Predicting the effect of improved socioeconomic health determinants on the tuberculosis epidemic
Authors: Giovanni Battista Migliori, Alberto L Garcia-Basteiro
Journal: The Lancet Global Health (2018)

Two important public health documents have recently established programmatic goals for tuberculosis control. The first is WHO's End TB Strategy, which represents the evolution of previous DOTS (directly observed treatment, short-course) and Stop TB strategies.1Sotgiu G Spanevello A Migliori GB History of tuberculosis and drug resistance.N Engl J Med. 2013; 368: 88-89Crossref PubMed Scopus (3) Google Scholar End TB is built around three pillars: pillar 1 focuses on diagnosis, treatment, and prevention; pillar 2 on ways to tackle socioeconomic factors (eg, poverty reduction, social protection, and universal access); and pillar 3 on scientific research. The second key document, published in 2016, sets out the UN's Sustainable Development Goals (SDGs), replacing the Millennium Developing Goals. There are 13 SDGs. SDG 3 is to ensure healthy lives and promote wellbeing for all at all ages. Within SDG 3 are several subtargets,2UNSDG indicators.https://unstats.un.org/sdgs/metadata/Google Scholar including ending the epidemics of HIV, tuberculosis, malaria, and neglected tropical diseases, and combating hepatitis, waterborne, and other communicable diseases by 2030. SDG 1 is aimed at ending extreme poverty in all its forms everywhere. The WHO's End TB Strategy and the UN's SDGs are clearly connected because the End TB Strategy specifies indicators, targets, and strategic thinking necessary for elimination of one of the three pandemics specified in SDG 3. Additionally, one of the three main indicators of the End TB strategy—namely, reducing costs by 100% by 20353Tanimura T Jaramillo E Weil D Raviglione M Lönnroth K Financial burden for tuberculosis patients in low- and middle-income countries: a systematic review.Eur Respir J. 2014; 43: 1763-1775Crossref PubMed Scopus (254) Google Scholar—is directly associated with SDG 1. The relation between poverty and disease is well known, and tuberculosis has provided a striking example throughout human history. Even in settings where tuberculosis treatment is cost-free, it has still been shown to generate catastrophic costs, so that individuals with lower resources have worse outcomes.4Wingfield T Boccia D Tovar M et al.Defining catastrophic costs and comparing their importance for adverse tuberculosis outcome with multi-drug resistance: a prospective cohort study, Peru.PLoS Med. 2014; 11: e1001675Crossref PubMed Scopus (125) Google Scholar Although it is methodologically complex to show the causal association between single interventions aimed at improving socioeconomic conditions and global tuberculosis incidence,5Grange JM Gandy M Farmer P Zumla A Historical declines in tuberculosis: nature, nurture and the biosocial model.Int J Tuberc Lung Dis. 2001; 5: 208-212PubMed Google Scholar the large decrease in tuberculosis incidence that occurred throughout the 20th century is unlikely to have happened without the advancement of living conditions and overall socioeconomic development.6Hermans S Horsburgh Jr, CR Wood R A century of tuberculosis epidemiology in the northern and southern hemisphere: the differential impact of control interventions.PLoS One. 2015; 10: e0135179Crossref PubMed Scopus (25) Google Scholar, 7Wilson LG The historical decline of tuberculosis in Europe and America: its causes and significance.J Hist Med Allied Sci. 1990; 45: 366-396Crossref PubMed Scopus (72) Google Scholar Historical studies show the relation between tuberculosis and poverty; the important reduction in tuberculosis incidence achieved, such as the 10% reduction achieved per year in Europe after World War 2, was largely due to the improvement of the socioeconomic conditions.5Grange JM Gandy M Farmer P Zumla A Historical declines in tuberculosis: nature, nurture and the biosocial model.Int J Tuberc Lung Dis. 2001; 5: 208-212PubMed Google Scholar, 7Wilson LG The historical decline of tuberculosis in Europe and America: its causes and significance.J Hist Med Allied Sci. 1990; 45: 366-396Crossref PubMed Scopus (72) Google Scholar To quantify this association, poverty has been defined in the scientific literature by