Association of serum vitamin D levels on Helicobacter pylori infection: a retrospective study with real-world data

OBJECTIVE

The aim of this study was to determine whether serum vitamin D levels are associated with H. pylori infection and whether low serum vitamin D levels are an independent risk factor for H. pylori infection.

METHODS

We conducted a retrospective analysis of a multicenter cohort study from 2017 to 2019. A total of 415 H. pylori+ patients and 257 H. pylori- patients aged between 18 and 75 years with both 13 C-urea breath test and serum vitamin D level results were included from four hospitals. A questionnaire was used to collect information on potential factors influencing H. pylori infection.

RESULTS

Serum vitamin D levels were significantly lower in the H. pylori+ group than in the H. pylori- group (16.7 ± 6.6 ng/ml vs. 19.2 ± 8.0 ng/ml, p < 0.05). Using a cutoff value of 20 ng/ml, the H. pylori infection rate was significantly higher in the vitamin D-deficient group (< 20 ng/ml) than in the vitamin D-nondeficiency group (≥ 20 ng/ml) (66.5% vs. 51.0%, p < 0.001). Ordered logistic regression analysis showed that serum vitamin D levels < 20 ng/ml (OR: 1.652, 95% CI: 1.160-2.351, p = 0.005), higher education levels (OR: 1.774, 95% CI: 1.483-2.119, p < 0.001), family size ≥ 4 (OR: 1.516, 95% CI: 1.081-2.123, p = 0.016), and lower annual income (OR: 1.508, 95% CI: 1.289-1.766, p < 0.001) were independent risk factors for H. pylori infection.

CONCLUSION

Lower serum vitamin D levels may be associated with an increased risk of H. pylori infection, and lower serum vitamin D levels are an independent risk factor for increasing H. pylori infection rates. Randomized controlled trials are needed to determine whether supplementation with vitamin D can reduce H. pylori infection rates.

Association Between Vitamin D Receptor Polymorphism and the Response to Helicobacter Pylori Treatment

Background & Aims

This research aimed to determine how variations in the vitamin D receptor gene affected the response of H. pylori infections to eradication therapy.

Patients and Methods

On 105 adult H. Pylori-positive patients, a prospective cohort study was carried out. PCR was used to genotype all patients' VDR gene polymorphisms. The patients in the study received standard triple eradication medication (clarithromycin 500 mg, amoxicillin 1000 mg, and omeprazole 20 mg) twice daily for 14 days. A stool test for H. pylori Ag was conducted 4 weeks following the end of treatment.

Results

In our study, the usual triple therapy's H. pylori eradication rate was 75.2%. The successful eradication of H. pylori and VDR rs 2228570 gene polymorphisms was more prevalent in CT gene polymorphism (64.6%) compared to non-responders (19.2%), while treatment failure was more prevalent in CC gene polymorphism (73.1% in non-responders compared to responders 24.1%), which is statistically significant. In regards to the eradication of H. pylori and VDR rs7975232 gene polymorphisms, the success of eradication was more prevalent in AC gene polymorphism (54.4%) vs non-responders (30.4%), while all patients (14) with gene AA (17.7%) are responders to standard treatment, while the failure of treatment was more prevalent in CC gene polymorphism (69.2% in non-responder vs 27.8% in responders) which is statistically significant. Our findings demonstrated a strong correlation between patients' responses to H. pylori treatment and polymorphisms in the VDR gene (ApaI and TaqI) (P 0.05).

Conclusion

As far as we are aware, this is the first study to identify a potential link between the FokI and Apal VDR polymorphism and treatment response in H pylori-positive patients. To evaluate the findings, more research with larger number of patients and different population is required.

25-hydroxyvitamin D levels in children of different ages and with varying degrees of Helicobacter pylori infection and immunological features

Background

Helicobacter pylori (HP) is a major cause of upper digestive tract diseases. However, the relationship between HP infection and 25-hydroxyvitamin D [25(OH)D] levels in children has not been fully elucidated. This study investigated the levels of 25(OH)D in children of different ages and with varying degrees of HP infection and immunological features as well as the correlations between 25(OH)D levels in children infected with HP and their ages and degrees of infection.

Materials and methods

Ninety-four children who underwent upper digestive endoscopy were divided into an HP-positive group without peptic ulcers (Group A), an HP-positive group with peptic ulcers (Group B) and an HP-negative control group (Group C). The serum levels of 25(OH)D and immunoglobulin and the percentages of lymphocyte subsets were determined. HP colonization, the degree of inflammation, and the degree of activity were further evaluated by HE staining and immunohistochemical staining in gastric mucosal biopsy.

