Vitamin D deficiency and TB disease phenotype

Prevalence of vitamin D deficiency and the effect of vitamin D3 supplementation on response to anti-tuberculosis therapy in patients with extrapulmonary tuberculosis

BACKGROUND

We aimed to assess serum 25-hydroxyvitamin D3 (25(OH)D3) concentrations in extrapulmonary tuberculosis (EPTB) patients and to evaluate the effect of vitamin D3 supplementation on their treatment course.

METHODS

Serum 25(OH)D3concentrations were measured in 47 newly diagnosed EPTB patients and 42 controls. Vitamin D-deficient EPTB patients were randomly assigned to receive 50,000 IU of vitamin D3 (cholecalciferol) orally once a week for 6 weeks (total 300,000 IU), followed by maintenance doses of 1000 IU a day besides anti-TB drugs or the first line anti-TB treatment only. Follow up serum 25(OH)D3 concentrations were measured after 3 months of starting vitamin D3 supplementation. Both groups were evaluated for clinical, laboratory, and radiological outcomes after treatment.

RESULTS

Serum 25(OH)D3 concentrations were significantly lower among TB cases (17.1 ± 5.5 nmol/L) compared to healthy controls (51.8 ± 27.3 nmol/L), and vitamin D deficiency was observed in all EPTB patients (n = 47). Patients in VD3 supplementation group had significantly higher weight gain and serum albumin level at 2 months and end of treatment, higher hemoglobin concentration at the end of treatment, significantly lower CRP and ESR at 2 months and at the end of treatment. In cases with TB pleurisy, a significant higher rate of full resolution of pleural fluid after 6 months of anti-TB treatment and shorter treatment duration were noted compared to the other group.

CONCLUSIONS

Vitamin D deficiency is prevalent in EPTB patients, in whom, vitamin D supplementation is a useful adjunctive therapy to anti-TB drugs and improves treatment course.

Comparative Study of Vitamin D Levels in Newly Diagnosed Tuberculosis and a Normal Population

Background and Objectives: Tuberculosis (TB) is an ancient disease caused by Mycobacterium tuberculosis, a member of the Mycobacterium tuberculosis complex. It contributes to significant morbidity and mortality. Treatment of TB poses a considerable challenge because of emerging drug resistance and the longer duration of therapy. Various past studies, both in vitro and in vivo, have established the role of vitamin D in the pathogenesis and treatment of TB. Results of in vivo studies are inconsistent, and this study aims to determine vitamin D levels and their association with newly diagnosed TB (pulmonary and extrapulmonary) cases and normal populations. Material and Methods: A Prospective Case-Control study with 116 subjects (58 cases and 58 controls) was conducted over two years. 29 cases of pulmonary TB and 29 cases of extrapulmonary TB constituted 58 cases of TB. Vitamin D levels were measured and compared in both the cases and controls. Data analysis was carried out using SPSS software 22.0. Results: The prevalence of vitamin D deficiency was 68.96% in the cases, while it was 51.72% in the controls. The reported median and quartile of serum vitamin D levels were 14.35 ng/mL (8.65, 25.48) in the TB group and 19.08 ng/mL (13.92, 26.17) in the control group. There was a significant statistical difference between the TB and non-TB populations with a p-value of 0.029 on the Mann-Whitney test. Conclusion: Vitamin D deficiency was more prevalent in individuals with TB than those without TB.

Assessment of Lipid Profile in Patients With Pulmonary Tuberculosis: An Observational Study

BACKGROUND

Mycobacterium tuberculosis causes tuberculosis (TB), an infectious lung disease. There is mounting evidence linking low lipid levels to a variety of human diseases, including TB. Cholesterol, mainly due to its involvement in heart disease, gets more attention in recent years. The objectives of the study were to look into the link that connects hypolipidemia to the existence of pulmonary/extrapulmonary TB; we have tried to find the link in relation to patients who have been recently diagnosed with TB as well as in those who are having TB in the long term.

MATERIALS AND METHODS

An observational study was performed on TB patients attending respiratory medicine at the Saveetha Medical College and Hospital, Chennai, Tamil Nadu, India, from February 2021 to January 2022, and their lipid levels were tested from patients with consent and correlated. Student's t-test was applied to the obtained data. To convey quantitative data, measurements such as mean along with standard deviation were applied, and a p-value of 0.05 was considered statistically significant.

