Seasonal variation of serum 25-hydroxyvitamin D levels in adult patients with inflammatory bowel disease

Target Values for 25-Hydroxy and 1,25-Dihydroxy Vitamin D Based on Their Associations with Inflammation and Calcium-Phosphate Metabolism

Target values for 25-hydroxy vitamin D and 1,25(OH)2D or 1,25-dihydroxy vitamin D remain a topic of debate among clinicians. We analysed data collected from December 2012 to April 2020 from two cohorts. Cohort A, comprising 455,062 subjects, was used to investigate the relationship between inflammatory indicators (white blood cell [WBC] count and C-reactive protein [CRP]) and 25(OH)D/1,25(OH)2D. Cohort B, including 47,778 subjects, was used to investigate the connection between 25(OH)D/1,25(OH)2D and mineral metabolism markers (phosphate, calcium, and intact parathyroid hormone [iPTH]). Quadratic models fit best for all tested correlations, revealing U-shaped relationships between inflammatory indicators and 25(OH)D and 1,25(OH)2D. Minimal CRP and WBC counts were observed at 1,25(OH)2D levels of 60 pg/mL and at 25(OH)D levels of 32 ng/mL, as well as of 42 ng/mL, respectively. iPTH correlated inversely with both 1,25(OH)2D and 25(OH)D, while phosphate as well as calcium levels positively correlated with both vitamin D forms. Calcium-phosphate product increased sharply when 25(OH)D was more than 50 ng/mL, indicating a possible risk for vascular calcification. Multiple regression analyses confirmed that these correlations were independent of confounders. This study suggests target values for 25(OH)D between 30-50 ng/mL and for 1,25(OH)2D between 50-70 pg/mL, based particularly on their associations with inflammation but also with mineral metabolism markers. These findings contribute to the ongoing discussion around ideal levels of vitamin D but require support from independent studies with data on clinical endpoints.

Bone health in inflammatory bowel disease

INTRODUCTION

Inflammatory bowel disease (IBD) is a chronic disease characterized by the presence of systemic inflammation, manifesting not only as gastrointestinal symptoms but also as extraintestinal bone complications, including osteopenia and osteoporosis. However, the association between IBD and osteoporosis is complex, and the presence of multifactorial participants in the development of osteoporosis is increasingly recognized. Unlike in adults, delayed puberty and growth hormone/insulin-like growth factor-1 axis abnormalities are essential risk factors for osteoporosis in pediatric patients with IBD.

AREAS COVERED

This article reviews the potential pathophysiological mechanisms contributing to osteoporosis in adult and pediatric patients with IBD and provides evidence for effective prevention and treatment, focusing on pediatric patients with IBD. A search was performed from PubMed and Web of Science inception to February 2023 to identify articles on IBD, osteoporosis, pediatric, and fracture risk.

EXPERT OPINION

A comprehensive treatment pattern based on individualized principles can be used to manage pediatric IBD-related osteoporosis.

Efficacy of low-fat milk and yogurt fortified with vitamin D3 on systemic inflammation in adults with abdominal obesity

Background

The prevalence of vitamin D deficiency is increasing globally and is associated with an increased risk of metabolic syndrome, autoimmune disease, and cardiovascular disease. Vit D deficiency is also associated with increased systemic inflammation. The current study aimed to determine the efficacy of low-fat milk and yogurt fortified with 1500 IU nano-encapsulated vitamin D, on systemic inflammation in abdominal obese participants.

Method

This multi-center study was conducted using a 2.5-month parallel total-blind randomized clinical trial design. Two hundred and eighty nine subjects were allocated to four groups: low-fat milk fortified by 1500 IU nano-encapsulated vitamin D₃ (200 mL/day). Simple milk (200 mL/day), low-fat yogurt fortified by 1500 IU nano-encapsulated vitamin D₃ (150 g/day), and simple yogurt (150 g/day).

Results

The results showed that serum levels of neutrophils, lymphocytes, platelets and red blood cell distribution width (RDW) were significantly lower before and after the intervention in fortified dairy groups. The results showed that serum levels of neutrophils, lymphocytes, platelets, and RDW before and after intervention in the fortified dairy groups were significantly lower (p < 0.05). The values of = neutrophil to lymphocyte ratio (NLR), platelets to lymphocyte ratio, and RDW to platelets ratio (RPR) reduced significantly in the fortification group (p < 0.05).

Conclusion

Fortification with nano-encapsulated vitamin D₃ of dairy products may decrease inflammation in individuals with abdominal obesity.

Pleiotropic Effects of Vitamin D in Patients with Inflammatory Bowel Diseases

The multifaceted activity of vitamin D in patients with inflammatory bowel disease (IBD) presents a challenge for further research in this area. Vitamin D is involved in the regulation of bone mineral metabolism, it participates in the regulation of the immune system, and it is an underlying factor in the pathogenesis of IBD. Additionally, vitamin D affects Th1 and Th2 lymphocytes, influencing the release of cytokines and inhibiting tumor necrosis factor (TNF) expression and the wnt/β-catenin pathway. As far as IBDs are concerned, they are associated with microbiota dysbiosis, abnormal inflammatory response, and micronutrient deficiency, including vitamin D hypovitaminosis. In turn, the biological activity of active vitamin D is regulated by the vitamin D receptor (VDR) which is associated with several processes related to IBD. Therefore, in terms of research on vitamin D supplementation in IBD patients, it is essential to understand the metabolic pathways and genetic determinants of vitamin D, as well as to identify the environmental factors they are subject to, not only in view of osteoporosis prevention and therapy, but primarily concerning modulating the course and supplementation of IBD pharmacotherapy.

[Inflammatory Bowel Disease and Vitamin D]

Vitamin D contributes to bone metabolism and acts as an immune modulator for both innate and adaptive immunity. The serum level of vitamin D has been associated with inflammatory diseases, such as inflammatory bowel disease (IBD). In epidemiologic studies, IBD patients have been shown to have low levels of vitamin D. The suboptimal circulating levels of vitamin D in IBD patients may be caused by low exposure to sunlight, dietary malabsorption, and the impaired conversion of active metabolites (1,25[OH]₂D). Recent studies have demonstrated that vitamin D deficiency in IBD can increase the chance of disease recurrence, IBD-related hospitalization or surgery, and deterioration of quality of life. Supplementation with vitamin D is therefore thought to reduce the risk of flare-ups and the improvement of the quality of life in IBD patients. This review aims to summarize the latest knowledge on the effects of vitamin D deficiency on IBD and the possible benefits of vitamin D supplementation in IBD patients.

Vitamin D and inflammatory bowel disease: what do we know so far?

