6.3 TB determinants

The tuberculosis (TB) epidemic is strongly influenced by social and economic development and health-related risk factors such as undernutrition, diabetes, HIV infection, alcohol use disorders and smoking. Achieving global targets for reductions in TB disease burden requires progress on these fronts, as highlighted in Section 6.1. For example, numbers of TB cases and deaths started to decline in western Europe, North America and some other parts of the world around the turn of the 20th century, as incomes grew, levels of poverty fell, and housing and nutrition improved ( 1, 2). The fastest declines in TB incidence and TB mortality in western Europe occurred in the 1950s and 1960s, in the context of progress towards universal health coverage (UHC), rapid social and economic development, and the availability of effective drug treatments.

The World Health Organization (WHO) has developed a framework for monitoring the Sustainable Development Goals (SDGs) related to TB. The framework comprises 14 indicators for which a relationship with TB incidence could be established, under seven SDGs (Table A6.1). Five are health-related risk factors for TB and six are broader socioeconomic determinants; the other 3 indicators, for UHC and current health expenditures, are covered in Section 6.1. There is a particularly clear relationship between TB incidence and undernutrition and gross domestic product (GDP) per capita (Fig. 6.3.1).

Globally in 2020, an estimated 1.9 million incident cases of TB were attributable to undernutrition, 0.74 million to HIV infection, 0.74 million to alcohol use disorders, 0.73 million to smoking and 0.37 million to diabetes (Table 6.3.1). However, there is considerable variation among countries in the relative contribution of the five factors (Table 6.3.2, Fig. 6.3.2), and thus also variation in which of these factors need to be prioritized as part of national efforts to reduce the burden of TB disease.

The most recent data for undernutrition and five socioeconomic indicators associated with TB incidence are shown for the 30 high TB burden and three global TB watchlist countries in Fig. 6.3.3. In this figure, the outer edge of the hexagon (100) is the ideal value for each indicator. Therefore, better performance corresponds to a larger shaded region. To represent this situation visually, the indicators “proportion of the urban population living in slums” and “proportion of the population living below the international poverty line” are inverted in the figure. All indicator values in the figure are for the general population as opposed to people with TB; values for TB patients specifically (e.g. out-of-pocket expenditure and access to social protection) may differ from these general values.

Based on the latest available data in the World Bank database, some upper-middle-income and lower-middle-income countries (e.g. Brazil, China, India, Indonesia, South Africa and Thailand) appear to be performing relatively well. However, progress is likely to have been set back by the COVID-19 pandemic. Even before the pandemic, other high TB burden countries already faced major challenges in achieving a range of TB-related SDG targets. Moreover, values for poor populations and vulnerable groups most at risk of developing TB are likely to be worse than national averages.

Addressing broader determinants of the TB epidemic requires multisectoral action and accountability. The political declaration at the UN high-level meeting on TB requested the WHO Director-General to develop a multisectoral accountability framework for TB (MAF-TB) and ensure its timely implementation. Following extensive development work, WHO finalized the framework and published it in 2019 (3). To support Member States to adapt and use it,, WHO has also developed a checklist that enables national assessments of the status of the main elements of the MAF-TB (4).

Further country-specific details for the 14 indicators related to TB incidence are available in the Global tuberculosis report app and online country profiles.

Fig. 6.3.1 The relationship between GDP per capita and the prevalence of undernutrition, and TB incidence per 100 000 population

TABLE 6.3.1 Global estimates of the number of TB cases attributable to selected risk factors, 2020

TABLE 6.3.2 Status of selected risk factors for TB, 30 high TB burden countries and three global TB watchlist countries, latest available year

Fig. 6.3.2 Estimated number of TB cases attributable to five risk factors, 30 high TB burden countries and three global TB watchlist countries, 2020

Best estimates (in colour) and uncertainty intervals (black) are shown.

Fig. 6.3.3 Status of selected SDG indicators beyond SDG 3 in high TB burden countries, latest available year