Hypovitaminosis D in developing countries-prevalence, risk factors and outcomes

Vitamin D levels in schoolchildren: a cross-sectional study in Kuwait

Background

Ongoing studies in the Middle East, particularly in the Arabian Gulf countries, have reported extremely low levels of serum vitamin D across age and gender. In Kuwait, vitamin D deficiency is prevalent in adolescent girls and in adult women. A number of risk factors have been reported, among which gender, age, and obesity are a few. Because adequate vitamin D status is necessary to promote bone mineral accrual in childhood, and because low vitamin D levels have been associated with a wide range of health problems, there is concern that growing children with low vitamin D may be at higher risk for developing diseases. The aim of this study was to assess vitamin D levels in elementary schoolchildren.

Methods

Kuwaiti schoolchildren were recruited and assessed for their serum vitamin D, 25(OH)D, parathyroid hormone (PTH) and adjusted serum calcium (adj-Ca). Anthropometric measurements and data on lifestyle and health status were recorded during an interview.

Results

In a total of 199 schoolchildren, median (IQR) age was 8.5 (7.0–9.5 years), 25(OH)D was 30 (22–39 nmol/L), PTH was 4.7 (3.8–5.9 pmol/L), and adj-Ca was 2.39 (2.33–2.44 mmol/L). Boys had higher levels of 25(OH)D (18.3% vs 6.6% had levels ≥50 nmol/L) and lower levels of PTH (94.6% vs 80.2% had levels <7 pmol/L) than girls. Significant risk factors for 25(OH)D levels <25 nmol/L included being ≤8.5 years old (OR 4.95, 95% CI: 1.92–12.74), having PTH ≥7 pmol/L (OR 2.28, 95% CI: 1.17–4.46), being female (OR 2.44, 95% CI: 1.22–4.88), and being overweight or obese (OR 2.18, 95% CI: 1.11–4.26).

Conclusions

The results show relatively low levels of 25(OH)D in young schoolchildren in Kuwait, with lower levels in girls. Given the association of 25(OH)D with a wide range of ailments, it is necessary to further examine the causes and risk factors of low vitamin D in this age group to prevent associated health problems.

Effects of 1α,25 Dihydroxyvitamin D3 on Pro-inflammatory Cytokines of Palmitic Acid Treated Thp-1 Cells

The level of saturated fatty acids, such as palmitic acid (PA), correlates with chronic inflammation in obese and metabolic syndrome patients. However, low level of vitamin D₃ is observed in those conditions. The aim of this study is to investigate effects of 1α,25(OH)₂ D₃ on PA-treated THP-1 cells. Using quantitative real-time polymerase chain reaction, we measure mRNA expression of pro-inflammatory cytokines: TNF-α, Interleukin (IL)-1β, IL-6, and chemokine IL-8 under PA and 1α,25(OH)₂ D₃ influence. PA, at all concentrations (25-100 μM), enhanced LPS stimulatory effect on those mRNA expression compared to LPS-treated and -untreated cells. Combination with 1α,25(OH)₂ D₃ increased cytokine expression at high (10^-6 M) and high-normal (10^-8 M) concentrations compared to PA + LPS and LPS alone, both for 2 and 24 h. However, low-normal (10^-10 M) and low (10^-12 M) levels of 1α,25(OH)₂ D₃ could not enhance PA effect, but mRNA expression of pro-inflammatory cytokine was higher than LPS-treated cells. Upstream pathway of 1α,25(OH)₂ D₃ , which is cholecalciferol, also gave the similar result. Further, inhibition of calcium pathway does not play a role in this mechanism. Thus, these findings support pro-inflammatory effect of PA and vitamin D₃ on innate immune response, especially on fat-induced inflammation.

PRACTICAL APPLICATION

The effect of vitamin D₃ on chronic inflammation in obesity is uncertain. This study shows an in vitro possibility that vitamin D₃ could exaggerate inflammation when combined with high SFAs. The idea of using vitamin D₃ supplement to modulate inflammation in fat-related inflammation needs further refined experiments before its clinical application.

Genetic and Racial Differences in the Vitamin D Endocrine System

Twin studies indicate that genetic factors may explain about 50% of the variation of serum 25-hydroxyvitamin D (25OHD). Polymorphisms of 3 genes, delta-7-sterol-reductase, CYP2R1, and DBP/GC (and maybe CYP24A1) combined, can explain about 5% to 10% of the variation in serum 25OHD. These polymorphisms are found in nearly all populations. The variation in serum 25OHD found in different areas and populations in the world is mainly due to environmental and lifestyle factors, not truly dependent on racial differences. One genetic variant of DBP, (GC2), is associated with a modest (∼10%) decrease in serum DBP and 25OHD concentrations for unexplained reasons.

Vitamin D deficiency in older adults and its associated factors: a cross-sectional analysis of the Mexican Health and Aging Study

Vitamin D deficiency was common in older adults from a country with adequate sun exposure. The variables associated with this deficiency provide insight into the next steps needed to characterize older adults with this deficiency and to treat it accordingly.

PURPOSE

The aim of this study was to describe the prevalence of and factors associated with vitamin D deficiency among Mexican older adults.

METHODS

This was a secondary analysis of the last wave of the Mexican Health and Aging Study. Vitamin D levels along with other biomarkers were obtained from a sub-sample of Mexican adults older than 60 years. Prevalence was described by sex and age group, and a multivariate analysis was performed to test the factors associated with this condition.

RESULTS

Data from 1088 adults over the age of 60 years were analyzed. The mean serum vitamin D level was 23.1 ± 8.1 ng/mL and was significantly higher among men than women (25.6 ± 0.6 and 22.8 ± 0.5 ng/mL, respectively; p < 0.001). In total, 37.3% (n = 406) presented with vitamin D deficiency, 65% of whom were women. Low 25-(OH)-vitamin D levels were associated with female sex (OR 1.74, 95% CI 1.59-2.42), current smoking (OR 2.21, 95% CI 1.47-3.39), education (OR 1.1, 95% CI 1.06-1.13), physical activity (OR 1.74, 95% CI 1.31-2.23), and high levels of glycated hemoglobin (OR 1.16, 95% CI 1.07-1.25).

CONCLUSIONS

Vitamin D deficiency was highly prevalent in Mexican older adults and was associated with a number of factors, indicating the multifactorial causality of this deficiency.

Genome-nutrition divergence: evolving understanding of the malnutrition spectrum

Humans adapted over a period of 2.3 million years to a diet high in quality and diversity. Genome-nutrition divergence describes the misalignment between modern global diets and the genome formed through evolution. A survey of hominin diets over time shows that humans have thrived on a broad range of foods. Earlier diets were highly diverse and nutrient dense, in contrast to modern food systems in which monotonous diets of staple cereals and ultraprocessed foods play a more prominent role. Applying the lens of genome-nutrition divergence to malnutrition reveals shared risk factors for undernutrition and overnutrition at nutrient, food, and environmental levels. Mechanisms for food system shifts, such as crop-neutral agricultural policy, agroecology, and social policy, are explored as a means to realign modern diets with the nutritional patterns to which humans may be better adapted to thrive.

A systematic review of vitamin D status in southern European countries

PURPOSE

Despite an acknowledged dearth of data on serum 25-hydroxyvitamin D (25(OH)D) concentrations from Southern European countries, inter-country comparison is hampered by inconsistent data reporting. The purpose of the current study was to conduct a systematic literature review of available data on serum 25(OH)D concentrations and estimate vitamin D status in Southern European and Eastern Mediterranean countries, both at a population level and within key population subgroups, stratified by age, sex, season and country.

METHODS

A systematic review of the literature was conducted to identify and retrieve scientific articles reporting data on serum 25(OH)D concentration and/or vitamin D status following standard procedures.

RESULTS

Data were extracted from 107 studies, stratified by sex and age group, representing 630,093 individuals. More than one-third of the studies reported mean 25(OH)D concentrations below 50 nmol/L and ~ 10% reported mean serum 25(OH)D concentrations below 25 nmol/L. Overall, females, neonates/ infants and adolescents had the higher prevalence of poor vitamin D status. As expected, there was considerable variability between studies. Specifically, mean 25(OH)D ranged from 6.0 (in Italian centenarians) to 158 nmol/L (in elderly Turkish men); the prevalence of serum 25(OH)D < 50 nmol/L ranged from 6.8 to 97.9% (in Italian neonates).

CONCLUSIONS

Contrary to expectations, there was a high prevalence of low vitamin D status in the Southern Europe and the Eastern Mediterranean regions, despite abundant sunshine. These data further emphasize the need for strategies, such as fortification of foods with vitamin D and/or vitamin D supplementation, which will be tailored to the needs of specific population groups with higher risk of insufficiency or deficiency, to efficiently tackle the pandemic of hypovitaminosis D in Europe.

