Latent tuberculosis infection, tuberculin skin test and vitamin D status in contacts of tuberculosis patients: a cross-sectional and case-control study

Association of variant vitamin statuses and tuberculosis development: a systematic review and meta-analysis

BACKGROUND

Several studies have suggested an association between vitamin deficiency and the development of tuberculosis; however, the precise impact remains unclear. This study aimed to elucidate the relationship between distinct vitamin statuses and the occurrence of tuberculosis.

MATERIALS AND METHODS

Retrieval was conducted using several databases without language restrictions to capture the eligible studies on tuberculosis and vitamin status. Pooled odds ratios (ORs), relative risks (RRs), and hazard ratios (HRs) were used with 95% confidence intervals (CIs) to clarify the relationship between the different vitamin statuses (A, B, D, and E) and the occurrence of tuberculosis. Subgroup analysis, sensitivity analysis, meta-regression analysis, and Galbraith plot were performed to determine sources of heterogeneity. Potential publication biases were detected using Begg's test, Egger's test, and the trim-and-fill test.

RESULTS

We identified 10,266 original records from our database searches, and 69 eligible studies were considered in this study. The random-effect model showed that people with tuberculosis may exhibit vitamin A deficiency (OR = 10.66, 95%CI: 2.61-43.63, p = .001), while limited cohort studies showed that vitamin A supplementation may reduce tuberculosis occurrence. Additionally, vitamin D deficiency was identified as a risk factor for tuberculosis development (RR = 1.69, 95%CI: 1.06-2.67, p = .026), and people with tuberculosis generally had lower vitamin D levels (OR = 2.19, 95%CI: 1.76-2.73, p < .001) compared to other groups. No publication bias was detected.

CONCLUSIONS

This meta-analysis indicated that people with tuberculosis exhibited low levels of vitamins A and D, while vitamin D deficiency was identified as a risk factor for tuberculosis. More randomized controlled interventions at the community levels should be recommended to determine the association between specific vitamin supplementation and tuberculosis onset.

Infectious and clinical tuberculosis trajectories: Bayesian modeling with case finding implications

The importance of finding people with undiagnosed tuberculosis (TB) hinges on their future disease trajectories. Assays for systematic screening should be optimized to find those whose TB will contribute most to future transmission or morbidity. In this study, we constructed a mathematical model that tracks the future trajectories of individuals with TB at a cross-sectional timepoint ("baseline"), classifying them by bacterial burden (smear positive/negative) and symptom status (symptomatic/subclinical). We used Bayesian methods to calibrate this model to targets derived from historical survival data and notification, mortality, and prevalence data from five countries. We combined resulting disease trajectories with evidence on infectiousness to estimate each baseline TB state's contribution to future transmission. For a person with smear-negative subclinical TB at baseline, the expected future duration of disease was short (mean 4.8 [95% uncertainty interval 3.3 to 8.4] mo); nearly all disease courses ended in spontaneous resolution, not treatment. In contrast, people with baseline smear-positive subclinical TB had longer undiagnosed disease durations (15.9 [11.1 to 23.5] mo); nearly all eventually developed symptoms and ended in treatment or death. Despite accounting for only 11 to 19% of prevalent disease, smear-positive subclinical TB accounted for 35 to 51% of future transmission-a greater contribution than symptomatic or smear-negative TB. Subclinical TB with a high bacterial burden accounts for a disproportionate share of future transmission. Priority should be given to developing inexpensive, easy-to-use assays for screening both symptomatic and asymptomatic individuals at scale-akin to rapid antigen tests for other diseases-even if these assays lack the sensitivity to detect paucibacillary disease.

Vitamin D and tuberculosis in children: a role in the prevention or treatment of the disease?

Despite the growing number of published studies, the role of vitamin D in the prevention or treatment of tuberculosis remains unclear. In this review we analyze current scientific literature to provide evidence about the relationship between vitamin D and TB, with a special focus on the pediatric population. While in vitro studies have shown relevant antimycobacterial immune-stimulatory and immunosuppressive effects of vitamin D, this has not panned out in vivo with active TB. On the contrary, there is some evidence that this tool could work as prevention - both against TB infection as well as progression from latent to active infection. However, only a few studies have evaluated this correlation in children. The potential link between tuberculosis and vitamin D levels is promising. If effective, vitamin D supplementation of at-risk populations would be an affordable public health intervention, particularly in light of the worldwide increase in identified TB cases and drug-resistance. Vitamin D might represent a new, affordable, safe and easy to access drug for the prevention and treatment of TB. For stronger evidence, considering the features of infection (relative low incidence of reactivation of latent infection in immunocompetent patients) we need clinical trials with large numbers of participants conducted in endemic regions with a prolonged follow-up time.

Vitamin D and the risk of latent tuberculosis infection: a systematic review and meta-analysis

Objective

Latent tuberculosis infection (LTBI) may be a risk of developing tuberculosis (TB) and thus a health hazard. The aim of this meta-analysis is to explore the association between vitamin D and LTBI.

Methods

Databases including PubMed, Embase, Scopus, and ProQuest were electronically searched to identify observational or interventional studies that reported the association between vitamin D and LTBI. The retrieval time is limited from inception to 30 September 2021. Two reviewers independently screened literature, extracted data, and assessed risk bias of included studies. Meta-analysis was performed by using STATA 12.0 software.

