Implications of the global increase of diabetes for tuberculosis control and patient care

Diabetes Mellitus and Increased Tuberculosis Susceptibility: The Role of Short-Chain Fatty Acids

Type 2 diabetes mellitus confers a threefold increased risk for tuberculosis, but the underlying immunological mechanisms are still largely unknown. Possible mediators of this increased susceptibility are short-chain fatty acids, levels of which have been shown to be altered in individuals with diabetes. We examined the influence of physiological concentrations of butyrate on cytokine responses to Mycobacterium tuberculosis (Mtb) in human peripheral blood mononuclear cells (PBMCs). Butyrate decreased Mtb-induced proinflammatory cytokine responses, while it increased production of IL-10. This anti-inflammatory effect was independent of butyrate's well-characterised inhibition of HDAC activity and was not accompanied by changes in Toll-like receptor signalling pathways, the eicosanoid pathway, or cellular metabolism. In contrast blocking IL-10 activity reversed the effects of butyrate on Mtb-induced inflammation. Alteration of the gut microbiota, thereby increasing butyrate concentrations, can reduce insulin resistance and obesity, but further studies are needed to determine how this affects susceptibility to tuberculosis.

Transcriptional profiles discriminate patients with pulmonary tuberculosis from non-tuberculous individuals depending on the presence of non-insulin diabetes mellitus

Our objective was to identify transcriptional biomarkers in peripheral blood mononuclear cells (PBMC) that discriminate individuals with latent tuberculosis infection (LTBI) from those with pulmonary tuberculosis (PTB) in subjects with non-insulin-dependent diabetes mellitus (NIDDM) and in individuals without NIDDM. Using gene expression microarrays we identified differentially expressed genes from lungs of mice infected with Mycobacterium tuberculosis (Mtb) or a mutant (ΔsigH) representing a non-inflammatory model. Genes expressed in blood, with inflammatory related functions were evaluated in humans by RT-qPCR. NCF1 and ORM transcripts have the better discriminatory capacity to identify PTB subjects from LTBI and non-infected controls (NICs) independently of the presence of NIDDM. The sequential evaluation of the mRNA levels of NCF1 and ORM as multiple diagnostic tests showed 95% Sensitivity (Se) and 80% Specificity (Sp). In addition, FPR2 promises to be a good biomarker for the PTB detection in subjects with NIDDM (Se=100%; Sp=90%).

Acquired immunodeficiencies and tuberculosis: focus on HIV/AIDS and diabetes mellitus

The spread of human immunodeficiency virus (HIV) infection within Africa led to marked increases in numbers of cases of tuberculosis (TB), and although the epidemic peaked in 2006, there were still 1.8 million new cases in 2013, with 29.2 million prevalent cases. Half of all TB cases in Africa are in those with HIV co-infection. A brief review of the well-documented main immunological mechanisms of HIV-associated increased susceptibility to TB is presented. However, a new threat is facing TB control, which presents itself in the form of a rapid increase in the number of people living with type II diabetes mellitus (T2DM), particularly in areas that are already hardest hit by the TB epidemic. T2DM increases susceptibility to TB threefold, and the TB burden attributable to T2DM is 15%. This review addresses the much smaller body of research information available on T2DM-TB, compared to HIV-TB comorbidity. We discuss the altered clinical presentation of TB in the context of T2DM comorbidity, changes in innate and adaptive immune responses, including lymphocyte subsets and T-cell phenotypes, the effect of treatment of the different comorbidities, changes in biomarker expression and genetic predisposition to the respective morbidities, and other factors affecting the comorbidity. Although significant gains have been made in improving our understanding of the underlying mechanisms of T2DM-associated increased susceptibility, knowledge gaps still exist that require urgent attention.

Diabetes-related tuberculosis in the Middle East: an urgent need for regional research

OBJECTIVES

Diabetes mellitus (DM) triples the risk of tuberculosis (TB) disease, complicates TB treatment, and increases the risk of a poor TB outcome. As DM prevalence is increasing across the Middle East, this review was performed to identify regional gaps in knowledge and research priorities for DM/TB.

METHODS

Online databases were searched for studies published from Middle East countries on DM and TB and the studies summarized based on topic and major findings. Studies included had a principle hypothesis related to both diseases, or described TB patients with individual data on DM.

RESULTS

Fifty-nine studies from 10 countries met search criteria. No published studies were found from Lebanon, Bahrain, Syria, Jordan, Cyprus, or the United Arab Emirates. DM prevalence among TB patients was high, but varied considerably across studies. The vast majority of studies were not specifically designed to compare DM/TB and non-DM/TB patients, but many suggested worse treatment outcomes for DM/TB, in accordance with reports from other regions.

CONCLUSIONS

Opportunity exists for the regional study of bidirectional screening, management strategies for both DM and TB diseases, and whether such efforts could take place through the integration of services.

Epidemiology and interaction of diabetes mellitus and tuberculosis and challenges for care: a review

The global burden of diabetes mellitus (DM) is immense, with numbers expected to rise to over 550 million by 2030. Countries in Asia, such as India and China, will bear the brunt of this unfolding epidemic. Persons with DM have a significantly increased risk of developing active tuberculosis (TB) that is two to three times higher than in persons without DM. This article reviews the epidemiology and interactions of these two diseases, discusses how the World Health Organization and International Union Against Tuberculosis and Lung Disease developed and launched the Collaborative Framework for the care and control of TB and DM, and examines three important challenges for care. These relate to 1) bi-directional screening of the two diseases, 2) treatment of patients with dual disease, and 3) prevention of TB in persons with DM. For each area, the gaps in knowledge and the priority research areas are highlighted. Undiagnosed, inadequately treated and poorly controlled DM appears to be a much greater threat to TB prevention and control than previously realised, and the problem needs to be addressed. Prevention of DM through attention to unhealthy diets, sedentary lifestyles and childhood and adult obesity must be included in broad non-communicable disease prevention strategies. This collaborative framework provides a template for action, and the recommendations now need to be implemented and evaluated in the field to lay down a firm foundation for the scaling up of interventions that work and are effective in tackling this dual burden of disease.

Screening tuberculosis patients for diabetes in a tribal area in South India

SETTING

Ten peripheral health institutions of a tribal tuberculosis unit, Saluru, Vizianagaram District, South India.

OBJECTIVE

To assess among tuberculosis (TB) patients: 1) the feasibility of screening for diabetes mellitus (DM), 2) the prevalence of DM, 3) the demographic and clinical features associated with DM, and 4) the number needed to screen (NNS) to find one new case of DM.