In the last years,several studies have focused on the involement of vitamin D in different physiological and pathological processes. One of the most interesting actions occurs in the Inflammatory bowel disease, where a higher prevalence of vitamin D deficiency has been observed. This study aimed to review the literature in order to explain its relationship with the disease, the risk factors, measuring the importance of sun exposure, describing how treatments are affected or observing the effect of vitamin supplementation in this type of patients.

A patient-level key performance indicator set to measure the effectiveness of fracture liaison services and guide quality improvement: a position paper of the IOF Capture the Fracture Working Group, National Osteoporosis Foundation and Fragility Fracture Network

The International Osteoporosis Foundation (IOF) Capture the Fracture® Campaign with the Fragility Fracture Network (FFN) and National Osteoporosis Foundation (NOF) has developed eleven patient-level key performance indicators (KPIs) for fracture liaison services (FLSs) to guide quality improvement.

INTRODUCTION

Fracture Liaison Services (FLSs) are recommended worldwide to reduce fracture risk after a sentinel fracture. Given not every FLS is automatically effective, the IOF Capture the Fracture working group has developed and implemented the Best Practice Framework to assess the organisational components of an FLS. We have now developed a complimentary KPI set that extends this assessment of performance to the patient level.

METHODS

The Capture the Fracture working group in collaboration with the Fragility Fracture Network Secondary Fragility Fracture Special Interest Group and National Osteoporosis Foundation adapted existing metrics from the UK-based Fracture Liaison Service Database Audit to develop a patient-level KPI set for FLSs.

RESULTS

Eleven KPIs were selected. The proportion of patients: with non-spinal fractures; with spine fractures (detected clinically and radiologically); assessed for fracture risk within 12 weeks of sentinel fracture; having DXA assessment within 12 weeks of sentinel fracture; having falls risk assessment; recommended anti-osteoporosis medication; commenced of strength and balance exercise intervention within 16 weeks of sentinel fracture; monitored within 16 weeks of sentinel fracture; started anti-osteoporosis medication within 16 weeks of sentinel fracture; prescribed anti-osteoporosis medication 52 weeks after sentinel fracture. The final KPI measures data completeness for each of the other KPIs. For these indicators, levels of achievement were set at the < 50%, 50-80% and > 80% levels except for treatment recommendation where a level of 50% was used.

CONCLUSION

This KPI set compliments the existing Best Practice Framework to support FLSs to examine their own performance using patient-level data. By using this KPI set for local quality improvement cycles, FLSs will be able to efficiently realise the full potential of secondary fracture prevention and improved clinical outcomes for their local populations.

Seasonal changes of circulating 25-hydroxyvitamin D correlate with the lower gut microbiome composition in inflammatory bowel disease patients

Higher probability of the development of Crohn's disease (CD) and ulcerative colitis (UC) as a possible consequence of the north-south gradient has been recently suggested. Living far north or south of the equator is manifested in fluctuation of vitamin D (vitD) levels depending on the season in both healthy and affected individuals. In the present study we investigate the possible link between the seasonal serum vitD level to the microbial composition of the lower gut of Inflammatory Bowel disease (IBD) patients using 16S rRNA sequencing. Decrease of serum vitD level in winter/spring season in a cohort of 35 UC patients and 39 CD patients was confirmed. Low gut microbiota composition of patients with IBD correlated with the serum level of 25(OH)D that directly coupled to seasonal variability of the sunshine in the central European countries. It is supposed to be related to increased abundance of Actinobacteria and Proteobacteria in UC and Actinobacteria, Fusobacteria, Firmicutes and Bacteroidetes in CD. In summer/autumn period, we observed a reduction in abundance of bacterial genera typical for inflammation like Eggerthella lenta, Fusobacterium spp., Bacteroides spp., Collinsella aerofaciens, Helicobacter spp., Rhodococcus spp., Faecalibacterium prausnitzii; and increased abundance of Pediococcus spp. and Clostridium spp. and of Escherichia/Shigella spp.

Serum 25-hydroxyvitamin D concentrations in Japanese postmenopausal women with osteoporotic fractures

Objectives

To assess the vitamin D status in postmenopausal women with osteoporotic fractures, determine its concentration by fracture site at the clinical setting, and compare the proportion of vitamin D deficiency with that reported in literature.

Methods

The prospective study included 317 postmenopausal women with osteoporotic fractures who were treated consecutively from 2016 to 2018. After obtaining informed consent for participation in the seamless treatment of osteoporosis against fractures study, which is our initiative to prevent secondary osteoporotic fractures, we registered the patients, examined bone mineral density (BMD) at the unfractured femoral neck and lumbar spine, serum 25-hydroxyvitamin D (25(OH)D) concentration, blood chemistry, and bone turnover markers.

Results

The mean age of the patients was 80.7 years. Moreover, 78% of patients of all fractures had 25(OH)D concentration < 20 ng/mL, whereas 12% of patients had 25(OH)D concentration ≥ 30 ng/mL 25(OH)D concentration in hip fractures was significantly lower than that in vertebral or distal radius fractures (P < 0.05). Multiple regression analysis revealed that 25(OH)D concentration is significantly associated with femoral neck BMD (β = 0.16; 95% confidence interval [CI], 0.78–12.17, P = 0.03) and serum albumin concentration (β = 0.21; 95% CI, 0.62–2.96, P < 0.001) in patients with 25(OH)D concentration < 30 ng/mL.

Conclusions

The results of this study show that the proportion of postmenopausal women with osteoporotic fractures who had vitamin D deficiency was higher than the proportion in previous reports that examined general postmenopausal women (35.2%–52.0%).

Systematic review with meta-analysis: association of vitamin D status with clinical outcomes in adult patients with inflammatory bowel disease

BACKGROUND

Vitamin D deficiency is highly prevalent among patients with IBD, however, data on its association with clinical outcomes are conflicting.

AIM

To perform a systematic review and meta-analysis to explore the association of low vitamin D status with clinical outcomes in patients with IBD.

METHODS

We searched PubMed, Embase, Scopus and Web of Science from inception to February 2018 for observational studies evaluating the association of low 25(OH)D status on IBD disease activity, mucosal inflammation, clinical relapse and quality of life. Odds ratios (ORs) were pooled and analysed using a random effects model.