Results

A total of 5 studies involving 2 case–control studies and 3 cohort studies were included. The meta-analysis result showed that the risk of LTBI among individuals was not associated with high vitamin D level (OR 0.51, 95% CI 0.05–5.65, P = 0.58). The result from cohort studies also suggested that relatively high vitamin D level was not a protective factor for LTBI (RR = 0.56, 95%CI 0.19–1.67, P = 0.300).

Conclusions

Our meta-analysis suggested that serum vitamin D levels were not associated with incidence of LTBI, and relatively high serum vitamin D level was not a protective factor for LTBI. Further RCTs are needed to verify whether sufficient vitamin D levels and vitamin D supplementation reduces the risk of LTBI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01830-5.

Impact of vitamin D status and cathelicidin antimicrobial peptide on adults with active pulmonary TB globally: A systematic review and meta-analysis

BACKGROUND

Tuberculosis remains a global threat and a public health problem that has eluded attempts to eradicate it. Low vitamin D levels have been identified as a risk factor for tuberculosis infection and disease. The human cathelicidin LL-37 has both antimicrobial and immunomodulatory properties and is dependent on vitamin D status. This systematic review attempts to compare vitamin D andLL-37 levels among adult pulmonary tuberculosis patients to non-pulmonary TB individuals between 16-75 years globally and to determine the association between vitamin D and cathelicidin and any contributing factor among the two study groups.

METHODS/DESIGN

We performed a search, through PubMed, HINARI, Google Scholar, EBSCOhost, and databases. A narrative synthesis through evaluation of vitamin D and LL-37 levels, the association of vitamin D and LL-37, and other variables in individual primary studies were performed. A random-effect model was performed and weighted means were pooled at a 95% confidence interval. This protocol is registered under the International Prospective Register of Systematic Reviews (PROSPERO), registration number CRD42019127232.

RESULTS

Of the 2507 articles selected12 studies were eligible for the systematic review and of these only nine were included in the meta-analysis for vitamin D levels and six for LL-37 levels. Eight studies were performed in Asia, three in Europe, and only one study in Africa. The mean age of the participants was 37.3±9.9 yrs. We found low vitamin D and high cathelicidin levels among the tuberculosis patients compared to non-tuberculosis individuals to non-tuberculosis. A significant difference was observed in both vitamin D and LL-37 levels among tuberculosis patients and non-tuberculosis individuals (p = < 0.001).

CONCLUSION

This study demonstrated that active pulmonary tuberculosis disease is associated with hypovitaminosis D and elevated circulatory cathelicidin levels with low local LL-37 expression. This confirms that vitamin D status has a protective role against tuberculosis disease.

Effectiveness of vitamin D supplementation on the outcome of pulmonary tuberculosis treatment in adults: a meta-analysis of randomized controlled trials

Supplemental Digital Content is available in the text

Background:

Tuberculosis (TB) is one of the most debilitating diseases worldwide. Current studies have shown that vitamin D plays a significant role in host immune defense against Mycobacterium tuberculosis, but clinical trials reported inconsistent results. Therefore, we systematically reviewed the literature to investigate whether vitamin D supplementation could improve the effect of anti-TB therapy.

Methods:

We systematically searched PubMed, Embase, and the Cochrane Central Register of Controlled Trials from their inception to February 8th, 2019 for randomized controlled trials on vitamin D supplementation in patients with pulmonary TB receiving anti-TB therapy. The primary outcomes were time to sputum culture and smear conversion and proportion of participants with negative sputum culture. The secondary outcomes were clinical response to treatment and adverse events. A random-effects model was used to pool studies. Data were analyzed using RevMan 5.3 software.

Results:

Five studies with a total of 1126 participants were included in our meta-analysis. Vitamin D supplementation did not shorten the time to sputum culture and smear conversion (hazard ratio [HR] 1.04, 95% confidence interval [CI] 0.89–1.23, P = 0.60; HR 1.15, 95% CI 0.93–1.41, P = 0.20, respectively) and did not lead to an increase in the proportion of participants with negative sputum culture (relative risk [RR] 1.04, 95% CI 0.97–1.11, P = 0.32). However, it reduced the time to sputum culture conversion in the sub-group of participants with TaqI tt genotype (HR 8.09, 95% CI 1.39–47.09, P = 0.02) and improved the multidrug-resistant (MDR) TB sputum culture conversion rate (RR 2.40, 95% CI 1.11–5.18, P = 0.03). There was no influence on secondary outcomes.

Conclusions:

Vitamin D supplementation had no beneficial effect on anti-TB treatment, but it reduced the time to sputum culture conversion in participants with tt genotype of the TaqI vitamin D receptor gene polymorphism and improved the MDR TB sputum culture conversion rate.

Association of vitamin D levels and risk of latent tuberculosis in the hemodialysis population

BACKGROUND

Vitamin D is essential in the host defense against tuberculosis (TB). Suboptimal vitamin D status is common in the hemodialysis population. Hemodialysis patients have an increased risk compared to the general population latent tuberculosis infection (LTBI). However, the association between vitamin D deficiency and LTBI in this population remains unclear.

MATERIALS AND METHODS

We conducted a cross-sectional study between March and May 2017. Interferon-gamma release assay (IGRA) through QuantiFERON-TB Gold In-Tube was used to assess LTBI. Plasma 25-hydroxycholecalciferol (25-OHD) levels were measured by Elecsys Vitamin D Total assay. Suboptimal vitamin D levels included vitamin D insufficiency 20-29 ng/mg and vitamin D deficiency <20 ng/mL. Predictors for LTBI were analyzed.