Results

The 25(OH)D level of the HP-positive groups (50.93 ± 16.51 nmol/L) was significantly lower than that of the HP-negative group (62.89 ± 19.18 nmol/L). The 25(OH)D level of Group B (47.79 ± 14.79 nmol/L) was lower than that of Group A (51.53 ± 17.05 nmol/L) and was significantly lower than that of Group C (62.89 ± 19.18 nmol/L). The 25(OH)D level decreased with increasing age, and there was a significant difference between Group C subjects who were ≤5 years old and those who were aged 6-9 years and ≥10 years. The 25(OH)D level was negatively correlated with HP colonization (r = -0.411, P < 0.01) and the degree of inflammation (r = -0.456, P < 0.01). The percentages of lymphocyte subsets and immunoglobulin levels among Groups A, B and C were not significantly different.

Conclusions

The 25(OH)D level was negatively correlated with HP colonization and the degree of inflammation. As the age of the children increased, the level of 25(OH)D decreased, and the susceptibility to HP infection increased.

Association between serum vitamin D levels and Helicobacter pylori cytotoxic-associated gene A seropositivity: a cross-sectional study in US adults from NHANES III

OBJECTIVE

To assess the association of serum vitamin D (VD) levels and Helicobacter pylori (H. pylori) cytotoxic-associated gene A (CagA) seropositivity, and further explore potential effect modifiers in this association.

DESIGN

Cross-sectional study.

SETTING

Data from phase I of the National Health and Nutrition Examination Survey (NHANES III, 1988-1991) led by the Center for Disease Control and Prevention.

PARTICIPANTS

A total of 3512 US adults (≥20 years) with both serum VD levels and H. pylori CagA antibody data from NHANES III were included in the analysis.

METHODS

VD deficiency was defined as serum 25(OH)D concentrations<20 ng/mL. Logistic regression models were used to assess the association of serum VD levels and H. pylori CagA seropositivity (VD-Hp CagA+), and stratification analyses were used to explore potential effect modifiers.

RESULTS

There was no significant association of VD-Hp CagA+ in the general population. But serum 25(OH)D concentrations were associated with H. pylori CagA+ in non-Hispanic whites (adjusted OR=1.02, 95% CI: 1.00 to 1.03), other races/ethnicities (adjusted OR=1.08, 95% CI: 1.01 to 1.06), populations born in other countries (adjusted OR=1.09, 95% CI: 1.04 to 1.15) or occasional drinkers (adjusted OR=0.93, 95% CI: 0.88 to 0.99). VD deficiency was associated with H. pylori CagA+ in non-Hispanic whites (adjusted OR=0.69, 95% CI: 0.53 to 0.92), populations born in other countries (adjusted OR=0.47, 95% CI: 0.25 to 0.89), non-drinkers (adjusted OR=0.80, 95% CI: 0.65 to 0.99), occasional drinkers (adjusted OR=2.53, 95% CI: 1.06 to 6.05), population with first quartile level of serum ferritin (adjusted OR=0.70, 95% CI: 0.51 to 0.96) or fourth quartile level of serum folate (adjusted OR=0.63, 95% CI: 0.46 to 0.87).

CONCLUSIONS

Racial/ethnic differences and different serum ferritin or serum folate levels may be effect modifiers for the association of VD-Hp CagA+.

The Effects of Vitamins and Micronutrients on Helicobacter pylori Pathogenicity, Survival, and Eradication: A Crosstalk between Micronutrients and Immune System

Helicobacter pylori as a class I carcinogen is correlated with a variety of severe gastroduodenal diseases; therefore, H. pylori eradication has become a priority to prevent gastric carcinogenesis. However, due to the emergence and spread of multidrug and single drug resistance mechanisms in H. pylori, as well as serious side effects of currently used antibiotic interventions, achieving successful H. pylori eradication has become exceedingly difficult. Recent studies expressed the intention of seeking novel strategies to improve H. pylori management and reduce the risk of H. pylori-associated intestinal and extragastrointestinal disorders. For which, vitamin supplementation has been demonstrated in many studies to have a tight interaction with H. pylori infection, either directly through the regulation of the host inflammatory pathways or indirectly by promoting the host immune response. On the other hand, H. pylori infection is reported to result in micronutrient malabsorption or deficiency. Furthermore, serum levels of particular micronutrients, especially vitamin D, are inversely correlated to the risk of H. pylori infection and eradication failure. Accordingly, vitamin supplementation might increase the efficiency of H. pylori eradication and reduce the risk of drug-related adverse effects. Therefore, this review aims at highlighting the regulatory role of micronutrients in H. pylori-induced host immune response and their potential capacity, as intrinsic antioxidants, for reducing oxidative stress and inflammation. We also discuss the uncovered mechanisms underlying the molecular and serological interactions between micronutrients and H. pylori infection to present a perspective for innovative in vitro investigations, as well as novel clinical implications.