Associations of serum 25-hydroxyvitamin D level with incidence of lung cancer and histologic types in Norwegian adults: a case-cohort analysis of the HUNT study

Previous prospective studies have shown inconsistent associations between serum 25-hydroxyvitamin D [25(OH)D] level and lung cancer incidence. The aim of the present study was to explore the associations of serum 25(OH)D levels with incidence of lung cancer overall and different histologic types. We performed a population-based prospective case-cohort study including 696 incident lung cancer cases and 5804 individuals in a subcohort who participated in the second survey of the Nord-Trøndelag Health Study in Norway. Cox proportional hazards regression models counting for the case-cohort design were used to estimate hazard ratios (HRs) with 95% confidence interval (CIs) for lung cancer overall or histologic types in relation to serum 25(OH)D levels. Compared with the fourth season-specific quartile of 25(OH)D (median 68.0 nmol/L), lower 25(OH)D levels were not associated with the incidence of overall, small or squamous cell lung cancer. However, the risk of adenocarcinoma was lower in the second and third quartiles (median 39.9 and 51.5 nmol/L) compared with the fourth quartile, with HRs of 0.63 (95% CI 0.41-0.98) and 0.58 (0.38-0.88), respectively. The associations of lower levels of 25(OH)D with a reduced risk of adenocarcinoma were only observed in the overweight/obese subjects [HRs for second and third quartiles: 0.40 (0.22-0.72) and 0.50 (0.27-0.92)] but not in the normal weight subjects [HRs: 0.95 (0.52-1.75) and 0.60 (0.32-1.10)]. Serum 25(OH)D levels were not associated with the risk of lung cancer in general. The observation that lower 25(OH)D levels were associated with a lower risk of adenocarcinoma should be interpreted with caution.

Factors associated to serum 25-hydroxyvitamin D levels among older adult populations in urban and suburban communities in Shanghai, China

BACKGROUND

Vitamin D deficiency is widespread in China, particularly among older adults. Factors associated with suboptimal vitamin D levels are not well defined. The present study was a population-based study that included 10 urban and suburban communities in Shanghai, to evaluate vitamin D status and its correlates among older adults.

METHOD

This cross-sectional study was based on study data for 3924 healthy men and women aged 65-95 years. Anthropometric and socioeconomic data were collected in June-July 2014. Serum 25(OH)D levels were detected using a chemiluminescence immunoassay. The following socioeconomic data were obtained through self-administered questionnaires: education level, lifestyle, residency, and dietary habits. A logistic regression model was used to assess associations between anthropometric factors, socioeconomic factors and serum 25(OH)D levels.

RESULTS

Median levels of serum 25(OH)D in men and women were 22.73 and 19.99 ng/mL, respectively. Vitamin D deficiency was common in subjects, even though data collection was conducted during summer. The general prevalence of serum 25(OH)D levels <20 ng/mL were 35.4% and 50.5% for men and women respectively. The general prevalence of serum 25(OH)D levels <10 ng/mL were 2.73% and 5.9% for men and women respectively. A multivariable model indicated serum 25(OH)D levels ≥20 ng/mL were significantly and positively correlated with male sex, calcium or vitamin D supplementation, and residency in suburban communities. The model also indicated that high level of physical activity was protective factors of vitamin D deficiency for men and milk consumption for women, respectively. By contrast, deficient serum 25(OH)D levels were significantly correlated with education level (lower than primary school) or obesity [body mass index (BMI) ≥ 26.06 kg/m²] for men or women, respectively.

CONCLUSION

This cross-sectional study of older adults in communities in Shanghai demonstrates that key factors positively correlated with serum 25(OH)D levels ≥20 ng/mL include male sex, residency in suburban communities, calcium or vitamin D supplementation, high physical activity and education level (for men), and dairy consumption and maintenance of normal BMI (for women).

Validation of summer and winter ELISA measurements of serum 25-hydroxyvitamin D concentrations in Mongolia

BACKGROUND AND OBJECTIVES

Assay cost, quality, and availability pose challenges for vitamin D surveys in limited resource settings. This study aimed to validate an inexpensive vitamin D assay (ELISA) under real-world conditions in Mongolia, the northernmost developing country, to characterize the assay's usefulness and inform the design of epidemiologic studies in similar regions.

METHODS AND STUDY DESIGN

We collected paired summer and winter serum samples from 120 men and women (aged 20-57 years) in urban and rural Mongolia, analyzed each sample for 25(OH)D concentration using both Immunodiagnostic Systems ELISA and DiaSorin LIAISON 25(OH)D TOTAL, and compared the assays using multiple statistics. LIAISON was itself validated by participation in the DEQAS program.

RESULTS

Correlation and agreement between assays were higher in summer (Pearson's correlation=0.60, Spearman's rank correlation=0.67, Lin's concordance correlation=0.56) than winter (rP=0.37, rS=0.43, rC=0.33), although ELISA less accurately assigned subjects to sufficiency categories in summer (percent agreement=44%) than winter (58%), during the latter of which most subjects were deficient ([25(OH)D] categories used: >75 nmol/L (optimal), 50-75 nmol/L (adequate), 25-50 nmol/L (inadequate), <25 nmol/L (deficient)). Compared with LIAISON, ELISA tended to indicate higher vitamin D status in both seasons (mean paired difference: 7.0 nmol/L (95% CI: 3.5-10.5) in summer, 5.2 nmol/L (95% CI: 2.9-7.5) in winter).

CONCLUSIONS

ELISA proved useful for measuring and ranking subjects' vitamin D status in Mongolia during summer, but levels were too low in winter to sensitively discriminate between subjects, and ELISA overestimated status in both seasons. These findings have implications for the timing and interpretation, respectively, of vitamin D surveys in highly deficient populations.

Vitamin D signaling in intestinal innate immunity and homeostasis

The lumen of the gut hosts a plethora of microorganisms that participate in food assimilation, inactivation of harmful particles and in vitamin synthesis. On the other hand, enteric flora, a number of food antigens, and toxins are capable of triggering immune responses causing inflammation, which, when unresolved, may lead to chronic conditions such as inflammatory bowel disease (IBD). It is important, therefore, to contain the gut bacteria within the lumen, control microbial load and composition, as well as ensure adequate innate and adaptive immune responses to pathogenic threats. There is growing evidence that vitamin D signaling has impacts on all these aspects of intestinal physiology, contributing to healthy enteric homeostasis. VD was first discovered as the curative agent for nutritional rickets, and its classical actions are associated with calcium absorption and bone health. However, vitamin D exhibits a number of extra-skeletal effects, particularly in innate immunity. Notably, it stimulates production of pattern recognition receptors, anti-microbial peptides, and cytokines, which are at the forefront of innate immune responses. They play a role in sensing the microbiota, in preventing excessive bacterial overgrowth, and complement the actions of vitamin D signaling in enhancing intestinal barrier function. Vitamin D also favours tolerogenic rather than inflammogenic T cell differentiation and function. Compromised innate immune function and overactive adaptive immunity, as well as defective intestinal barrier function, have been associated with IBD. Importantly, observational and intervention studies support a beneficial role of vitamin D supplementation in patients with Crohn's disease, a form of IBD. This review summarizes the effects of vitamin D signaling on barrier integrity and innate and adaptive immunity in the gut, as well as on microbial load and composition. Collectively, studies to date reveal that vitamin D signaling has widespread effects on gut homeostasis, and provide a mechanistic basis for potential therapeutic benefit of vitamin D supplementation in IBD.

Association Between 25-Hydroxyvitamin D and Epicardial Adipose Tissue in Chinese Non-Obese Patients with Type 2 Diabetes

Background

Epicardial adipose tissue (EAT) is recognized as a useful indicator for type 2 diabetes mellitus (T2DM) and obesity. However, studies on the association between vitamin D status and EAT thickness in type 2 diabetes (T2D) are limited. In this study, we aimed to evaluate the association of vitamin D (Calcifediol) status and EAT thickness (EATT) in Chinese non-obese patients with T2D.

Material/Methods

A cross-sectional study was performed among 167 non-obese T2D Chinese patients and 82 non-diabetic patients, who are age- and gender-matched during the winter months. EATT was evaluated by two-dimensional transthoracic echocardiography. Serum 25-hydroxyvitamin D [25(OH)D, Calcifediol] was examined in the diabetic patients and in the control group.

Results

The concentration of 25(OH)D was 32.00 nmol/l (19.30–53.70 nmol/l) among diabetic patients. Most (93.4%) of the diabetic patients had hypovitaminosis D. We confirmed a clear negative association between 25(OH)D level and EATT in non-obese T2D patients (p=0.01). EATT was significantly correlated with 25(OH)D level (p=0.001) and HOMA-IR (p=0.001). Results of multivariate logistic regression analysis demonstrated increased EATT, which was remarkably associated with 25(OH)D levels (p=0.039), systolic blood pressure (SBP) (p=0.013), HOMA-IR (p=0.030), and waist circumference (p<0.001) in T2D patients after adjusting for the confounding factors.

Conclusions

Increased EATT was found in Chinese non-obese T2D patients. 25(OH)D and HOMA-IR were independently associated with increased EATT after adjusting for multiple confounders.