RESULTS

Twenty-seven studies were eligible for inclusion comprising 8316 IBD patients (3115 ulcerative colitis, 5201 Crohn's disease). Among IBD patients, low 25(OH)D status was associated with increased odds of disease activity (OR 1.53, 95% CI 1.32-1.77, I²  = 0%), mucosal inflammation (OR 1.25, 95% CI 1.06-1.47, I²  = 0%), low quality of life (QOL) scores (OR 1.30, 95% CI 1.06-1.60, I²  = 0%) and future clinical relapse (OR 1.23, 95% CI 1.03-1.47, I²  = 0%). In subgroup analysis, low vitamin D status was associated with Crohn's disease activity (OR 1.66, 95% CI 1.36-2.03, I²  = 0%), mucosal inflammation (OR 1.39, 95% CI 1.03-1.85, I²  = 0%), clinical relapse (OR 1.35, 95% CI 1.14-1.59, I²  = 0%), and low QOL scores (OR 1.25, 95% CI 1.04-1.50, I²  = 0%) and ulcerative colitis disease activity (OR 1.47, 95% CI 1.03-2.09, I²  = 0%) and clinical relapse (OR 1.20, 95% 1.01-1.43, I²  = 0%).

CONCLUSIONS

Low 25(OH)D status is a biomarker for disease activity and predictor of poor clinical outcomes in IBD patients.

[Osteomalacia-Clinical aspects, diagnostics and treatment]

Osteomalacia is a bone disease caused by impaired skeletal mineralization. Vitamin D dependent types have to be distinguished from hypophosphatemic forms. Typical signs and symptoms include diffuse bone pain, muscle weakness and fragility fractures. The fracture pattern in osteomalacia is typically different from that of osteoporosis. Fragility fractures of the pelvis, sacrum, distal parts of the foot, proximal tibia and ribs are indicators for osteomalacia, whereas femoral neck and vertebral fractures (wedged vertebra, fish vertebra, vertebra plana and cover plate impression fractures) are typical for osteoporosis. Unspecific clinical features may be the reason for a delayed diagnosis. The correct classification of the complaint is dependent on the knowledge of the pathophysiology of osteomalacia and performance of additional bone-specific examinations. Determination of specific laboratory parameters should follow a rational algorithm, supplemented by imaging methods and a bone biopsy.

Seasonal variability of vitamin D status in patients with inflammatory bowel disease - A retrospective cohort study

Objectives

Vitamin D deficiency predicts unfavorable disease outcomes in inflammatory bowel disease. Endogenous vitamin D synthesis is affected by seasonal factors including sunlight exposure, raising the question whether seasonality determines the risk of vitamin D deficiency and may mask other clinical risk factors.

Methods

Univariable and multiple regression analyses were performed in a retrospective cohort of 384 patients to determine risk factors for vitamin D deficiency. Since the observed 25-hydroxyvitamin D [25(OH)D] concentrations followed a sinusoidal pattern over the year, all 25(OH)D concentrations were normalized for the predicted variability of the respective day of analysis based on a sinusoidal regression analysis of 25(OH)D test results obtained in more than 86,000 control serum samples.

Results

Vitamin D deficiency was highly prevalent in patients with Crohn’s disease or ulcerative colitis (63% and 55%, respectively) and associated with winter/spring seasons. After normalization of 25(OH)D concentrations for the day of analysis, vitamin D deficiency was associated with histories of complications related to inflammatory bowel disease, surgery, smoking and ongoing diarrhea while initial disease manifestation during adulthood, ongoing vitamin D supplementation and diagnosis of ulcerative colitis vs. Crohn’s disease appeared to be protective. Multiple regression analyses revealed that vitamin D deficiency was associated with disease activity in Crohn’s disease and anemia in ulcerative colitis patients. Only few deficient patients achieved sufficient 25(OH)D concentrations over time. However, increasing 25(OH)D concentrations correlated with improved Crohn’s disease activity.

Conclusions

Vitamin D deficiency was highly prevalent in patients with Crohn’s disease and ulcerative colitis and dependent on the season of the year. Following normalization for seasonality by sinusoidal regression analysis, vitamin D deficiency was found to be associated with parameters of complicated disease course while increasing 25(OH)D concentrations over time correlated with reduced activity of Crohn’s disease.

The Role of Vitamin D in Inflammatory Bowel Disease: Mechanism to Management

Vitamin D has been linked to human health benefits that extend far beyond its established actions on calcium homeostasis and bone metabolism. One of the most well studied facets of extra-skeletal vitamin D is its activity as an immuno-modulator, in particular its potent anti-inflammatory effects. As a consequence, vitamin D deficiency has been associated with inflammatory diseases including inflammatory bowel disease (IBD). Low serum levels of the major circulating form of vitamin D, 25-hydroxyvitamin D (25-OH-D) are significantly more prevalent in patients with IBD, particularly in the winter and spring months when UV-induced synthesis of vitamin D is lower. Dietary malabsorption of vitamin D may also contribute to low serum 25(OH)D in IBD. The benefits of supplementation with vitamin D for IBD patients are still unclear, and improved vitamin D status may help to prevent the onset of IBD as well as ameliorating disease severity. Beneficial effects of vitamin D in IBD are supported by pre-clinical studies, notably with mouse models, where the active form of vitamin D, 1,25-dihydroxyvitamin D (1,25-(OH)2D) has been shown to regulate gastrointestinal microbiota function, and promote anti-inflammatory, tolerogenic immune responses. The current narrative review aims to summarise the different strands of data linking vitamin D and IBD, whilst also outlining the possible beneficial effects of vitamin D supplementation in managing IBD in humans.

Vitamin D deficiency in a European inflammatory bowel disease inception cohort: an Epi-IBD study

BACKGROUND

Serum vitamin D level is commonly low in patients with inflammatory bowel disease (IBD). Although there is a growing body of evidence that links low vitamin D level to certain aspects of IBD such as disease activity and quality of life, data on its prevalence and how it varies across disease phenotype, smoking status and treatment groups are still missing.

MATERIALS AND METHODS

Patients diagnosed with IBD between 2010 and 2011 were recruited. Demographic data and serum vitamin D levels were collected. Variance of vitamin D level was then assessed across different treatment groups, disease phenotype, disease activity and quality of life scores.

RESULTS

A total of 238 (55.9% male) patients were included. Overall, 79% of the patients had either insufficient or deficient levels of vitamin D at diagnosis. Patients needing corticosteroid treatment at 1 year had significantly lower vitamin D levels at diagnosis (median 36.0 nmol/l) (P=0.035). Harvey-Bradshaw Index (P=0.0001) and Simple Clinical Colitis Activity Index scores (P=0.0001) were significantly lower in patients with higher vitamin D level. Serum vitamin D level correlated significantly with SIBQ score (P=0.0001) and with multiple components of SF12. Smokers at diagnosis had the lowest vitamin D levels (vitamin D: 34 nmol/l; P=0.053).