Helicobacter pylori metabolites exacerbate gastritis through C-type lectin receptors

Helicobacter pylori causes gastritis, which has been attributed to the development of H. pylori-specific T cells during infection. However, the mechanism underlying innate immune detection leading to the priming of T cells is not fully understood, as H. pylori evades TLR detection. Here, we report that H. pylori metabolites modified from host cholesterol exacerbate gastritis through the interaction with C-type lectin receptors. Cholesteryl acyl α-glucoside (αCAG) and cholesteryl phosphatidyl α-glucoside (αCPG) were identified as noncanonical ligands for Mincle (Clec4e) and DCAR (Clec4b1). During chronic infection, H. pylori-specific T cell responses and gastritis were ameliorated in Mincle-deficient mice, although bacterial burdens remained unchanged. Furthermore, a mutant H. pylori strain lacking αCAG and αCPG exhibited an impaired ability to cause gastritis. Thus H. pylori-specific modification of host cholesterol plays a pathophysiological role that exacerbates gastric inflammation by triggering C-type lectin receptors.

Association of Vitamin D receptor gene variations with Gastric cancer risk in Kashmiri population

Vitamin D receptor (VDR) mediates cellular processes like cell cycle arrest and apoptosis which effect cancer susceptibility. VDR single nucleotide polymorphisms (SNPs) have a significant influence on functioning of VDR protein and subsequently contribute to the risk of cancer occurrence and progression. The present case-control study was carried out between 2016 and 2020 to investigate the association of VDR BsmI/ApaITaqI SNPs with Gastric Cancer (GC) risk in ethnic Kashmiri population not only for establishing a molecular marker for GC but also to facilitate the outcomes of personalized medicine in future. The polymorphisms of BsmI and ApaI of the VDR gene were evaluated using Polymerase Chain Reaction-Restriction Fragment Length Polymorphism followed by Di-Deoxy Sanger sequencing in 143 GC cases and 150 controls. The mean age (in years) was 53.5 ± 7.92 and 51.2 ± 8.25 and mean Body mass index was 22.68 ± 4.27 kg/m² and 23.81 ± 3.71 kg/m² for cases and controls respectively. The mean CEA levels of GC cases was 40.2 ± 10.9 ng/ml. Genotypic distribution of VDR BsmI differed significantly between GC cases and controls (GG vs GA + AA; adjusted P = 0.014) and followed dominant mode of inheritence. Stratification of VDR BsmI revealed that frequency of variant genotype (GA + AA) was significantly higher in Preobese GC cases (P = 0.001), GC patients consuming < 5 cups of salt tea/day (P < 0.0001) and with no family history of gastrointestinal cancer (P = 0.014) compared to healthy controls. ATC haplotype associated with high GC risk. In conclusion, our study suggests that VDR BsmI SNP has a significant association with increased risk of GC especially in preobese population and BsmI/ApaITaqI SNPs significantly decreased the overall survival in GC patients of Kashmiri population.

The Association between Serum Vitamin D Levels and Helicobacter pylori Presence and Eradication

Background: The success of Helicobacter pylori (H. pylori) eradication depends on several host and treatment factors. Serum vitamin D levels may be associated with H. pylori infection and eradication rates. We investigated the association between vitamin D and H. pylori infection and eradication, using a large electronic database based on medical records from a population-based health maintenance organization. Methods: Data regarding adults who underwent H. pylori testing and had vitamin D measurements within one month of H. pylori testing were collected. H. pylori infection was ascertained using urea breath or stool antigen tests. A negative H. pylori test following a positive result implied eradication. Multivariate regression models were constructed to assess associations between H. pylori infection, eradication, and vitamin D. Results: Among 150,483 members who underwent H. pylori testing from 2009 to 2018, 27,077 (18%) had vitamin D measurements. Vitamin D levels were inversely associated with H. pylori infection, p < 0.001. The odds of a positive H. pylori test were 31% higher among patients with vitamin D levels <20 ng/mL, compared with those with levels ≥20 ng/mL (OR 1.31, 99% CI 1.22–1.4, p < 0.001). Purchase of vitamin D supplements was associated with a negative subsequent H. pylori test (p < 0.001). Mean vitamin D levels were moderately higher in those with successful vs. failed H. pylori eradication (19.34 ± 9.55 vs. 18.64 ± 9.61, p < 0.001). Conclusions: Vitamin D levels are associated with H. pylori infection. Increased vitamin D levels are associated with successful H. pylori eradication. Vitamin D may have a role in H. pylori eradication.