DESIGN

Cross-sectional study: all TB patients registered from January to September 2012 were screened for DM using a screening questionnaire and random blood glucose, followed by fasting blood glucose (FBG) measurements using a glucometer. DM was diagnosed if FBG was ≥126 mg/dl.

RESULTS

Of 381 patients, 374 (98%) were assessed for DM, suggesting feasibility of screening, and 19 (5%) were found to have DM (12 were newly diagnosed and 7 had a previous diagnosis of DM). The only characteristic associated with DM was age ≥40 years. The NNS to detect a new case of DM among all TB patients was 31; among those aged ≥40 years, the NNS was 20, and among current smokers it was 21.

CONCLUSION

Screening of TB patients for DM was feasible and effective, and this should inform national scale-up. Other key considerations include the continued provision of free TB-DM screening, with co-location and integration of services.

Statin, calcium channel blocker and Beta blocker therapy may decrease the incidence of tuberculosis infection in elderly Taiwanese patients with type 2 diabetes

Background: It is well known that diabetes mellitus impairs immunity and therefore is an independent risk factor for tuberculosis. However, the influence of associated metabolic factors, such as hypertension, dyslipidemia and gout has yet to be confirmed. This study aimed to investigate whether the strong association between tuberculosis and diabetes mellitus is independent from the influence of hypertension and dyslipidemia, and its treatment in elderly Taiwanese patients. Methods: A total of 27,958 patients aged more than 65 years were identified from the National Health Insurance Research Database (NIHRD) in 1997 and were followed from 1998 to 2009. The demographic characteristics between the patients with and without diabetes were analyzed using the χ2 test. A total of 13,981 patients with type 2 diabetes were included in this study. Cox proportional hazard regression models were used to determine the independent effects of diabetes on the risk of tuberculosis. Results: After adjusting for age, sex, other co-morbidities and medications, calcium channel blocker, beta blocker and statin users had a lower independent association, with risk ratios of 0.76 (95% CI, 0.58–0.98), 0.72 (95% CI, 0.58–0.91) and 0.76 (95% CI, 0.60–0.97), respectively. Conclusion: Calcium channel blocker, beta blocker and statin therapy may decrease the incidence of tuberculosis infection in elderly Taiwanese patients with type 2 diabetes.

Screening of patients with diabetes mellitus for tuberculosis in community health settings in China

OBJECTIVE

To assess the feasibility and results of screening of patients with DM for TB in routine community health services in China.

METHOD

Agreement on how to screen patients with DM for TB and monitor and record the results was obtained at a stakeholders meeting. Subsequent training was carried out for staff at 10 community health centres, with activities implemented from June 2013 to April 2014. Patients with DM were screened for TB at each clinical visit using a symptom-based enquiry, and those positive to any symptom were referred to the TB clinic for TB investigation.

RESULTS

A total of 2942 patients with DM visited these ten clinics. All patients received at least one screening for TB. Two patients were identified as already known to have TB. In total, 278 (9.5% of those screened) who had positive TB symptoms were referred for TB investigations and 209 arrived at the TB centre or underwent a chest radiograph for TB investigation. One patient (0.5% of those investigated) was newly diagnosed with active TB and was started on anti-TB treatment. The TB case notification rate of those screened was 102/100,000.

CONCLUSION

This pilot project shows it is feasible to carry out TB screening among patients with DM in community settings, but further work is needed to better characterise patients with DM at higher risk of TB. This may require a more targeted approach focused on high-risk groups such as those with untreated DM or poorly controlled hyperglycaemia.

The influence of diabetes, glycemic control, and diabetes-related comorbidities on pulmonary tuberculosis

Background

To assess the influence of diabetes mellitus (DM), glycemic control, and diabetes-related comorbidities on manifestations and outcome of treatment of pulmonary tuberculosis (TB).

Methodology/Principal Findings

Culture positive pulmonary TB patients notified to health authorities in three hospitals in Taiwan from 2005–2010 were investigated. Glycemic control was assessed by glycated haemoglobin A1C (HbA1C) and diabetic patients were categorized into 3 groups: HbA1C<7%, HbA1C 7–9%, HbA1C>9%. 1,473 (705 with DM and 768 without DM) patients were enrolled. Of the 705 diabetic patients, 82 (11.6%) had pretreatment HbA1C<7%, 152 (21.6%) 7%–9%, 276 (39.2%) >9%, and 195 (27.7%) had no information of HbA1C. The proportions of patients with any symptom, cough, hemoptysis, tiredness and weight loss were all highest in diabetic patients with HbA1C>9%. In multivariate analysis adjusted for age, sex, smoking, and drug resistance, diabetic patients with HbA1C>9% (adjOR 3.55, 95% CI 2.40–5.25) and HbA1C 7–9% (adjOR 1.62, 95% CI 1.07–2.44) were significantly more likely to be smear positive as compared with non-diabetic patients, but not those with HbA1C<7% (adjOR 1.16, 95% CI 0.70–1.92). The influence of DM on outcome of TB treatment was not proportionately related to HbA1C, but mainly mediated through diabetes-related comorbidities. Patients with diabetes-related comorbidities had an increased risk of unfavorable outcome (adjOR 3.38, 95% CI 2.19–5.22, p<0.001) and one year mortality (adjOR 2.80, 95% CI 1.89–4.16). However, diabetes was not associated with amplification of resistance to isoniazid (p = 0.363) or to rifampicin (p = 0.344).

Conclusions/Significance

Poor glycemic control is associated with poor TB treatment outcome and improved glycemic control may reduce the influence of diabetes on TB.

Screening for diabetes mellitus in tuberculosis patients in a referral center in Iran

BACKGROUND

A significant link between diabetes mellitus (DM) and tuberculosis (TB) has been widely demonstrated. DM increases the risk of TB in all aspects. The aims of this study were to assess the prevalence of DM among newly diagnosed TB patients, to screen these patients for DM, and to determine the number needed to screen (NNS) to diagnose new cases of DM.

METHODS

A prospective cohort descriptive study was carried out in Iranian adults admitted to the National Research Institute of Tuberculosis and Lung Disease from 2012 to 2013 with a new diagnosis of TB. Glycated hemoglobin (HbA1c) and fasting blood glucose (FBG) were measured for all patients.

RESULTS

Of the 293 patients included, 101 (34.5%) had DM. DM was newly diagnosed in 45 (19%) patients. The number needed to screen was 5 to identify one new DM case. Age ≥ 40 years was associated with DM in this population (odds ratio (OR) = 3.91, 95% confidence interval (CI) = 1.47-10.38).

CONCLUSION

Screening for DM should be performed routinely in patients with TB and may improve treatment outcomes.