RESULTS

This research included 80 subjects, 40 of whom were diagnosed with TB, and the rest (40 controls) were deemed healthy. The age group with the highest low lipid levels in pulmonary TB was 40-50 years. A chi-square test of association was conducted; this test revealed that the fraction of TB patients having lower than normal levels of total cholesterol (p = 0.0001), triglyceride level (p = 0.006), high-density lipoprotein (p = 0.009), low-density lipoprotein (p = 0.006), and body mass index (p = 0.000) was statistically significantly higher in contrast to the control group. Thus, there was a significant correlation between a higher prevalence of hypolipidemia in patients with pulmonary tuberculosis (PTB) and normal healthy individuals.

CONCLUSIONS

We observed a strong relationship between hypolipidemia and TB, indicating that patients with low lipid levels tend to have severe inflammation as compared to patients with normal lipid levels.

The Potential Role of Vitamin D in the Development of Tuberculosis in Chinese Han Population: One Case-Control Study

Background and aims:

Spinal serum 25-hydroxyvitamin D [25[OH]D] status plays an important role in mediating innate immune responses by acting as a cofactor for induction of antimycobacterial activity and is thus involved in the development of Tuberculosis (TB). Results reported regarding the association of vitamin D with TB remained controversial. We aimed to identify any common association between 25[OH]D status and TB in the Chinese Han population.

Methods

280 subjects (70 TB patients and 210 matched controls) were recruited. TB cases were diagnosed based on the presence of acid-fast bacilli on smears from sputum and MTB isolation. Healthy controls were randomly selected from four local community-based populations. 25[OH]D was detected by electrochemiluminescence immunoassay (ECLIA) on Roche Elecsys before the initial treatment. Multivariable logistic regression analysis was used to examine the association of Vitamin D with TB.

Results

There was no significant difference in the serum vitamin D level between total cases and controls, but we found a strong tendency toward a higher serum vitamin D level in male population (P < 0.05) with TB but not in females. High serum vitamin D increased the risk of TB in the Chinese Han population (OR = 1.035, 95%CI: 1.001–1.070, P < 0.05). The serum vitamin D level was significantly decreased with age increasing in cases and controls (all P < 0.001).

Conclusions

High serum vitamin D may be an independent risk factor for TB in the Chinese Han population.

Tuberculosis incidence in country of origin is a key determinant of the risk of active tuberculosis in people living with HIV: Data from a 30-year observational cohort study

INTRODUCTION

People living with HIV (PLWH) are at high risk of active tuberculosis (TB) but this risk in the era of antiretroviral treatment (ART) remains unclear. It is critical to identify the groups who should be prioritised for latent TB (LTBI) screening. In this study we identified the risk factors associated with developing incident TB disease, by analysing a 30-year observational cohort.

METHODS

We evaluated PLWH in Leicester, UK, between 1983 and 2017 to ascertain those who developed active TB and the timing of this in relation to HIV diagnosis; whether before, concurrently with, or more than 3 months after the diagnosis of HIV (incident TB). Predictors of incident TB were ascertained using Cox proportional hazards models.

RESULTS

In all, 325 out of 2158 (15.1%) PLWH under care had had active TB; 64/325 (19.7%) prior to HIV diagnosis, 161/325 (49.5%) concurrently with/within 3 months of HIV diagnosis and 100/325 (30.8%) had incident TB. Incident TB risk was 4.57/1000 person-years. Increased TB incidence in the country of birth was associated with an increased risk of developing incident TB [50-149/100 000 population, adjusted hazard ratio (AHR) = 3.10, 95% CI: 0.94-10.20; 150-249/100 000 population, AHR = 7.14, 95% CI: 3.46-14.74; 250-349/100 000 population, AHR = 5.90, 95% CI: 2.32-14.99; ≥ 350/100 000 population, AHR = 3.96, 95% CI: 1.39-11.26].

CONCLUSIONS

Tuberculosis risk remains high among PLWH and is related to TB incidence in the country of birth. Further work is required to determine whether specific groups of PLWH should be targeted for programmatic LTBI screening, and whether it will result in high uptake and completion of chemoprophylaxis and is cost-effective for widespread implementation.