CONCLUSION

This study demonstrates the high prevalence of low vitamin D levels in treatment-naive European IBD populations. Furthermore, it demonstrates the presence of low vitamin D levels in patients with IBD who smoke.

Vitamin D increases programmed death receptor-1 expression in Crohn's disease

Background: Vitamin D modulates inflammation in Crohns disease (CD). Programmed death (PD)-1 receptor contributes to the maintenance of immune tolerance. Vitamin D might modulate PD-1 signalling in CD.

Aim: To investigate PD-1 expression on T cell subsets in CD patients treated with vitamin D or placebo.

Methods: We included 40 CD patients who received 1200 IU vitamin D3 for 26 weeks or placebo and eight healthy controls. Peripheral blood mononuclear cells (PBMCs) and plasma were isolated at baseline and week 26. The expressions of PD-1, PD-L1, and surface activation markers were analysed by flow cytometry. Soluble PD-1 plasma levels were measured by ELISA.

Results: PD-1 expression upon T cell stimulation was increased in CD4⁺CD25^+int T cells in vitamin D treated CD patients from 19% (range 10 39%) to 29% (11 79%)(p = 0.03) compared with placebo-treated patients. Vitamin D treatment, but not placebo, decreased the expression of the T cell activation marker CD69 from 42% (31 62%) to 33% (19 - 54%)(p = 0.01). Soluble PD-1 levels were not influenced by vitamin D treatment.

Conclusions: Vitamin D treatment increases CD4⁺CD25^+int T cells ability to up-regulate PD-1 in response to activation and reduces the CD69 expression in CD patients.

The Association of Vitamin D Status with Disease Activity in a Cohort of Crohn's Disease Patients in Canada

We determined the association between vitamin D status as 25hydroxyvitamin D [25(OH)D] and disease activity in a cohort of 201 Crohn’s Disease (CD) patients in Saskatoon, Canada over three years. The association between high-sensitivity C-reactive protein (hs-CRP) and 25(OH)D and several disease predictors were evaluated by the generalized estimating equation (GEE) over three time-point measurements. A GEE binary logistic regression test was used to evaluate the association between vitamin D status and the Harvey-Bradshaw Index (HBI). The deficient vitamin D group (≤29 nmol/L) had significantly higher mean hs-CRP levels compared with the three other categories of vitamin D status (p < 0.05). CRP was significantly lower in all of the other groups compared with the vitamin D-deficient group, which had Coef. = 12.8 units lower (95% CI −19.8, −5.8), Coef. 7.85 units (95% CI −14.9, −0.7), Coef. 9.87 units (95% CI −17.6, −2.0) for the vitamin D insufficient, adequate, and optimal groups, respectively. The vitamin D status was associated with the HBI active disease category. However, the difference in the odds ratio compared with the reference category of deficient vitamin D category was only significant in the insufficient category (odds ratio = 3.45, p = 0.03, 95% CI 1.0, 10.8). Vitamin D status was inversely associated with indicators of disease activity in Crohn’s disease, particularly with the objective measures of inflammation.

Associations of seasonal patterns and vitamin D levels with onset and flares of pediatric inflammatory bowel disease

BACKGROUND

As inflammatory bowel disease (IBD) might be associated with environmental factors such as seasonal patterns and low vitamin D levels we aimed to assess their association with IBD onset and flares in a large cohort of children.

METHODS

The records of 623 pediatric onset IBD patients were reviewed retrospectively including age at onset, gender, severity indices, month of first symptom, and vitamin D levels at diagnosis. For a subgroup of patients, data included date of first flare and vitamin D levels during flare and remission.

RESULTS

Median age at diagnosis was 14 years (IQR 11.66-15.58). Disease onset did not vary significantly between either month (P=0.367) or seasons (P=0.460). Vitamin D deficiency at the time of diagnosis was prevalent in 21% of patients with no significant association with month, season or disease's type. Vitamin D deficiency was significantly more prevalent in patients with malnutrition (P<0.001) and was associated with hypoalbuminemia (P=0.02) but did not correlate with low bone mineral density. Analysis of 169 first flares showed that flares were more common in June and less common in April (P=0.016). Mean vitamin D level was significantly lower during flares compared with remission (55.25±19.28 vs. 64.16±26.6, respectively, P=0.012).

CONCLUSIONS

IBD onset in school aged children is not associated with seasonal patterns whereas flares may follow a specific monthly pattern. Disease flares are associated with low vitamin D blood levels. Vitamin D deficiency is associated with malnutrition and hypoalbuminemia.

Vitamin D status in pediatric irritable bowel syndrome

Importance

Irritable bowel syndrome (IBS) is associated with significant morbidity in children and adolescents, and the therapeutic efficacy of available treatment options is limited. The role of vitamin D supplementation in pediatric IBS is unclear as the vitamin D status of pediatric patients with IBS is unknown. Equally, the relationship of vitamin D status with psychosomatic symptoms in children and adolescents is unclear.

Aim

To characterize the vitamin D status of pediatric patients with IBS using a case-control study design.

Hypothesis

Serum 25-hydroxyvitamin D [25(OH)D] concentration will be similar between patients with IBS and controls.

Subjects and methods

A retrospective case-controlled study of 116 controls (age 14.6 ± 4.3 y), female (n = 67; 58%) and 55 subjects with IBS (age 16.5 ± 3.1y), female (n = 44; 80%). Overweight was defined as BMI of ≥85^th but <95^th percentile, and obesity as BMI ≥95^th percentile. Vitamin D deficiency was defined as 25(OH)D of <50 nmol/L, while seasons of vitamin D draw were categorized as summer, winter, spring, and fall. Major psychosomatic manifestations included in the analysis were depression, anxiety, and migraine.

Results

More than 50% of IBS subjects had vitamin D deficiency at a cut-off point of <50 nmol/L (53% vs. 27%, p = 0.001); and >90% of IBS subjects had vitamin D deficiency at a cut-off point of <75 nmol/L (93% vs. 75%, p = 0.006). IBS subjects had significantly lower mean 25(OH)D: 53.2 ± 15.8 nmol/L vs. 65.2 ± 28.0 nmol/L, p = 0.003; and albumin: 6.2 ± 0.6 vs. 6.5 ± 0.6 μmol/L, p = 0.0.01. IBS subjects with migraine had significantly lower mean 25(OH)D concentration compared to controls (p = 0.01). BMI z-score was similar between the controls and IBS subjects (0.5 ± 1.4 vs. 1.2 ± 2.9, p = 0.11).