Diabetes and Other Risk Factors for Multi-drug Resistant Tuberculosis in a Mexican Population with Pulmonary Tuberculosis: Case Control Study

BACKGROUND AND AIMS

Multidrug resistant tuberculosis (MDR-TB) poses problems in treatment, costs and treatment outcomes. It is not known if classically described risk factors for MDR-TB in other countries are the same in Mexico and the frequency of the association between diabetes mellitus (DM) and MDR-TB in our country is not clear. We undertook this study to analyze risk factors associated with the development of MDR-TB, with emphasis on DM.

METHODS

A case-control study in the state of San Luis Potosi (SLP), Mexico was carried out. All pulmonary MDR-TB patients diagnosed in the state of SLP between 1998 and 2013 (36 cases) evaluated at a state pharmacoresistant tuberculosis (TB) clinic and committee; 139 controls were randomly selected from all pulmonary non-multidrug-resistant tuberculosis (non-MDR-TB) cases identified between 2003 and 2008. Cases and controls were diagnosed and treated under programmatic conditions.

RESULTS

Age, gender, malnutrition, being a health-care worker, HIV/AIDS status, and drug abuse were not significantly different between MDR-TB and non-MDR-TB patients. Significant differences between MDR-TB and non-MDR-TB patients were DM (47.2 vs. 28.1%; p = 0.028); previous anti-TB treatments (3 vs. 0, respectively; p <0.001), and duration of first anti-TB treatment (8 vs. 6 months, respectively; p <0.001).

CONCLUSIONS

MDR-TB and DM are associated in 47.2% of MDR TB cases (17/36) in this study. Other recognized factors were not found to be significantly different in MDR-TB compared to non-MDR-TB in this study. Cost-feasible strategies must be implemented in the treatment of DM-TB in order to prevent the selection of MDR-TB.

The effect of hyperglycaemia on in vitro cytokine production and macrophage infection with Mycobacterium tuberculosis

Type 2 diabetes mellitus is an established risk factor for tuberculosis but the underlying mechanisms are largely unknown. We examined the effects of hyperglycaemia, a hallmark of diabetes, on the cytokine response to and macrophage infection with Mycobacterium tuberculosis. Increasing in vitro glucose concentrations from 5 to 25 mmol/L had marginal effects on cytokine production following stimulation of peripheral blood mononuclear cells (PBMCs) with M. tuberculosis lysate, LPS or Candida albicans, while 40 mmol/L glucose increased production of TNF-α, IL-1β, IL-6 and IL-10, but not of IFN-γ, IL-17A and IL-22. Macrophage differentiation under hyperglycaemic conditions of 25 mmol/L glucose was also associated with increased cytokine production upon stimulation with M. tuberculosis lysate and LPS but in infection experiments no differences in M. tuberculosis killing or outgrowth was observed. The phagocytic capacity of these hyperglycaemic macrophages also remained unaltered. The fact that only very high glucose concentrations were able to significantly influence cytokine production by macrophages suggests that hyperglycaemia alone cannot fully explain the increased susceptibility of diabetes mellitus patients to tuberculosis.

Symptom reporting among prevalent tuberculosis cases who smoke, are HIV-positive or have hyperglycaemia

Data from a tuberculosis (TB) prevalence survey conducted in 24 communities in Zambia and the Western Cape, South Africa, January-December 2010, were analysed to determine the influence of smoking, hyperglycaemia and human immunodeficiency virus (HIV) infection on TB symptom reporting in culture-confirmed TB cases. Of 123 790 adults eligible for enrolment, 90 601 (73%) consented and 64 463 had evaluable sputum samples. ORs and 95%CIs were calculated using a robust standard errors logistic regression model adjusting for clustering at community level. HIV-positive TB cases were more likely to report cough, weight loss, night sweats and chest pain than non-HIV-positive TB cases. TB cases who smoked or had hyperglycaemia did not report symptoms differently from cases without these comorbidities.

Increased risk of tuberculosis in patients with type 1 diabetes mellitus: results from a population-based cohort study in Taiwan

The studies on the risk of tuberculosis (TB) in patients with type 1 diabetes mellitus (T1DM) alone are limited. We examined this relationship using a population-based retrospective cohort study. From claims data of the National Health Insurance system of Taiwan, we identified 5195 patients with T1DM newly diagnosed from 2002 to 2011 and 20,780 randomly selected controls without T1DM, frequency matched by age, sex, and year of diagnosis. Both cohorts were followed up until the end of 2011 to evaluate the risk of TB. The overall incidence of TB was 4.07-fold higher in the T1DM cohort than in the control cohort (1.18 vs 0.29 per 1000 person-years, P < 0.001). Compared with the controls, the Cox model estimated adjusted hazard ratios (HRs) of TB in patients with T1DM were greater in men than in women (4.62 vs 3.59) and in adults than in children (4.06 vs 3.37), but not significant. The adjusted HR was much greater for those with comorbidities than those without comorbidities (14.6 vs 1.62, P < 0.001). Compared with the controls, the patients with T1DM were also more likely to develop TB with multiple emergency room visits (adjusted HR: 116.1, 95% confidence interval [CI] = 43.8-307.4) or hospitalizations (adjusted HR: 86.5, 95% CI = 33.7-222.4). Patients with T1DM are at elevated risks of developing TB with much higher HRs for those with comorbidities, within the first year of diagnosis, and with frequent emergency cares or hospitalizations.

Improving tuberculosis prevention and care through addressing the global diabetes epidemic: from evidence to policy and practice

Diabetes triples the risk of tuberculosis and is also a risk factor for adverse tuberculosis treatment outcomes, including death. Prevalence of diabetes is increasing globally, but most rapidly in low-income and middle-income countries where tuberculosis is a grave public health problem. Growth in this double disease burden creates additional obstacles for tuberculosis care and prevention. We review how the evolution of evidence on the link between tuberculosis and diabetes has informed global policy on collaborative activities, and how practice is starting to change as a consequence. We conclude that coordinated planning and service delivery across communicable and non-communicable disease programmes is necessary, feasible, and creates synergies that will help to reduce the burden of both tuberculosis and diabetes.