Comparative analysis of nutritional guidelines for vitamin D

Vitamin D is essential for calcium and bone homeostasis. Humans are largely dependent on UVB-radiation-induced photosynthesis of vitamin D, as few foods contain vitamin D. However, the same radiation that produces vitamin D is also carcinogenic, albeit with a long lag time, and causes DNA damage. In view of the increasing life expectancy, avoiding excessive sun exposure is prudent. Several groups of people have a shortfall between their requirements for vitamin D and their combined endogenous synthesis and intake from natural foods, and therefore need vitamin D supplementation. Governments and scientific societies are regularly updating their recommendations for intake of vitamin D, especially for groups that should (infants) or prefer to (especially elderly individuals) avoid direct sunlight. An overview of such guidelines is presented in this Review. A fairly large consensus exists that all infants should receive 400 international units (IU) (10 μg) daily during their first year of life and that elderly individuals should have access to vitamin D supplementation (at recommended dosages varying from 400 IU to 800 IU daily in most governmental guidelines but at higher dosages in other guidelines). All guidelines unanimously agree that serum levels of 25-hydroxyvitamin D (25OHD) <25 nmol/l (10 ng/ml) should be avoided at all ages. Children and adults who have limited sun exposure should receive vitamin D supplementation, but the recommended doses vary widely (from 200 IU to 2,000 IU daily), in line with disagreement regarding the minimal desirable serum concentration of 25OHD (which varies from 25 nmol/l to >100 nmol/l).

Association of vitamin D receptor gene polymorphism (VDR) with vitamin D deficiency, metabolic and inflammatory markers in Egyptian obese women

Vitamin D deficiency might contribute to the pathogenesis of metabolic syndrome and could cause immune disturbance. The aim of this study is to analyze the associations between Vitamin D receptor (VDR) gene polymorphism, serum 25-hydroxy vitamin D, metabolic and inflammatory biomarkers in Egyptian obese women. The study included 201 obese women with vitamin D deficiency and 249 obese matched age healthy controls with sufficient vitamin D levels. Their age ranged between 25 and 35 years. Inflammatory biomarkers (interleukin-6 and C-reactive protein) and serum 25(OH) D were measured by enzyme-linked immunosorbent assay. Insulin resistance (IR) was determined by the homeostasis model assessment of insulin resistance (HOMA-IR).Vitamin D receptor (VDR) gene polymorphisms of FokI, ApaI, and TaqI were studied by PCR using the restriction fragment length polymorphism (RFLP) technique. Obese women with vitamin D deficiency had significant higher values of inflammatory and metabolic parameters compared to controls. Multivariable-logistic regression showed associations between 25(OH) D deficiency and metabolic components when comparing cases with controls. Moreover, cases carrying polymorphic alleles showed significant lower levels of serum 25(OH) D and higher HOMA-IR, blood pressure levels and lipid parameters compared to those with the wild type homozygote in obese cases with vitamin D deficiency. Vitamin D deficiency in Egyptian obese women with vitamin D deficiency is associated with abnormal metabolic components and abnormal inflammatory biomarkers. Moreover, VDR polymorphisms play important role in immune and inflammation status.

Vitamin D Deficiency in Patients Referred for Evaluation of Obstructive Sleep Apnea

STUDY OBJECTIVES

A recent study reported an association between obstructive sleep apnea (OSA) and low vitamin D levels. In this study, we measured vitamin D levels in patients referred for evaluation of suspected OSA and sought to identify associated risk factors for vitamin D deficiency. Our objective was to determine whether evaluations of patients with suspected OSA should include routine screening for vitamin D deficiency.

METHODS

Using a cross-sectional study design, we measured vitamin D levels in consecutively enrolled patients referred for an OSA evaluation to Dr. Lutfi Kirdar Kartal Training and Research Hospital in Istanbul, Turkey. We conducted full-night polysomnography and compared vitamin D levels both between patients with OSA and patients without OSA and across the various severity levels of OSA. We evaluated the association between vitamin D levels and various clinical and demographic characteristics, including the apnea-hypopnea index and body mass index.

RESULTS

From April 2014 to June 2015, 195 patients were referred for OSA evaluation. Of these, 181 patients (93%) consented to participate and underwent full polysomnography and measurement of vitamin D levels. The mean ± standard deviation age was 49 ± 12 years and body mass index of 31 ± 6 kg/m². Polysomnography led to the diagnosis of OSA in 162 of the patients (89.5%): 52 (32%) were categorized as having mild OSA, 38 (23.5%) as having moderate OSA, and 72 (44.5%) as having severe OSA. Vitamin D level was 15.5 ± 11.6 ng/mL (95% confidence interval; 13-17 ng/mL) and 134 patients (74%) met the criterion for vitamin D deficiency (< 20 ng/mL). Sex, vitamin D levels, and percentage of patients with vitamin D deficiency were similar in patients with and without OSA (P > .05). Vitamin D levels were similar across OSA severity categories (P = .68). We found no association between vitamin D levels and the apnea-hypopnea index or body mass index.

CONCLUSION

A large proportion of patients referred for OSA evaluation had vitamin D deficiency. Vitamin D levels did not differ by OSA diagnosis status or severity. Patients referred for polysomnography should undergo routine screening for vitamin D deficiency as well as clinically indicated treatment to prevent associated comorbidities.

Association of self-reported symptoms with serum levels of vitamin D and multivariate cytokine profile in healthy women

BACKGROUND

Although a large number of studies have investigated possible relationships among serum levels of vitamin D or cytokines with disease progress and prognosis, similar studies on self-reported symptoms are still controversial. The overall objective of this study was to look into the association between serum levels of vitamin D or cytokines with self-reported symptoms related to musculoskeletal pain, sleep disorders, and premenstrual syndrome (PMS) in healthy adult women.

SUBJECTS AND METHODS

Venous blood samples were collected from 117 healthy adult women, and serum levels of vitamin D, pro-inflammatory cytokines (IL-1β, IL-6, IL-8, IL-17, IFN-γ, and TNF-α) and anti-inflammatory cytokines (IL-4, IL-10, and IL-13) were measured. Groups were tested for differences in single parameters, pro-:anti-inflammatory cytokine ratios, and differences in multivariate patterns.

RESULTS

There were no significant associations between serum levels of vitamin D and any of the self-reported symptoms studied. However, serum levels of certain pro-inflammatory cytokines were significantly higher in subjects with musculoskeletal pain (IL-8, P=0.008), sleep disorders (IFN-γ, P=0.02), and PMS (IL-8 and TNF-α, P=0.009 and 0.002, respectively) compared to subjects who reported no symptoms. The pro-:anti-inflammatory cytokine ratios showed pro-inflammatory cytokine dominance in subjects with self-reported symptoms, particularly in the groups with deficient levels of vitamin D. However, the multivariate cytokine-pattern analysis was significantly different between PMS groups only.

CONCLUSION

These data point to a possible role of pro-inflammatory cytokines as a contributing factor in self-reported symptoms related to musculoskeletal pain, sleep disorders, and PMS.

Association between serum 25-hydroxyvitamin D and carotid atherosclerotic plaque in Chinese type 2 diabetic patients

In this study, we investigated the distribution of vitamin D and its association with carotid atherosclerotic plaque (CP) in Chinese type 2 diabetic (T2D) patients. We performed a cross-sectional study in 210 T2D and 94 age- and gender-matched nondiabetic patients during winter months, by determining serum 25-hydroxyvitamin D (25(OH)D) levels in both diabetic and nondiabetic controls. We carried out measurements of B-mode ultrasonography of carotid arteries in each T2D patient. The 25(OH)D concentration was 26.25 nmol/L among the T2D patients. About 93.3% T2D patients suffered from hypovitaminosis D. First, we found a clear inverse correlation between the 25(OH)D concentration and CP (P <0.001). Second, an association between 25(OH)D and macrovascular disease was significant (P = 0.005). In multivariate logistic regression analysis, decreasing 25(OH)D concentration was markedly associated with CP in T2D patients. Third, after adjusting for the confounding factors, we also observed a positive correlation between low levels of 25(OH)D in T2D patients with CP, when the following parameters were measured: old age (odds ratio [OR] = 2.533, P = 0.013); smoking (OR = 3.872, P = 0.001); and high level of low-density lipoprotein (LDL) cholesterol (OR = 2.776, P = 0.009). Thus, we concluded that high prevalence of hypovitaminosis D exists in Chinese T2D patients. Further, we found a significant association between low concentration of serum 25(OH)D and the existence of high body mass index, and high circulating LDL to be substantially positive predictors of patients with CP in T2D.

