Nutritional Status and Tuberculosis Risk in Adult and Pediatric Household Contacts

Diabetes as a risk factor for tuberculosis disease

BACKGROUND

Tuberculosis (TB) is amongst the leading causes of death from an infectious disease, with an estimated 1.3 million deaths from TB in 2022. Approximately 25% of the global population is estimated to be infected with the TB bacterium, giving rise to 10.6 million episodes of TB disease in 2022. The prevalence of diabetes influences TB incidence and TB mortality. It is associated not only with an increased risk of TB disease but also death during TB treatment, TB relapse after treatment completion and multidrug-resistant TB. Since 2011, the World Health Organization (WHO) has recommended collaborative TB and diabetes activities as outlined in the Collaborative Framework for Care and Control of TB and Diabetes.

OBJECTIVES

To determine the prognostic value of diabetes mellitus (DM) in the general population of adults, adolescents and children for predicting tuberculosis disease.

SEARCH METHODS

We searched the literature databases MEDLINE (via PubMed) and WHO Global Index Medicus, and the WHO International Clinical Trials Registry Platform (ICTRP) on 3 May 2023 (date of last search for all databases); we placed no restrictions on the language of publication.

SELECTION CRITERIA

We included retrospective and prospective cohort studies, irrespective of publication status or language. The target population comprised adults, adolescents and children from diverse settings, encompassing outpatient and inpatient cohorts, with varying comorbidities and risk of exposure to tuberculosis.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology and the Quality In Prognosis Studies (QUIPS) tool. Prognostic factors assessed at enrolment/baseline included diabetes, as defined by the individual studies, encompassing patient-reported status, abstracted from medical records or claims data, or diagnosed by plasma glucose/glycosylated haemoglobin. The primary outcome was the incidence of tuberculosis disease. The secondary outcome was recurrent TB disease. We performed a random-effects meta-analysis for the adjusted hazard ratios, risk ratios, or odds ratios, employing the restricted maximum likelihood estimation. We rated the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included 48 cohort studies with over 61 million participants from the six WHO regions. However, the representation was variable as eight population-based studies were from South Korea and 19 from China, with overlapping study periods, and only one from the African region (Ethiopia). All studies included adults, and nine studies also included children and adolescents. Most studies diagnosed DM based on clinical records, including fasting blood glucose levels or glucose-lowering treatments. The studies did not distinguish between type 1 and type 2 DM; only one study focused on type 1 DM. Diagnosis and exclusion of TB were performed using culture or molecular WHO-recommended rapid diagnostic tests (mWRD) in only 12 studies, which could have biassed the effect estimate. The median follow-up time was five years (interquartile range 1.5 to 10, range 1 to 16.9), and the studies primarily reported an adjusted hazard ratio from a multivariable Cox-proportional hazard model. Hazard Ratios (HR) The HR estimates represent the highest certainty of the evidence, explored through sensitivity analyses and excluding studies at high risk of bias. We present 95% confidence intervals (CI) and prediction intervals, which show between-study heterogeneity represented in measuring the variability of effect sizes (i.e. the interval within which the effect size of a new study would fall considering the same population of studies included in the meta-analysis). DM may increase the risk of tuberculosis disease (HR 1.90, 95% CI 1.51 to 2.40; prediction interval 0.83 to 4.39; 10 studies; 11,713,023 participants). The certainty of the evidence is low, due to a moderate risk of bias across studies and inconsistency. Considering a risk without diabetes of 129 cases per 100,000 population, this represents 102 more (59 to 153 more) cases per 100,000. When stratified by follow-up time, the results are more consistent across < 10 years follow-up (HR 1.52, 95% CI 1.47 to 1.57; prediction interval 1.45 to 1.59; 7 studies; 10,380,872 participants). This results in a moderate certainty of the evidence due to a moderate risk of bias across studies. However, at 10 or more years of follow-up, the estimates yield a wider CI and a higher HR (HR 2.44, 95% CI 1.22 to 4.88; prediction interval 0.09 to 69.12; 3 studies; 1,332,151 participants). The certainty of the evidence is low due to the moderate risk of bias and inconsistency. Odds Ratio (OR) DM may increase the odds of tuberculosis disease (OR 1.61, 95% CI 1.27 to 2.04; prediction interval 0.96 to 2.70; 4 studies; 167,564 participants). Stratification by follow-up time was not possible as all studies had a follow-up < 10 years. The certainty of the evidence is low due to a moderate risk of bias and inconsistency. Risk Ratio (RR) The RR estimates represent the highest certainty of the evidence, explored through sensitivity analyses and excluding studies at high risk of bias. DM probably increases the risk of tuberculosis disease (RR 1.60, 95% CI 1.42 to 1.80; prediction interval 1.38 to 1.85; 6 studies; 44,058,675 participants). Stratification by follow-up time was not possible as all studies had a follow-up < 10 years. The certainty of the evidence is moderate due to a moderate risk of bias.