Clinical management of concurrent diabetes and tuberculosis and the implications for patient services

Diabetes triples the risk for active tuberculosis, thus the increasing burden of type 2 diabetes will help to sustain the present tuberculosis epidemic. Recommendations have been made for bidirectional screening, but evidence is scarce about the performance of specific tuberculosis tests in individuals with diabetes, specific diabetes tests in patients with tuberculosis, and screening and preventive therapy for latent tuberculosis infections in individuals with diabetes. Clinical management of patients with both diseases can be difficult. Tuberculosis patients with diabetes have a lower concentration of tuberculosis drugs and a higher risk of drug toxicity than tuberculosis patients without diabetes. Good glycaemic control, which reduces long-term diabetes complications and could also improve tuberculosis treatment outcomes, is hampered by chronic inflammation, drug-drug interactions, suboptimum adherence to drug treatments, and other factors. Besides drug treatments for tuberculosis and diabetes, other interventions, such as education, intensive monitoring, and lifestyle interventions, might be needed, especially for patients with newly diagnosed diabetes or those who need insulin. From a health systems point of view, delivery of optimum care and integration of services for tuberculosis and diabetes is a huge challenge in many countries. Experience from the combined tuberculosis and HIV/AIDS epidemic could serve as an example, but more studies are needed that include economic assessments of recommended screening and systems to manage concurrent tuberculosis and diabetes.

Worldwide increase in diabetes: implications for tuberculosis control

Diabetes presents a greater threat to global tuberculosis (TB) control than previously appreciated, with risk of reversing the achievements of several decades. An estimated 382 million people worldwide currently have diabetes, half of whom are undiagnosed. Most live in low- and middle-income countries alongside many of the two billion individuals infected with TB. Though the frequency of TB in type 1 diabetes was known for centuries, only recently have we observed the tripling of TB in type 2 diabetes, most significantly in high-burden TB populations such as in Peru, Russia, and the People's Republic of China. In India diabetes is estimated to have increased TB cases by 46% between 1998 and 2008. Diabetes is a greater long-term threat to TB control than human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) since ten-fold more people are affected by diabetes than HIV/AIDS in larger geographic areas. Diabetes in TB increases drug resistance, treatment failure, and mortality, and may increase the spread of drug-resistant strains. Delayed or missed diagnosis fuels transmission of TB and hinders control of diabetes. Tailored treatment for diabetes patients requires well-designed clinical trials. The World Health Organization (WHO) framework for care and control of diabetes and TB needs improved screening strategies. Determination of how best to establish bi-directional screening is hampered by lack of affordable and reliable methods. Recommendations include education of health care providers, patients, and communities. Structured diabetes programs with registries and effective follow-up could be modeled on and communicate with existing TB programs. Vital research should address new diagnostic tools, lowering cost and evaluation of intervention strategies, as well as better understanding of the impaired immune responses that make diabetes patients more susceptible to TB leading to targeted therapies. Solutions will require the combination of good science, good decision-making, adequate funding, and political will.

Undiagnosed diabetes mellitus in tuberculosis: A Lagos report

BACKGROUND

Tuberculosis (TB) and diabetes mellitus (DM) are two diseases that are individually relatively common and of immense public health significance globally. There is a growing awareness on a global scale on the possible relationship between TB and DM. Nigeria is a country with a high burden of TB and an increasing incidence of DM. We set out to determine the frequency of occurrence of undiagnosed DM in TB patients.

MATERIALS AND METHODS

This was an observational study that was carried out in TB patients recruited from 56 DOT centers in Lagos, Nigeria. The main objective of the study was to determine the disease burden of DM in patients with TB by comparing the frequency of occurrence of DM in TB to the occurrence of DM in people without TB. Screening was carried out by staff-nurses and community health workers-of these DOT facilities who all had capacity building on the detection of DM at the start of the project.

RESULTS

Of 4000 TB patients, a total of 480 (12.3%) had DM. Of the pool of DM patients, newly diagnosed cases of DM were 310 (8%) in number and previously known persons with DM were 170 (4.3%). The newly diagnosed cases of DM made up 64% of the cases of DM. In the study population without TB, a total of 112 (5.6%) had DM. The number of newly diagnosed cases of DM were 40 in number and these made up 2% of this study group. The number of persons who were already known to have DM was 72 and these made up 3.6% of the study population. New cases of DM made up 44% of the total number of cases of DM detected in persons without TB.

CONCLUSION

The detection rates of DM in patients with TB are higher than in persons without TB. Given the fact that DM may negatively impact TB treatment, we suggest that routine screening be carried out for TB in persons with DM.

Impact of diabetes on clinical presentation and treatment outcome of pulmonary tuberculosis in Beijing

Diabetes mellitus (DM) is currently known to be one of the risk factors for pulmonary tuberculosis (PTB) and the proportion of DM in PTB is rising along with the increased prevalence of DM in countries with high PTB burden. This study was designed to explore the impact of DM on clinical presentation and treatment outcome of PTB in China. In an urban setting in Beijing, 1126 PTB patients, 30·6% with positive sputum smear, registered in two PTB dispensaries from January 2010 to December 2011 were screened for DM and were followed up prospectively during PTB treatment. DM was observed in 16·2% of patients with PTB. PTB with DM appeared to be associated with older age and a higher proportion of re-treatment. On presentation, DM was associated with more severe PTB signs with higher proportions of smear positivity [odds ratio (OR) 2·533, 95% confidence interval (CI) 1·779-3·606], cavity (OR 2·253, 95% CI 1·549-3·276) and more symptoms (OR 1·779, 95% CI 1·176-2·690). DM was also associated with non-TB deaths (OR 5·580, 95% CI 2·182-14·270, P < 0·001) and treatment failure (OR 6·696, 95% CI 2·019-22·200, P = 0·002). In Beijing, the findings of this study underlined the need to perform early bi-directional screening programmes and explore the underlying mechanism for different treatment outcomes for PTB with DM.

Prevalence of Diabetes Mellitus among Tuberculosis Patients in Urban Puducherry

Background:

Diabetes and Tuberculosis often present together and complicate each other at many levels. A collaborative framework for care and control of diabetes and tuberculosis developed by World Health Organisation and International Union against Tuberculosis and Lung Diseases emphasizes routine bi-directional screening for the two diseases.

Aims:

The study was to assess the prevalence of diabetes in tuberculosis patients currently on treatment.

Materials and Methods:

This facility-based cross-sectional study was undertaken in four randomly selected peripheral health institutions providing directly observed treatment short-course, treatment for tuberculosis patients. All cases of tuberculosis, more than 18 years of age were screened for diabetes. Risk factors like age, sex, family history of diabetes, alcohol, smoking and obesity were assessed.

Results:

The prevalence of diabetes in tuberculosis patients was found to be 29% (known diabetics - 20.7%, new Diabetes cases - 8.3%). Diabetes was significantly associated with older age, family history of diabetes, consumption of alcohol and sputum positivity.