Vitamin D Status in South Asian Populations - Risks and Opportunities

Human body acquires a significant amount of vitamin D by cutaneous synthesis under the action of sunlight and less is supplied through nutritional sources. Diversified sociocultural and economic determinants have been identified that limit the dietary intake of vitamin D and enough distribution of sunlight to maintain optimal levels of 25-hydroxyvitamin D (25(OH)D). Consequently, the world has witnessed a high prevalence of hypovitaminosis D in resource-limited South Asian countries. The purpose of this review is to provide a South Asian perspective of vitamin D status, critically examining India, Pakistan, Bangladesh, and Sri Lanka, and to shed light on potential determinants (latitude and season, sunshine exposure habits, age, gender, and genetic factors) leading to hypovitaminosis D among a variety of population groups. Literature search was carried out using bibliographic databases "PubMed," "Google Scholar," and "ScienceDirect.com." Serum 25(OH)D level, 20-50 nmol/L, was mainly taken as vitamin D deficiency, and determinants of low serum 25(OH)D concentration of the population under study were also considered. The review concludes that vitamin D deficiency is highly prevalent among South Asian populations and global efforts are needed to overcome hypovitaminosis in the region. In addition, dietary diversification, supplementation and fortification of foods with vitamin D, adequate exposure to sunlight, and consumption of animal foods were suggested as viable approaches to maintain 25(OH)D levels for optimal health.

Vitamin D deficiency: What does it mean for chronic obstructive pulmonary disease (COPD)? a compherensive review for pulmonologists

OBJECTIVES

Vitamin D deficiency and Chronic Obstructive Pulmonary Disease (COPD) are both under-recognized health problems, world-wide. Although Vitamin D has long been known for calcemic effects it also has less known noncalcemic effects. Recent data have shown that Vitamin D deficiency is highly prevalent in patients with COPD and correlates with forced expiratory volume in one second (FEV₁ ) and FEV₁ decline. The objective of this work was to review the current literature on vitamin D deficiency in relation with COPD.

DATA SOURCE

A literature search, using the words "vitamin D" and "COPD", was undertaken in Pubmed database.

RESULTS

The noncalcemic effects of vitamin D relating with COPD may be summarised as increasing antimicrobial peptide production, regulation of inflammatory response and airway remodelling. Vitamin D inhibits the production of several proinflammatory cytokines and leads to suppression Th1 and Th17 responses which may be involved in the pathogenesis of COPD. Vitamin D insufficiency may also contribute to chronic respiratory infections and airway colonization so returning vitamin D concentrations to an optimal range in patients with COPD might reduce bacterial load and concomitant exacerbations.Vitamin D is also important for COPD-related comorbodities such as osteoporosis, muscle weakness and cardiovascular diseases. Data about the effect of Vitamin D supplementation on those comorbidities in relation with COPD are been scarce.

CONCLUSION

Improving the blood level of Vitamin D into the desired range may have a beneficial effect bones and muscles, but more studies are needed to test to test that hypothesis.

Impact of vitamin D replacement in adults and elderly in the Middle East and North Africa: a systematic review and meta-analysis of randomized controlled trials

In the Middle East and North Africa (MENA), a vitamin D dose ≥2000 IU/day may be needed to allow to the majority of the population to reach the target 25-hydroxyvitamin D (25(OH)D) level ≥20 ng/ml. Data in the region on the effect of vitamin D supplementation on various skeletal and extra-skeletal effects are scarce.

INTRODUCTION

Hypovitaminosis D is prevalent worldwide, more so in the Middle East and North Africa (MENA). This study aims to determine the effects of vitamin D replacement on the mean difference in 25-hydroxyvitamin D [25(OH)D] level reached and other outcomes, in the MENA.

METHODS

This is a meta-analysis of randomized trials from the MENA, administering vitamin D supplementation for at least 3 months, without language or time restriction. We conducted a comprehensive search in seven databases until July 2015. We abstracted data from published reports, independently and in duplicate. We calculated the mean difference (MD) and 95 % CI of 25(OH)D level reached for eligible comparisons, and pooled data using RevMan version 5.3.

RESULTS

We identified 2 studies in elderly and 17 in adults; for the latter, 11 were included in the meta-analysis. Comparing a high vitamin D dose (>2000 IU/day) to placebo (nine studies), the MD in 25(OH)D level achieved was 18.3 (CI 14.1; 22.5) ng/ml; p value < 0.001; I ² = 92 %. Comparing an intermediate dose (800-2000 IU/day) to placebo (two studies), the MD in 25(OH)D level achieved was 14.7 (CI 4.6; 24.9) ng/ml; p value 0.004; I ² = 91 %. Accordingly, 89 and 71 % of participants, in the high and intermediate dose groups, respectively, reached the desirable level of 20 ng/ml. The risk of bias in the included studies was unclear to high, except for three studies.

CONCLUSION

In the MENA region, vitamin D doses ≥2000 IU/day may be needed to reach the target 25(OH)D level ≥20 ng/ml. The long-term safety and the efficacy of such doses on various outcomes are unknown.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

CYP2R1 polymorphisms are important modulators of circulating 25-hydroxyvitamin D levels in elderly females with vitamin insufficiency, but not of the response to vitamin D supplementation

We studied the association between CYP2R1 genetic polymorphisms and circulating 25-hydroxyvitamin D [25(OH)D] before and after supplementation with vitamin D3 in 218 elderly. We found differences between 3 and 8 ng/ml in circulating levels at baseline in women but not in the response after 1 year of supplementation.

INTRODUCTION

This study evaluated the association between polymorphisms in four single nucleotide polymorphisms (SNPs) of the CYP2R1 gene and 25(OH)D levels before and 1 year after supplementation with two different doses of vitamin D3 (600 IU daily or a dose equivalent to 3750 IU daily), in a cohort of 218 (96 men and 122 women) Lebanese elderly overweight subjects.

METHODS

Genotyping was performed for rs12794714, rs10741657, rs1562902, and rs10766197 SNPs using real-time PCR. The 25(OH)D levels were measured by liquid chromatography tandem mass spectrometry.

RESULTS

At baseline, the mean ± SD age was 71.0 ± 4.7 years, BMI 30.3 ± 4.6 kg/m², and 25(OH)D level was 20.5 ± 7.6 ng/ml. There were significant differences in mean 25(OH)D levels between genotypes in women, but not in men. After adjustment for age, season, and BMI, the homozygous for the low frequency gene variant (HLV) of rs1562902 and rs10741657 SNPs had the highest mean 25(OH)D levels with difference of 7.6 ng/ml for rs1562902 SNP (p < 0.01) and of 5.9 ng/ml for rs10741657 (p = 0.05) compared to the homozygous for the major polymorphisms (HMPs). Conversely, for rs10766197 and rs12794714 SNPs, HMP had the highest mean 25(OH)D levels with difference of 6 ng/ml for rs10766197 (p = 0.003) and of 4.8 ng/ml (p = 0.02) for rs12794714, compared to the HLV. CYP2R1 genetic polymorphisms explained 4.8 to 9.8 % of variability in 25(OH)D in women. After 1 year, there was no difference in the response to vitamin D3 supplementation between genotypes in either gender.

CONCLUSION

This study showed a difference in 25(OH)D levels between CYP2R1 genotypes that equates a daily supplementation of 400-800 IU vitamin D, depending on genotype. It underscores possible important genetic contributions for the high prevalence of hypovitaminosis D in the Middle East.

Targeted next generation sequencing of the entire vitamin D receptor gene reveals polymorphisms correlated with vitamin D deficiency among older Filipino women with and without fragility fracture

This study aimed to discover genetic variants in the entire 101 kB vitamin D receptor (VDR) gene for vitamin D deficiency in a group of postmenopausal Filipino women using targeted next generation sequencing (TNGS) approach in a case-control study design. A total of 50 women with and without osteoporotic fracture seen at the Philippine Orthopedic Center were included. Blood samples were collected for determination of serum vitamin D, calcium, phosphorus, glucose, blood urea nitrogen, creatinine, aspartate aminotransferase, alanine aminotransferase and as primary source for targeted VDR gene sequencing using the Ion Torrent Personal Genome Machine. The variant calling was based on the GATK best practice workflow and annotated using Annovar tool. A total of 1496 unique variants in the whole 101-kb VDR gene were identified. Novel sequence variations not registered in the dbSNP database were found among cases and controls at a rate of 23.1% and 16.6% of total discovered variants, respectively. One disease-associated enhancer showed statistically significant association to low serum 25-hydroxy vitamin D levels (Pearson chi-square P-value=0.009). The transcription factor binding site prediction program PROMO predicted the disruption of three transcription factor binding sites in this enhancer region. These findings show the power of TNGS in identifying sequence variations in a very large gene and the surprising results obtained in this study greatly expand the catalog of known VDR sequence variants that may represent an important clue in the emergence of vitamin D deficiency. Such information will also provide the additional guidance necessary toward a personalized nutritional advice to reach sufficient vitamin D status.

Long-term adherence and effects on grip strength and upper leg performance of prescribed supplemental vitamin D in pregnant and recently pregnant women of Somali and Swedish birth with 25-hydroxyvitamin D deficiency: a before-and-after treatment study

Background

Muscular weakness and severe vitamin D deficiency is prevalent in Somali (veiled) pregnant women, Sweden. The study aims here were to explore adherence to prescribed supplemental vitamin D in new mothers with vitamin D deficiency and its effects on grip strength and upper leg performance in Somali (target group TG) and Swedish women (reference group RG) from spring through winter.