AUTHORS' CONCLUSIONS

Diabetes probably increases the risk of developing TB disease in the short term (< 10 years) and may also increase the risk in the long term (≥ 10 years). As glycaemic control and access to care may be potential effect modifiers of the association between diabetes and the risk of TB disease, the overall estimates should be interpreted with caution when applied locally. Policies targeted at reducing the burden of diabetes are needed to contribute to the aims of ending TB. Large population-based cohorts, including those derived from high-quality national registries of exposures (diabetes) and outcomes (TB disease), are needed to provide estimates with a high certainty of evidence of this risk across different settings and populations, including low- and middle-income countries from different WHO regions. Moreover, studies including children and adolescents and currently recommended methods for diagnosing TB would provide more up-to-date information relevant to practice and policy.

FUNDING

World Health Organization (203256442) REGISTRATION: PROSPERO registration: CRD42023408807.

The Impact of Vaccination Status on Anthropometric Indices of Growth Among Children: A Cross-Sectional Study

Background Childhood immunization programs in underdeveloped nations can improve children's growth and nutritional status and prevent growth delays while protecting against infectious diseases and meeting growth norms. This study aimed to assess the impact of vaccination status on the anthropometric indices of children aged 12-18 months at an Expanded Programme on Immunization vaccination center and compare the anthropometric indices of growth in children with complete and incomplete vaccination statuses. Methodology This study was conducted at the rural health center in Kala Shah Kaku, Pakistan, from November 2023 to December 2023. Children aged 12-18 months were enrolled and their vaccination status was recorded. Height and weight were measured using World Health Organization growth charts. The data were analyzed using descriptive statistics and chi-square and Fisher's exact tests. A p-value <0.05 was considered statistically significant. Results The mean age of the 110 children who visited the vaccination site for this study was 16.36 months ± 2.415. There were 28 (25.5%) stunted children. In the study, 17.6 (16%) participants were underweight, and 15.95 (14.5%) were wasted. Of the children, 79% had received all recommended vaccinations. A statistically significant (p < 0.05) association was found between vaccination and nutritional status. Conclusions This study emphasizes the significance of vaccination in promoting child health and nutrition, reducing stunting risk, and ensuring equitable access to vaccination services and comprehensive healthcare interventions. This can help mitigate the malnutrition burden and promote optimal growth, contributing to global health and development goals.

Undernutrition as a risk factor for tuberculosis disease

BACKGROUND

Tuberculosis (TB) is a leading cause of mortality due to an infectious disease, with an estimated 1.6 million deaths due to TB in 2022. Approximately 25% of the global population has TB infection, giving rise to 10.6 million episodes of TB disease in 2022. Undernutrition is a key risk factor for TB and was linked to an estimated 2.2 million TB episodes in 2022, as outlined in the World Health Organization (WHO) Global Tuberculosis Report.

OBJECTIVES

To determine the prognostic value of undernutrition in the general population of adults, adolescents, and children for predicting tuberculosis disease over any time period.

SEARCH METHODS

We searched the literature databases MEDLINE (via PubMed) and WHO Global Index Medicus, as well as the WHO International Clinical Trials Registry Platform (ICTRP) on 3 May 2023 (date of last search for all databases). We placed no restrictions on the language of publication.