RESULTS

A total of 287 participants were enrolled. The suboptimal vitamin D level was 31.4% (90/287), which including the vitamin D deficiency was 13.9% (40/287). A total of 49.1% (141/287) people received nutritional vitamin D supplementation. The prevalence of IGRA positivity in this study was 25.1% (72/287). There was no significant difference in vitamin D concentrations or the proportion of vitamin D supplementation among the IGRA-positive and IGRA-negative groups (p = 0.789 and 0.496, respectively). In multivariate analysis, age >65 years old (odds ratio (OR), 1.89; 95% CI, 1.08-3.31; p = 0.026) and TB history (OR, 3.51; 95% CI, 1.38-8.91; p = 0.008) were independent predictors of IGRA positivity.

CONCLUSION

This is the first study to report that vitamin D deficiency was not associated with IGRA positivity in a hemodialysis population. Aging and TB history were both independent predictors for LTBI.

Association between vitamin D and latent tuberculosis infection in the United States: NHANES, 2011-2012

Background

Latent tuberculosis infection (LTBI) is a precursor of active tuberculosis diseases and an important issue in the United States and worldwide. The association between vitamin D deficiency and LTBI is poorly understood.

Methods

From 2011 to 2012, the National Health and Nutrition Examination Survey (NHANES) assessed LTBI (according to tuberculin skin testing and QuantiFERON^®-TB Gold In-Tube) and measured serum levels of vitamin D. We evaluated the association between LTBI and vitamin D using multivariate logistic regression models adjusted for known confounders.

Results

The LTBI group had a lower 25-hydroxyvitamin D [25(OH)D] level than the non-LTBI group (p=0.0012). The adjusted risk of LTBI was significantly higher among participants with serum 25(OH)D levels <12 ng/ml (adjusted OR [aOR], 2.27; 95% CI, 1.40-3.66) and 12-19 ng/ml (aOR, 1.75; 95% CI, 1.25-2.46) compared to those with a level ≥30 ng/ml. The higher risk of LTBI among the participants with serum 25(OH)D levels <12 ng/ml and 12-19 ng/ml remained unchanged in both male and summer season subgroups.

Conclusions

A low serum 25(OH)D level was significantly associated with the risk of LTBI in this US cohort.

Efficacy and safety of cholecalciferol-augmented anti-tuberculosis therapy for treatment of naïve patients with pulmonary tuberculosis: A randomized, controlled, clinical study

BACKGROUND/OBJECTIVE

Vitamin D deficiency may contribute to the therapeutic failure of antituberculosis therapy (ATT). The aim of this study is to explore the role of adding cholecalciferol to the standard ATT in improving the therapeutic outcome among the naïve patients with pulmonary tuberculosis (TB).

METHODS

A randomized, controlled, clinical study, which included 496 naïve patients with pulmonary TB, was carried out. The patients were randomly allocated to two groups. Group-A included 247 patients who received ATT, while group-B included 249 patients who received ATT with cholecalciferol.

RESULTS

The rate of therapeutic failure among the study population was 29.4%; it was significantly lower among patients of group-B compared to those of group-A (22.1% (95% CI 14.7-26.2) vs 38.1% (95% CI 31.5-46.1), p 0.036). In addition, the rate of early therapeutic response was significantly higher among patients of group-B compared to those of group-A (35.3% (95% CI 29.6-42.3) vs 19.4% (95% CI 15.1-24.6), p 0.041). Incidence rate of adverse effects was 19.3%; it was higher (although not statistically significant) among patients of group-A compared to those of group-B (21.9% vs 16.9%).

CONCLUSIONS

In conclusion, cholecalciferol-augmented ATT can be more efficacious in treating naïve patients with pulmonary TB compared to the standard ATT. In addition, adding vitamin D3 to ATT provides extra protection against the hepatic and muscular adverse effects of ATT.

Serum vitamin D levels and risk of prevalent tuberculosis, incident tuberculosis and tuberculin skin test conversion among prisoners

Poor vitamin D status has been associated with tuberculosis (TB); whether poor status is cause or consequence of disease is uncertain. We conducted a case-control study and two nested case-control studies to determine whether vitamin D levels were associated with active TB, tuberculin skin test (TST) conversion, and risk of progression to the active TB in prisoners in Brazil. In multivariable conditional logistic regression, subnormal vitamin D levels (OR, 3.77; 95% CI, 1.04–13.64) were more likely in prisoners with active TB. In contrast, vitamin D was not found to be a risk factor for either TST conversion (OR, 2.49; 95% CI, 0.64–9.66) or progression to active disease (OR, 0.59; 95% CI, 0.13–2.62). Black race (OR, 11.52; 95% CI, 2.01–63.36), less than 4 years of schooling (OR, 2.70; 95% CI, 0.90–8.16), cigarette smoking (OR, 0.23; 95% CI, 0.06–0.79) were identified as risk factors for TST conversion. Risk of progression to active TB was found to be associated with cigarette smoking (OR, 7.42; 95% CI, 1.23–44.70). Our findings in the prison population show that poor vitamin D status is more common in individuals with active TB, but is not a risk factor for acquisition of latent TB or progression to active TB.

