [15.1 (2.4) d vs 15.6 (2.5) d; P = .3]. 25(OH)D concentration was 69 (13) and 29 (11) nmol/L (P < .0001), and the DBP concentration was 259 (33) and 269 (23) mg/L (P = .4) in The Gambia and United Kingdom, respectively. Half-lives were positively associated with plasma DBP concentration for countries combined [25(OH)D2 half-life: regression coefficient (SE) 0.03 (0.01) d per 1 mg/L DBP, P = .03; 25(OH)D3 half-life: 0.04 (0.02) d, P = .02] and in Gambians [25(OH)D2 half-life: 0.04 (0.01) d; P = .02; 25(OH)D3 half-life: 0.06 (0.02) d, P = .01] but not in UK participants. The DBP concentration × country interactions were not significant. DBP Gc1f/1f homozygotes had shorter 25(OH)D2 half-lives compared with other combined genotypes (P = .007) after correction for country.

CONCLUSIONS

25(OH)D2 half-life was shorter than 25(OH)D3 half-life, and half-lives were affected by DBP concentration and genotype. The stable isotope 25(OH)D half-life measurements provide a novel tool to investigate vitamin D metabolism and vitamin D expenditure and aid in the assessment of vitamin D requirements.

Vitamin D: a critical and essential micronutrient for human health

Vitamin D is a micronutrient that is needed for optimal health throughout the whole life. Vitamin D₃ (cholecalciferol) can be either synthesized in the human skin upon exposure to the UV light of the sun, or it is obtained from the diet. If the photoconversion in the skin due to reduced sun exposure (e.g., in wintertime) is insufficient, intake of adequate vitamin D from the diet is essential to health. Severe vitamin D deficiency can lead to a multitude of avoidable illnesses; among them are well-known bone diseases like osteoporosis, a number of autoimmune diseases, many different cancers, and some cardiovascular diseases like hypertension are being discussed. Vitamin D is found naturally in only very few foods. Foods containing vitamin D include some fatty fish, fish liver oils, and eggs from hens that have been fed vitamin D and some fortified foods in countries with respective regulations. Based on geographic location or food availability adequate vitamin D intake might not be sufficient on a global scale. The International Osteoporosis Foundation (IOF) has collected the 25-hydroxy-vitamin D plasma levels in populations of different countries using published data and developed a global vitamin D map. This map illustrates the parts of the world, where vitamin D did not reach adequate 25-hydroxyvitamin D plasma levels: 6.7% of the papers report 25-hydroxyvitamin D plasma levels below 25 nmol/L, which indicates vitamin D deficiency, 37.3% are below 50 nmol/Land only 11.9% found 25-hydroxyvitamin D plasma levels above 75 nmol/L target as suggested by vitamin D experts. The vitamin D map is adding further evidence to the vitamin D insufficiency pandemic debate, which is also an issue in the developed world. Besides malnutrition, a condition where the diet does not match to provide the adequate levels of nutrients including micronutrients for growth and maintenance, we obviously have a situation where enough nutrients were consumed, but lacked to reach sufficient vitamin D micronutrient levels. The latter situation is known as hidden hunger. The inadequate vitamin D status impacts on health care costs, which in turn could result in significant savings, if corrected. Since little is known about the effects on the molecular level that accompany the pandemic like epigenetic imprinting, the insufficiency-triggered gene regulations or the genetic background influence on the body to maintain metabolic resilience, future research will be needed. The nutrition community is highly interested in the molecular mechanism that underlies the vitamin D insufficiency caused effect. In recent years, novel large scale technologies have become available that allow the simultaneous acquisition of transcriptome, epigenome, proteome, or metabolome data in cells of organs. These important methods are now used for nutritional approaches summarized in emerging scientific fields of nutrigenomics, nutrigenetics, or nutriepigenetics. It is believed that with the help of these novel concepts further understanding can be generated to develop future sustainable nutrition solutions to safeguard nutrition security.