The relationship between seasonality, latitude and tuberculosis notifications in Pakistan

Background

Pakistan ranks amongst the top 20 highest burden tuberculosis (TB) countries in the world. Approximately 369,548 cases of TB (all forms) were notified in 2018, with an estimated incidence of 265 per 100,000 people per year. In other settings, TB has been shown to demonstrate seasonal variation, with higher incidence in the spring/summer months and lower incidence in the autumn/winter; the amplitude of seasonal variation has also been reported to be higher with increasing distance from the equator.

Methods

Notifications of newly-diagnosed pulmonary and extrapulmonary TB cases were obtained for 139 districts in Pakistan from 2011 to 2017. Data were provided by the Pakistan National TB Control Programme, Islamabad, Pakistan. Statistical analyses were performed to determine whether there was seasonal variation in TB notifications in Pakistan; whether the amplitude of seasonal variation in TB notifications varied according to latitude; whether the amplitude of seasonal variation of TB in Pakistan differed between extrapulmonary TB vs. pulmonary TB. To assess the quarterly seasonality of TB, we used the X-13-ARIMA-SEATS seasonal adjustment programme from the United States Census Bureau. The mean difference and corresponding 95% confidence intervals of seasonal amplitudes between different latitudes and clinical phenotype of TB were estimated using linear regression.

Results

TB notifications were highest in quarter 2, and lowest in quarter 4. The mean amplitude of seasonal variation was 25.5% (95% CI 25.0 to 25.9%). The mean seasonal amplitude of TB notifications from latitude 24.5°N- < 26.5°N was 29.5% (95% CI 29.3 to 29.7%) whilst the mean seasonal amplitude of TB notifications from latitude 34.5°N - < 36.5°N was 21.7% (95% CI 19.6 to 23.9%). The mean seasonal amplitude of TB notifications across Pakistan between latitudes 24.5°N to 36.5°N reached statistically significant difference (p < 0.001). The amplitude of seasonal variation was greater for extrapulmonary TB (mean seasonal amplitude: 32.6, 95% CI 21.4 to 21.8%) vs. smear positive pulmonary TB mean seasonal amplitude: 21.6, 95% CI 32.1 to 33.1%), p < 0.001.

Conclusion

TB notifications in Pakistan exhibit seasonal variation with a peak in quarter 2 (April–June) and trough in quarter 4 (October–December). The amplitude of seasonality decreases with increasing latitude, and is more pronounced for extrapulmonary than for pulmonary TB.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-05899-x.

The Assessment of Vitamin D Serum Level in Patients With Pulmonary and Extra-Pulmonary Tuberculosis in Karaj, Iran, During 2017-2018

Background: It is important to determine the type of tuberculosis and its related factors in order for effectively treating a disease and reducing its side effects in the society. Objective: This study aimed to determine vitamin D level in patients with pulmonary and extra-pulmonary tuberculosis in Karaj, Iran in 2017-2018. Materials and Methods: In this observational study, 102 patients suffering from pulmonary and extra-pulmonary tuberculosis disease were availably selected in Karaj, Iran in 2017-2018. They were examined and, then, their vitamin D level were assessed and compared according to the type of tuberculosis. Results: The study results showed that vitamin D level was normal in 39.2% of the case study population, but it was abnormal in 60.8% of it (18.6% deficiency and 42.2% insufficiency). Vitamin D deficiency was 15.8% in pulmonary tuberculosis patients and it was 22.2% in extra-pulmonary tuberculosis ones, showing no significant difference (P>0.05) statistically. Conclusion: According to the obtained results, hypovitaminosis-D was detected in more than half of the patients with pulmonary and extra pulmonary tuberculosis, which was not associated with the type of tuberculosis. Seemingly, the patients needed the same amount of – or even more – food, medical supplements, sports, and sunlight compared to healthy people.