Vitamin D3 Inhibits Helicobacter pylori Infection by Activating the VitD3/VDR-CAMP Pathway in Mice

Helicobacter pylori (H. pylori) infection is closely associated with the occurrence and development of gastric diseases. Therefore, eliminating H. pylori infection should help to prevent gastric diseases. Vitamin D3 (VitD3, 1,25(OH)₂D₃) was previously observed to exhibit anti-H. pylori infection activity in clinic, but these results were reported in heterogeneous in vivo studies without elucidation of the underlying mechanisms. In the present study, we established H. pylori infection models in both wild-type and VDR knockdown (VDR^-KD) mice, which were used to demonstrate that VitD3 inhibits H. pylori infection by enhancing the expression of VitD receptor (VDR) and cathelicidin antimicrobial peptide (CAMP). Furthermore, VDR^-KD mice that exhibited lower VDR expression were more susceptible to H. pylori infection. In cultured mouse primary gastric epithelial cells, we further demonstrated that the VitD3/VDR complex binds to the CAMP promoter region to increase its expression. These data provide a mechanistic explanation of the anti-H. pylori infection activity of VitD3 at the molecular level in mice and suggest a new avenue for the clinical management of H. pylori eradication therapy.

Association of Helicobacter pylori Infection with Vitamin D Deficiency in Infants and Toddlers

Helicobacter pylori (H. pylori), a gram-negative pathogen, has been shown to colonize multiple organs and cause various forms of extra-gastrointestinal diseases. The association of H. pylori infection with vitamin D status in apparently healthy children remained unclear; therefore, we investigated the relationship between vitamin D and H. pylori infection among apparently healthy infants and toddlers. In this large cross-sectional study, the examination data of children were collected from January 2013 to September 2017 in the Center for Children's Health Care. Among these children, 6,896 infants and toddlers were screened for our study. Helicobacter pylori infection and vitamin D status were the main indicators, and micronutrients (zinc, iron, copper, magnesium), and growth parameters (height, weight, and weight for age Z score [WAZ], height for age Z score [HAZ]) were also analyzed in this study. Among the 6,896 infants and toddlers, the detection rate of H. pylori seropositivity was 30.6%. The prevalence of vitamin D deficiency in H. pylori seropositive and seronegative groups was 20.7% and 12.1%, respectively (P < 0.001). The logistic regression analysis suggested children with H. pylori-positive antibody were 2.06 times more likely to be vitamin D deficient compared with children who had negative H. pylori antibody (odds ratio: 2.06; 95% CI: 1.77, 2.38) after controlling for confounding factors. These data suggested that there was a significant association between H. pylori seropositivity and vitamin D deficiency in children aged 6-36 months, which would make a contribution to the treatment and monitoring of vitamin D deficiency and H. pylori infection.

Effect of vitamin D on Helicobacter pylori infection and eradication: A meta-analysis

BACKGROUND

Various studies reported the relationship between Helicobacter pylori (H pylori) and vitamin D, but there is some controversy around that. This study aimed to conduct a meta-analysis to clarify the relationship between vitamin D and H pylori infection, and vitamin D and H pylori eradication.

METHODS

Articles published until June 1, 2019, in the PubMed, MEDLINE, and EMBASE databases with English-language medical studies were searched. According to the inclusion criteria, relevant statistical data were extracted to Microsoft Excel and analyzed by STATA15.1.

RESULTS

Ten articles were finally included. It was demonstrated that average 25(OH)D level in H pylori-positive patients was lower than H pylori-negative (SMD = -0.53 ng/mL, 95% CI = (-0.91, -0.16 ng/mL)). For H pylori eradication individuals, the result showed that average 25(OH)D level in H pylori successful eradication individuals was higher than unsuccessful (SMD = 1.31 ng/mL, 95% CI = [0.60, 2.02 ng/mL]). In addition, individuals with vitamin D deficiency had lower H pylori eradicate rate (OR = 0.09, 95% CI = [0.02, 0.41]). Sensitivity analysis showed that the meta-analysis results were stable and reliable.