Conclusions

Pediatric patients with IBS had significantly lower 25(OH)D concentration compared to controls despite having similar mean BMI values as controls. Only 7% of the children and adolescents with IBS were vitamin D sufficient, and >50% of the subjects with IBS had vitamin D deficiency. This is a much higher prevalence of vitamin D deficiency compared to IBD and other malabsorption syndromes. Monitoring for vitamin D deficiency should be part of the routine care for patients with IBS. Randomized control trials are warranted to determine the role of adjunctive vitamin D therapy in pediatric IBS.

High-resolution Quantitative Computed Tomography Demonstrates Structural Defects in Cortical and Trabecular Bone in IBD Patients

BACKGROUND AND AIMS

To investigate the macro- and microstructural changes of bone in patients with inflammatory bowel disease [IBD] and to define the factors associated with bone loss in IBD.

METHODS

A total of 148 subjects, 59 with Crohn's disease [CD], 39 with ulcerative colitis [UC], and 50 healthy controls were assessed for the geometric, volumetric and microstructural properties of bone using high-resolution peripheral quantitative computed tomography. In addition, demographic and disease-specific characteristics of IBD patients were recorded.

RESULTS

IBD patients and controls were comparable in age, sex, and body mass index. Total [p = 0.001], cortical [p < 0.001], and trabecular volumetric bone mineral density [BMD] [p = 0.03] were significantly reduced in IBD patients compared with healthy controls. Geometric and microstructural analysis revealed significantly lower cortical area [p = 0.001] and cortical thickness [p < 0.001] without differences in cortical porosity, pore volume, or pore diameter. CD showed a more severe bone phenotype than UC: cortical bone loss was observed in both diseases, but CD additionally showed profound trabecular bone loss with reduced trabecular BMD [p = 0.008], bone volume [p = 0.008], and trabecular thickness [p = 0.009]. Multivariate regression models identified the diagnosis of CD, female sex, lower body mass index, and the lack of remission as factors independently associated with bone loss in IBD.

CONCLUSION

IBD patients develop significant cortical bone loss, impairing bone strength. Trabecular bone loss is limited to CD patients, who exhibit a more severe bone phenotype compared with UC patients.

Vitamin D status in relation to Crohn's disease: Meta-analysis of observational studies

OBJECTIVES

Inconsistent findings have been published regarding vitamin D status among patients with Crohn's disease (CD) and the association with disease severity. We aimed to perform a meta-analysis evaluating serum 25-hydroxy vitamin D and 1,25 dehydroxyvitamin D among CD patients compared with healthy and non-healthy controls, the prevalence of vitamin D deficiency, and the association with disease.

METHODS

We searched MEDLINE, SCOPUS, EMBASE, and Google Scholar up to March 2015 for observational studies assessing serum vitamin D levels in CD patients. A total of 63 studies were included in the following four meta-analyses: 1) a meta-analysis on the mean difference of 25(OH)D levels in CD patients compared with healthy (number of studies = 27) and non-healthy (n = 25) controls; 2) a meta-analysis on the mean difference of 1,25(OH)2 D3 levels in CD patients compared with healthy (n = 7) and non-healthy (n = 8) controls; 3) a meta-analysis on the prevalence of vitamin D deficiency (n = 34); 4) a meta-analysis on the correlation coefficients between vitamin D status severity of CD (n = 6). Subgroup analysis and meta-regression were used to discover possible sources of between-study heterogeneity.

RESULTS

It was found that CD patients had lower levels of 25(OH)D compared with healthy (-3.99 ng/mL; 95% confidence interval [CI]: -5.91 to -2.08) but not non-healthy controls (-1.07 ng/mL; 95% CI: -2.84 to 0.70). There was also no significant mean difference for 1,25(OH)2 D3 for both healthy and non-healthy controls. Meta-analysis on the prevalence of vitamin D deficiency showed an overall prevalence of 57.7% (95% CI: 0.502-0.649). An inverse association was observed between serum vitamin D and severity of CD (-0.36; 95% CI: -0.48 to -0.24). Meta-regression showed that mean levels of 25(OH)D were decreased 0.09 for each unit change of latitude among CD patients compared with healthy controls (B = -0.09, P = 0.004, I(2) residual = 86.08%).

CONCLUSIONS

We found that patients with Crohn's disease had lower serum 25(OH)D concentrations compared with their healthy counterparts, and more than half of them have hypovitaminosis D. Moreover, there was an inverse correlation between circulating 25(OH)D concentrations and severity of Crohn's disease.

1,25-hydroxyvitamin D relieves colitis in rats via down-regulation of toll-like receptor 9 expression

AIM

To investigate the therapeutic and immunoregulatory effects of 1,25-dihydroxyvitamin D (1,25(OH)D3) on 2,4,6-trinitrobenzenesulfonic acid (TNBS) -induced colitis in rats.

METHODS

Experimental colitis induced by enema administration of TNBS plus ethanol was treated with 5-aminosalicylic acid (5-ASA) and/or 1,25(OH)D3. Disease activity was measured using the disease activation index (DAI), colon macroscopic damage index (CMDI), histological colonic damage score, and myeloperoxidase (MPO) activity. The expression of toll-like receptor 9 (TLR9) in the colon was determined by reverse transcription-polymerase chain reaction and immunohistochemistry.

RESULTS

Rats with TNBS-induced colitis had significantly elevated DAI, CMDI, histological colonic damage score, and MPO activity (all P<0.001) compared to rats without colitis. Treatment with 5-ASA or 1,25(OH)D3 ameliorated colitis by lowering CMDI (P=0.049, P=0.040, respectively), histological colonic damage score (P=0.010, P=0.005, respectively), and MPO activity (P=0.0003, P=0.0013, respectively) compared with the TNBS group. Combined treatment with 5-ASA and 1,25(OH)D3 significantly decreased MPO activity (P=0.003). 1,25(OH)D3 attenuated colitis without causing hypercalcemia or renal insufficiency. TNBS significantly increased the number of TLR9 positive cells compared to control (P<0.010), while 5-ASA, 1,25(OH)D3, and combined treatment with 5-ASA and 1,25(OH)D3 significantly decreased it compared to TNBS group (all P<0.010). In TNBS group a moderate correlation was observed between MPO activity and the number of TLR9-positive cells (r=0.654, P<0.001).

CONCLUSION

TLR9 expression correlates with the extent of inflammation in TNBS-induced colitis. 1,25(OH)D3 relieves this inflammation possibly by decreasing TLR9 expression.