High prevalence of hypovitaminosis D in Sicilian children affected by growth hormone deficiency and its improvement after 12 months of replacement treatment

PURPOSE

Although the correlation between vitamin D and growth hormone (GH)-insulin-like growth factor 1 (IGF1) axis is documented, as of date, few and conflicting studies have prospectively analyzed vitamin D before and after GH treatment. Our aim was to evaluate as to how the condition of GH deficiency (GHD) or GH treatment influences vitamin D in children.

METHODS

Eighty Sicilian GHD children (M/F 58/22; mean age 10.3 years), grouped according to the season of evaluation in group A (June-September; 41 children) and group B (November-February; 39 children), were evaluated at baseline and after 12 months of GH treatment.

RESULTS

Twenty-eight children (35 %) were vitamin D insufficient and 32 (40 %) deficient at baseline, and lower vitamin D levels were found in group B than in A (17.3 ± 5.3 vs. 31.1 ± 11.1 ng/ml; p < 0.001). A positive correlation between vitamin D and baseline GH levels (p < 0.001) was found. After 12 months, increased vitamin D was found both in all children (34.4 ± 16.4 vs. 24.5 ± 11.1 ng/ml; p = 0.002) and in group A (38.5 ± 14 vs. 31.1 ± 11.1 ng/ml; p < 0.001) and B (30 ± 17.7 vs. 17.3 ± 5.3 ng/ml; p < 0.001). Overall, only 25 (31 %) children remained insufficient and 15 (19 %) deficient, with an increase in prevalence of children with normal levels (p = 0.001).

CONCLUSIONS

Our data demonstrated a very high prevalence of hypovitaminosis D in Sicilian GHD children, with an improvement after 12 months of GH treatment. Vitamin D assessment should therefore be considered routinely in GHD children both at diagnosis and during the follow-up.

Review: the impacts of circulating 25-hydroxyvitamin D levels on cancer patient outcomes: a systematic review and meta-analysis

CONTEXT

Circulating levels of 25-hydroxyvitamin D [25(OH)D] may affect the prognosis of cancer patients; however, the epidemiological results are not consistent.

OBJECTIVE

To perform a meta-analysis of all published studies to assess the associations of circulating 25(OH)D levels measured at or near the time of diagnosis and outcomes for cancer patients.

DATA SOURCES

Searches of the PubMed and MEDLINE databases were performed and updated to December 2013.

STUDY SELECTION

Studies reporting an association between circulating 25(OH)D levels at or near the time of diagnosis and outcomes for the patients were included.

DATA EXTRACTION

Data extraction was performed independently by two authors, and conflicts were resolved by a third investigator.

DATA SYNTHESIS

Included in the meta-analysis were 25 studies with 17 332 cases. Significant associations between circulating 25(OH)D levels at or near the time of diagnosis and the outcomes for cancer patients were found. The pooled hazard ratio for the highest vs the lowest quartile of circulating 25(OH)D levels was 0.55 (95% confidence interval [CI] = 0.33-0.91) for overall survival of colorectal cancer patients, 0.63 (95% CI = 0.51-0.77) for breast cancer patients, and 0.48 (95% CI = 0.36-0.64) for lymphoma patients. Higher 25(OH)D levels were significantly associated with reduced cancer-specific mortality for patients with colorectal cancer (P = .005) and lymphoma (P < .001) and improved disease-free survival for patients with breast cancer (P < .001) or lymphoma (P < .05). A 10-nmol/L increment in circulating 25(OH)D levels conferred a hazard ratio of 0.96 (95% CI = 0.95-0.97) for overall survival of the cancer patients.

CONCLUSIONS

The results indicate that cancer patients with higher circulating 25(OH)D levels at or near the time of diagnosis have better outcomes.

Vitamin D deficiency in women with polycystic ovary syndrome

Objective

To investigate: the prevalence of vitamin D deficiency in Korean women with polycystic ovary syndrome (PCOS), and the relationship between vitamin D status and clinical or metabolic features in this group.

Methods

We recruited 38 women with PCOS using the Rotterdam criteria. A total of 109 premenopausal control women were matched with patients based on age and body mass index. Serum 25-hydroxy vitamin D concentrations less than 20 ng/mL were classified as frank vitamin D deficiency. Since vitamin D may play a significant role in metabolic disturbances in women with PCOS, correlations between clinical or metabolic parameters and vitamin D status were analyzed separately in patients and controls.