CONCLUSIONS

Vitamin D was a protective factor to H pylori infection. Moreover, vitamin D can improve the success rate of H pylori eradication.

Vitamin D in Acute Campylobacteriosis-Results From an Intervention Study Applying a Clinical Campylobacter jejuni Induced Enterocolitis Model

Human Campylobacter infections are progressively rising and of high socioeconomic impact. In the present preclinical intervention study we investigated anti-pathogenic, immuno-modulatory, and intestinal epithelial barrier preserving properties of vitamin D applying an acute campylobacteriosis model. Therefore, secondary abiotic IL-10^−/− mice were perorally treated with synthetic 25-OH-cholecalciferol starting 4 days before peroral Campylobacter jejuni infection. Whereas, 25-OH-cholecalciferol application did not affect gastrointestinal pathogen loads, 25-OH-cholecalciferol treated mice suffered less frequently from diarrhea in the midst of infection as compared to placebo control mice. Moreover, 25-OH-cholecalciferol application dampened C. jejuni induced apoptotic cell responses in colonic epithelia and promoted cell-regenerative measures. At day 6 post-infection, 25-OH-cholecalciferol treated mice displayed lower numbers of colonic innate and adaptive immune cell populations as compared to placebo controls that were accompanied by lower intestinal concentrations of pro-inflammatory mediators including IL-6, MCP1, and IFN-γ. Remarkably, as compared to placebo application synthetic 25-OH-cholecalciferol treatment of C. jejuni infected mice resulted in lower cumulative translocation rates of viable pathogens from the inflamed intestines to extra-intestinal including systemic compartments such as the kidneys and spleen, respectively, which was accompanied by less compromised colonic epithelial barrier function in the 25-OH-cholecalciferol as compared to the placebo cohort. In conclusion, our preclinical intervention study provides evidence that peroral synthetic 25-OH-cholecalciferol application exerts inflammation-dampening effects during acute campylobacteriosis.

Influence of serum vitamin D level on Helicobacter pylori eradication: A multi-center, observational, prospective and cohort study

OBJECTIVES

This study was designed to test whether serum vitamin D levels affected Helicobacter pylori (H. pylori) infection and eradication rates.

METHODS

A multicenter observational prospective cohort study was conducted. A total of 496 H. pylori^- positive (H. pylori⁺ ) and 257 H. pylori-negative (H. pylori^- ) patients were enrolled from four hospitals in China. Baseline serum vitamin D levels were measured and a ¹³ C-urea breath test (UBT) was performed for all the participants. The H. pylori⁺ patients were divided into two subgroups based on their serum vitamin D levels (<10 or ≥10 ng/mL). A second ¹³ C-UBT was performed between 4 and 8 weeks after 14-day bismuth-containing quadruple eradication therapies. Factors potentially affecting H. pylori eradication were determined using a questionnaire survey.

RESULTS

Serum vitamin D levels were significantly lower in the H. pylori⁺ group than in the H. pylori^- group ([17.0 ± 6.9] ng/mL vs [19.2 ± 8.0] ng/mL, P = 0.000). H. pylori eradication rate significantly differed between patients with serum vitamin D levels of <10 ng/mL and ≥10 ng/mL (71.7% vs 87.3%, P = 0.005). A multivariate analysis showed that having serum vitamin D level ≥10 ng/mL was an independent risk factor for a successful H. pylori eradication (odds ratio 0.381, 95% confidence interval 0.183-0.791, P = 0.010).

CONCLUSIONS

Serum vitamin D level may affect H. pylori infection and its eradication. Randomized controlled trials are needed to find out whether vitamin D supplements may increase the H. pylori eradication rate.

Vitamin D deficiency and risk of Helicobacter pylori infection in older adults: a cross-sectional study

BACKGROUND

Vitamin D deficiency is known to cause increased predisposition to various infectious diseases and the addition of vitamin D to antimicrobial treatment may improve treatment responses. However, the relationship between vitamin D and Helicobacter pylori (H. pylori) remains to be determined.

AIMS

To assess the association between vitamin D deficiency and H. pylori infection.

METHODS

This cross-sectional study included patients aged 65 and over, who underwent gastroscopy and had gastric biopsy performed between 2010 and 2017. Of the 441 patients, 254 had available 25-hydroxyvitamin D level results and were included in the analyses. Patients were categorized into H. pylori (+) and H. pylori (-) groups, according to histopathological examination results of gastric biopsies. Serum 25(OH) vitamin D levels less than 20 ng/mL were defined as vitamin D deficiency.