The importance of vitamin D in the pathology of bone metabolism in inflammatory bowel diseases

Etiological factors of bone metabolism disorders in inflammatory bowel diseases have been the subject of interest of many researchers. One of the questions often raised is vitamin D deficiency. Calcitriol acts on cells, tissues and organs through a vitamin D receptor. The result of this action is the multi-directional effect of vitamin D. The reasons for vitamin D deficiency are: decreased exposure to sunlight, inadequate diet, inflammatory lesions of the intestinal mucosa and post-gastrointestinal resection states. This leads not only to osteomalacia but also to osteoporosis. Of significance may be the effect of vitamin D on the course of the disease itself, through modulation of the inflammatory mechanisms. It is also necessary to pay attention to the role of vitamin D in skeletal pathology in patients with inflammatory bowel diseases and thus take measures aimed at preventing and treating these disorders through the supplementation of vitamin D.

The Prognostic Role of Red Blood Cell Distribution Width in Coronary Artery Disease: A Review of the Pathophysiology

Red blood cell distribution width (RDW) is a measure of red blood cell volume variations (anisocytosis) and is reported as part of a standard complete blood count. In recent years, numerous studies have noted the importance of RDW as a predictor of poor clinical outcomes in the settings of various diseases, including coronary artery disease (CAD). In this paper, we discuss the prognostic value of RDW in CAD and describe the pathophysiological connection between RDW and acute coronary syndrome. In our opinion, the negative prognostic effects of elevated RDW levels may be attributed to the adverse effects of independent risk factors such as inflammation, oxidative stress, and vitamin D₃ and iron deficiency on bone marrow function (erythropoiesis). Elevated RDW values may reflect the intensity of these phenomena and their unfavorable impacts on bone marrow erythropoiesis. Furthermore, decreased red blood cell deformability among patients with higher RDW values impairs blood flow through the microcirculation, resulting in the diminution of oxygen supply at the tissue level, particularly among patients suffering from myocardial infarction treated with urgent revascularization.

Flow cytometry detection of vitamin D receptor changes during vitamin D treatment in Crohn's disease

Crohn's disease (CD) is a chronic inflammatory disease associated with a dysregulated T cell response towards intestinal microflora. Vitamin D has immune modulatory effects on T cells through the nuclear vitamin D receptor (VDR) in vitro. It is unclear how oral vitamin D treatment affects VDR expression. The aim of this study was to establish a flow cytometry protocol, including nuclear and cytoplasmic VDR expression, and to investigate the effects of vitamin D treatment on T cell VDR expression in CD patients. The flow cytometry protocol for VDR staining was developed using the human acute monocytic leukaemia cell line (THP-1). The protocol was evaluated in anti-CD3/CD28-stimulated peripheral blood mononuclear cells (PBMCs) from vitamin D3- (n = 9) and placebo-treated (n = 9) CD patients. Anti-VDR-stained PBMCs were examined by flow cytometry, and their cytokine production was determined by cytokine bead array. VDR, CYP27B1 and RXRα mRNA expression levels in CD4(+) T cells were measured by quantitative reverse transcriptase polymerase chain reaction. The flow cytometry protocol enabled detection of cytoplasmic and nuclear VDR expression. The results were confirmed by confocal microscopy and supported by correlation with VDR mRNA expression. VDR expression in CD4(+) T cells increased following stimulation. This VDR up-regulation was inhibited with 30% by vitamin D treatment compared to placebo in CD patients (P = 0027). VDR expression was correlated with in-vitro interferon-γ production in stimulated PBMCs (P = 0.01). Flow cytometry is a useful method with which to measure intracellular VDR expression. Vitamin D treatment in CD patients reduces T cell receptor-mediated VDR up-regulation.

Vitamin D therapy in inflammatory bowel diseases: who, in what form, and how much?

BACKGROUND

The north–south geographical gradient of inflammatory bowel disease (IBD) prevalence, its epidemiology, the genetic association of vitamin D receptor polymorphisms, and results in animal models suggest that vitamin D plays an important role in the pathogenesis of IBD.

AIMS

The purpose of this review was to critically appraise the effectiveness and safety of vitamin D therapy in patients with IBD.

METHODS

MEDLINE, Scopus and Google Scholar were searched from inception to May 20, 2014 using the terms ‘Crohn’s disease’, ‘ulcerative colitis’ and ‘vitamin D’. Results: Vitamin D deficiency is common in patients with IBD. Limited clinical data suggest an association between low vitamin D concentration and increased disease activity in both ulcerative colitis (UC) and Crohn’s disease (CD). To date, only two small open label trials and one randomized controlled trial have shown a positive effect of vitamin D supplementation on disease activity in patients with CD; no effect has been shown for UC. An optimal vitamin D supplementation protocol for patients with IBD remains undetermined, but targeting serum 25-hydroxy vitamin D [25(OH)D] levels between 30 and 50 ng/mL appears safe and may have benefits for IBD disease activity. Depending on baseline vitamin D serum concentration, ileal involvement in CD, body mass index, and perhaps smoking status, daily vitamin D doses between 1800–10,000 international units/day are probably necessary.

CONCLUSION

Increasing preclinical and clinical evidence suggests a role for vitamin D deficiency in the development and severity of IBD. The possible therapeutic role of vitamin D in patients with IBD merits continued investigation.

Higher vitamin D serum concentration increases health related quality of life in patients with inflammatory bowel diseases

AIM

To investigate the effect of vitamin D (VD) concentrations and VD supplementation on health related quality of life in inflammatory bowel disease (IBD) patients.

METHODS

A cohort of 220 IBD patients including 141 Crohn's disease (CD) and 79 ulcerative colitis (UC) patients was followed-up at a tertiary IBD center. A subgroup of the cohort (n = 26) took VD supplements for > 3 mo. Health related quality of life was assessed using the short IBD questionnaire (sIBDQ). VD serum concentration and sIBDQ score were assessed between August and October 2012 (summer/autumn period) and between February and April 2013 (winter/spring period). The mean VD serum concentration and its correlation with disease activity of CD were determined for each season separately. In a subgroup of patients, the effects of VD supplementation on winter VD serum concentration, change in VD serum concentration from summer to winter, and winter sIBDQ score were analyzed.

RESULTS

During the summer/autumn and the winter/spring period, 28% and 42% of IBD patients were VD-deficient (< 20 ng/mL), respectively. In the winter/spring period, there was a significant correlation between sIBDQ score and VD serum concentration in UC patients (r = 0.35, P = 0.02), with a trend towards significance in CD patients (r = 0.17, P = 0.06). In the winter/spring period, VD-insufficient patients (< 30 ng/mL) had a significantly lower mean sIBDQ score than VD-sufficient patients; this was true of both UC (48.3 ± 2.3 vs 56.7 ± 3.4, P = 0.04) and CD (55.7 ± 1.25 vs 60.8 ± 2.14, P = 0.04) patients. In all analyzed scenarios (UC/CD, the summer/autumn period and the winter/spring period), health related quality of life was the highest in patients with VD serum concentrations of 50-59 ng/mL. Supplementation with a median of 800 IU/d VD day did not influence VD serum concentration or the sIBDQ score.

