Tuberculosis (TB)

TB comorbidities and risk factors

TB treatment and care

Several medical conditions are risk factors for TB and for poor TB treatment results, while TB can complicate the disease course of some diseases. It is therefore important to identify these comorbidities in people diagnosed with TB in order to ensure early diagnosis and improve co-management.

Father and daughter in hospital for TB and HIV diagnostics, Jayapura, Indonesia
WHO/SEARO/Gary Hampton

When these conditions are highly prevalent in the general population they can be important contributors to the TB burden. Consequently, reducing the prevalence of these conditions can help prevent TB.

TB share underlying social determinants with many of these conditions. Addressing the social determinants of health is a shared responsibility across disease programmes and other stakeholders within and beyond the health sector.

TB and HIV

People living with HIV are from 26-31 times more likely to develop TB than persons without HIV. TB is the most common presenting illness among people living with HIV, including among those taking antiretroviral treatment and it is the major cause of HIV-related death. In 2016, there were an estimated 1.3 million TB deaths among HIV-negative people and an additional 374 000 deaths among HIV-positive people. Sub-Saharan Africa bears the brunt of the dual epidemic, accounting for approximately 74% of the estimated burden in 2016.

TB and diabetes

Diabetes triples the risk of TB. Consequently, rates of TB are higher in people with diabetes than in the general population, and diabetes is a common comorbidity in people with TB. Diabetes can worsen the clinical course of TB, and TB can worsen glycaemic control in people with diabetes. Individuals with both conditions thus require careful clinical management. Strategies are needed to ensure that optimal care is provided to patients with both diseases.

Diabetes prevalence is increasing globally. The most dramatic increase is in low- and middle income countries undergoing rapid economic, social, and lifestyle changes. Further increase in the number of diabetes-associated TB cases risks jeopardizing progress that has been made in the global fight against TB. Therefore, prevention and care of diabetes should be a priority not only for stakeholders involved in care and control of non-communicable diseases, but also for those working on TB care and prevention. This should be part of broader actions on risk factors and social determinants.

TB and nutrition

Malnutrition increases the risk of TB and TB can lead to malnutrition. Malnutrition is therefore often highly prevalent among people with TB. While appropriate TB treatment often helps normalize nutritional status, many TB patients are still malnourished at the end of TB treatment. Therefore, nutritional assessment and counselling, and management of malnutrition based on the nutritional status are an important part of the TB treatment package.

Undernutrition, and underlying food insecurity, are among the most important determinants of TB. Improving nutritional status at population level is important for TB prevention. This should be part of broader actions on social determinants.

TB and tobacco smoking

Tobacco smoking increases the risk of TB 2-3 fold, and is associated with poor TB treatment results. Smoking prevalence is often high among people with TB, and prevalence of other smoking-related conditions can be high as well. People diagnosed with TB should be asked about smoking, and should be offered advice about smoking cessation. This is part of the practical approach to lung health.

High smoking prevalence in the population is an important contributor to high TB burden. Public health and regulatory efforts to reduce smoking prevalence can have significant impact on TB incidence. It is key that TB prevention efforts are linked up with efforts to reduce other smoking related conditions in the population.

TB and harmful use of alcohol

Harmful use of alcohol increases the risk of TB threefold, and is also a strong risk factor for poor TB treatment adherence. In countries with high prevalence of alcohol use disorders, and especially in intermediate- and low-incidence countries where TB has become highly concentrated to certain vulnerable groups, harmful alcohol use can be an important population level risk factor for TB, and is often a common co-morbidity among TB patients. As part of a comprehensive care package it is important, especially in those countries, to identify problem drinkers, diagnose alcohol use disorder, and refer for appropriate alcohol interventions.

A few countries have experimented with systematic screening for harmful alcohol use of all TB patients. Screening and diagnosis of other mental health problems may also be warranted.

Journal articles

Lönnroth K, Roglic G, Harries AD. Addressing the global diabetes epidemic to improve tuberculosis prevention and care – from evidence to policy and practice. Lancet Diabetes and Endocrinology 2014; 2: 730–39

Lönnroth K, Williams BG, Stadlin S, Jaramillo E, Dye C. Alcohol use as a risk factor for tuberculosis – a systematic review. BMC Public Health 2008; 8: 289 doi:10.1186/1471-2458/8/289

Rehm J, Samokhvalov AV, Popova S, Neuman M, Room R, Parry C, Lönnroth K, Patra J, Poznyak V. Alcohol consumption, alcohol use disorders and incidence and disease course of tuberculosis (TB) – is there a causal connection? BMC Public Health 2009, 9:450 doi:10.1186/1471-2458-9-450

Viiklepp P, de Colombani P, Kurbatova A, Sandgren A, Lönnroth K. Collaborative action on tuberculosis and alcohol abuse in Estonia. First report of a demonstration project. Copenhagen: World Health Organization Regional Office for Europe, 2013