Results

Women with PCOS showed no differences in the level of 25-hydroxy vitamin D (19.6±6.6 ng/mL in patients vs. 20.1±7.4 ng/mL in controls, respectively, p=0.696) or prevalence of vitamin D deficiency (57.9% in patients vs. 56.5% in controls, respectively, p=0.880). In addition, we did not find any correlations between serum vitamin D level and clinical or metabolic profiles in either PCOS patients or controls.

Conclusion

Our study found no differences in the absolute level of serum vitamin D between PCOS patients and matched controls. Prevalence of vitamin D deficiency was equally common among both patients and controls. Additionally, we did not find any correlations between serum vitamin D level and clinical or metabolic profiles, suggesting that the role of vitamin D in the pathogenesis of PCOS is not yet clear.

Associations between serum vitamin D levels and precocious puberty in girls

PURPOSE

Vitamin D deficiency has been linked to chronic diseases, such as diabetes mellitus, obesity and autoimmune disease. However, data on the vitamin D status and its association with precocious puberty in girls are limited. We aimed to investigate the association between serum 25-hydroxyvitamin D (25OHD) and precocious puberty in girls.

METHODS

A total of 60 girls with central precocious puberty (CPP) and 30 control girls were enrolled. Anthropometric measurement and serum level of 25OHD were estimated for all subjects.

RESULTS

There was a significant difference in the mean serum 25OHD concentration between the precocious puberty group and the control group (17.1±4.5 ng/mL vs. 21.2±5.0 ng/mL, P<0.05). Forty-two of the 60 girls with CPP (70%) had vitamin D deficiency (defined as serum 25OHD<20 ng/mL) and 18 (30%) had vitamin D insufficiency. Of the 30 girls in the control group, vitamin D deficiency was seen in 13 subjects (43.3%), 15 subjects (50%) had vitamin D insufficiency, and 2 subjects (6.7%) had sufficient serum vitamin D (defined as serum 25OHD>30 ng/mL). Vitamin D deficient girls had a significantly higher odds ratio (OR, 3.05; 95% CI, 1.22-7.57, P=0.021).

CONCLUSION

These results showed that vitamin D levels may be associated with precocious puberty. Further studies are required to establish the potential effect of vitamin D status on puberty.

Rickets

Rickets, historically referred to as "the English disease", is common worldwide. Absence of phosphate at the growth plate and mineralising bone surfaces due to inadequate vitamin D supply either from sunlight exposure or diet is the main cause. Inherited disorders causing hypophosphataemia have shown the intricacies of phosphate metabolism. Present advice about the provision of vitamin D to young infants needs to be clarified; the existing guidance is fragmentary and contradictory, and will not help to eradicate the disease.

Diet, sun, and lifestyle as determinants of vitamin D status

Vitamin D status can be assessed by measuring concentrations of 25-hydroxyvitamin D (25(OH)D). Sunlight is the most important source of vitamin D and stimulates the production of vitamin D3 in the skin during the summer, depending on age, skin pigmentation, clothing style, and sunscreen use. Seasonal variation in serum 25(OH)D is between 10 and 20 nmol/L in adults and almost absent in nursing home residents. Sunscreen use decreases, but does not abolish, vitamin D production in the skin. Clothing style has a large influence on vitamin D production. Furthermore, vitamin D status can be improved by ingestion of fatty fish and the fortification of milk or orange juice. A high dietary calcium intake has a vitamin D-sparing effect, because it increases the half-life of 25(OH)D. A combination of sunlight exposure, nutrition, food fortification, and supplements is desirable to obtain sufficient vitamin D status in the population of most countries throughout the year.