various different indicators, mostly with economic measures of individual or household income. SDG 1 introduces new concepts and indicators. Among them are social protection schemes, which aim to alleviate general poverty, vulnerability, and social exclusion. Higher spending on social protection programmes has been shown to be associated with lower tuberculosis prevalence, incidence, and mortality.8Siroka A Ponce NA Lönnroth K Association between spending on social protection and tuberculosis burden: a global analysis.Lancet Infect Dis. 2016; 16: 473-479Summary Full Text Full Text PDF PubMed Scopus (54) Google Scholar Social protection includes measures designed to reduce vulnerability to poverty, labour market interventions, contributory welfare programmes, and cash transfers. SDG 1 subtargets are linked to the four main risk factors for tuberculosis (malnutrition, HIV, health behaviours, and housing quality), which directly affect tuberculosis incidence. In The Lancet Global Health, Daniel J Carter and colleagues9Carter DJ Glaziou P Lönnroth K et al.The impact of social protection and poverty elimination on global tuberculosis incidence: a statistical modelling analysis of Sustainable Development Goal 1.Lancet Glob Health. 2018; (published online March 23.)http://dx.doi.org/10.1016/S2214-109X(18)30195-5Summary Full Text Full Text PDF PubMed Scopus (50) Google Scholar modelled the effects of social protection and poverty elimination to quantify tuberculosis incidence reduction. The authors developed a conceptual framework linking the core indicators of SDG 1 to tuberculosis incidence using a pathway of risk factors and real WHO data from 192 countries. The results show that the achievement of the goals in these two subtargets, even on their own, will greatly affect the tuberculosis epidemic. Ending extreme poverty (living on less than US$1·90) is estimated to reduce global tuberculosis incidence by 33·4% (95% credible intervals 15·5–44·5) and expanding social protection is estimated to reduce the incidence by 76·1% (45·2–89·9); achievement of both pathways is estimated to reduce incidence by 84·3% (54·7–94·9). These results, which highlight the clear need for multisectoral approaches to tackle global pandemics, have major policy implications and suggest the need for monitoring their implementation at the country level. In Moscow, in November, 2017, WHO organised the Global Inter-Ministerial Conference on Ending Tuberculosis, which had the unprecedented participation of Ministries of Health from all over the world. The key message from the conference was that the tuberculosis services (under the Ministry of Health of each country) need to work in strict collaboration with other ministries dealing with socioeconomic issues. Thanks largely to WHO, the technical elements of tuberculosis control and elimination are now established throughout most of the world: active case-finding, effective diagnosis and treatment of infectious cases, and management of latent tuberculosis infection.10Gilpin C, Korobitsyn A, Migliori GB, Raviglione MC, Weyer K. The World Health Organization standards for tuberculosis care and management. Eur Respir J (in press).Google Scholar The statistical model presented by Carter and colleagues9Carter DJ Glaziou P Lönnroth K et al.The impact of social protection and poverty elimination on global tuberculosis incidence: a statistical modelling analysis of Sustainable Development Goal 1.Lancet Glob Health. 2018; (published online March 23.)http://dx.doi.org/10.1016/S2214-109X(18)30195-5Summary Full Text Full Text PDF PubMed Scopus (50) Google Scholar underlines the need to tackle socioeconomic determinants just as vigorously as these technical elements if we are to see the final demise of tuberculosis throughout the world. We declare no competing interests. The impact of social protection and poverty elimination on global tuberculosis incidence: a statistical modelling analysis of Sustainable Development Goal 1Full achievement of SDG 1 could have a substantial effect on the global burden of tuberculosis. Cross-sectoral approaches that promote poverty reduction and social protection expansion will be crucial complements to health interventions, accelerating progress towards the End TB targets. Full-Text PDF Open Access