Conclusions:

Screening patients with Tuberculosis for fasting blood sugar estimation will help in early detection of diabetes

Diabetes mellitus and tuberculosis facts and controversies

Tuberculosis (TB) and diabetes mellitus (DM) are both important health issues. A bidirectional association between them has been demonstrated by many researchers. The link of DM and TB is more prominent in developing countries where TB is endemic and the burden of diabetes mellitus is increasing. The association between diabetes and tuberculosis may be the next challenge for global tuberculosis control worldwide. Proper planning and collaboration are necessary to reduce the dual burden of diabetes and TB. One model similar to the TB-HIV program for prevention, screening and treatment of both diseases can be the best approach. In this paper, we review existing data and discuss the matters of controversy that would be helpful for determining research priorities in different countries.

Screening patients with tuberculosis for diabetes mellitus in Gujarat, India

SETTING

Anklav Tuberculosis Unit, Anand, Gujarat, India.

OBJECTIVE

To determine in a cohort of TB patients 1) the prevalence of diabetes (DM) and impaired fasting glucose (IFG), 2) the time taken for diagnosis, 3) demographic and clinical factors associated with DM and IFG, and 4) the number needed to screen (NNS) for diagnosing new cases of DM and IFG.

DESIGN

Descriptive study. TB patients registered between January and September 2012 were asked whether they had a history of DM. Those with unknown DM were tested for random and fasting blood glucose (FBG). FBG of ≥126 mg/dl and 110-125 mg/dl were considered indicative of DM and IFG, respectively.

RESULTS

Of 556 TB patients, 553 (99%) were assessed: 36 (6.5%) had diabetes (14 had been previously diagnosed DM and 22 were newly diagnosed), and 39 (7%) had IFG. The median (interquartile range) time to DM diagnosis was 5 (1-17) days. Age ≥35 years was associated with DM. The NNS was 25 and 14 for one new case of DM and IFG, respectively, with a lower NNS in males, those aged ≥35 years, those with smear-positive pulmonary TB, retreatment patients and smokers.

CONCLUSION

This pilot project shows that it is feasible and valuable to screen patients with TB for DM in a routine setting, resulting in earlier identification of DM and opportunities for better management of comorbidity.

Obesity, diabetes and pneumonia: the menacing interface of non-communicable and infectious diseases

OBJECTIVES

To review current knowledge on the epidemiological, clinical and biological impact of the pandemic of obesity and diabetes on pneumonias.

METHODS

We conducted a literature review using PubMed and EMBASE, supplemented by various sources. Given the disparate and fragmented nature of the literature, a formal systematic review was not possible.

RESULTS

In 2008, globally 10% of men and 14% of women were obese and an estimated 371 million had diabetes; half undiagnosed and many obese. Numbers are rising rapidly in low- and middle-income countries where the majority reside, but reliable data are lacking. The most frequent pneumonias in obesity and diabetes are tuberculosis, influenza and pneumococcal, staphylococcal and opportunistic pathogens. Diabetes impacts tuberculosis control and increases drug resistance and mortality. Mortality and morbidity from pneumococcal pneumonia and influenza are increased in obesity and diabetes. In addition to mechanical and physiological effects, there are considerable immunological abnormalities characterised by chronic, low-grade inflammation. Simultaneous up-regulation and dysregulation of both innate and adaptive immune responses impair control and killing of invading organisms. Prevention in those at risk is poorly practised, although screening for tuberculosis in diabetes is beginning in high-burden settings.

CONCLUSIONS

Pneumonia is a threat globally in obesity and diabetes with increased incidence and severity of disease. There is uncertainty about whether vaccines are equally effective in those with obesity and diabetes. Increased epidemiological, clinical and biological knowledge will be crucial to face this 21st century challenge.

Risk factors for extensively drug-resistant tuberculosis: a review

INTRODUCTION

Extensively drug-resistant tuberculosis (XDR-TB) is emerging as a global public health problem. Its treatment is more expensive and difficult, and the outcomes much severe. The identification of risk factors for XDR-TB is of paramount importance to design effective TB control strategies.

OBJECTIVE

To review published articles on risk factors for XDR-TB.

METHODS

We identified 249 English articles on PubMed, and 182 were excluded by the abstract. The remaining articles were retrieved for full-text detailed evaluation by authors, and 27 relevant articles were selected for final review.

RESULTS

Some risk factors were consistently present, mainly previous TB treatment and its length. Other conditions often associated were immigration, alcoholism and HIV coinfection. Pre-XDR-TB points to an increased risk of XDR-TB.

CONCLUSION

The information regarding determinants of XDR-TB is relatively weak. However, special emphasis should be given to minimize the risks of TB retreatment to prevent the emergence of highly resistant TB.

Dipstick urinalysis for diabetes screening in TB patients

INTRODUCTION

Diabetes knowledge among TB patients can contribute to improved TB treatment outcomes, but lack of diabetes diagnosis awareness is a limitation in developing countries. Given its low cost, the sensitivity of urine glucose dipsticks for diabetes screening in TB patients was assessed.

METHODS

Glycosuria was assessed in 90 newly diagnosed TB patients (38 with diabetes) in south Texas, USA (n = 20) and northeast Mexico (n = 70) during January 2009-December 2010.

RESULTS

Glycosuria was detected in 65% of the diabetic patients with chronic hyperglycemia (positive predictive value 91%, negative predictive value 84%).

CONCLUSION

We propose that TB clinics with limited budgets where portable glucometers may not be available conduct universal screening for diabetes with urine dipsticks. This could be followed by blood glucose or HbA1c testing in the subset of patients requiring confirmation or higher sensitivity assessment, to improve the comanagement of TB and diabetes.

Diabetes is a strong predictor of mortality during tuberculosis treatment: a prospective cohort study among tuberculosis patients from Mwanza, Tanzania

OBJECTIVE

Strong evidence suggests diabetes may be associated with tuberculosis (TB) and could influence TB treatment outcomes. We assessed the role of diabetes on sputum culture conversion and mortality among patients undergoing TB treatment.

METHODS

A total of 1250 Tanzanian TB patients were followed prospectively during TB treatment with sputum culture after 2 and 5 months. Survival status was assessed at least 1 year after initiation of treatment. At baseline, all participants underwent testing for diabetes and HIV, and the serum concentration of the acute phase reactant alpha-1 glycoprotein (AGP) was determined.