SELECTION CRITERIA

We included retrospective and prospective cohort studies, irrespective of publication status or language. The target population comprised adults, adolescents, and children from diverse settings, encompassing outpatient and inpatient cohorts, with varying comorbidities and risk of exposure to tuberculosis.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology and the Quality In Prognosis Studies (QUIPS) tool to assess the risk of bias of the studies. Prognostic factors included undernutrition, defined as wasting, stunting, and underweight, with specific measures such as body mass index (BMI) less than two standard deviations below the median for children and adolescents and low BMI scores (< 18.5) for adults and adolescents. Prognostication occurred at enrolment/baseline. The primary outcome was the incidence of TB disease. The secondary outcome was recurrent TB disease. We performed a random-effects meta-analysis for the adjusted hazard ratios (HR), risk ratios (RR), or odds ratios (OR), employing the restricted maximum likelihood estimation. We rated the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included 51 cohort studies with over 27 million participants from the six WHO regions. Sixteen large population-based studies were conducted in China, Singapore, South Korea, and the USA, and 25 studies focused on people living with HIV, which were mainly conducted in the African region. Most studies were in adults, four in children, and three in children and adults. Undernutrition as an exposure was usually defined according to standard criteria; however, the diagnosis of TB did not include a confirmatory culture or molecular diagnosis using a WHO-approved rapid diagnostic test in eight studies. The median follow-up time was 3.5 years, and the studies primarily reported an adjusted hazard ratio from a multivariable Cox-proportional hazard model. Hazard ratios (HR) The HR estimates represent the highest certainty of the evidence, explored through sensitivity analyses and excluding studies at high risk of bias. We present 95% confidence intervals (CI) and prediction intervals, which present between-study heterogeneity represented in a measurement of the variability of effect sizes (i.e. the interval within which the effect size of a new study would fall considering the same population of studies included in the meta-analysis). Undernutrition may increase the risk of TB disease (HR 2.23, 95% CI 1.83 to 2.72; prediction interval 0.98 to 5.05; 23 studies; 2,883,266 participants). The certainty of the evidence is low due to a moderate risk of bias across studies and inconsistency. When stratified by follow-up time, the results are more consistent across < 10 years follow-up (HR 2.02, 95% CI 1.74 to 2.34; prediction interval 1.20 to 3.39; 22 studies; 2,869,077 participants). This results in a moderate certainty of evidence due to a moderate risk of bias across studies. However, at 10 or more years of follow-up, we found only one study with a wider CI and higher HR (HR 12.43, 95% CI 5.74 to 26.91; 14,189 participants). The certainty of the evidence is low due to the moderate risk of bias and indirectness. Odds ratio (OR) Undernutrition may increase the odds of TB disease, but the results are uncertain (OR 1.56, 95% CI 1.13 to 2.17; prediction interval 0.61 to 3.99; 8 studies; 173,497 participants). Stratification by follow-up was not possible as all studies had a follow-up of < 10 years. The certainty of the evidence is very low due to the high risk of bias and inconsistency. Contour-enhanced funnel plots were not reported due to the few studies included. Risk ratio (RR) Undernutrition may increase the risk of TB disease (RR 1.95, 95% CI 1.72 to 2.20; prediction interval 1.49 to 2.55; 4 studies; 1,475,867 participants). Stratification by follow-up was not possible as all studies had a follow-up of < 10 years. The certainty of the evidence is low due to the high risk of bias. Contour-enhanced funnel plots were not reported due to the few studies included.

AUTHORS' CONCLUSIONS

Undernutrition probably increases the risk of TB two-fold in the short term (< 10 years) and may also increase the risk in the long term (> 10 years). Policies targeted towards the reduction of the burden of undernutrition are not only needed to alleviate human suffering due to undernutrition and its many adverse consequences, but are also an important part of the critical measures for ending the TB epidemic by 2030. Large population-based cohorts, including those derived from high-quality national registries of exposures (undernutrition) and outcomes (TB disease), are needed to provide high-certainty estimates of this risk across different settings and populations, including low and middle-income countries from different WHO regions. Moreover, studies including children and adolescents and state-of-the-art methods for diagnosing TB would provide more up-to-date information relevant to practice and policy.

FUNDING

World Health Organization (203256442).

REGISTRATION

PROSPERO registration: CRD42023408807 Protocol: https://doi.org/10.1002/14651858.CD015890.

Respiratory Tract Infections in Diabetes - Lessons From Tuberculosis and Influenza to Guide Understanding of COVID-19 Severity

Patients with type-2 diabetes (T2D) are more likely to develop severe respiratory tract infections. Such susceptibility has gained increasing attention since the global spread of Coronavirus Disease 2019 (COVID-19) in early 2020. The earliest reports marked T2D as an important risk-factor for severe forms of disease and mortality across all adult age groups. Several mechanisms have been proposed for this increased susceptibility, including pre-existing immune dysfunction, a lack of metabolic flexibility due to insulin resistance, inadequate dietary quality or adverse interactions with antidiabetic treatments or common comorbidities. Some mechanisms that predispose patients with T2D to severe COVID-19 may indeed be shared with other previously characterized respiratory tract infections. Accordingly, in this review, we give an overview of response to Influenza A virus and to Mycobacterium tuberculosis (Mtb) infections. Similar risk factors and mechanisms are discussed between the two conditions and in the case of COVID-19. Lastly, we address emerging approaches to address research needs in infection and metabolic disease, and perspectives with regards to deployment or repositioning of metabolically active therapeutics.