RESULTS

Of all patients, 43 were H. pylori (+) and 211 were H. pylori (-). More patients had vitamin D deficiency (< 20 ng/mL) in the H. pylori (+) group than the H. pylori (-) group (86% vs 67.3%, p = 0.014). The proportion of H. pylori (+) patients decreased across increasing quartiles of 25(OH) vitamin D levels (p for trend = 0.010). In multivariable logistic regression analysis, vitamin D deficiency was associated with increased odds of H. pylori infection after adjustment for age, gender, and Charlson Comorbidity Index (OR = 3.02, 95% CI 1.19-7.69, p = 0.020).

CONCLUSION

Vitamin D deficiency can be associated with increased risk of H. pylori infection. The potential protective effect of vitamin D against H. pylori infection and its possible role in the treatment of H. pylori should be evaluated in prospective trials.

Pathogenic roles of alterations in vitamin D and vitamin D receptor in gastric tumorigenesis

Gastric cancer is currently the second leading cause of cancer-related death worldwide, especially in Japan, Korea and China, and the 5-year survival rate of gastric cancer is less than 30%. Thus, it is important to shed more lights on novel agents to prevent gastric cancer or to improve survival rate of the patients. Vitamin D not only maintains calcium and bone homeostasis, but also mostly inhibits tumor genesis, invasion, and metastasis through activation of vitamin D receptor. Although epidemiological results are not consistent, accumulating evidence from gastric cancer cells, animal models, and clinical trials suggest that vitamin D deficiency may increase the risk and mortality of gastric cancer, but vitamin D supplement might be a safe and economical way to prevent or treat gastric cancer. Here, we reviewed the current studies on vitamin D and its receptor and focused on the pathogenic roles of their alterations in gastric tumorigenesis.

Dietary habits and Helicobacter pylori infection: a cross sectional study at a Lebanese hospital

BACKGROUND

To examine the association between dietary habits and Helicobacter pylori (H. pylori) infection among patients at a tertiary healthcare center in Lebanon.

METHODS

This cross-sectional study was conducted on 294 patients in 2016, at a hospital in Northern Lebanon. Participants were interviewed using a structured questionnaire to collect information on socio-demographic and lifestyle characteristics; dietary habits were ascertained via a short food frequency questionnaire (FFQ). H. pylori status (positive vs. negative) was determined after upper GI endoscopy where gastric biopsy specimens from the antrum, body, and fundus region were collected and then sent for pathology analysis. Multivariable logistic regression was conducted to identify the association between socio-demographic, lifestyle, dietary and other health-related variables with H pylori infection.

RESULTS

The prevalence of H. pylori infection was found to be 52.4% in this sample. Results of the multivariable analysis showed that H. pylori infection risk was higher among participants with a university education or above (OR = 2.74; CI = 1.17-6.44), those with a history of peptic ulcers (OR = 3.80; CI = 1.80-8.01), gastric adenocarcinoma (OR = 3.99; CI = 1.35-11.83) and vitamin D level below normal (OR = 29.14; CI = 11.77-72.13). In contrast, hyperglycemia was protective against H. pylori (OR = 0.18; CI = 0.03-0.89). No relationship between dietary habits and H. pylori infection was found in the adjusted analysis.

CONCLUSIONS

Socio-demographic and clinical variables are found to be associated with H. pylori, but not with dietary factors. Further studies are needed to investigate the effect of diet on H. pylori risk.

Nutritional modulation of age-related changes in the immune system and risk of infection

The immune system undergoes some adverse alterations during aging, many of which have been implicated in the increased morbidity and mortality associated with infection in the elderly. In addition to intrinsic changes to the immune system with aging, the elderly are more likely to have poor nutritional status, which further impacts the already impaired immune function. Although the elderly often have low zinc serum levels, several manifestations commonly observed during zinc deficiency are similar to the changes in immune function with aging. In the case of vitamin E, although its deficiency is rare, the intake above recommended levels is shown to enhance immune functions in the elderly and to reduce the risk of acquiring upper respiratory infections in nursing home residents. Vitamin D is a critical vitamin in bone metabolism, and its deficiency is far more common, which has been linked to increased risk of infection as demonstrated in a number of observational studies including those in the elderly. In this review, we focus on zinc, vitamin E, and vitamin D, the 3 nutrients which are relatively well documented for their roles in impacting immune function and infection in the elderly, to discuss the findings in this context reported in both the observational studies and interventional clinical trials. A perspective will be provided based on the analysis of information under review.