Ethnic differences in calcium, phosphate and bone metabolism

The prevalence of osteoporosis and the incidence of age-related fragility fracture vary by ethnicity. There is greater than 10-fold variation in fracture probabilities between countries across the world. Mineral and bone metabolism are intimately interlinked, and both are known to exhibit patterns of daily variation, known as the diurnal rhythm (DR). Ethnic differences are described for Ca and P metabolism. The importance of these differences is described in detail between select ethnic groups, within the USA between African-Americans and White-Americans, between the Gambia and the UK and between China and the UK. Dietary Ca intake is higher in White-Americans compared with African-Americans, and is higher in White-British compared with Gambian and Chinese adults. Differences are observed also for plasma 25-hydroxy vitamin D, related to lifestyle differences, skin pigmentation and skin exposure to UVB-containing sunshine. Higher plasma 1,25-dihydroxy vitamin D and parathyroid hormone are observed in African-American compared with White-American adults. Plasma parathyroid hormone is also higher in Gambian adults and, in winter, in Chinese compared with White-British adults. There may be ethnic differences in the bone resorptive effects of parathyroid hormone, with a relative skeletal resistance to parathyroid hormone observed in some, but not all ethnic groups. Renal mineral excretion is also influenced by ethnicity; urinary Ca (uCa) and urinary P (uP) excretions are lower in African-Americans compared with White-Americans, and in Gambians compared with their White-British counterparts. Little is known about ethnic differences in the DR of Ca and P metabolism, but differences may be expected due to known differences in lifestyle factors, such as dietary intake and sleep/wake pattern. The ethnic-specific DR of Ca and P metabolism may influence the net balance of Ca and P conservation and bone remodelling. These ethnic differences in Ca, P and the bone metabolism may be important factors in the variation in skeletal health.

Vitamin D3 supplementation during weight loss: a double-blind randomized controlled trial

BACKGROUND

Vitamin D deficiency is associated with obesity; whether repletion supports weight loss and changes obesity-related biomarkers is unknown.

OBJECTIVE

We compared 12 mo of vitamin D3 supplementation with placebo on weight, body composition, insulin, and C-reactive protein (CRP) in postmenopausal women in a weight-loss intervention.

DESIGN

A total of 218 overweight/obese women (50-75 y of age) with serum 25-hydroxyvitamin D [25(OH)D] ≥10 ng/mL but <32 ng/mL were randomly assigned to weight loss + 2000 IU oral vitamin D3/d or weight loss + daily placebo. The weight-loss intervention included a reduced-calorie diet (10% weight loss goal) and 225 min/wk of moderate-to-vigorous aerobic activity. Mean 12-mo changes in weight, body composition, serum insulin, CRP, and 25(OH)D were compared between groups (intent-to-treat) by using generalized estimating equations.

RESULTS

A total of 86% of participants completed the 12-mo measurements. The mean (95% CI) change in 25(OH)D was 13.6 (11.6, 15.4) ng/mL in the vitamin D3 arm compared with -1.3 (-2.6, -0.3) ng/mL in the placebo arm (P < 0.0001). Changes in weight [-7.1 (-8.7, -5.7) compared with -7.4 (-8.1, -5.4) kg], body mass index (in kg/m(2): both -2.8), waist circumference [-4.9 (-6.7, -2.9) compared with -4.5 (-5.6, -2.6) cm], percentage body fat [-4.1 (-4.9, -2.9) compared with -3.5 (-4.5, -2.5)], trunk fat [-4.1 (-4.7, -3.0) compared with -3.7 (-4.3, -2.9) kg], insulin [-2.5 (-3.4, -1.7) compared with -2.4 (-3.3, -1.4) μU/mL], and CRP [-0.9 (-1.2, -0.6) compared with -0.79 (-0.9, -0.4) mg/L] [corrected] were similar between groups (all P > 0.05). Compared with women who achieved 25(OH)D <32 ng/mL, women randomly assigned to vitamin D who became replete (ie, 25(OH)D ≥32 ng/mL) lost more weight [-8.8 (-11.1, -6.9) compared with -5.6 (-7.2, -5.0) kg; P = 0.05], waist circumference [-6.6 (-9.3, -4.3) compared with -2.5 (-4.6, -2.0) cm; P = 0.02], and percentage body fat [-4.7 (-6.1, -3.5) compared with -2.6 (-3.9, -2.2); P = 0.04]. Among women with complete pill counts (97% adherence), the mean decrease in CRP was 1.18 mg/mL (46%) in the vitamin D arm compared with 0.46 mg/mL (25%) in the placebo arm (P = 0.03).