Methods

A before- and after study was designed. A cross-sectional sample of women in antenatal care with serum 25-OHD ≤50 nmol/L were prescribed one or two tablets daily (800 or 1600 IU vitamin D3 with calcium) for 10 months. Reminders were made by Somali nurses (TG) or Swedish doctors (RG). Baseline and 10 month measurements of plasma nmol/L 25-OHD, maximal grip strength held for 10 s (Newton, N) and ability to squat (yes;no) were done. Total tablet intake (n) was calculated. Outcome variables were changes from baseline in grip strength and ability to squat. Predicting variables for change in grip strength and ability to squat were calculated using linear and binary regression in final models. Undetectable 25-OHD values (<10 nmol/L) were replaced with ‘9’ in statistic calculations.

Results

Seventy-one women (46 TG, 1/3 with undetectable baseline 25-OHD; 25 RG) participated. At the 10-month follow up, 17% TG and 8% RG women reported having refrained from supplement. Mean 25-OHD increased 16 to 49 nmol/L (TG) and 39 nmol/L to 67 nmol/L (RG), (both p < 0.001). Grip strength had improved from 153 to 188 N (TG) (p < 0.001) and from 257 to 297 N (RG) (p = 0.003) and inability to squat had decreased in TG (35 to 9, p < 0.001). Intake of number of tablets predicted increased grip strength (B 0.067, 95%CI 0.008–0.127, p = 0.027). One tablet daily (>300 in total) predicted improved ability to squat (OR 16; 95% CI 1.8–144.6).

Conclusions

Adherence to supplemental vitamin D and calcium should be encouraged as an even moderate intake was associated to improved grip strength and upper leg performance, which was particularly useful for the women with severe 25-OHD deficiency and poor physical performance at baseline.

Trial registration

ClinicalTrials.gov Identifier: NCT02922803. Date of registration: September 28, 2016.

Children with lower respiratory tract infections and serum 25-hydroxyvitamin D3 levels: A case-control study

BACKGROUND

Pneumonia is the leading cause of death in children under age of 5 years worldwide. The role of vitamin D in respiratory infections including pneumonia is unclear; therefore, we aimed to determine if children with lower respiratory tract infections had low serum 25-hydroxyvitamin D₃ .

METHODS

We performed a case-control study of children ages 3-60 months from the Guatemala City metropolitan area, hospitalized with community-acquired pneumonia between September and December 2012. Controls were selected from the well-baby/care immunization clinics serving the population from which cases emerged. We analyzed serum 25-hydroxyvitamin D₃ levels and conducted parental interviews to assess subject age, sex, race, feeding type, vitamin D supplementation, frequency of sun exposure, and maternal education. Height and weight were ascertained from medical records. Complete information was available for 70 (83%) of 84 eligible cases and 68 (60%) of 113 eligible controls.

RESULTS

The median (IQR) serum 25-hydroxyvitamin D₃ concentration for cases was 23.2 ng/ml (14.4-29.9) compared to 27.5 ng/ml (21.4-32.3) in controls (P = 0.006). Multiple regression analysis using an a priori cut-point for vitamin D of <20 ng/ml showed that children with lower respiratory tract infections were more likely to have low 25-hydroxyvitamin D₃ levels than controls (adjusted odds ratio 2.4, 95% confidence interval 1.1-5.2, P = 0.02).

CONCLUSIONS

Children with lower respiratory tract infections in Guatemala had low 25-hydroxyvitamin D₃ levels. Pediatr Pulmonol. 2016;51:1080-1087. © 2016 Wiley Periodicals, Inc.

Seasonal Epidemiology of Serum 25-Hydroxyvitamin D Concentrations among Healthy Adults Living in Rural and Urban Areas in Mongolia

Many factors put Mongolians at risk of vitamin D deficiency. Despite low levels observed in Mongolian children and pregnant women, there are few data published on the vitamin D status of non-pregnant adults. Between summer 2011 and winter 2013, paired summer and winter blood samples were collected from 320 healthy men and women (20–58 years) living in eight Mongolian provinces. Mean serum 25(OH)D concentrations were 22.5 ng/mL (95% CI: 14.5, 32.5) in summer and 7.7 ng/mL (95% CI: 4.6, 10.8) in winter, with a distribution (<10/10–20/20–30/≥30 ng/mL) of 3.1%/39.3%/39.6%/17.9% in summer and 80.1%/19.5%/0.3%/0.0% in winter. Residents of the capital, Ulaanbaatar, had lower levels in both seasons than any other region, whereas residents of the Gobi desert had the highest. In summer, indoor workers had significantly lower levels than outdoor workers (−2.3 ng/mL; 95% CI: −4.1, −5.7) while levels in males exceeded those in females (4.0 ng/mL; 95% CI: 2.3, 5.7). Effects of region, occupation, and sex were also significant in multivariable regression. In conclusion, Mongolian adults had extremely low serum 25(OH)D, particularly in winter, when 80.1% had concentrations below 10 ng/mL. These results indicate a need for effective vitamin D interventions for the Mongolian adult population, particularly among women and residents of Ulaanbaatar.

High levels of serum vitamin D are associated with a decreased risk of metabolic diseases in both men and women, but an increased risk for coronary artery calcification in Korean men

Background

There are conflicting results for relationships between serum vitamin D levels and metabolic diseases. The aim of this study was to investigate whether serum vitamin D levels were associated with various metabolic diseases including insulin resistance (IR), metabolic syndrome (MS), fatty liver (FL), and coronary artery calcification (CAC), along with assessing gender differences for these relationships in Korean adults.

Methods

A total of 180,918 subjects (98,412 men and 82,506 women) who participated in a comprehensive health examination in the 2012–2013 period at Kangbuk Samsung Hospital, College of Medicine, Sungkyunkwan University were included. Serum vitamin D and metabolic markers were analyzed and CAC was estimated. Subjects were divided according to quartile groups of serum vitamin D. To examine the relationships of serum vitamin D to metabolic diseases and metabolic factors, multivariate logistic analysis was conducted.

Results

High levels of serum vitamin D was associated with lower ORs for MS, IR and FL both in men and women (all p < 0.05). For men, ORs for CAC were significantly higher in third and the highest quartile groups for serum vitamin D in all the analyzed models (all p < 0.05). However, women showed no significant results between serum vitamin D and CAC.

Conclusions

High levels of serum vitamin D were associated with lower risk of MS, IR and FL in both Korean men and women, but were associated with higher risk of CAC only in men, and not in women.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-016-0432-3) contains supplementary material, which is available to authorized users.

Effect of vitamin D replacement on indexes of insulin resistance in overweight elderly individuals: a randomized controlled trial

BACKGROUND

It is unclear whether and at what dose vitamin D supplementation affects insulin resistance (IR).

OBJECTIVE

We sought to investigate whether vitamin D at doses higher than currently recommended decreases indexes of IR in an ambulatory population of overweight elderly subjects.

DESIGN

This double-blind, randomized, controlled multicenter trial enrolled 257 elderly overweight individuals aged ≥65 y with baseline 25-hydroxyvitamin D [25(OH)D] concentrations between 10 and 30 ng/mL. All subjects received 1000 mg calcium citrate/d, with vitamin D administered weekly at an equivalent dose of 600 or 3750 IU/d. The homeostasis model assessment (HOMA) of IR index at 1 y was the primary outcome. We also assessed the McAuley index.

RESULTS

In total, 222 subjects (55% women) with a mean ± SD age and body mass index (BMI; in kg/m(2)) of 71 ± 4 y and 30 ± 4, respectively, completed the study. Subjects' baseline characteristics, including IR indexes, were similar across groups: 69% had prediabetes, 54% had hypertension (47% were taking antihypertensive medications), and 60% had hyperlipidemia, nearly half of whom were receiving lipid-lowering drugs. At 1 y, mean ± SD serum 25(OH)D increased from 20 ± 7 to 26 ± 7 ng/mL in the low-dose arm (P < 0.0001) and from 21 ± 8 to 36 ± 10 ng/mL in the high-dose arm (P < 0.001). Median HOMA-IR indexes did not change compared with baseline concentrations and were similar in the high- [2.2 (IQR: 1.5, 2.9)] and low-dose [2.3 (IQR: 1.6, 3.3] treatment groups. Adjusted analyses showed that HOMA-IR was predicted by the baseline HOMA index and BMI but not by vitamin D dose, baseline serum 25(OH)D, or change in 25(OH)D.

CONCLUSION

Vitamin D3 at 3750 IU/d did not improve HOMA-IR compared with the Institute of Medicine Recommended Dietary Allowance of 600 IU/d in elderly overweight individuals. This trial was registered at clinicaltrials.gov as NCT01315366.

Vitamin D status in children and adolescents with autoimmune thyroiditis

BACKGROUND

Vitamin D deficiency is a global health problem. Its role as an immune modulator has been recently emphasized. There is increasing evidence for the significant role of vitamin D in reducing the incidence of autoimmune diseases. However, little is known about the status of vitamin D in children and adolescents with autoimmune thyroiditis (AIT).