Genetic variations in vitamin D receptor were associated with the outcomes of hepatitis C virus infection among Chinese population

Vitamin D has been considered as an immune modulator, and exerted the effect through the vitamin D receptor (VDR). This study investigated the associations of single-nucleotide polymorphisms (SNPs) of VDR with the outcomes of Hepatitis C virus (HCV) infection. Three SNPs (rs2228570, rs757343 and rs739837) were genotyped by TaqMan assay among Chinese population, including 538 HCV spontaneous clearance subjects, 834 persistent infection subjects and 1030 uninfected subjects. Binary logistic analyses were used to control the effects of confounding factors. The results showed that subjects with the rs757343 A allele and rs739837 A allele had the significantly reduced risk of HCV susceptibility (all PBonferroni<0.05 in dominant/additive model). In the stratified analysis, the protection of rs757343 A allele and rs739837 A allele against HCV infection remained effective in some subgroups. In addition, patients carrying rs739837 CA genotype were less prone to develop persistent infection (PBonferroni=0.033) and such effect still work in several subgroups in the stratified analysis. Furthermore, haplotype analysis indicated that when compared with the most frequent GC haplotype, the haplotype carrying AA (odds ratio (OR)=0.66, 95% confidence interval (CI)=0.56-0.78) and GA (OR=0.64, 95% CI=0.47-0.85) suggested a protective effect. Our findings indicated that the polymorphisms of VDR are associated with the outcomes of HCV infection among Chinese population.

Identification and characterization of a vitamin D₃ decomposition product bactericidal against Helicobacter pylori

This study demonstrated that the vitamin D₃ decomposition product VDP1 exerts an antibacterial action against Helicobacter pylori but not against other bacteria. Treatment with VDP1 induced a collapse of cell membrane structures of H. pylori and ultimately lysed the bacterial cells. A unique dimyristoyl phosphatidylethanolamine in the membrane lipid compositions contributed to the interaction of VDP1 with H. pylori cells. In separate experiments, VDP1 had no influence on the viability of the human cancer cell lines MKN45 and T47D and lacked any vitamin D₃-like hormonal action against the latter. In both ¹H and ¹³C NMR analyses, the spectra patterns of VDP1 corresponded with those of Grundmann's ketone. These results suggest that VDP1 (or Grundmann's ketone-type indene compound) may become a fundamental structure for the development of new antibacterial substances with selective bactericidal action against H. pylori.

How important is vitamin D in preventing infections?

Interaction with the immune system is one of the most recently established nonclassic effects of vitamin D (VitD). For many years, this was considered to be limited to granulomatous diseases in which synthesis of active 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) or calcitriol is known to be increased. However, recent reports have supported a role for 1,25(OH)2D3 in promoting normal function of the innate and adaptive immune systems. Crucially, these effects seem to be mediated not only by the endocrine function of circulating calcitriol but also via paracrine (i.e., refers to effects to adjacent or nearby cells) and/or intracrine activity (i.e., refers to a hormone acting inside a cell) of 1,25(OH)2D3 from its precursor 25(OH)D3, the main circulating metabolite of VitD. The ability of this vitamin to influence human immune responsiveness seems to be highly dependent on the 25(OH)D3 status of individuals and may lead to aberrant response to infection or even to autoimmunity in those who are lacking VitD. The potential health significance of this has been underlined by increasing awareness of impaired status in populations across the globe. This review will examine the current understanding of how VitD status may modulate the responsiveness of the human immune system. Furthermore, we discuss how it may play a role in host resistance to common pathogens and how effective is its supplementation for treatment or prevention of infectious diseases in humans.

Prevalence and severity of vitamin D deficiency in patients with diabetic foot infection