Methylation Status of VDR Gene and its Association with Vitamin D Status and VDR Gene Expression in Pediatric Tuberculosis Disease

Deficiency in circulatory vitamin D level and vitamin D receptor DNA methylation could be associated with weakened innate immune response and increased susceptibility to tuberculosis (TB) disease in children. Therefore, we aimed to study the effect of vitamin D receptor (VDR) gene methylation on plasma vitamin D level and the expression of the VDR gene in children with active-TB disease. A cross-sectional comparative study was conducted in 43 children with active-TB and 33 healthy control children (HC). The vitamin D level was measured in plasma, while the levels of VDR gene promoter methylation and VDR gene expression were measured in peripheral blood. Children with active-TB showed a significantly lower median vitamin D level than HC [Cases 17.18 ng/mL (IQR, 8.3-18.6 ng/mL); HC 41.34 ng/mL (IQR, 40.2-43.49 ng/mL) (p<0.0001)] and decreased mRNA expression level of VDR gene [Cases 0.51 (IQR, 0.40-0.70); HC 1.06 (IQR, 0.8-1.2) (p<0.0001)] and increased VDR DNA methylation [Cases 75% (IQR, 50-75%); HC 10% (IQR, 10-25%) (p<0.0001)]. The VDR hypermethylation is significantly associated with reduced vitamin D level and decreased expression level of VDR gene. Therefore this inverse association could be involved in the impairment in the VDR mediated cytolytic and antimicrobial effector cell response in pediatric TB disease.

New perspectives on difficult-to-treat tuberculosis based on old therapeutic approaches

Tuberculosis (TB) is an important clinical and public health issue worldwide. Despite improved treatment success rates following the introduction of antibiotics in daily clinical practice, the expected decline in incidence has been hampered by HIV epidemics and multi- and extensively drug-resistant TB. During the pre-antibiotic era, TB therapies were mainly based on improving hygiene conditions, strengthening the immune system, and targeting the rest of the affected lungs with invasive techniques. Detailed knowledge of old non-pharmacological therapies might support physicians and researchers in the identification of new solutions for difficult-to-treat patients. We performed a narrative literature review on the main old therapeutic options prescribed for patients with TB. The main recommendations and contraindications of sanatorium therapies (i.e., bed rest, fresh air, sunlight) and pulmonary collapse techniques are reviewed, evaluating their physiological basis and their impact on patient outcomes. We report studies describing new interventional pulmonary and surgical techniques and assess new perspectives based on old medical and surgical treatments, whose potential implementation could help complicated patients.

More Than Malnutrition: A Review of the Relationship Between Food Insecurity and Tuberculosis

Despite a significant reduction in tuberculosis (TB) mortality over the past decade, TB remains a leading cause of death worldwide. Food insecurity-through pathways such as malnutrition, mental health impact, and high-risk health behaviors-affects the risk of TB disease, treatment failure, and mortality. We searched the literature for studies reporting on the links between food insecurity and TB. In contrast to the well-documented interactions between food insecurity and HIV/AIDS, we found that the association between food insecurity and TB remains largely understudied-this is especially true with regard to non-nutritional correlations. Mental health and behavioral linkages between TB and food insecurity deserve further attention. An improved understanding of the pathways through which food insecurity impacts TB is crucial to inform evidence-based integration of interventions such as psychological counseling, psychiatric care, harm reduction programs, and efforts to address social determinants of disease within current TB programs.

Drivers of Seasonal Variation in Tuberculosis Incidence: Insights from a Systematic Review and Mathematical Model

BACKGROUND

Seasonality in tuberculosis incidence has been widely observed across countries and populations; however, its drivers are poorly understood. We conducted a systematic review of studies reporting seasonal patterns in tuberculosis to identify demographic and ecologic factors associated with timing and magnitude of seasonal variation.

METHODS

We identified studies reporting seasonal variation in tuberculosis incidence through PubMed and EMBASE and extracted incidence data and population metadata. We described key factors relating to seasonality and, when data permitted, quantified seasonal variation and its association with metadata. We developed a dynamic tuberculosis natural history and transmission model incorporating seasonal differences in disease progression and/or transmission rates to examine magnitude of variation required to produce observed seasonality in incidence.

RESULTS

Fifty-seven studies met inclusion criteria. In the majority of studies (n=49), tuberculosis incidence peaked in spring or summer and reached a trough in late fall or winter. A standardized seasonal amplitude was calculated for 34 of the studies, resulting in a mean of 17.1% (range: 2.7-85.5%) after weighting by sample size. Across multiple studies, stronger seasonality was associated with younger patients, extrapulmonary disease, and latitudes farther from the Equator. The mathematical model was generally able to reproduce observed levels of seasonal case variation; however, substantial variation in transmission or disease progression risk was required to replicate several extreme values.