Pulmonary tuberculosis among prisoners in Southern Thailand: prevalence and its association with imprisonment status

PURPOSE

This study aims to measure the prevalence of pulmonary tuberculosis (PTB), its association with imprisonment status and to document the treatment success rate (TSR) among prisoners in Songkhla province, Southern Thailand.

DESIGN/METHODOLOGY/APPROACH

A retrospective cross-sectional study was conducted in five prisons in Songkhla province, including all prisoners in the fiscal of year 2019, who had an annual chest radiography (CXR) screening result. Information of prisoners who had been imprisoned from 1 October 2018 to 30 September 2019, were reviewed for PTB diagnosis. Imprisonment status and other associated factors with PTB were analyzed using multiple logistic regression.

FINDINGS

The prevalence of PTB was 2.72%. Prisoners having new or transfer-in status were more likely to have PTB. Those aged 40-80 years, who had smoked for ten years or more, or who were underweight, had higher odds of having PTB. TSR among prisoners with PTB in this study was 94.9%.

ORIGINALITY/VALUE

The prevalence of PTB among prisoners having annual CXR screening was high. Detection of PTB was higher among new or transfer-in prisoners; therefore, the CXR for PTB screening before admission to prison should be performed to prevent transmission to other prisoners.

Diabetes-Associated Susceptibility to Tuberculosis: Contribution of Hyperglycemia vs. Dyslipidemia

Diabetes is a major risk factor for tuberculosis (TB). Diabetes increases the risk of the progression from latent tuberculosis infection (LTBI) to active pulmonary TB and TB patients with diabetes are at greater risk of more severe disease and adverse TB treatment outcomes compared to TB patients without co-morbidities. Diabetes is a complex disease, characterised not only by hyperglycemia but also by various forms of dyslipidemia. However, the relative contribution of these underlying metabolic factors to increased susceptibility to TB are poorly understood. This review summarises our current knowledge on the epidemiology and clinical manifestation of TB and diabetes comorbidity. We subsequently dissect the relative contributions of body mass index, hyperglycemia, elevated cholesterol and triglycerides on TB disease severity and treatment outcomes. Lastly, we discuss the impact of selected glucose and cholesterol-lowering treatments frequently used in the management of diabetes on TB treatment outcomes.

Vitamin D concentrations in infancy and the risk of tuberculosis in childhood: A prospective birth cohort in Cape Town, South Africa

INTRODUCTION

Low vitamin D may increase the risk of tuberculosis; however, previous observational cohort studies have had variable results. We investigated the relationship between vitamin D levels in infancy and subsequent development of tuberculosis throughout childhood.

METHODS

We enrolled pregnant women between 20-28 weeks' gestation attending antenatal care in a peri-urban South African setting in the Drakenstein Child Health Study. Serum 25(OH)D concentrations were measured in newborn infants between 6-10 weeks of age. Children were followed prospectively for tuberculosis infection and disease using annual tuberculin skin testing, radiographic examinations, and microbiological diagnosis with GeneXpert, culture, and smear testing. Univariable and multivariable Cox regression was performed and hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated.

RESULTS

Children were followed for tuberculosis for a median of 7.2 years (IQR, 6.2-7.9). Among 744 children (< 1% living with HIV, 21% HIV-exposed living without HIV), those who were vitamin D deficient in early infancy were not at increased risk of developing tuberculosis (AHR, 0.8; 95% CI, 0.4-1.6). Infants in the lowest vitamin D concentration tertile were at similar risk of tuberculosis compared to the highest tertile (AHR, 0.7; 95% CI, 0.4-1.4). Vitamin D deficiency was associated with tuberculin conversion ≤2 years of age at a <30nmol/l (AOR, 1.9; 95% CI, 1.2-3.2), but not <50nmol/l (AOR, 1.5; 95% CI, 0.8-2.9), cutoff.

CONCLUSION

In a setting with hyperendemic tuberculosis, vitamin D levels in infancy did not predict tuberculosis at any point in childhood. However, very low vitamin D levels were associated with tuberculin conversion in young children.