RESULTS

There were no differences between participants with and without diabetes regarding the proportion of positive cultures at 2 (3.8% vs. 5.8%) and 5 (1.3% vs. 0.9%) months (P > 0.46). However, among patients with a positive TB culture, relatively more patients with diabetes died before the 5-month follow-up. Within the initial 100 days of TB treatment, diabetes was associated with a fivefold increased risk of mortality (RR 5.09, 95% CI 2.36; 11.02, P < 0.001) among HIV uninfected, and a twofold increase among HIV co-infected patient (RR 2.33 95% CI 1.20; 4.53, P = 0.012), while diabetes was not associated with long-term mortality. Further adjustment with AGP did not change the estimates.

CONCLUSION

Diabetes considerably increases risk of early mortality during TB treatment. The effect may not be explained by increased severity of TB, but could be due to impaired TB treatment response. Research is needed to clarify the mechanism and to assess whether glycaemic control improves survival.

Socio-demographic and clinical differences in subjects with tuberculosis with and without diabetes mellitus in Brazil--a multivariate analysis

BACKGROUND

Several studies have evaluated the relationship between diabetes mellitus (DM) and tuberculosis (TB), but the nature of this relationship is not fully understood. TB incidence may be influenced by immunosuppression from DM, but this association may be confounded by other clinical and socioeconomic factors. We aimed to assess socio-demographic and clinical differences in TB patients with and without DM.

METHODS

Using the Brazilian national surveillance system (SINAN), we compared 1,797 subjects with TB and DM with 29,275 subjects diagnosed with TB only in 2009. We performed multivariate analysis to identify factors associated with the presence of DM among TB patients.

RESULTS

Subjects with TB - DM were older; have initial positive sputum smear test (OR = 1.42, 95% CI 1.26-1.60), and were more likely to die from TB (OR = 1.44, 95% CI 1.03-2.01). They were less likely to have been institutionalized [in prison, shelter, orphanage, psychiatric hospital (OR = 0.74, 95% CI 0.60-0.93)]; developed extra pulmonary TB (OR = 0.62, 95% CI 0.51-0.75) and to return to TB treatment after abandonment (OR = 0.66, 95% CI 0.51-0.86).

CONCLUSIONS

Prevalence of NCD continues to rise in developing countries, especially with the rise of elderly population, the prevention and treatment of infectious diseases will be urgent. DM and TB represent a critical intersection between communicable and non-communicable diseases in these countries and the effect of DM on TB incidence and outcomes provide numerous opportunities for collaboration and management of these complex diseases in the national public health programs.

Screening of patients with tuberculosis for diabetes mellitus in India

OBJECTIVE

To assess feasibility and results of screening patients with tuberculosis (TB) for diabetes mellitus (DM) within the routine healthcare setting across the country at: eight tertiary care hospitals and more than 60 peripheral health institutions in eight tuberculosis units.

METHODS

Agreement on how to screen, monitor and record was reached in October 2011 at a stakeholders' meeting, and training was carried out for staff in the facilities in December 2011 and January 2012. Implementation started from January 2012, and we report on activities up to 30 September 2012.

RESULTS

Of 8269 TB patients diagnosed and initiated on treatment in participating facilities, 8109 (98%) were assessed for DM and 1084 (13%) were found to have DM; of these, 682 (8%) had a previously known diagnosis of DM and 402 (5%) were newly diagnosed. There was a higher prevalence of DM in patients with TB diagnosed in tertiary care hospitals (16%) than in those diagnosed in tuberculosis units (9%) (P < 0.001) and amongst those from South India (20%) than from North India (10%) (P < 0.001). The screening and referral process worked well although significantly more patients with DM diagnosed in hospitals were referred to DM care (96%) than patients diagnosed in tuberculosis units (92%) (P < 0.05).

CONCLUSION

This pilot project shows that it is important and feasible to screen patients with TB for DM in the routine setting, resulting in earlier identification of DM in some patients and opportunities for better management of comorbidity. A policy decision has since been made by the National TB Control Programme of India to implement this intervention countrywide.

Screening of patients with diabetes mellitus for tuberculosis in India

OBJECTIVE

To assess the feasibility, results and challenges of screening patients with diabetes mellitus (DM) for tuberculosis (TB) within the healthcare setting of six DM clinics in tertiary hospitals across India.

METHOD

Agreement on how to screen, monitor and record the screening was reached in October 2011 at a national stakeholders' meeting, and training was carried out for staff in the six tertiary care facilities in December 2011. Implementation started in the first quarter of 2012, and we report on activities up to 30th September 2012. Patients with DM were screened for TB on each clinic attendance using a symptom-based enquiry, and those with positive symptoms were referred for TB investigations.

RESULTS

In the three quarters, 26% of 7218, 52% of 12237 and 48% of 11691 patients with DM were screened for TB. A total of 254 patients were identified with TB, of whom 46% had smear-positive pulmonary disease. There were 18 patients newly diagnosed with TB as a result of screening and referral, with the remainder being patients already diagnosed from elsewhere. TB case rates per 100,000 patients attending the DM clinic each quarter were 859, 956 and 642. Almost 90% of patients with TB were recorded as starting or being on anti-TB treatment. Major implementation challenges related to human resources and recording systems.

CONCLUSION

In India, it is feasible to screen patients with DM for TB resulting in high rates of TB detection. More attention to detail, human resource requirements and electronic medical records are needed to improve performance.

Clinical characteristics, drug resistance, and treatment outcomes among tuberculosis patients with diabetes in Peru

OBJECTIVES

Diabetes is a risk factor for active tuberculosis (TB). Data are limited regarding the association between diabetes and TB drug resistance and treatment outcomes. We examined characteristics of TB patients with and without diabetes in a Peruvian cohort at high risk for drug-resistant TB. Among TB patients with diabetes (TB-DM), we studied the association between diabetes clinical/management characteristics and TB drug resistance and treatment outcomes.

METHODS

During 2005-2008, adults with suspected TB with respiratory symptoms in Lima, Peru, who received rapid drug susceptibility testing (DST), were prospectively enrolled and followed during treatment. Bivariate and Kaplan-Meier analyses were used to examine the relationships of diabetes characteristics with drug-resistant TB and TB outcomes.

RESULTS

Of 1671 adult TB patients enrolled, 186 (11.1%) had diabetes. TB-DM patients were significantly more likely than TB patients without diabetes to be older, have had no previous TB treatment, and to have a body mass index (BMI) >18.5 kg/m(2) (p<0.05). In patients without and with previous TB treatment, the prevalence of multidrug-resistant TB was 23% and 26%, respectively, among patients without diabetes, and 12% and 28%, respectively, among TB-DM patients. Among 149 TB-DM patients with DST results, 104 (69.8%) had drug-susceptible TB and 45 (30.2%) had drug-resistant TB, of whom 29 had multidrug-resistant TB. There was no association between diabetes characteristics and drug-resistant TB. Of 136 TB-DM patients with outcome information, 107 (78.7%) had a favorable TB outcome; active diabetes management was associated with a favorable outcome.