CONCLUSIONS

We observed seasonal variation in tuberculosis, with consistent peaks occurring in spring, across countries with varying tuberculosis burden. Future research is needed to explore and quantify potential gains from strategically conducting mass screening interventions in the spring.

Vitamin D₃ Status and the Association with Human Cathelicidin Expression in Patients with Different Clinical Forms of Active Tuberculosis

Low vitamin D (vitD₃) is one of the most common nutritional deficiencies in the world known to be associated with numerous medical conditions including infections such as tuberculosis (TB). In this study, vitD₃ status and its association with the antimicrobial peptide, human cathelicidin (LL-37), was investigated in Ethiopian patients with different clinical forms of TB. Patients with active TB (n = 77) and non-TB controls (n = 78) were enrolled in Ethiopia, while another group of non-TB controls (n = 62) was from Sweden. Active TB included pulmonary TB (n = 32), pleural TB (n = 20), and lymph node TB (n = 25). Concentrations of 25-hydroxyvitamin D₃ (25(OH)D₃) were assessed in plasma, while LL-37 mRNA was measured in peripheral blood and in samples obtained from the site of infection. Median 25(OH)D₃ plasma levels in active TB patients were similar to Ethiopian non-TB controls (38.5 versus 35.0 nmol/L) and vitD₃ deficiency (.

Vitamin D and tuberculosis: where next?

Tuberculosis (TB) has troubled mankind for millennia, but current treatment strategies are long and complicated and the disease remains a major global health problem. The risk of Mycobacterium tuberculosis (Mtb) infection or progression of active TB disease is elevated in individuals with vitamin D deficiency. High-dose vitamin D was used to treat TB in the preantibiotic era, and in vitro experimental data show that vitamin D supports innate immune responses that restrict growth of Mtb. Several randomized controlled trials have tested whether adjunctive vitamin D supplementation enhances the clinical and microbiological response to standard antimicrobial chemotherapy for pulmonary TB. The effects have been modest at best, and attention is turning to the question of whether vitamin D supplementation might have a role in preventing acquisition or reactivation of latent Mtb infection. In this article, we describe the effects of vitamin D on host immune responses to Mtb in vitro and in vivo and review the results of clinical trials in the field. We also reflect on the findings of clinical trials of vitamin D supplementation for the prevention of acute respiratory tract infections, and discuss how these findings might influence the design of future trials to evaluate the role of vitamin D in the prevention and treatment of TB.

Seasonal variation in the performance of QuantiFERON-TB Gold In-Tube assays used for the diagnosis of tuberculosis infection

This study aimed to determine whether there are seasonal changes in the performance of QuantiFERON-TB Gold In-Tube (QFT-GIT) assays, an interferon-gamma release assay widely used for the diagnosis of tuberculosis infection. Results of 31,932 QFT-GIT assays performed at a large independent, accredited diagnostic service provider in London, UK over a 4.5-year-period were analysed. The proportion of positive results was significantly lower in autumn (14.8%) than in spring (16.0%; p = 0.0366) and summer (17.5%; p < 0.0001), but similar to winter (15.2%; p = 0.4711). The proportion of indeterminate results was significantly higher in autumn (8.2%) than in spring (6.2%; p < 0.0001), summer (4.8%; p < 0.0001), and winter (6.2%; p < 0.0001). The highest proportions of indeterminate results were observed in October (8.4%) and November (8.8%), the lowest in June (4.5%). Our data show that significant seasonal variation occurs in the performance of QFT-GIT assays in a temperate climate setting. Potential underlying mechanisms, including host and environmental factors, are discussed.

Factors influencing the higher incidence of tuberculosis among migrants and ethnic minorities in the UK

Migrants and ethnic minorities in the UK have higher rates of tuberculosis (TB) compared with the general population. Historically, much of the disparity in incidence between UK-born and migrant populations has been attributed to differential pathogen exposure, due to migration from high-incidence regions and the transnational connections maintained with TB endemic countries of birth or ethnic origin. However, focusing solely on exposure fails to address the relatively high rates of progression to active disease observed in some populations of latently infected individuals. A range of factors that disproportionately affect migrants and ethnic minorities, including genetic susceptibility, vitamin D deficiency and co-morbidities such as diabetes mellitus and HIV, also increase vulnerability to infection with Mycobacterium tuberculosis (M.tb) or reactivation of latent infection. Furthermore, ethnic socio-economic disparities and the experience of migration itself may contribute to differences in TB incidence, as well as cultural and structural barriers to accessing healthcare. In this review, we discuss both biological and anthropological influences relating to risk of pathogen exposure, vulnerability to infection or development of active disease, and access to treatment for migrant and ethnic minorities in the UK.