Vitamin D deficiency among newly diagnosed tuberculosis patients and their household contacts: a comparative cross-sectional study

Background

Recent studies suggest that the incidence and severity of tuberculosis is associated with low levels of vitamin D. Even though individuals living in Ethiopia have a high exposure to sunlight which is a source of vitamin D, tuberculosis is still one of the major causes of morbidity and mortality in the country. Therefore, this study aimed to determine the prevalence and associated factors of vitamin D deficiency in newly diagnosed tuberculosis patients, household contacts and community controls in Gondar, Ethiopia.

Methods

A comparative cross-sectional study design was conducted. Blood samples were collected from newly diagnosed smear positive pulmonary TB patients, their household contacts and community controls. Serum 25(OH)-vitamin D₃ was determined by an Enzyme Linked Immunosorbent Assay. A serum level of 25(OH)-vitamin D₃ below < 50 nmol/L was defined as vitamin D deficiency and <25 nmol/L as severe vitamin D deficiency.

Results

A total of 126 newly diagnosed smear positive TB patients, 57 house hold contacts and 70 apparently community controls were included in the study. The mean ± SD age (years) of TB patients, house hold contacts and community controls was 29.8 ± 11.9, 24.3 ± 14.7 and 27.3 ± 7.6 respectively. Ninety out of 126 (71.4%) TB patients were underweight with a BMI of < 18.5 kg/m². The mean 25(OH)-vitamin D₃ level of TB patients (30.1 ± 19.3 nmol/L) was significantly lower than community controls (38.5 ± 20.9 nmol/L, P = 0.005 and household contacts (37.7 ± 12.8 nmol/L, P =0.031).). The prevalence of vitamin D deficiency was higher in TB patients (83.3%) than in community controls (67.1%, P = 0.009). The prevalence of vitamin D deficiency was also found higher in household contacts (80.7%). Severe vitamin D deficiency was observed in 53%(67/126), 30% (21/70), 19.3%(11/57) of TB patients, community controls and household contacts respectively. Low BMI (AOR = 2.13; 95%CI: 1.02, 3.28) and being positive for tuberculosis (AOR = 1.93; 95%CI: 1.06, 2.86) were significant predictors of severe vitamin D deficiency.

Conclusion

High prevalence of vitamin D deficiency was found among newly diagnosed TB patients and in their household contacts. The present study warrants further studies to determine the role of vitamin D supplementation in the prevention and treatment of tuberculosis in Ethiopia.

Association of vitamin D deficiency, season of the year, and latent tuberculosis infection among household contacts

OBJECTIVES

Vitamin D (VD) enhances the immune response against Mycobacterium tuberculosis in vitro, and VD deficiency has been described in patients with active tuberculosis (TB). However, the role of hypovitaminosis D in the pathogenesis of early TB infection acquisition is unclear. We aimed to evaluate the association of VD deficiency, season of the year, and latent TB infection in household contacts (HHC), given that this is a potentially modifiable condition often related to nutritional deficiencies and lack of sun exposure.

METHODS

We prospectively enrolled new pulmonary TB cases (n = 107) and their HHC (n = 144) over a 2-year period in Santiago, Chile. We compared plasma 25-hydroxycholecalciferol (25OHD) levels and examined the influence of season, ethnic background, living conditions, and country of origin.

RESULTS

Over 77% of TB cases and 62.6% of HHC had VD deficiency (<20 ng/ml). Median 25OHD concentration was significantly lower in TB cases than in HHC (11.7 vs. 18.2 ng/ml, p<0.0001). Migrants HHC had lower 25OHD levels than non-migrants (14.6 vs. 19.0 ng/ml, p = 0.026), and a trend towards a higher burden of latent TB infection (52.9% vs. 35.2%, p = 0.066). Multivariate analysis found VD deficiency in HHC was strongly associated with being sampled in winter/spring (adOR 25.68, 95%CI 7.35-89.7), corresponding to the seasons with lowest solar radiation exposure. Spring enrollment-compared with other seasons-was the chief risk factor for latent TB infection in HHC (adOR 3.14, 95%CI 1.28-7.69).

CONCLUSIONS

Hypovitaminosis D was highly prevalent in TB cases and also in HHC. A marked seasonality was found for both VD levels and latent TB in HHC, with winter being the season with lowest VD levels and spring the season with the highest risk of latent TB infection.

Vitamin D Deficiency among Adults with History of Pulmonary Tuberculosis in Korea Based on a Nationwide Survey

We investigated the prevalence of vitamin D deficiency among individuals who have a history of tuberculosis (TB) diagnosis in Korea. Using the 5th Korean National Health and Nutrition Examination Survey, we selected 805 individuals with a history of TB diagnosis and 16,049 controls without a history of TB. Vitamin D deficiency was defined as a 25(OH)D level less than 20 ng/mL. Vitamin D deficiency was revealed in 71.7% of the individuals with a history of TB diagnosis and in 72.1% of the controls. Vitamin D deficiency was more likely in women than in men, in people who engaged in other jobs or were unemployed than in people who engaged in skilled agricultural, forestry, and fishery jobs, and in people who walked 3–5 days per week than in people who walked 6–7 days per week. Vitamin D deficiency was highly prevalent in the TB group. Regular examination and strategies to increase vitamin D levels in individuals with a history of TB are needed, as vitamin D is associated with TB conditions and bone disease.