CONCLUSIONS

Diabetes was common in a cohort of TB patients at high risk for drug-resistant TB. Despite prevalent multidrug-resistant TB among TB-DM patients, the majority had a favorable TB treatment outcome.

Risk factors for tuberculosis

The risk of progression from exposure to the tuberculosis bacilli to the development of active disease is a two-stage process governed by both exogenous and endogenous risk factors. Exogenous factors play a key role in accentuating the progression from exposure to infection among which the bacillary load in the sputum and the proximity of an individual to an infectious TB case are key factors. Similarly endogenous factors lead in progression from infection to active TB disease. Along with well-established risk factors (such as human immunodeficiency virus (HIV), malnutrition, and young age), emerging variables such as diabetes, indoor air pollution, alcohol, use of immunosuppressive drugs, and tobacco smoke play a significant role at both the individual and population level. Socioeconomic and behavioral factors are also shown to increase the susceptibility to infection. Specific groups such as health care workers and indigenous population are also at an increased risk of TB infection and disease. This paper summarizes these factors along with health system issues such as the effects of delay in diagnosis of TB in the transmission of the bacilli.

Management of diabetes in resource-poor settings

Diabetes mellitus is an emerging problem in the developing world. In sub-Saharan Africa, for example, the incidence and prevalence of the disease is unknown, diagnosis is often made on the basis of poor information and a loosely defined set of criteria, and access to oral hypoglycaemic agents and insulin is patchy and expensive. The best system of management is currently unclear and this article explores lessons learnt, good practice and the applicability of the structured 'directly observed treatment, short course' (DOTS) approach (the current best care system for tuberculosis disease management in resource-poor settings) to the management of chronic diseases such as diabetes.

Epidemiology of tuberculosis immunology

Immunological impairment plays a major role in the epidemiology of TB. Globally, the most common causes of immunological impairment are malnutrition, diabetes, HIV/AIDS, aging, and smoking. With the notable exception of HIV, each factor leads to relatively mild immunological impairment in individuals. However, as these conditions affect a significant proportion of the population, they contribute substantially to the incidence of TB at a global scale. Understanding immunological impairment is central to understanding the global TB pandemic, and vital to the development of effective disease control strategies.

Diabetes and tuberculosis: a review of the role of optimal glycemic control

Developing countries shoulder most of the burden of diabetes and tuberculosis. These diseases often coexist. Suboptimal control of diabetes predisposes the patient to tuberculosis, and is one of the common causes of poor response to anti-tubercular treatment. Tuberculosis also affects diabetes by causing hyperglycemia and causing impaired glucose tolerance. Impaired glucose tolerance is one of the major risk factors for developing diabetes. The drugs used to treat tuberculosis (especially rifampicin and isoniazid) interact with oral anti-diabetic drugs and may lead to suboptimal glycemic control. Similarly some of the newer oral anti-diabetic drugs may interact with anti-tuberculosis drugs and lower their efficacy. Therefore diabetes and tuberculosis interact with each other at multiple levels - each exacerbating the other. Management of patients with concomitant tuberculosis and diabetes differs from that of either disease alone. This article reviews the association between diabetes and tuberculosis and suggests appropriate management for these conditions.

Convergence of non-communicable and infectious diseases in low- and middle-income countries

The convergence of non-communicable disease (NCD) and infectious disease (ID) in low- and middle-income countries (LMICs) presents new challenges and new opportunities to enact responsive changes in policy and research. Most LMICs have significant dual disease burdens of NCDs such as cardiovascular disease, diabetes and cancer, and IDs including tuberculosis, HIV/AIDS and parasitic diseases. A combined strategy is needed in surveillance and disease control; yet, experts, institutions and policies that support prevention and control of these two overarching disease categories have limited interaction and alignment. NCDs and IDs share common features, such as long-term care needs and overlapping high-risk populations, and there are also notable direct interactions, such as the association between certain IDs and cancers, as well as evidence of increased susceptibility to IDs in individuals with NCDs. Enhanced simultaneous surveillance of NCD and ID comorbidity in LMIC populations would generate the empirical data needed to better understand the dual burden, and to target coordinated care. Where IDs and NCDs are endemic, focusing on vulnerable populations by strengthening social protections and improving access to health services is crucial, as is the re-alignment of efforts to combine NCD and ID screening, treatment programmes, and the assessment of their impact. Integrating public health activities for ID and NCD should extend beyond health care services to prevention, which is widely seen as crucial to successful NCD and ID control campaigns alike. The convergence of NCD and ID in LMICs has the potential to overstretch already strained health systems. With some LMICs now focused on major health system reforms, a unique opportunity is available to address NCD and ID challenges with newfound urgency and novel approaches.

Prevalence of diabetes and pre-diabetes and associated risk factors among tuberculosis patients in India

BACKGROUND

Diabetes mellitus (DM) is recognised as an important risk factor to tuberculosis (TB). India has high TB burden, along with rising DM prevalence. There are inadequate data on prevalence of DM and pre-diabetes among TB cases in India. Aim was to determine diabetes prevalence among a cohort of TB cases registered under Revised National Tuberculosis Control Program in selected TB units in Tamil Nadu, India, and assess pattern of diabetes management amongst known cases.

METHODS

827 among the eligible patients (n = 904) underwent HbA1c and anthropometric measurements. OGTT was done for patients without previous history of DM and diagnosis was based on WHO criteria. Details of current treatment regimen of TB and DM and DM complications, if any, were recorded. A pretested questionnaire was used to collect information on sociodemographics, habitual risk factors, and type of TB.

FINDINGS

DM prevalence was 25.3% (95% CI 22.6-28.5) and that of pre-diabetes 24.5% (95% CI 20.4-27.6). Risk factors associated with DM among TB patients were age (31-35, 36-40, 41-45, 46-50, >50 years vs <30 years) [OR (95% CI) 6.75 (2.36-19.3); 10.46 (3.95-27.7); 18.63 (6.58-52.7); 11.05 (4.31-28.4); 24.7 (9.73-62.7) (p<0.001)], positive family history of DM [3.08 (1.73-5.5) (p<0.001)], sedentary occupation [1.69 (1.10-2.59) (p = 0.016)], and BMI (18.5-22.9, 23-24.9 and ≥25 kg/m(2) vs <18.5 kg/m(2)) [2.03 (1.32-3.12) (p = 0.001); 0.87 (0.31-2.43) (p = 0.78); 1.44 (0.54-3.8) (p = 0.47)]; for pre-diabetes, risk factors were age (36-40, 41-45, 46-50, >50 years vs <30 years) [2.24 (1.1-4.55) (p = 0.026); 6.96 (3.3-14.7); 3.44 (1.83-6.48); 4.3 (2.25-8.2) (p<0.001)], waist circumference [<90 vs. ≥90 cm (men), <80 vs. ≥80 cm (women)] [3.05 (1.35-6.9) (p = 0.007)], smoking [1.92 (1.12-3.28) (p = 0.017)] and monthly income (5000-10,000 INR vs <5000 INR) [0.59 (0.37-0.94) (p = 0.026)]. DM risk was higher among pulmonary TB [3.06 (1.69-5.52) (p<0.001)], especially sputum positive, than non-pulmonary TB.