Factors influencing the higher incidence of tuberculosis among migrants and ethnic minorities in the UK

Migrants and ethnic minorities in the UK have higher rates of tuberculosis (TB) compared with the general population. Historically, much of the disparity in incidence between UK-born and migrant populations has been attributed to differential pathogen exposure, due to migration from high-incidence regions and the transnational connections maintained with TB endemic countries of birth or ethnic origin. However, focusing solely on exposure fails to address the relatively high rates of progression to active disease observed in some populations of latently infected individuals. A range of factors that disproportionately affect migrants and ethnic minorities, including genetic susceptibility, vitamin D deficiency and co-morbidities such as diabetes mellitus and HIV, also increase vulnerability to infection with Mycobacterium tuberculosis (M.tb) or reactivation of latent infection. Furthermore, ethnic socio-economic disparities and the experience of migration itself may contribute to differences in TB incidence, as well as cultural and structural barriers to accessing healthcare. In this review, we discuss both biological and anthropological influences relating to risk of pathogen exposure, vulnerability to infection or development of active disease, and access to treatment for migrant and ethnic minorities in the UK.

The Troika Host-Pathogen-Extrinsic Factors in Tuberculosis: Modulating Inflammation and Clinical Outcomes

The already enormous burden caused by tuberculosis (TB) will be further aggravated by the association of this disease with modern epidemics, as human immunodeficiency virus and diabetes. Furthermore, the increasingly aging population and the wider use of suppressive immune therapies hold the potential to enhance the incidence of TB. New preventive and therapeutic strategies based on recent advances on our understanding of TB are thus needed. In particular, understanding the intricate network of events modulating inflammation in TB will help to build more effective vaccines and host-directed therapies to stop TB. This review integrates the impact of host, pathogen, and extrinsic factors on inflammation and the almost scientifically unexplored complexity emerging from the interactions between these three factors. We highlight the exciting data showing a contribution of this troika for the clinical outcome of TB and the need of incorporating it when developing novel strategies to rewire the immune response in TB.

Severe hypovitaminosis D in active tuberculosis patients and its predictors

BACKGROUND & AIMS

Tuberculosis (TB) patients have a significant vitamin D deficiency (VDD) endemic, which may be closely related to the onset and progress of the disease. The comorbidity of diabetes (DM) and TB has posed an increasing challenge in recent years. However, the influence of DM on TB and the possible mechanism are still uncertain. We carried out this study to identify the nutritional status of vitamin D (VD) in TB patients in a northern city in China (latitude 36° N) and investigate the possible predictors of severe vitamin D deficiency (SVDD).

METHODS

A cross-sectional study including 461 active TB patients (192 with and 269 without DM) were randomly selected from Qingdao Chest Hospital from June 2015 to August 2016. We measured serum 25 hydroxyvitamin D [25(OH)D], and investigated the association between sociodemographic, dietary intake, DM, body mass index (BMI), severity of initial TB signs and symptoms (TB score) and VD status. Multivariate logistic regression analysis was used to define the possible predictors of SVDD.

RESULTS

The median serum 25(OH)D concentration was 8.50 ng/mL. Of the 461 TB patients included, 383 (83.1%) had VDD [25(OH)D < 20 ng/mL], and 217 (47.1%) had SVDD [25(OH)D < 8 ng/mL]. The variables associated with serum 25(OH)D concentrations were DM, outdoor activity level, TB score and BMI (p < 0.05). Patients with severe TB score had nearly 5 fold higher risk of having SVDD compared with those in mild subgroup [OR (95% CI) = 4.919 (2.644-9.150), p < 0.001]. Low outdoor activity level also increased the odds of SVDD, while DM and high fish consumption showed protect effects.

CONCLUSIONS

Severe hypovitaminosis D is prevalent in active TB patients, and the main predictors of SVDD were severe TB score, low outdoor activity, inadequate fish consumption. Lowered serum 25(OH)D may be associated with increased risk of TB in DM.