The aim of the present research was to study the prevalence and severity of vitamin D deficiency in patients with diabetic foot infection. Patients were enrolled in two groups: diabetic patients with foot infection (n 125) as cases and diabetic patients without the infection as controls (n 164). Serum 25-hydroxyvitamin D (25(OH)D) was measured by RIA. Data were presented as means and standard deviations unless otherwise indicated and were analysed by SPSS. Results revealed that 25(OH)D (nmol/l) was significantly lower (40·25 (sd 38·35) v. 50·75 (sd 33·00); P < 0·001) in cases than in controls. Vitamin D inadequacy (25(OH)D < 75 nmol/l) was equally common in cases and controls (OR 1·45, 95 % CI 0·8, 3·0; P = 0·32), but cases had a greater risk of vitamin D deficiency (25(OH)D < 50 nmol/l) than controls (OR 1·8, 95 % CI 1·1, 3·0; P = 0·02). Risk of severe vitamin D deficiency (25(OH)D < 25 nmol/l) was significantly higher in cases than in controls (OR 4·0, 95 % CI 2·4, 6·9; P < 0·0001). Age, duration of diabetes and HbA1c were significantly higher in cases than in controls and therefore adjusted to nullify the effect of these variables, if any, on study outcome. The study concluded that vitamin D deficiency was more prevalent and severe in patients with diabetic foot infection. This study opens up the issue of recognising severe vitamin D deficiency (< 25 nmol/l) as a possible risk factor for diabetic foot infections and the need for vitamin D supplementation in such patients for a better clinical outcome. This could be substantiated by similar data from future studies.

Vitamin D receptor gene polymorphism in children with urinary tract infection

It is known that small alterations leading to different vitamin D receptor (VDR) alleles affect resistance or susceptibility to infections. In this study, we examined VDR gene polymorphisms in urinary tract infections (UTI), which are common and an important cause of morbidity in children and subsequently of renal scar formation. We evaluated 92 patients diagnosed with UTI and 105 children without prior history of UTI as a control group. The VDR gene polymorphisms BsmI, FokI, ApaI, and TaqI were evaluated in patients and controls. BsmI polymorphism genotype distribution was similar between groups. There was a significant difference between groups for FokI (p =0 < 001); for the ff genotype, the risk of UTI was significantly increased (p < 0.01) ,at 3.94 times higher (odds ratio = 3.94; 95% confidence interval 1.71-9.09). ApaI polymorphism was significantly increased in the control group (p < 0.01) and evaluated as a protective factor. Comparing the TaqI genotype between groups, there was no statistically significant difference, but in both Tt and tt genotypes, there was minimal increased risk of UTI. The results of this study suggest that VDR gene polymorphisms can be important for susceptibility to UTI and renal scar formation. Association between VDR polymorphisms and UTI is in accordance with the understanding of how vitamin D modulates the immune response against infections.

A review of the critical role of vitamin D in the functioning of the immune system and the clinical implications of vitamin D deficiency

This review looks at the critical role of vitamin D in improving barrier function, production of antimicrobial peptides including cathelicidin and some defensins, and immune modulation. The function of vitamin D in the innate immune system and in the epithelial cells of the oral cavity, lung, gastrointestinal system, genito-urinary system, skin and surface of the eye is discussed. Clinical conditions are reviewed where vitamin D may play a role in the prevention of infections or where it may be used as primary or adjuvant treatment for viral, bacterial and fungal infections. Several conditions such as tuberculosis, psoriasis, eczema, Crohn's disease, chest infections, wound infections, influenza, urinary tract infections, eye infections and wound healing may benefit from adequate circulating 25(OH)D as substrate. Clinical diseases are presented in which optimization of 25(OH)D levels may benefit or cause harm according to present day knowledge. The safety of using larger doses of vitamin D in various clinical settings is discussed.

Vitamin D for treatment and prevention of infectious diseases: a systematic review of randomized controlled trials

OBJECTIVE

To review the existing human controlled intervention studies of vitamin D as adjunctive therapy in settings of infection and provide recommendations for design and implementation of future studies in this field on the basis of the evidence reviewed.

METHODS

We conducted a systematic review of randomized controlled clinical trials that studied vitamin D for treatment or prevention of infectious diseases in humans. Studies from 1948 through 2009 were identified through search terms in PubMed and Ovid MEDLINE.

RESULTS

Thirteen published controlled trials were identified by our search criteria. Ten trials were placebo controlled, and 9 of the 10 were conducted in a rigorous double-blind design. The selected clinical trials demonstrated substantial heterogeneity in baseline patient demographics, sample size, and vitamin D intervention strategies. Serious adverse events attributable to vitamin D supplementation were rare across all studies. On the basis of studies reviewed to date, the strongest evidence supports further research into adjunctive vitamin D therapy for tuberculosis, influenza, and viral upper respiratory tract illnesses. In the selected studies, certain aspects of study design are highlighted to help guide future clinical research in the field.

CONCLUSION

More rigorously designed clinical trials are needed for further evaluation of the relationship between vitamin D status and the immune response to infection as well as for delineation of necessary changes in clinical practice and medical care of patients with vitamin D deficiency in infectious disease settings.