Regional solar radiation is inversely correlated with incidence and severity of tuberculosis in Chile

Vitamin D (VD) deficiency has been linked to increased incidence and morbidity of tuberculosis (TB). Chile has large variations in solar radiation (SR; a proxy of VD status) and high prevalence of VD deficiency in its southernmost regions with low SR. We investigated the correlation between regional SR and rates of TB incidence, admissions and deaths in Chile by reviewing national records on prospectively collected mandatory disease notifications, admissions and mortality between 2001 and 2011. Over the study period, 26 691 new TB notifications were registered. The TB incidence rate was 14·77 (95% confidence intervals (CIs) 14·60-14·95), admission rate was 12·12 (95% CI 11·96-12·28) and mortality rate was 1·61 (95% CI 1·55-1·67) per 100 000 population per year. Multivariable linear regressions adjusting for significant demographic TB risk factors in Chile (regional prevalence of HIV infection, rates of migration from TB-endemic countries and rates of imprisonment) revealed an independent and highly statistically significant inverse association between SR and TB incidence rate (β -1·05, 95% CI -1·73 to -0·36, P = 0·007), admission rate (β -1·58, 95% CI -2·23 to -0·93, P < 0·001), and mortality rate (β -0·15, 95% CI -0·23 to -0·07, P = 0·002). These findings support a potential pathogenic role of VD deficiency in TB incidence and severity.

Effect of DOTS Treatment on Vitamin D Levels in Pulmonary Tuberculosis

INTRODUCTION

Vitamin D (Vit D) modulates a variety of processes and regulatory systems including host defense, inflammation, immunity, and repair. Vit D Deficiency (VDD) is been implicated as a cause in diabetes, immune dysfunction and Tuberculosis (TB). Impaired metabolism of Vit D and an adverse outcome is associated with Pulmonary Tuberculosis (PTB). Directly Observed Treatment Short Course (DOTS) consist of drugs like rifampicin and isoniazid, which respectively cause accelerated loss of Vit D due to increased clearance and impairment of 25-hydroxylation causing diminished Vit D action.

AIM

The aim of the present study was to estimate and compare serum Vit D status in newly diagnosed PTB patients before and after DOTS to validate the supplementation of Vit D in PTB patients.

MATERIALS AND METHODS

Forty four newly diagnosed PTB patients of both the sexes in the age group of 18 to 60 years before starting DOTS were recruited to participate in this non- randomized controlled trial with their voluntary consent. Vit D status in these patients and the effect of DOTS on Vit D were evaluated.

RESULTS

Mean Vit D levels of the study population aged 43±13 years was 20.74 ng/ml (normal >30 ng/ml) at the time of diagnosis. After completion of six months of therapy mean Vit D reduced to 17.49 ng/ml (p-value=0.041). On individual observations, 70% of the participants showed a decrease in Vit D levels from their baseline, whereas 30% showed an increase. Comparison between the two groups indicated the possible role of younger age in the improved status.

CONCLUSION

VDD was seen in PTB patients, which worsened in majority of the study population after treatment; hence it would be advisable to recommend Vit D supplementation in PTB patients for a better outcome.

Vitamin D deficiency and the risk of tuberculosis: a meta-analysis

BACKGROUND AND AIM

To conduct meta-analyses of all published studies on various aspects of association between vitamin D and tuberculosis (TB).

METHODS

PubMed and Web of Knowledge were searched for all properly controlled studies on vitamin D and TB. Pooled odds ratio, mean difference or standardized mean difference, and its corresponding 95% confidence interval were calculated with the Cochrane Review Manager 5.3.

RESULTS

A significantly lower vitamin D level was found in TB patients vs controls; vitamin D deficiency (VDD) was associated with an increased risk of TB, although such an association was lacking in the African population and in the human immunodeficiency virus-infected African population. A significantly lower vitamin D level was found in human immunodeficiency virus-TB-coinfected African patients receiving antiretroviral treatment who developed TB-associated immune reconstitution inflammatory syndrome vs those who did not develop TB-associated immune reconstitution inflammatory syndrome. VDD was associated with an increased risk of developing active TB in those subjects with latent TB infection and with an increased risk of tuberculin skin test conversion/TB infection conversion, and the trend toward a lower vitamin D level in active TB patients vs latent TB infection subjects did not reach statistical significance, indicating that VDD was more likely a risk factor than a consequence of TB. This concept was further strengthened by our result that anti-TB treatment did not affect vitamin D level in TB patients receiving the treatment.

CONCLUSION

Our analyses revealed an association between vitamin D and TB. VDD is more likely a risk factor for TB than its consequence. More studies are needed to determine whether vitamin D supplementation is beneficial to TB prevention and treatment.

Low vitamin D level and impact on severity and recurrence of Clostridium difficile infections

BACKGROUND

Clostridium difficile infection (CDI) has recently markedly increased, incurring greater health care-associated costs and hospitalizations especially in vitamin D deficient patients. Accordingly, the aim of this study was to evaluate the relationship between low vitamin D levels and the severity and recurrence of CDI.

METHODS

A retrospective case-control study evaluated patients hospitalized between 2007 and 2013 with CDI and a positive C. difficile toxin assay. Severe complicated CDI was defined based on (1) laboratory or radiological criteria correlated clinically and (2) sepsis requiring intensive care unit admission. Recurrent CDI (RCDI) was defined as a new episode of diarrhea occurring within 90 days of resolution of the initial episode for at least 10 days after discontinuing therapy and confirmed by positive stool C. difficile toxin assay or polymerase chain reaction. Patients were divided into 4 groups based on vitamin D level (ng/mL): severely deficient (<10), insufficient (10-19.9), predeficient (20-29.9), and control group (≥30).