Pre-Diabetes Increases Tuberculosis Disease Severity, While High Body Fat Without Impaired Glucose Tolerance Is Protective

Type 2 diabetes (T2D) is a well-known risk factor for tuberculosis (TB), but little is known about pre-diabetes and the relative contribution of impaired glucose tolerance vs. obesity towards susceptibility to TB. Here, we developed a preclinical model of pre-diabetes and TB. Mice fed a high fat diet (HFD) for 12 weeks presented with impaired glucose tolerance and hyperinsulinemia compared to mice fed normal chow diet (NCD). Infection with M. tuberculosis (Mtb) H₃₇R_v after the onset of dysglycemia was associated with significantly increased lung pathology, lower concentrations of TNF-α, IFN-γ, IFN-β and IL-10 and a trend towards higher bacterial burden at 3 weeks post infection. To determine whether the increased susceptibility of pre-diabetic mice to TB is reversible and is associated with dysglycemia or increased body fat mass, we performed a diet reversal experiment. Pre-diabetic mice were fed a NCD for 10 additional weeks (HFD/NCD) at which point glucose tolerance was restored, but body fat mass remained higher compared to control mice that consumed NCD throughout the entire experiment (NCD/NCD). Upon Mtb infection HFD/NCD mice had significantly lower bacterial burden compared to NCD/NCD mice and this was accompanied by restored IFN-γ responses. Our findings demonstrate that pre-diabetes increases susceptibility to TB, but a high body mass index without dysglycemia is protective. This murine model offers the opportunity to further study the underlying immunological, metabolic and endocrine mechanisms of this association.

Systematic analysis for the relationship between obesity and tuberculosis

OBJECTIVES

Underweight or low body mass index (BMI) is an established risk factor for active tuberculosis. Recent evidence, however, suggests that overweight is associated with lower incidence of tuberculosis. The objective of this systematic review and meta-analysis is to understand the relationship between obesity and tuberculosis and document the extent of association between the two conditions over the range of BMI from underweight to obesity.

METHODS

A comprehensive literature search was conducted to identify studies reporting prevalence of the different BMIs in patients with tuberculosis and controls. Thirty studies of adult humans reporting the incidence of tuberculosis at different weight categories were selected for inclusion for meta-analysis in the present study.

RESULTS

In tuberculosis, the prevalence of underweight was 3-fold higher than that in controls (P = 0.001) whereas the proportion of overweight and obesity was 2-fold lower (P = 0.001). One unit increase in BMI was associated with 2% reduction in tuberculosis incidence (P < 0.001). Adjusted odds ratio of tuberculosis was 4.96 (95% confidence interval: 4.87-5.05) in underweight and 0.26 in obesity.

CONCLUSION

This study further establishes low body weight as a risk factor for tuberculosis whilst overweight and obesity are associated with lower disease risk. Body weight can be considered as a prognostic indictor in the clinical course of tuberculosis.

Transmission Dynamics in Tuberculosis Patients with Human Immunodeficiency Virus: A Systematic Review and Meta-Analysis of 32 Observational Studies

BACKGROUND

There are large knowledge gaps on the transmission dynamics of Mycobacterium tuberculosis in settings where both tuberculosis and HIV are endemic. We aimed to assess the infectiousness of tuberculosis patients coinfected with HIV.

METHODS

We systematically searched for studies of contacts of both HIV-positive and negative tuberculosis index cases. Our primary outcome was Mycobacterium tuberculosis infection in contacts. Data on sputum smear and lung cavitation status of index cases was extracted from each study to assess effect modification. Secondary outcomes included prevalent tuberculosis and HIV in contacts of HIV-positive and negative index cases.

RESULTS

Of 5,255 original citations identified, 32 studies met inclusion criteria including 25 studies investigating M. tuberculosis infection (Nparticipants=36,893), 13 on tuberculosis (Nparticipants=18,853), and 12 on HIV positivity (Nparticipants=18,424). Risk of M. tuberculosis infection was lower in contacts of HIV-positive index cases (Odds Ratio [OR], 0.67, 95% CI, 0.58-0.77) but was heterogeneous (I2=75.1%). Two factors modified this relationship: the lung cavitary status of the index case and immunosuppression (measured through CD4 counts or HIV or AIDS diagnoses) among index patients living with HIV. Rates of HIV were consistently higher in contacts of coinfected index cases (OR, 4.9, 95% CI, 3.0-8.0). This was modified by whether the study was in sub-Saharan Africa (OR, 2.8, 1.6-4.9) or in another global region (OR, 9.8, 5.9-16.3).

CONCLUSIONS

Tuberculosis patients coinfected with HIV are less infectious than HIV-uninfected cases when they have severe immunosuppression or paucibacillary disease. Contacts of coinfected index cases are almost five times more likely to also have HIV.