CONCLUSION

VD serum concentration correlated with health related quality of life in UC and CD patients during the winter/spring period.

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

BACKGROUND AND AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Lower regional and temporal ultraviolet exposure is associated with increased rates and severity of inflammatory bowel disease hospitalisation

BACKGROUND

In the northern hemisphere, the incidence of inflammatory bowel diseases (IBD) has a north-south gradient, suggesting a link between ultraviolet (UV) exposure or vitamin D status and the pathogenesis of IBD.

AIM

To test the association of UV exposure with the rates and severity of IBD hospitalisation.

METHODS

We conducted a retrospective nationwide analysis of 649 932 Crohn's disease (CD), 384 267 ulcerative colitis (UC), and 288 894 297 non-IBD hospitalisations in the US between 1998 and 2010. Mean UV exposure was assigned to each hospitalisation using surface measures from the National Oceanic and Atmospheric Administration. Relative rates across UV exposures were estimated for IBD hospitalisations, prolonged hospitalisations, bowel surgeries and deaths.

RESULTS

Among IBD patients, lower UV exposures had increased hospitalisation rates for CD (217.8 vs. 182.5 per 100 000 overall hospitalisations with low and very high UV, respectively; P trend <0.001) and UC (123.2 vs. 113.8 per 100 000; P trend = 0.033). Low UV groups had greater relative rates of prolonged hospitalisations [CD: 1.13, 95% confidence interval (CI) 1.07-1.19; UC: 1.21, 95% CI 1.13-1.30], bowel surgeries (CD: 1.24, 95% CI 1.16-1.32; UC: 1.21, 95% CI 1.09-1.33), and CD deaths (CD: 1.76, 95% CI 1.14-2.71; UC: 1.24, 95% CI 0.92-1.67). Among non-IBD patients, low UV was associated with prolonged hospitalisations (1.09; 95% CI 1.07-1.11) and deaths (1.13; 95% CI 1.09-1.17), but not bowel surgeries (1.01; 95% CI 0.99-1.03).

CONCLUSIONS

Lower ultraviolet exposure is associated with greater rates of hospitalisation, prolonged hospitalisation and the need for bowel surgery in IBD. This trend for bowel surgery was not seen with non-IBD encounters.

Vitamin D levels and bone metabolism in Chinese adult patients with inflammatory bowel disease

OBJECTIVE

We aimed to investigate the serum 25-hydroxyvitamin D3 (25[OH]D3 ) levels and bone metabolism in adult Chinese patients with inflammatory bowel disease (IBD) and to evaluate the correlation between vitamin D levels and the disease activity as well as the potential risk factors.

METHODS

Age- and gender-matched cohort of IBD patients (124 with ulcerative colitis [UC] and 107 with Crohn's disease [CD]) and 122 healthy controls were enrolled in this study. Serum levels of 25(OH)D3 and bone mineral density (BMD) were measured, and the correlation between the two parameters and the severity of the disease as well as the clinical risk factors were analyzed.

RESULTS

Serum 25(OH)D3 levels were lower in UC (10.32 ± 4.46 ng/mL, P < 0.001) and CD patients (11.57 ± 5.02 ng/mL, P = 0.029) than that in healthy controls (12.87 ± 4.40 ng/mL). 25(OH)D3 levels were negatively correlated with the disease severity of both UC (r = -0.371, P < 0.001) and CD (r = -0.285, P = 0.030). The incidences of osteopenia and osteoporosis were high in the IBD patients (37.9% and 3.2% in UC and 30.8% and 4.7% in CD, respectively). Cumulative quantity of glucocorticoids use was significantly associated with osteopenia and osteoporosis in both UC (odds ratio [OR] 1.219, 95% confidence interval [CI] 1.054-1.410, P = 0.008) and CD patients (OR 1.288, 95% CI 1.033-1.606, P = 0.025).

CONCLUSIONS

Vitamin D deficiency is likely to occur in Chinese patients with IBD and is closely associated with the severity of the disease. Glucocorticoids accumulation is a risk factor for osteopenia and osteoporosis.

Risk factors and management of osteoporosis in inflammatory bowel disease

PURPOSE OF REVIEW

To provide a synopsis on established and new research evaluating bone disease in patients with inflammatory bowel disease (IBD).

RECENT FINDINGS

Persons with IBD, including Crohn's disease and ulcerative colitis are believed to be at high risk for osteoporosis and fracture. As osteoporosis is clinically silent and persons with IBD are not universally screened, the burden of bone disease in IBD has been difficult to accurately assess. It is also unclear whether bone disease is due to inflammatory activity, medication use, poor nutrient intake/absorption, or body habitus characteristics. Recent studies using population-wide databases of bone mineral density (BMD) analyses suggest that Crohn's disease is responsible for a small effect on BMD after adjusting for other risk factors for low BMD, whereas ulcerative colitis does not appear to confer an independent risk. Furthermore, IBD does not appear to be a risk for overall fracture once controlling for factors which are associated with both IBD and fracture risk. The ability to assess BMD on incidentally performed computed tomography scans may allow detection of low BMD in IBD patients.

SUMMARY

Although reduced BMD and fracture are more common in persons with IBD, the precise burden is not well characterized. Also, the relative impact of IBD-associated factors and IBD-specific inflammation on bone health is still uncertain.

Linking vitamin d deficiency to inflammatory bowel disease

Inflammatory bowel disease is associated with industrialization, and its incidence has increased markedly over time. The prospect of reversing these trends motivates the search for the agent(s) involved. Modernity entails several physical and behavioral modifications that compromise both the photosynthesis of cholecalciferol in the skin and of its bioavailability. Although deficiency in this "vitamin" has therefore emerged as a leading candidate, and despite the publication of a randomized control trial that showed a trend toward statistically significant benefit in Crohn's disease, its causal agency has yet to be demonstrated by an adequately powered study. We discuss the strengths and weaknesses of the case being made by epidemiologists, geneticists, clinicians, and basic researchers, and consolidate their findings into a model that provides mechanistic plausibility to the claim. Specifically, converging data sets suggest that local activation of vitamin D coordinates the activity of the innate and adaptive arms of immunity, and of the intestinal epithelium, in a manner that promotes barrier integrity, facilitates the clearance of translocated flora, and diverts CD4 T cell development away from inflammatory phenotypes. Because smoking is an important risk-altering exposure, we also discuss its newly established melanizing effect and other emerging evidence linking tobacco use to immune function through vitamin D pathways.