CONCLUSIONS

Vitamin D3 supplementation during weight loss did not increase weight loss or associated factors compared with placebo; however, women who became replete experienced greater improvements. This trial was registered at clinicaltrials.gov as NCT01240213.

Vitamin D intake determines vitamin d status of postmenopausal women, particularly those with limited sun exposure

Few detailed data are available on the wide range of determinants of vitamin D status among postmenopausal women, and it is also unclear whether there may be undiscovered determinants. The objective of this study was to comprehensively evaluate determinants of serum 25-hydroxyvitamin D [25(OH)D] concentrations in a large cohort of postmenopausal women. Data from a subset of the Women's Health Initiative Observational Study were analyzed (50-79 y; n = 3345). Information on diet, lifestyle behaviors, secondhand smoke, use of dietary supplements and medication, chronic diseases, and anthropometry was collected at baseline (1993-1998) and on sun exposure at year 4 follow-up. Linear regression was performed to estimate regression coefficients (β). Significant determinants were total vitamin D intake (food plus supplements per 100 IU/d, β = 2.08), years of supplemental vitamin D use (β = 0.15), total fat intake (grams per day, β = -0.03), smoking status (β = -2.64, current vs. never), regional solar irradiance (β = 6.26, 475-500 vs. 300-325 Langleys), daylight time spent outdoors in summer (β = 5.15, >2 h vs. <30 min/d), recreational physical activity (metabolic equivalent task per hour per week, β = 0.13), waist circumference (centimeters, β = -0.26), and race/ethnicity (β = -11.94, black vs. white). Total vitamin D intake (partial R(2) = 0.09) explained the most variance in serum 25(OH)D concentrations (total R(2) = 0.29). The association between total vitamin D intake and serum 25(OH)D concentrations was stronger among participants who spent less rather than more daylight time outdoors in summer (P-interaction = 0.026). History and medications for hypertension, hyperlipidemia, and type 2 diabetes and secondhand smoke exposure were not associated with serum 25(OH)D. In conclusion, dietary factors and sun exposure remain important determinants of vitamin D status in postmenopausal women. Vitamin D intake should be emphasized for those with limited sun exposure.

Vitamin D deficiency among native Dutch and first- and second-generation non-Western immigrants

The aim of this study was to determine the prevalence of 25-hydroxyvitamin D (25(OH)D) deficiency in a hospital-based population of both native Dutch and non-Western immigrants and to investigate the influence of immigrant status on the prevalence of vitamin D deficiency. A cross-sectional survey was conducted among 132 patients (1-18 years of age) visiting the paediatric outpatient department. Serum levels of 25(OH)D were measured using high-performance liquid chromatography. Cut-off levels of 30 and 50 nmol/l for serum 25(OH)D were evaluated. One third of the patients had serum 25(OH)D levels below 30 nmol/l, and half of the study population had serum levels below 50 nmol/l. Non-Western immigrants had an increased risk for vitamin D deficiency compared to their native Dutch peers [25(OH)D of <30 nmol/l, p = 0.03, odds ratio (OR) 3.87 (95 % confidence interval (CI) 1.13-13.29); 25(OH)D of <50 nmol/l, p = 0.02, OR 3.57 (95 % CI 1.26-10.14)] with the highest risk for first-generation non-Western immigrants.

CONCLUSION

Vitamin D deficiency in the paediatric population is still a matter of concern in the Netherlands, in particular among first-generation non-Western immigrants. We therefore strongly recommend vitamin D supplementation for all non-Western immigrants, regardless of age, skin type or season. Health-care staff who work with non-Western immigrants should be aware of the prevalence and implications of vitamin D deficiency.

Vitamin D and health-related quality of life in a community sample of older Canadians

Purpose

To assess how vitamin D status is associated with health-related quality of life (HRQOL) among older residents of Canada.