Overweight, Obesity, and Older Age Favor Latent Tuberculosis Infection among Household Contacts in Low Tuberculosis-Incidence Settings within Panama

Latent tuberculosis infection (LTBI) remains the main source of new active tuberculosis (TB) cases worldwide. Household close contacts (HCCs) are at high risk of acquiring LTBI and subsequent development of TB. In this study, we aim to identify risk factors associated with LTBI in HCCs of TB patients living in a low TB-incidence setting. Our results revealed that HCCs who are aged more than 50 years (OR = 4.05) and overweight (OR = 15.3) are at higher risk of acquiring LTBI. None of these LTBI household contacts progressed to active TB. These findings suggest that HCCs who are young adults and children with normal and low body mass index are less likely to acquire LTBI after exposure to TB patients, even in low TB-incidence settings.

Improvement of Nutritional Status among Tuberculosis Patients by Channa striata Supplementation: A True Experimental Study in Indonesia

OBJECTIVE

To analyze the effect of Channa striata supplementation on body mass index among tuberculosis patients, in which their health status is also investigated.

METHODS

This study employed a true experiment. The study was designed randomized pretest-posttest with a control group, in which 200 respondents were enrolled. Body mass index (BMI), used as a nutritional status indicator, was measured every week for a month. Chi-square test was used to analyze the data with a significance level of 5% by STATA 13.

RESULTS

The mean BMI of all groups increases during the month, in which rapid alteration occurs in the treatment group. The mean BMI (kg/m2) in the treatment group at weeks 0-4 was reported to be 17.43, 17.65, 17.90, 18.04, and 18.22, respectively. Meanwhile, the mean BMI (kg/m2) at weeks 0-4 in the control group was reported to be 17.20, 17.36, 17.57, 17.71, and 17.96, respectively. Furthermore, the alteration from severe thinness to higher BMI level in the treatment group is the highest. Based on the statistical test, there were no differences in BMI between the treatment and control groups (p > 0.05). However, the alteration of nutritional status in the treatment group is faster than that in the control group. In addition, there is no difference in their health status between the treatment and control groups (p > 0.05), except vomiting (p < 0.05).

CONCLUSION

The BMI among tuberculosis patients with Channa striata supplementation is increasing faster than that in the control group within a month with a minimum potential negative effect.

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.

Achieving TB elimination in India: The role of latent TB management

The elimination of Tuberculosis (TB) in settings with a high dual burden of active and latent TB is one of the most important public health challenges of the 21st century. India has the highest TB burden in the world and nearly 40% of the population being infected with TB. There also exist large often overlapping socially and medically vulnerable populations like the PLHIV, pediatric TB contacts, children with protein-energy malnutrition, homeless people, workers in silica industry and adults with low BMI. A significantly higher risk of progression into active tubercular disease exists in those with compromised immune or nutritional status. It is uncertain if global TB elimination targets can be achieved in the absence of aggressive LTBI treatment strategies for interrupting the chain of transmission of the disease. India hence needs to accelerate and prioritize capacity building in latent TB research. A research agenda is outlined for generating evidence towards the evolution of critical evidence-based policy for LTBI management under Indian health settings.

Development and Validation of a Food Frequency Questionnaire to Estimate Intake among Children and Adolescents in Urban Peru

Tools to assess intake among children in Latin America are limited. We developed and assessed the reproducibility and validity of a semi-quantitative food frequency questionnaire (FFQ) administered to children, adolescents, and their caregivers in Lima, Peru. We conducted 24-h diet recalls (DRs) and focus groups to develop a locally-tailored FFQ prototype for children aged 0-14 years. To validate the FFQ, we administered two FFQs and three DRs to children and/or their caregivers (N = 120) over six months. We examined FFQ reproducibility by quartile agreement and Pearson correlation coefficients, and validity by quartile agreement and correlation with DRs. For reproducibility, quartile agreement ranged from 60-77% with correlations highest for vitamins A and C (0.31). Age-adjusted correlations for the mean DR and the second-administered FFQ were highest in the 0-7 age group, in which the majority of caregivers completed the FFQ on behalf of the child (total fat; 0.67) and in the 8-14 age group, in which both the child and caregiver completed the FFQ together (calcium, niacin; 0.54); correlations were <0.10 for most nutrients in the 8-14 age group in which the caregiver completed the FFQ on the child's behalf. The FFQ was reproducible and the first developed and validated to assess various nutrients in children and adolescents in Peru.

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.