OBJECTIVE

The goal of the present study was to assess vitamin D status in Egyptian children and adolescents with AIT and to explore its relation to biomarkers of autoimmunity and thyroid function.

DESIGN

A prevalence case-control study that included 56 children with AIT and 56 healthy, age- and sex-matched subjects that served as the control group. The following was done for all participants: thorough history, physical examination, thyroid ultrasound, measurement of thyroid-stimulating hormone (TSH), free thyroxin (FT4), anti-thyroid peroxidase antibodies (TPOAb), anti-thyroglobulin antibody (TgAb) and assessment of serum 25-hydroxy vitamin D (25OHD) level.

RESULTS

Overt hypothyroidism was detected in 42/56 while subclinical hypothyroidism was detected in 14/56 of the studied patients. Vitamin D deficiency rate was significantly higher in the AIT group compared to the control subjects (71.4 vs 21.4 %, P < 0.001). In AIT group, the mean level of 25OHD was significantly lower compared to the control group (16.2 ± 8.2 vs 33.9 ± 12.7 nmol/L, P < 0.001). The difference was more evident in patients with overt hypothyroidism than those with subclinical hypothyroidism (P < 0.01). There were significant negative correlations between serum 25OHD and age, duration of the disease, BMI, anti-TPOAb, anti-TGAb and TSH (P < 0.001 each). On the other hand, serum 25OHD correlated positively with FT4 levels. While 25OHD level was an independent risk factor for AIT, it failed to qualify as an independent risk for the progression of AIT to overt hypothyroidism after adjustment for other potential confounding factors; age, sex and BMI.

CONCLUSIONS

Low serum vitamin D is significantly associated with AIT in Egyptian children. However, vitamin D level is not an independent risk for the progression of AIT to overt hypothyroidism. BMI may have an influence on serum 25OHD levels.

Role of Vitamin D in Cognitive Function in Chronic Kidney Disease

Both vitamin D deficiency and cognitive impairment are common in patients with chronic kidney disease (CKD). Vitamin D exerts neuroprotective and regulatory roles in the central nervous system. Hypovitaminosis D has been associated with muscle weakness and bone loss, cardiovascular diseases (hypertension, diabetes and hyperlipidemia), inflammation, oxidative stress, immune suppression and neurocognitive impairment. The combination of hypovitaminosis D and CKD can be even more debilitating, as cognitive impairment can develop and progress through vitamin D-associated and CKD-dependent/independent processes, leading to significant morbidity and mortality. Although an increasingly recognized comorbidity in CKD, cognitive impairment remains underdiagnosed and often undermanaged. Given the association of cognitive decline and hypovitaminosis D and their deleterious effects in CKD patients, determination of vitamin D status and when appropriate, supplementation, in conjunction with neuropsychological screening, should be considered integral to the clinical care of the CKD population.

Umbilical Cord Serum 25-Hydroxyvitamin D Concentrations and Relation to Birthweight, Head Circumference and Infant Length at Age 14 Days

BACKGROUND

Insufficient supply of vitamin D during early development may negatively affect offspring growth.

METHODS

We examined the association between umbilical cord (UC) serum 25-hydroxyvitamin D (25(OH)D) concentrations and infant size in a study of two Faroese birth cohorts of 1038 singleton infants. In the third trimester, the pregnant women completed questionnaires, and clinical examination included birthweight, head circumference, and infant length at age 14 days.

RESULTS

Fifty-three percent of the newborn population had UC 25(OH)D < 25 nmol/L as determined by LC-MS/MS. Using multiple linear regression models with adjustment for pre-pregnancy BMI, sex, parity, gestational age, or infant age at examination, season of birth, smoking, gestational diabetes, examiner, and cohort identity, we found no relationship between birthweight or head circumference and UC 25(OH)D. However, infants with vitamin D status <12 nmol/L had a 0.49 (95% confidence interval 0.05, 0.93) cm lower length than infants with vitamin D status >50 nmol/L in models further adjusted for birthweight.

CONCLUSION

Our data suggest that umbilical cord serum 25(OH)D concentrations are positively associated with infant length but not with birthweight and head circumference. Although the paediatric relevance of the observed association is unclear, the possible long-term consequences of late-pregnancy hypovitaminosis D deserve attention.

Association between levels of vitamin D and inflammatory markers in healthy women

Background

No one can deny that the biological importance of vitamin D is much beyond its classical role in bone metabolism. Several recent publications have highlighted its potential role in the functioning of the immune system. The overall objective of this study was to look into possible correlations between levels of vitamin D and inflammatory markers in sera of healthy adult women. These markers included proinflammatory cytokines (interleukin [IL]-1β, IL-6, IL-8, IL-17, interferon [IFN]-γ, and tumor necrosis factor [TNF]-α), anti-inflammatory cytokines (IL-4, IL-10, and IL-13), as well as C-reactive protein (CRP) as a general indicator of inflammation.

Methods

Venous blood samples were collected from 118 healthy adult women and serum levels of vitamin D, CRP, proinflammatory cytokines (IL-1β, IL-6, IL-8, IL-17, IFN-γ, and TNF-α), and anti-inflammatory cytokines (IL-4, IL-10, and IL-13) were measured.

Results

There were no significant direct correlations between serum levels of vitamin D and any of the inflammatory markers measured. However, subjects with deficient levels of vitamin D and high CRP produced significantly higher levels of the proinflammatory cytokines (TNF-α and IL-8) as compared to subjects with low CRP levels with nondeficient and deficient levels of vitamin D. Further, the anti-inflammatory/proinflammatory ratios suggest a role of vitamin D in maintaining an anti-inflammatory environment at low levels of CRP, an association that is weaker at high CRP levels in subjects with subclinical inflammatory situations.

Conclusion

These data point to a possible role of vitamin D as a contributing factor in balancing cytokines toward an anti-inflammatory role in inflammatory situations.

Endotoxin exposure, serum vitamin D, asthma and wheeze outcomes

BACKGROUND

Endotoxin has been shown to induce neutrophilic asthma and wheeze after binding toll-like receptor 4 to produce pro-inflammatory cytokines. Animal models have demonstrated that vitamin D might inhibit lipopolysaccharide-induced cytokines. However, whether endotoxin exposure and serum vitamin D deficiency interact to affect asthma and wheeze in humans has never been investigated in an epidemiological study.

METHODS

Joint associations of house dust endotoxin and vitamin D with asthma and wheeze were examined using logistic regression adjusted for covariates in 5924 US participants of the National Health and Nutrition Examination Survey (NHANES). Interactions were assessed on the multiplicative as well as additive scale using the relative excess risk, the attributable portion due to additive interaction, and the synergy index.

RESULTS

The median endotoxin concentration was 19.1 EU/mg. Prevalence of vitamin D inadequacy (20-30 ng/ml) and deficiency (<20 ng/ml) were respectively 42.9 and 33.4%. The combination of high endotoxin and low vitamin D was associated with current asthma (OR: 1.56, 95% CI: 1.09, 2.23), wheeze in the past 12 months (OR: 1.72, 95% CI: 1.10, 3.71), recurrent wheeze (OR: 1.97, 95% CI: 1.00, 4.00), asthma diagnosis or recurrent wheeze (OR: 1.88, 95% CI: 1.33, 2.66), and current asthma or recurrent wheeze (OR:1.81, 95% CI: 1.23, 2.68) when compared to low endotoxin and normal vitamin D. The interactions between the exposures were not significant on the multiplicative or additive scale for any of the outcomes.

CONCLUSIONS

Combination of high endotoxin exposure and low vitamin D increases the odds of asthma and wheeze, but the exposures do not interact or modify each other's effect in the NHANES cohort.

Effect of vitamin D replacement on maternal and neonatal outcomes: a randomised controlled trial in pregnant women with hypovitaminosis D. A protocol

INTRODUCTION

The vitamin D recommended doses during pregnancy differ between societies. The WHO guidelines do not recommend routine prenatal supplementation, but they underscore the fact that women with the lowest levels may benefit most. The effects of routine supplementation during pregnancy on maternal and neonatal clinical outcomes have not been investigated in the Middle East, where hypovitaminosis D is prevalent. Our hypothesis is that in Middle Eastern pregnant women, a vitamin D dose of 3000 IU/day is required to reach a desirable maternal 25-hydroxyvitamin D [25(OH)D] level, and to positively impact infant bone mineral content (BMC).

METHODS AND ANALYSIS

This is a multicentre blinded randomised controlled trial. Pregnant women presenting to the Obstetrics and Gynaecology clinics will be approached. Eligible women will be randomised to daily equivalent doses of cholecalciferol, 600 IU or 3000 IU, from 15 to 18 weeks gestation until delivery. Maternal 25(OH)D and chemistries will be assessed at study entry, during the third trimester and at delivery. Neonatal anthropometric variables and 25(OH)D level will be measured at birth, and bone and fat mass assessment by dual-energy X-ray absorptiometry scan at 1 month. A sample size of 280 pregnant women is needed to demonstrate a statistically significant difference in the proportion of women reaching a 25(OH)D level ≥ 50 nmol/L at delivery, and a difference in infant BMC of 6 (10)g, for a 90% power and a 2.5% level of significance. The proportions of women achieving a target 25(OH)D level will be compared between the two arms, using χ(2). An independent t test will be used to compare mean infant BMC between the two arms. The primary analysis is an intention-to-treat analysis of unadjusted results.