Increased fracture risk and osteoporosis not associated with vitamin D levels in Malaysian patients with inflammatory bowel disease

INTRODUCTION

Osteoporosis and osteopenia are well-recognized complications of inflammatory bowel disease. Previous studies have suggested that vitamin D deficiency is an important risk factor for the development of osteoporosis. We hypothesized that low vitamin D levels is the main reason for reduced bone mineral density in patients with inflammatory bowel disease. We aimed to study its potential role in Malaysia, which is a tropical country with 3 large ethnic groups. We also sought to examine the relationship between fracture risk and bone mineral density in this group.

METHODOLOGY

Relevant history as well as 25-hydroxycholecalciferol (vitamin D) levels and bone mineral density were obtained. Normal, inadequate, and low vitamin D levels were defined as 61-160 nmol/L (24-64 ng/mL), 30-60 nmol/L (12-24 ng/mL), and less than 30 nmol/L (<12 ng/mL), respectively.

RESULTS

Seventy-two patients were recruited. The prevalence of osteopenia and osteoporosis, respectively, were 58% and 17% in the spine and 51% and 14% in the hip. Mean vitamin D level in the group was low at 45.12 ± 17.4 nmol/L (18.05 ± 6.96 ng/mL), but there was no significant association between bone mineral density and vitamin D level. Twelve patients (16.7%) had a fragility fracture after the diagnosis of inflammatory bowel disease. The cumulative fracture incidence was 10% at 5 years and 35% at 10 years. There was a statistically significant association between osteoporosis of hip and a history of fracture (odds ratio 5.889; 95% confidence interval 1.41-24.53, P = .009).

CONCLUSION

Osteoporosis is prevalent among Malaysian patients with inflammatory bowel disease and is associated with a 6-fold increased risk of fractures. Most inflammatory bowel disease patients had inadequate or low vitamin D levels, but there was no association between vitamin D levels and BMD.

Active vitamin D (1,25-dihydroxyvitamin D3) increases host susceptibility to Citrobacter rodentium by suppressing mucosal Th17 responses

Vitamin D deficiency affects more that 1 billion people worldwide and is associated with an increased risk of developing a number of inflammatory/autoimmune diseases, including inflammatory bowel disease (IBD). At present, the basis for the impact of vitamin D on IBD and mucosal immune responses is unclear; however, IBD is known to reflect exaggerated immune responses to luminal bacteria, and vitamin D has been shown to play a role in regulating bacteria-host interactions. Therefore, to test the effect of active vitamin D on host responses to enteric bacteria, we gave 1,25(OH)(2)D(3) to mice infected with the bacterial pathogen Citrobacter rodentium, an extracellular microbe that causes acute colitis characterized by a strong Th1/Th17 immune response. 1,25(OH)(2)D(3) treatment of infected mice led to increased pathogen burdens and exaggerated tissue pathology. In association with their increased susceptibility, 1,25(OH)(2)D(3)-treated mice showed substantially reduced numbers of Th17 T cells within their infected colons, whereas only modest differences were noted in Th1 and Treg numbers. In accordance with the impaired Th17 responses, 1,25(OH)(2)D(3)-treated mice showed defects in their production of the antimicrobial peptide REG3γ. Taken together, these studies show that 1,25(OH)(2)D(3) suppresses Th17 T-cell responses in vivo and impairs mucosal host defense against an enteric bacterial pathogen.

Similarly high prevalence of hypovitaminosis D in HIV-infected subjects with and without low bone mineral density

Background: Hypovitaminosis D is highly prevalent among HIV-infected patients. Since hypovitaminosis D is a secondary cause of low bone mineral density (BMD), we assessed its prevalence and associated factors in HIV-infected patients with osteopenia/osteoporosis, compared with HIV-infected patients with normal BMD. Materials & methods: Serum 25-hydroxy vitamin D (25[OH]D) concentration were collected from 149 HIV-infected subjects with low BMD and 36 with normal BMD from April to October, 2010. Regression analyses were fitted to predict the probability of hypovitaminosis D in all patients. Results: Of the 149 patients with low BMD (51.8 ± 8 years old, 76.5% men), 83% had vitamin D insufficiency (<30 ng/ml) and 7.4% had severe deficiency (<10 ng/ml). In comparison, insufficiency was present in 75% of subjects from the group with normal BMD (p = 0.60) and no subject was severely deficient (p = 0.13). Among subjects with low BMD, 1.8% of men had low levels of testosterone, 5.4% of patients had high levels of thyroid-stimulating hormone, (all with normal free thyroxine levels) and 14.6% had high levels of parathyroid hormone. Univariate analysis showed significant associations between hypovitaminosis D and the current use of non-nucleosides (β-coefficient: -3.797; standard deviation: 1.538; p = 0.015), whereas protease inhibitors were associated with higher levels of vitamin D (β-coefficient: 4.640; standard deviation: 1.673; p = 0.006). Conclusion: Hypovitaminosis D was highly prevalent in our patients with low BMD but also in those with normal bone dual x-ray energy absorptionmetry scan. 25(OH)D should be periodically monitored, although the benefit of vitamin D and calcium supplements on bone mineralization has not yet been investigated in this population.

Solar radiation and vitamin D: mitigating environmental factors in autoimmune disease

This paper looks at the environmental role of vitamin D and solar radiation as risk reduction factors in autoimmune disease. Five diseases are considered: multiple sclerosis, type 1 diabetes, rheumatoid arthritis, autoimmune disease of the thyroid, and inflammatory bowel disease. Clinical relevant studies and factors that may indicate evidence that autoimmune disease is a vitamin D-sensitive disease are presented. Studies that have resulted in prevention or amelioration of some autoimmune disease are discussed. An example of the utility of supplementing vitamin D in an unusual autoimmune disease, idiopathic thrombocytic purpura, is presented.

The Vitamin D Receptor, Inflammatory Bowel Diseases, and Colon Cancer

The nuclear receptor is an emerging therapeutic target in various human diseases. Vitamin D receptor (VDR), a nuclear receptor, mediates the biological functions of vitamin D. Classically, vitamin D is recognized as an essential contributor to mineral and bone homeostasis. Increasing evidence demonstrates that vitamin D is involved in inflammatory responses. Persistent intestinal inflammation is associated with colon cancer. This review focuses on vitamin D and VDR in inflammatory bowel diseases and colon cancer. We place emphasis on the regulatory roles of vitamin D/VDR on in inflammation, enteric bacteria, and tumorigenesis. We summarize the signaling pathways regulated by VDR in intestinal homeostasis. Finally, we discuss the potential application of the insights gleaned from these findings to personalized therapies in chronic inflammation and colon cancer.