Design

We analysed baseline data of 1,493 Canadians aged 50 years and over in Alberta on HRQOL (EQ-5D-5L) and serum 25-hydroxyvitamin D (25(OH)D) as a measure of vitamin D status. We applied multivariable regression methods to examine the association between vitamin D status and each of the five dimensions and the summary index of the EQ-5D-5L.

Results

Participants with higher serum 25(OH)D levels were significantly less likely to report problems with mobility, usual activities, and depression and anxiety. Specifically, age- and gender-adjusted odds ratios for reporting problems with mobility, usual activities, and depression and anxiety were 0.58 (95 % confidence interval 0.44–0.78), 0.67 (0.50–0.89), and 0.67 (0.51–0.88) per 100 nmol/L increase in 25(OH)D, respectively. No significant associations were observed for problems with self-care and with pain and discomfort. HRQOL scores combining the responses of each of the five dimensions increased significantly with increasing serum 25(OH)D levels.

Conclusions

This is the first study to reveal the importance of vitamin D for the five dimensions of HRQOL in a community-based sample. The observed associations of vitamin D and HRQOL call for intervention studies to strengthen the evidence of the potential benefits of vitamin D supplementation for HRQOL among older adults.

Vitamin D status and its relationship with metabolic syndrome risk factors among adolescent girls in Boukan, Iran

OBJECTIVE

To investigate vitamin D status and its association with components of the metabolic syndrome (MetS) in adolescent girls attending high school in Boukan, Iran during winter 2012.

DESIGN

A cross-sectional study.

SETTING

High schools of Boukan city, Iran.

SUBJECTS

A sample of 216 girls aged 14-17 years was selected by multistage random sampling from four districts of Boukan. Weight, height, waist circumference, blood pressure, daily energy intake, physical activity and serum 25-hydroxyvitamin D (25(OH)D), fasting blood glucose, TAG and HDL-cholesterol levels of all participants were evaluated. Serum 25(OH)D level <20 ng/ml was defined as vitamin D deficiency.

RESULTS

Mean serum 25(OH)D was 7.26 (sd 2.81) ng/ml and 96 % of the participants had vitamin D deficiency. According to age-modified definitions of the National Cholesterol Education Program Adult Treatment Panel III, MetS was diagnosed in 10.6% of the participants. In multivariable regression analysis after adjustment for BMI, energy intake and physical activity level, serum 25(OH)D was inversely associated with fasting blood glucose (β = -0.143, P = 0.04). No significant relationship was found between serum 25(OH)D and other components of MetS.

CONCLUSIONS

The high prevalence of vitamin D deficiency warrants national polices and interventions towards improving this major health problem among adolescent girls. Low 25(OH)D level was significantly associated with increased fasting blood glucose. Prospective studies are needed to determine the effects of vitamin D deficiency on the development of MetS and related metabolic diseases in adolescent girls.

Measurement of serum total vitamin D (25-OH) using automated immunoassay in comparison [corrected] with liquid chromatography tandem-mass spectrometry

BACKGROUND

The associations of vitamin D deficiency with many nonskeletal diseases are still being discovered. We evaluated the use of an automated immunoassay to measure serum total vitamin D (25-OH) and assessed vitamin D status in a Korean adult population.

METHODS

We compared the Elecsys Vitamin D (25-OH) Total Assay (Roche Diagnostics) with liquid chromatography-tandem mass spectrometry (LC-MS/MS) using 300 serum samples. Total imprecision was calculated using three levels of quality control materials and serum samples. We also investigated the vitamin D status using data for 70,762 cases who had a routine health check-up in our hospitals.

RESULTS

The regression equation: Elecsys = 0.882 × LC-MS/MS + 6.814 (r = 0.926). Total imprecision was within 10% for all quality control materials and serum samples. The prevalence of vitamin D deficiency using cut-off values of <50 nmol/l (<20 ng/ml) were 70.3% in males and 86.4% in females, respectively. The prevalence of vitamin D deficiency was higher in younger subjects than in older subjects (P for linear-by-linear association was <0.001). Serum vitamin D levels were highest in September and lowest in February.