ETHICS AND DISSEMINATION

The protocol has been approved by the Institutional Review Board at the American University of Beirut-Lebanon (IM.GEHF.22). The trial results will be published in peer-reviewed medical journals and presented at scientific conferences.

TRIAL REGISTRATION NUMBER

NCT02434380.

The evaluation of vitamin D levels in patients with carpal tunnel syndrome

The aim of this study was to evaluate the relationship between 25-hydroxyvitamin D (25(OH)D) levels and carpal tunnel syndrome (CTS). 25(OH)D levels were checked in 108 consecutive patients with CTS symptoms and 52 healthy controls. All patients underwent nerve conduction studies and completed Boston Carpal Tunnel Questionnaire (BQ) symptom severity and functional status scales to quantify symptom severity, pain status and functional status. There were 57 patients with electrophysiological confirmed CTS (EP+ group) and 51 electrophysiological negative symptomatic patients (EP- group). 25(OH) D deficiency (25(OH)D < 20 ng/ml) was found in 96.1 % of EP- group, in 94.7 % of EP+ group and in 73.8 % of control group. 25(0H) D level was found significantly lower both in EP+ and EP- groups compared to control group (p = 0.006, p < 0.001, respectively). Although mean vitamin D level in EP- group was lower than EP+ group, statistically difference was not significant between EP+ and EP- groups (p = 0.182). BQ symptom severity and functional status scores and BQ pain sum score were not significantly different between EP+ and EP- groups. We found no correlation with 25(OH) D level for BQ symptom severity, functional status and pain sum scores. 25(OH) D deficiency is a common problem in patients with CTS symptoms. As evidenced by the present study, assessment of serum 25(OH)D is recommended in CTS patients even with electrophysiological negative results.

Prevalence of Hypovitaminosis D Among Jordanian Healthy Infants: A Descriptive Cross Sectional Study

To determine vitamin D deficiency and associated risk factors of hypovitaminosis D among Jordanian healthy infants.

DESIGN AND METHODS

A total of 171 infants receiving a routine health check at a Maternal and Child Health Care Center were recruited. Plasma vitamin D 25-OHD level was assessed using a standard analysis of a blood sample. Other data collected included age, gender, birth order, season of birth, and mode of feeding.

RESULTS

Prevalence of vitamin D deficiency (≤15 ng/mL) was 77% (132 out of 171 infants). Infants at risk of vitamin D deficiency were those between 1 to 6 months of age, male, third born or later, born in winter, and exclusively breastfed. The multivariate model showed birth order to be the largest contributor of vitamin D deficiency (R(2)=0.196), followed by breastfed infants (R(2)=0.071), infants born in winter (R(2)=0.037), male gender (R(2)=0.028), and infants aged between 1 and 6 months (R(2)=0.027).

CONCLUSION

Hypovitaminosis D appears to be more common among healthy infants in Jordan. Hypovitaminosis D was found to be common among third or later exclusively breastfeed male infants aged 1 to 6 months who were born during winter.

PRACTICE IMPLICATION

Maternal and child health nurses have a critical role to play in educating mothers about the importance of preventing hypovitaminosis D through adequate sun exposure and ensuring adequate supplementation. A higher dose of vitamin D supplementation for high-risk infants beyond the age of 1 year from developing countries should be administered.

Correlation of Vitamin D and Body Mass Index with Modic Changes in Patients with Non-Specific Low Back Pain in a Sub-Tropical Asian Population

Study Design

Cross-sectional study by non-probability consecutive sampling.

Purpose

The objective of this study was to assess body mass index (BMI) and investigate vitamin D levels in patients with low back pain (LBP) and study a possible relationship with myopathy-related symptoms and Modic changes.

Overview of Literature

LBP is a multifactorial problem and the search for its patho-anatomical causes is ongoing. Modic changes seem to be a cause of back pain but the pathological mechanisms underlying this are not completely defined. Hypovitaminosis D and obesity have also been shown to cause chronic musculoskeletal pain. The relationship between vitamin D deficiency and BMI with Modic changes has not been studied in detail.

Methods

Three hundred and sixteen patients with chronic LBP was selected for the study by non-probability consecutive sampling. The study was conducted over a period of 12 months from January 2014 to December 2014 at St. John's Medical College, Banglore. Questionnaires were provided to the participants and demographic information, symptoms, weight and height were recorded from the study subjects. BMI was calculated. Serum vitamin D level was assessed and Modic changes studied on magnetic resonance imaging. Correlations between vitamin D, BMI and Modic changes were studied using correlation coefficients and odds ratios obtained from logistic regression.

Results

Two hundred and fifty-six out of 316 patients (80%) had low vitamin D. 83% of patients with BMI>25 kg/m² had low vitamin D levels as compared to 69% with BMI<25 kg/m². Statistically significant correlation coefficients were found between vitamin D levels, BMI and Modic changes. Significant association was found between low vitamin D levels and Modic changes (odds ratio 1.75).

Conclusions

Vitamin D deficiency and obesity have significant relations with LBP. Low vitamin D levels is associated with Modic changes but whether they represent a subgroup of patients whose low backpain is associated with low vitamin D needs to be further evaluated.

Vitamin D deficiency in critically ill children with sepsis

BACKGROUND

Data on the prevalence of vitamin D deficiency (VDD) in critically ill children with sepsis and its association with illness severity and outcome are limited.

AIM

To investigate the prevalence of VDD in critically ill children with sepsis.

METHODS

One hundred and twenty-four critically ill children with sepsis aged 1-12 years were prospectively enrolled in a paediatric intensive care unit (PICU) in North India over a 1-year period. Demographic data, clinical signs and risk factors for VDD, Paediatric Index of Mortality III (PRISM III) score, and sequential organ failure assessment (SOFA) score were recorded. Plasma 25-hydroxy vitamin D [25(OH)D] levels were measured by ELISA within 24 hours of admission. The occurrence of septic shock, multiple organ dysfunction syndrome (MODS) and healthcare-associated infection (HCAI), need for mechanical ventilation and catecholamines, length of PICU stay and mortality were also recorded. Cases were compared with 338 apparently healthy children for baseline variables and vitamin D status.

RESULTS

Prevalence of VDD [25(OH)D level < 50 nmol/L] was higher among critically ill children with sepsis compared to healthy controls (50.8% vs 40.2%, P = 0.04). VDD was not associated with any significant difference in baseline demographic variables or risk factors for VDD. Although there was a trend toward increased PRISM III score, septic shock, MODS, HCAI, need for mechanical ventilation and catecholamines, length of PICU stay, and mortality, the difference was not statistically significant.

CONCLUSION

A high prevalence of VDD in critically ill children with sepsis was found but it was not associated with greater severity of illness or other clinical outcomes.

Correlation between disease activity of pediatric-onset systemic lupus erythematosus and level of vitamin D in Taiwan: A case-cohort study

BACKGROUND

Vitamin D deficiency has been associated with systemic lupus erythematosus (SLE), but there is no consensus on the role of serum vitamin D in evaluating or predicting disease activity. This study aimed to demonstrate the direct correlation between vitamin D level and pediatric-onset SLE disease activity by a retrospective cohort study design.

PATIENTS AND METHODS

Thirty-five patients with pediatric-onset SLE and paired sera at the active and inactive disease states were enrolled. Disease activity was defined by Systemic Lupus Erythematosus Disease Activity Index 2000, and active lupus nephritis (LN) was defined as active urine sediment, and proteinuria >2+ on stick or >500 mg/day. All data were reviewed and calculated from previous medical records. The levels of both vitamin D2 and vitamin D3 were checked by electrochemiluminescence immunoassay.

RESULTS

Serum 25-hydroxyvitamin D (25-OH D) levels in the active status were significantly lower compared to that in inactive disease status (12.0 ± 7.2 ng/mL vs. 15.4 ± 7.4 ng/mL, p = 0.005). A subgroup analysis revealed that at active disease status, patients with LN had lower 25-OH D levels than patients without LN (16.3 ± 8.2 ng/mL vs. 9.8 ± 5.6 ng/mL, p = 0.023). Moreover, there is a significant inverse correlation between serum 25-OH D levels and Systemic Lupus Erythematosus Disease Activity Index 2000 at both inactive (r = -0.335, p = 0.003) and active (r = -0.373, p = 0.016) disease status.

CONCLUSION

Serum vitamin D levels are inversely correlated with SLE disease activity at both active and inactive disease status, and also with the presence of LN at active disease stage.