RESULTS

Two hundred seventy-one patients were diagnosed with CDI, of which 48 had RCDI distributed as 5 (12.5%), 15 (16.1%), 10 (15.6%), and 13 (17.5%) patients in each of the aforementioned groups, respectively (P=0.55). Severe complicated CDI was identified in 7 (17.5%), 17 (18.2%), 9 (14%), and 3 (4%) patients, respectively (P=0.04). Thirty-day mortality was 1 of 40, 1 of 93, 2 of 64, and 2 of 74 patients, respectively (P=0.43).

CONCLUSIONS

Normal vitamin D level has a protective effect against severe CDI, and low vitamin D is associated with greater severity of CDI but not with an increased risk of RCDI or 30-day mortality.

Vitamin D Status, Receptor Gene Polymorphisms, and Supplementation on Tuberculosis: A Systematic Review of Case-Control Studies and Randomized Controlled Trials

OBJECTIVE

To investigate the impacts of vitamin D status, supplementation and vitamin D receptor (VDR) gene polymorphisms on tuberculosis (TB).

METHODS

We conducted a systematic review of published studies pertaining to case-control and randomized-control trials from 2002 to 2014 using the PubMed database.

RESULTS AND CONCLUSION

Individuals with TB have lower vitamin D status than healthy individuals. Some VDR gene polymorphisms are associated with increased susceptibility to TB while others may not. Supplementation with vitamin D leads to improved clinical outcomes. However, further studies with a larger patient population and different ethnicities are needed to confirm these effects.

Status of vitamin D, antimicrobial peptide cathelicidin and T helper-associated cytokines in patients with diabetes mellitus and pulmonary tuberculosis

Pulmonary tuberculosis (PTB) is a high burden infectious disease in China. The immune function is damaged in patients with diabetes mellitus (DM) who are easy to infect with Mycobacterium tuberculosis (Mtb). The growth of Mtb has been shown to be restrained following the administration of vitamin D and antimicrobial peptide cathelicidin (LL-37); however, the effect in patients with DM and PTB remains unclear. Vitamin D can regulate the immune system through Vitamin D receptors expressed in T helper (Th) cells. The aim of the present study was to analyze the status and correlations of vitamin D, LL-37 and Th-associated cytokines in patients with PTB or PTB with DM (DMPTB). Serum 25-hydroxyvitamin D₃ [25(OH)D₃] levels were measured by liquid chromatography-tandem mass spectrometry, while plasma LL-37 levels were analyzed using a solid-phase enzyme-linked immunosorbent assay. Flow cytometry was used to analyze the levels of Th cytokines, including Th1-associated IFN-γ, Th2-associated IL-4 and Th17-associated IL-17. The results revealed that patients with PTB and DMPTB were vitamin D deficient or had insufficient vitamin D levels. Furthermore, the levels of LL-37, IFN-γ, IL-4 and IL-17 were higher in the PTB and DMPTB groups when compared with the normal controls. These results indicated that vitamin D supplementation is necessary for PTB and DMPTB patients. In addition, LL-37, IFN-γ and IL-17 may be diagnostic indexes that become elevated in the compensatory response caused by Mtb infection. Vitamin D can regulate the immune status in patients suffering from PTB.

Vitamin D status and incidence of tuberculosis infection conversion in contacts of pulmonary tuberculosis patients: a prospective cohort study

The objective of this study was to estimate the relationship between serum vitamin D (VitD) status and tuberculosis (TB) infection conversion (TBIC), measured by the tuberculin skin test (TST) and an interferon-gamma release assay, the QuantiFERON-TB Gold In-Tube (QFT-GIT) test, in the contacts of pulmonary TB patients in Castellon (Spain) in a prospective cohort study from 2010 to 2012. Initially, the participants were negative to latent TB infection after a screening that included TST and QFT-GIT tests, and other examinations. A baseline determination of 25-hydroxyvitamin D [25(OH)D] was obtained by chemiluminescence immunoassay. After 8-10 weeks, participants were screened for a second time to determine TB infection conversion (TBIC). Poisson regression models were used in the statistical analysis. Of the 247 participants in the cohort, 198 (80·2%) were screened twice and 18 (9·1%) were TBIC cases. The means of VitD concentration in the TBIC cases and the non-cases were 20·7±11·9 and 27·2±11·4 ng/ml (P = 0·028), respectively. Adjusted for high exposure and TB sputum acid-fast bacilli (AFB)-positive index case, higher serum VitD concentration was associated with low incidence of TBIC (P trend = 0·005), and an increase of 1 ng/ml VitD concentration decreased the incidence of TBIC by 6% (relative risk 0·94, 95% confidence interval 0·90-0·99, P = 0·015). The results suggest that sufficient VitD level could be a protective factor of TBIC.