CONCLUSION

The Elecsys Vitamin D (25-OH) Total Assay was comparable to LC-MS/MS and appropriate for routine clinical use. Vitamin D deficiency is common in Korean adults.

Vitamin D and maternal and child health: overview and implications for dietary requirements

The essentiality of vitamin D for normal growth and development has been recognized for over 80 years, and vitamin D fortification programs have been in place in the United States for more than 70 years. Despite the above, vitamin D deficiency continues to be a common finding in certain population groups. Vitamin D deficiency has been suggested as a potential risk factor for the development of preeclampsia, and vitamin D deficiency during infancy and early childhood is associated with an increased risk for numerous skeletal disorders, as well as immunological and vascular abnormalities. Vitamin D deficiency can occur through multiple mechanisms including the consumption of diets low in this vitamin and inadequate exposure to environmental ultraviolet B rays. The potential value of vitamin D supplementation in high-risk pregnancies and during infancy and early childhood is discussed. Currently, there is vigorous debate concerning what constitutes appropriate vitamin D intakes during early development as exemplified by differing recommendations from the Institute of Medicine Dietary Reference Intake report and recent recommendations by the Endocrine Society. As is discussed, a major issue that needs to be resolved is what key biological endpoint should be used when making vitamin D recommendations for the pregnant woman and her offspring.

Prevalence of 25-hydroxyvitamin D deficiency in Korean adolescents: association with age, season and parental vitamin D status

OBJECTIVE

We aimed to assess the prevalence and associated factors of vitamin D deficiency in healthy adolescents and to determine parent-adolescent association in vitamin D status.

DESIGN

A cross-sectional study.

SETTING

Data from the Korean National Health and Nutrition Examination Survey (KNHANES) 2008-2009. Serum 25-hydroxyvitamin D (25(OH)D) levels were measured using 125I-labelled RIA kits. Vitamin D deficiency in adolescents was defined as 25(OH)D level <27·5 nmol/l, and 25(OH)D levels between 27·5 and <50 nmol/l were considered insufficient. For the parents, vitamin D deficiency was defined as 25(OH)D level <50 nmol/l.

SUBJECTS

The study population consisted of 2062 adolescents (1095 boys, 967 girls; aged 10-18 years) and their parents (1005 fathers, 1341 mothers).

RESULTS

Overall, 13·4% of adolescents (boys 11·7%, girls 15·4%) were 25(OH)D deficient, 54·7% were 25(OH)D insufficient. Prevalence of vitamin D deficiency increased with age (P < 0·0001). Parental vitamin D deficiency was more prevalent in vitamin D-deficient adolescents than in non-deficient adolescents (all P < 0·0001). In multivariate logistic regression analyses, predictors for vitamin D deficiency were senior high school students (OR = 3·45-4·33), winter/spring season (OR = 3·18-5·11/5·35-7·36) and parental vitamin D deficiency (OR = 1·78-4·88; all P < 0·05).

CONCLUSIONS

Vitamin D insufficiency is prevalent among healthy Korean adolescents and the parent-offspring association warrants vitamin D screening for family members of deficient individuals.

Prevalence of vitamin D deficiency in international adoptees within the first 6 months after adoption

BACKGROUND

Vitamin D deficiency impairs bone health and development.

OBJECTIVE

To determine the prevalence of and risk factors for vitamin D deficiency in pediatric international adoptees.

METHODS

A prospective cohort (N = 189) study from a single international adoption clinic was conducted. Total 25-hydroxy vitamin D [25(OH)D] level was measured at the initial clinical assessment (within 6 months of adoption). Vitamin D deficiency was defined as a 25(OH)D <20 ng/mL (<8 nmol/L) and insufficiency as 25(OH)D <30 ng/mL (<12 nmol/L).

RESULTS

Vitamin D deficiency was diagnosed in 8% and insufficiency in 27% of the cohort. Lower body mass index and longer time in an institution were associated with vitamin D deficiency and insufficiency independent of age.

CONCLUSIONS

Vitamin D insufficiency was common in our cohort of international adoptees. The significance of vitamin D insufficiency on bone development during the typical "catch-up" growth following international adoption needs to be determined.