Food-Based Interventions to Modify Diet Quality and Diversity to Address Multiple Micronutrient Deficiency

Global data indicate a high prevalence of hidden hunger among population. Deficiencies of certain micronutrients such as folic acid, iodine, iron, and vitamin A have long lasting effects on growth and development and therefore have been a National priority from many decades. The strategy implemented so far limits to the use of supplemental sources or fortified foods in alleviating the burden of deficiencies. These approaches however undermine the food-based strategies involving dietary diversification as the long-term sustainable strategy. There is lack of understanding on the level of evidence needed to implement such strategies and the level of monitoring required for impact evaluation. Dietary diversity concerns how to ensure access for each individual to a quality and safe diet with adequate macro- and micronutrients. The key to success in using dietary diversity as a strategy to tackle hidden hunger is in integrating it with the principles of bioavailability, translated to efficient food synergies with due emphasis on food accessibility, affordability, and outdoor physical activity/life style modifications. Promoting enabling environment and sustainable agriculture is crucial for practicing dietary diversification with behavior change communication as an integral segment. It can be concluded that food-based strategies require careful understanding of the factors associated with it and moderate it to form an effective strategy for controlling multiple micronutrient deficiencies.

Geo-Epidemiology of Age-Related Macular Degeneration: New Clues Into the Pathogenesis

PURPOSE

To evaluate the demographic, geographic, and race-related variables that account for geographic variability in prevalence rates of age-related macular degeneration (AMD).

DESIGN

Systematic review, meta-regression, and decision-tree analysis.

METHODS

A systematic literature review of PubMed, Medline, Web of Science, and Embase databases identified population-based studies on the prevalence of AMD published before May 2014. Only population-based studies that took place in a spatially explicit geographic area that could be geolocalized, and used retinal photographs and standardized grading classifications, were included. Latitude and longitude data (geolocalization) and the mean annual insolation for the area where survey took place were obtained. Age-standardized prevalence rates across studies were estimated using the direct standardization method. Correlations between the prevalence of AMD and longitude and latitude were obtained by regression analysis. A hierarchical Bayesian meta-regression approach was used to assess the association between the prevalence of AMD and other relevant factors. We further investigated the interplay between location and these factors on the prevalence of AMD using regression based on conditional-inference decision trees.

RESULTS

We observed significant inverse correlations between latitude or longitude, and crude or age-standardized prevalence rates, of early and late AMD (P < .001). Metaregression analysis showed that insolation, latitude, longitude, age, and race have a significant effect on the prevalence rates of early and late AMD (P < .001). Decision-tree analysis identified that the most important predictive variable was race for early AMD (P = .002) and insolation for late AMD (P = .001).

CONCLUSIONS

Geographic position and insolation are key factors in the prevalence of AMD.

Rapid calcitriol increase and persistent calcidiol insufficiency in the first 6 months after kidney transplantation

INTRODUCTION

Vitamin D deficiency or insufficiency is prevalent in kidney transplant recipients. Little is known about post-transplantation changes in vitamin D forms, which are essential for bone health and other health outcomes. The aim was to measure the levels of calcidiol and calcitriol during the first 6 months after kidney transplantation and examine their relation with other bone mineral metabolic parameters.

PATIENTS AND METHODS

A prospective study was performed on 98 patients recruited between April 2010 and June 2011. Calcidiol and calcitriol levels were measured at baseline and at days 15, 30, 90, and 180 after kidney transplantation.

RESULTS

Serum calcidiol levels remained persistently low: 14.3 (9-22) ng/ml at baseline and 16.3 (10.1-20.6) ng/ml at 6 months (P=0.641). At 6 months, calcidiol levels showed an inverse correlation with simultaneously measured parathyroid hormone levels. Calcidiol showed a trend to be higher in patients transplanted in spring but with no statistically significant difference. Calcitriol levels increased from 17 (13-23.7) pg/ml at baseline to 24 (16-32) pg/ml (P=0.002) in the first 2 weeks after transplantation and reached 37 (25-50) pg/ml (P=0.000) after 6 months. During the follow-up, calcitriol levels showed a significant inverse correlation with baseline fibroblast growth factor-23 levels. At month 6, calcitriol levels were inversely correlated with baseline fibroblast growth factor-23 levels and directly correlated with calcidiol levels.

CONCLUSION

In most patients, calcidiol levels remain low 6 months after kidney transplantation, whereas calcitriol levels rapidly return to normal. Lower calcidiol blood levels promoted lower calcitriol blood levels and higher parathyroid hormone concentrations.

Vitamin D deficiency and its characteristics among patients with acute stroke at a national referral hospital in Kampala Uganda

BACKGROUND

Vitamin D deficiency has been associated with acute stroke and other cardiovascular diseases in the developed world. Low 25-hydroxyvitamin D (25OHD) has been described in some populations in Sub-Saharan Africa (SSA) in spite of adequate sunshine all year round. There is no information on the magnitude of vitamin D deficiency among patients with stroke and other cardiovascular diseases in Uganda or SSA. The aim of this study was to determine the burden and characteristics of vitamin D deficiency among patients with acute stroke, the most common form of cardiovascular events in SSA.

METHODS

We conducted a cross-sectional study between October 2012 and March 2013. We consecutively recruited 142 subjects with acute stroke admitted to the medical wards of Mulago hospital. We administered a pre-tested questionnaire to the study participants, and did a detailed physical examination and laboratory evaluation. Serum levels of 25OHD were determined using an electrochemiluminescence assay. Data were analyzed using STATA version 12 software.

RESULTS

The prevalence of vitamin D deficiency (25OHD < 20 ng/ml) was 15 %. Longer hours of sunshine exposure decreased the likelihood vitamin D deficiency significantly (adjusted OR 0.85, p = 0.03). Higher HDL cholesterol had a significant inverse association with vitamin D deficiency (adjusted OR 0.15, p = 0.02). In addition, the likelihood of vitamin D deficiency increased with rising age (adjusted OR 1.03, p = 0.05).

CONCLUSIONS

There was a relatively low burden of vitamin D deficiency among patients with acute stroke in Uganda. With increasing longevity and indoor lifestyles vitamin D deficiency may assume a greater role in stroke and other cardiovascular diseases in tropical sub Saharan Africa. Future studies on the mechanisms of vitamin D deficiency and its relationship to outcomes among patients with stroke may be necessary.

Global summary of maternal and newborn vitamin D status - a systematic review

Pregnant women and newborns are at increased risk of vitamin D deficiency. Our objective was to create a global summary of maternal and newborn vitamin D status. We completed a systematic review (1959-2014) and meta-analysis of studies reporting serum 25-hydroxyvitamin D [25(OH)D] concentration in maternal and newborn populations. The 95 identified studies were unevenly distributed by World Health Organization (WHO) region: Americas (24), European (33), Eastern Mediterranean (13), South-East Asian (7), Western Pacific (16) and African (2). Average maternal 25(OH)D concentrations (nmol L(-1) ) by region were 47-65 (Americas), 15-72 (European), 13-60 (Eastern Mediterranean), 20-52 (South-East Asian), 42-72 (Western Pacific) and 92 (African). Average newborn 25(OH)D concentrations (nmol L(-1) ) were 35-77 (Americas), 20-50 (European), 5-50 (Eastern Mediterranean), 20-22 (South-East Asian), 32-67 (Western Pacific) and 27-35 (African). The prevalences of 25(OH)D <50 and <25 nmol L(-1) by WHO region in pregnant women were: Americas (64%, 9%), European (57%, 23%), Eastern Mediterranean (46%, 79%), South-East Asian (87%, not available) and Western Pacific (83%, 13%). Among newborns these values were: Americas (30%, 14%), European (73%, 39%), Eastern Mediterranean (60%, not available), South-East Asian (96%, 45%) and Western Pacific (54%, 14%). By global region, average 25(OH)D concentration varies threefold in pregnant women and newborns, and prevalence of 25(OH)D <25 nmol L(-1) varies eightfold in pregnant women and threefold in newborns. Maternal and newborn 25(OH)D concentrations are highly correlated. Addressing vitamin D deficiency in pregnant women and newborns should be a global priority. To protect children from the adverse effects of vitamin D deficiency requires appropriate interventions during both pregnancy and childhood.

Circulating levels of vitamin D and colorectal adenoma: A case-control study and a meta-analysis

AIM: To examine the association between circulating 25-hydroxyvitamin D [25(OH)D] levels and colorectal adenoma in a case-control study and a meta-analysis.

METHODS: We conducted a matched case-control study (112 cases and 112 matched controls) and combined 15 studies, including our study, in a meta-analysis. The study-specific odds ratios (ORs) and 95% confidence intervals (CIs) were pooled using a random-effects model. In total, 5454 colorectal adenomas and 6656 controls were included in the meta-analysis.

RESULTS: In a meta-analysis including 14 previous studies and our study, we observed a significant inverse association between circulating 25(OH)D levels and colorectal adenoma (OR = 0.68; 95%CI: 0.54-0.82) when comparing the highest category with the lowest category. Stratification by adenoma location (proximal or distal adenoma) showed similar estimates. When we stratified by study region, the ORs (95%CIs) were 0.70 (0.52-0.88) in the US and 0.66 (0.34-0.97) in Asia.

CONCLUSION: These data suggest an inverse association between circulating 25(OH)D levels and colorectal adenoma in both Western and Asian populations.