Early clearance of Mycobacterium tuberculosis: a new frontier in prevention

Early clearance (EC) is the successful eradication of inhaled Mycobacterium tuberculosis before an adaptive immune response develops. Evidence for EC comes from case contact studies that consistently show that a proportion of heavily exposed individuals do not develop M. tuberculosis infection. Further support for the existence of this phenotype comes from genetic loci associated with tuberculin reactivity. In this review we discuss aspects of the innate response that may underpin EC and hypotheses that can be tested through field laboratory link studies in M. tuberculosis case contacts. Specifically, we consider mechanisms whereby alveolar macrophages recognize and kill intracellular M. tuberculosis, and how other cell types, such as neutrophils, natural killer T cells, mucosa-associated invariant T cells and cd T cells may assist. How EC may be impaired by HIV infection or vitamin D deficiency is also explored. As EC is a form of protective immunity, further study may advance the development of vaccines and immunotherapies to prevent M. tuberculosis infection.

The seasonality of tuberculosis, sunlight, vitamin D, and household crowding

Background. Unlike other respiratory infections, tuberculosis diagnoses increase in summer. We performed an ecological analysis of this paradoxical seasonality in a Peruvian shantytown over 4 years.

Methods. Tuberculosis symptom-onset and diagnosis dates were recorded for 852 patients. Their tuberculosis-exposed cohabitants were tested for tuberculosis infection with the tuberculin skin test (n = 1389) and QuantiFERON assay (n = 576) and vitamin D concentrations (n = 195) quantified from randomly selected cohabitants. Crowding was calculated for all tuberculosis-affected households and daily sunlight records obtained.

Results. Fifty-seven percent of vitamin D measurements revealed deficiency (<50 nmol/L). Risk of deficiency was increased 2.0-fold by female sex (P < .001) and 1.4-fold by winter (P < .05). During the weeks following peak crowding and trough sunlight, there was a midwinter peak in vitamin D deficiency (P < .02). Peak vitamin D deficiency was followed 6 weeks later by a late-winter peak in tuberculin skin test positivity and 12 weeks after that by an early-summer peak in QuantiFERON positivity (both P < .04). Twelve weeks after peak QuantiFERON positivity, there was a midsummer peak in tuberculosis symptom onset (P < .05) followed after 3 weeks by a late-summer peak in tuberculosis diagnoses (P < .001).

Conclusions. The intervals from midwinter peak crowding and trough sunlight to sequential peaks in vitamin D deficiency, tuberculosis infection, symptom onset, and diagnosis may explain the enigmatic late-summer peak in tuberculosis.

Review article: vitamin D and inflammatory bowel diseases

BACKGROUND

Vitamin D is traditionally associated with bone metabolism. The immunological effects of vitamin D have increasingly come into focus.

AIM

To review the evidence supporting a role of vitamin D in inflammatory bowel diseases.

METHODS

A comprehensive search was performed on PubMed using the terms 'crohn's disease' 'ulcerative colitis' and 'vitamin D'.

RESULTS

Vitamin D deficiency is common in patients with inflammatory bowel diseases (IBD) (16-95%) including those with recently diagnosed disease. Evidence supports immunological role of vitamin D in IBD. In animal models, deficiency of vitamin D increases susceptibility to dextran sodium sulphate colitis, while 1,25(OH)2 D3 ameliorates such colitis. One prospective cohort study found low predicted vitamin D levels to be associated with an increased risk of Crohn's disease (CD). Limited data also suggest an association between low vitamin D levels and increased disease activity, particularly in CD. In a large cohort, vitamin D deficiency (<20 ng/mL) was associated with increased risk of surgery (OR 1.8, 95% CI 1.2-2.5) in CD and hospitalisations in both CD (OR 2.1, 95% CI 1.6-2.7) and UC (OR 2.3, 95% CI 1.7-3.1). A single randomised controlled trial demonstrated that vitamin D supplementation may be associated with reduced frequency of relapses in patients with CD compared with placebo (13% vs. 29%, P = 0.06).

CONCLUSIONS

There is growing epidemiological evidence to suggest a role for vitamin D deficiency in the development of IBD and also its influence on disease severity. The possible therapeutic role of vitamin D in patients with IBD merits continued investigation.

Effect of micronutrient deficiency on QuantiFERON-TB Gold In-Tube test and tuberculin skin test in diagnosis of childhood intrathoracic tuberculosis

BACKGROUND/OBJECTIVES

Data on performance of QuantiFERON-TB Gold In-Tube test (QFT) and tuberculin skin test (TST) in children with active tuberculosis from high burden countries in the context of micronutrient deficiency are scarce. The objective of this study was to evaluate the effect of micronutrient deficiency on the performance of TST and QFT in children with intrathoracic tuberculosis.

SUBJECTS/METHODS

Children with probable intrathoracic tuberculosis underwent TST, QFT, gastric lavages and induced sputum examination for AFB (Acid-Fast Bacilli) smear and culture. Zinc, copper, ferritin and vitamin D were measured on stored serum samples. The study used cross-sectional data at initiation of anti-tubercular therapy.

RESULTS

Three hundred and sixty-two children (median age 115.5 months (interquartile range: 73, 144), 200 (55.3%) girls) were enrolled in the study. Microbiological confirmation of tuberculosis could be obtained in 128 patients. TST and QFT were positive in 337 (93%) and 297 (82%) children, respectively. Performance of both the tests was unaffected by weight-for-age and height-for-age 'z-scores' or by serum copper levels. TST was not affected by serum zinc and ferritin levels. Children with negative QFT results had lower mean serum zinc level (P=0.01) and higher ferritin levels (P=0.007) as compared to those with positive test. Higher proportion of children with positive TST were vitamin D deficient/insufficient (P=0.003).