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.

Recommendations for Optimizing Tuberculosis Treatment: Therapeutic Drug Monitoring, Pharmacogenetics, and Nutritional Status Considerations

Although tuberculosis is largely a curable disease, it remains a major cause of morbidity and mortality worldwide. Although the standard 6-month treatment regimen is highly effective for drug-susceptible tuberculosis, the use of multiple drugs over long periods of time can cause frequent adverse drug reactions. In addition, some patients with drug-susceptible tuberculosis do not respond adequately to treatment and develop treatment failure and drug resistance. Response to tuberculosis treatment could be affected by multiple factors associated with the host-pathogen interaction including genetic factors and the nutritional status of the host. These factors should be considered for effective tuberculosis control. Therefore, therapeutic drug monitoring (TDM), which is individualized drug dosing guided by serum drug concentrations during treatment, and pharmacogenetics-based personalized dosing guidelines of anti-tuberculosis drugs could reduce the incidence of adverse drug reactions and increase the likelihood of successful treatment outcomes. Moreover, assessment and management of comorbid conditions including nutritional status could improve anti-tuberculosis treatment response.

Association between tuberculosis, diabetes and 25 hydroxyvitamin D in Tanzania: a longitudinal case control study

Background

Vitamin D level is inversely associated with tuberculosis (TB) and diabetes (DM). Vitamin D could be a mediator in the association between TB and DM. We examined the associations between vitamin D, TB and DM.

Methods

Consecutive adults with TB and sex- and age-matched volunteers were included in a case-control study in Dar es Salaam, Tanzania. Glycemia and total vitamin D (25(OH)D) were measured at enrolment and after TB treatment in cases. The association between low 25(OH)D (<75 nmol/l) and TB was evaluated by logistic regression adjusted for age, sex, body mass index, socioeconomic status, sunshine hours, HIV and an interaction between low 25(OH)D and hyperglycemia.

Results

The prevalence of low 25(OH)D was similar in TB patients and controls (25.8 % versus 31.0 %; p = 0.22). In the subgroup of patients with persistent hyperglycemia (i.e. likely true diabetic patients), the proportion of patients with low 25(OH)D tended to be greater in TB patients (50 % versus 29.7 %; p = 0.20). The effect modification by persistent hyperglycemia persisted in the multivariate analysis (p_interaction = 0.01).

Conclusions

Low 25(OH)D may increase TB risk in patients with underlying DM. Trials should examine if this association is causal and whether adjunct vitamin D therapy is beneficial in this population.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1960-x) contains supplementary material, which is available to authorized users.

Vitamin D3 intake modulates diaphragm but not peripheral muscle force in young mice

Recent data support an important role for vitamin D in respiratory health. We tested the hypothesis that dietary vitamin D3 (VD3) intake modulates diaphragm (DIA) strength. Four-week-old female A/J mice (n = 10/group) were randomized to receive diets containing 100 IU VD3/kg (low), 1,000 IU VD3/kg (reference), or 10,000 IU VD3/kg (pharmacologic). After 6 wk of dietary intervention, plasma 25-hydroxyvitamin D3 (25D3) levels, DIA and extensor digitorum longus (EDL) in vitro contractile properties, and fiber cross-sectional area (CSA) were measured. Myosin heavy chain (MHC) composition and Akt/Foxo3A growth signaling were studied in the DIA and tibialis anterior. Mice fed the low, reference, and pharmacologic diets had average 25D3 levels of 7, 21, and 59 ng/ml, respectively. Maximal DIA force, twitch force, and fiber CSA were reduced 26%, 28%, and 10% (P < 0.01), respectively, in mice receiving the low-VD3 diet compared with the reference and pharmacologic diets. EDL force parameters were unaltered by diet. Effects of VD3 intake on DIA force were not observed in mice that began dietary intervention at 12 wk of age. VD3 intake did not alter the MHC composition of the DIA, indicating that decreases in force and CSA in young mice were not due to a switch in fiber type. Paradoxically, low VD3 intake was associated with activation of anabolic signaling in muscle (hyperphosphorylation of Akt and Foxo3A and decreased expression of autophagy marker LC3). These studies identify a potential role of dietary VD3 in regulating DIA development and insulin sensitivity.