INTERPRETATION

Nearly 50% of TB patients had either diabetes or pre-diabetes.

Quantifying the association between tuberculosis and diabetes in the US: a case-control analysis

Historically, an association between tuberculosis and diabetes was recognised clinically, and the recent global rise in diabetes prevalence has reignited interest. We therefore quantified the tuberculosis-diabetes association using US survey data. A case-control analysis was performed using cross-sectional data from the second National Health and Nutrition Examination Survey (1976-1980; civilian non-institutionalised US population aged 20-74). Cases were respondents ever diagnosed with tuberculosis, and controls were respondents who reported never receiving a tuberculosis diagnosis. Exposure to diabetes and intermediate hyperglycaemia was defined using a self-reported measure, an oral glucose tolerance test, or both. We used logistic regression to estimate an adjusted odds ratio, controlling for potential major confounders. In relation to the main exposure measure, the adjusted odds ratio for the association between tuberculosis and diabetes varied between 2.31 (95% confidence interval 1.36-3.93) and 2.36 (95% confidence interval 1.40-3.97), depending on the model. No association was found for intermediate hyperglycaemia, with adjusted odds ratio varying between 1.33 (95% confidence interval 0.49-3.64) and 1.34 (95% confidence interval 0.50-3.62), depending on model. Irrespective of the exposure measure and the confounders controlled for, diabetes was associated with an increased tuberculosis risk. This study may underestimate the true association due to exposure misclassification.

Infections in patients with diabetes mellitus: A review of pathogenesis

In general, infectious diseases are more frequent and/or serious in patients with diabetes mellitus, which potentially increases their morbimortality. The greater frequency of infections in diabetic patients is caused by the hyperglycemic environment that favors immune dysfunction (e.g., damage to the neutrophil function, depression of the antioxidant system, and humoral immunity), micro- and macro-angiopathies, neuropathy, decrease in the antibacterial activity of urine, gastrointestinal and urinary dysmotility, and greater number of medical interventions in these patients. The infections affect all organs and systems. Some of these problems are seen mostly in diabetic people, such as foot infections, malignant external otitis, rhinocerebral mucormycosis, and gangrenous cholecystitis. In addition to the increased morbidity, infectious processes may be the first manifestation of diabetes mellitus or the precipitating factors for complications inherent to the disease, such as diabetic ketoacidosis and hypoglycemia. Immunization with anti-pneumococcal and influenza vaccines is recommended to reduce hospitalizations, deaths, and medical expenses.

The timing of death in patients with tuberculosis who die during anti-tuberculosis treatment in Andhra Pradesh, South India

Background

India has 2.0 million estimated tuberculosis (TB) cases per annum with an estimated 280,000 TB-related deaths per year. Understanding when in the course of TB treatment patients die is important for determining the type of intervention to be offered and crucially when this intervention should be given. The objectives of the current study were to determine in a large cohort of TB patients in India:- i) treatment outcomes including the number who died while on treatment, ii) the month of death and iii) characteristics associated with "early" death, occurring in the initial 8 weeks of treatment.

Methods

This was a retrospective study in 16 selected Designated Microscopy Centres (DMCs) in Hyderabad, Krishna and Adilabad districts of Andhra Pradesh, South India. A review was performed of treatment cards and medical records of all TB patients (adults and children) registered and placed on standardized anti-tuberculosis treatment from January 2005 to September 2009.

Results

There were 8,240 TB patients (5183 males) of whom 492 (6%) were known to have died during treatment. Case-fatality was higher in those previously treated (12%) and lower in those with extra-pulmonary TB (2%). There was an even distribution of deaths during anti-tuberculosis treatment, with 28% of all patients dying in the first 8 weeks of treatment. Increasing age and new as compared to recurrent TB disease were significantly associated with "early death".

Conclusion

In this large cohort of TB patients, deaths occurred with an even frequency throughout anti-TB treatment. Reasons may relate to i) the treatment of the disease itself, raising concerns about drug adherence, quality of anti-tuberculosis drugs or the presence of undetected drug resistance and ii) co-morbidities, such as HIV/AIDS and diabetes mellitus, which are known to influence mortality. More research in this area from prospective and retrospective studies is needed.

Nutrition, diabetes and tuberculosis in the epidemiological transition

Background

Diabetes prevalence and body mass index reflect the nutritional profile of populations but have opposing effects on tuberculosis risk. Interactions between diabetes and BMI could help or hinder TB control in growing, aging, urbanizing populations.

Methods and Findings

We compiled data describing temporal changes in BMI, diabetes prevalence and population age structure in rural and urban areas for men and women in countries with high (India) and low (Rep. Korea) TB burdens. Using published data on the risks of TB associated with these factors, we calculated expected changes in TB incidence between 1998 and 2008. In India, TB incidence cases would have increased (28% from 1.7 m to 2.1 m) faster than population size (22%) because of adverse effects of aging, urbanization, changing BMI and rising diabetes prevalence, generating an increase in TB incidence per capita of 5.5% in 10 years. In India, general nutritional improvements were offset by a fall in BMI among the majority of men who live in rural areas. The growing prevalence of diabetes in India increased the annual number of TB cases in people with diabetes by 46% between 1998 and 2008. In Korea, by contrast, the number of TB cases increased more slowly (6.1% from 40,200 to 42,800) than population size (14%) because of positive effects of urbanization, increasing BMI and falling diabetes prevalence. Consequently, TB incidence per capita fell by 7.8% in 10 years. Rapid population aging was the most significant adverse effect in Korea.

Conclusions

Nutritional and demographic changes had stronger adverse effects on TB in high-incidence India than in lower-incidence Korea. The unfavourable effects in both countries can be overcome by early drug treatment but, if left unchecked, could lead to an accelerating rise in TB incidence. The prevention and management of risk factors for TB would reinforce TB control by chemotherapy.