CONCLUSION

Micronutrient status, especially serum levels of zinc, may influence the performance of QFT in children with intrathoracic tuberculosis. Considering the high prevalence of zinc deficiency in developing countries, QFT should be used cautiously for diagnosing tuberculosis.

Low vitamin D level is an independent predictor of poor outcomes in Clostridium difficile-associated diarrhea

BACKGROUND

The incidence, recurrence, and all-cause mortality rate for Clostridium difficile-associated diarrhea (CDAD) has increased markedly over the past 10 years despite treatment. Low vitamin D levels are known to impair immune responses to infection and are associated with increased mortality. We compared the role of patient comorbidity measured by the Charlson Comorbidity Index (CCI) with vitamin D levels to ascertain whether vitamin D levels were an independent variable affecting the outcome of CDAD or a marker of overall comorbidity.

METHODS

A prospective cohort study studied 62 patients hospitalized between 2008 and 2009 with manifestations of CDAD and a positive C. difficile toxin assay. All patients received standard antibiotics (metronidazole and/or vancomycin). Their status at 30-day follow up was classified as resolved or recurred/expired. Patients' CCI was calculated using their medical history. Logistic regression analysis of variables including 25-hydroxyvitamin D, CCI, age, gender, white blood cell count (WBC), albumin and residence type were performed.

RESULTS

There were 62 patients (43.6% men, 56.4% women) with CDAD; mean age was 75 ± 17 years. At 30-day follow up, 28 (45.2%) expired, 10 (16.1%) had persistent or recurrent diarrhea and 24 (38.7%) resolved. Nonresolution was seen in 38 (61.3%). There was no significant association between 30-day resolution status and CCI, gender, WBC, albumin level or residence type. Two variables were found to be independent predictors of resolution of CDAD: normal vitamin D levels (p = 0.028) and age <70 years (p = 0.024). Subjects with low vitamin D were 4.75 times more likely to fail to resolve CDAD than subjects with normal Vitamin D.

CONCLUSION

In this study, vitamin D level and age are independent predictors of CDAD resolution in hospitalized patients. Low vitamin D levels and age >70 years old are associated with increased likelihood of recurrence. Low vitamin D levels are not a marker of comorbidity or advanced age.

[Tuberculosis: plasma levels of vitamin D and its relation with infection and disease]

BACKGROUND AND OBJECTIVE

Vitamin D (vitD) is involved in the phosphor-calcium metabolism and bone pathology, but also in inflammatory and infectious processes such as tuberculosis. The present study evaluates the clinical and epidemiological aspects of active tuberculosis cases and latently infected contacts in whom plasma concentrations of vitD were obtained to determine whether the deficiency of vitD is a risk factor to develop active tuberculosis, especially the more severe forms.

METHOD

Observational, retrospective study that included 86 tuberculosis patients and 80 contacts with latent infection in a 2-year period.

RESULTS

When comparing active tuberculosis cases with latent infection contacts, deficiency of vitD (vitD levels <10 ng/mL, odds ratio [OR]: 2.02, 95% confidence interval [CI]: 1.04 to 3.93), male sex (OR: 1.9, 95% CI: 0.96 to 3.71) and non-white race (OR: 0.7, 95% CI: 0.34 to 1.42) were factors independently associated with the diagnosis of tuberculosis.

CONCLUSION

Despite the limited number of subjects studied, there was a association between severe deficit of vitD and the presentation of tuberculosis.

Vitamin D, tuberculin skin test conversion, and latent tuberculosis in Mongolian school-age children: a randomized, double-blind, placebo-controlled feasibility trial

BACKGROUND

By modulating immune function, vitamin D might increase innate immunity and inhibit the growth of initial bacterial invasion and protect against tuberculosis infection.

OBJECTIVE

We examined the effect of vitamin D supplementation on tuberculin skin test (TST) conversion.

DESIGN

A double-blind, placebo-controlled study was conducted in 120 Mongol schoolchildren. We estimated the prevalence of latent tuberculosis infection at baseline and examined the effect of vitamin D (800 IU/d) on serum concentrations of 25-hydroxyvitamin D [25(OH)D] and TST conversion.

RESULTS

At baseline, the mean (±SD) 25(OH)D concentration was 7 ± 4 ng/mL, and all concentrations were <20 ng/mL. Vitamin D supplementation increased serum 25(OH)D by a mean of 12.7 ng/mL compared with placebo (P < 0.0001). At baseline, 16 children in the vitamin D group and 18 in the placebo group were TST positive (P = 0.7). Over 6 mo, TSTs converted to positive in 5 (11%) children receiving vitamin D compared with 11 (27%) receiving placebo (RR: 0.41; 95% CI: 0.16, 1.09; P = 0.06). Only one TST conversion occurred among those whose serum 25(OH)D concentration increased to >20 ng/mL, whereas 8 TST conversions occurred in those whose final 25(OH)D concentration remained <10 ng/mL (P = 0.05). The mean increase in stature was 2.9 ± 1.6 cm in the vitamin D group and 2.0 ± 1.7 cm in the placebo group (95% CI: 2.16, 2.81; P < 0.003).

CONCLUSIONS

Vitamin D supplementation for 6 mo had significant favorable effects on serum 25(OH)D concentrations and on growth in stature. A trend was seen toward fewer TST conversions in the vitamin D group. This trial was registered at clinicaltrials.gov as NCT01244204.