In May 2014, the World Health Assembly approved the action framework of the World Health Organization (WHO) Towards tuberculosis elimiation1 with the objective of eliminating tuberculosis (TB) as a global health problem by 2035. This would require a 95% reduction in TB mortality and a 90% reduction in its incidence relative to 2015. The action framework includes policy and budget measures at the national and international levels ranging from guaranteeing universal access to health care to addressing the social and economic factors that have an impact on this disease.2 Tuberculosis is associated with poverty, social exclusion and inequality, and there is evidence that factors such as low educational attainment, unemployment and low socioeconomic status (SES) are associated with an increased incidence and prevalence of TB.3

Low-resource countries have the highest incidence of TB and the highest associated mortality. Nevertheless, the action framework of the WHO also includes strategies for low-incidence countries (fewer than 10 cases/100 000 inhabitants/year) such as Spain.2 According to the latest report of the Red Nacional de Vigilancia Epidemiológica (Spanish National Network of Epidemiological Surveillance), the overall incidence of TB in Spain in 2016 was 10.38 cases per 100 000 inhabitants (4.10 in children aged less than 15 years).4 The incidence in the population aged less than 15 years in Spain in years 2013, 2014 and 2015 was of 5.33, 4.35 and 5.05 cases per 100 000 inhabitants, respectively. Although there is a decreasing trend in the incidence of TB nationwide, the incidence is decreasing by less than 11% per year (the target established by the WHO).

In order to analyse the distribution of cases of TB in children aged less than 15 years living in Seville based on the SES of the neighbourhoods where they resided, we calculated the annual incidence of cases of TB in children notified to the Department of Epidemiology of the Health District of Seville of the Department of Health of Andalusia in years 2013, 2014 and 2015. We obtained data on the geographical distribution by administrative subdistricts of the city of Seville and the total population aged less than 15 years residing in each subdistrict through the Urban Audit Project of the Instituto Nacional de Estadística (National Institute of Statistics).5 Since data for the population distribution by subdistrict was not available for 2014, we calculated the incidence for 2014 using the population distribution of 2013. We defined low-SES subdistricts as those containing 1 or more of the areas established as areas in need of social transformation (ANSTs) in the city of Seville based on the classification of residential areas with structural poverty established by the Government of Andalusia (based on data on variables such as income, education, unemployment, social exclusion etc).6 We calculated the incidence ratio (IR) of the incidence in subdistricts containing ANSTs relative to those that did not contain ANSTs for each of the 3 years under study.

The annual incidence of TB in the population aged less than 15 years in the city of Seville in the 3 years under study were higher than the nationwide average in Spain of this age group: 6.61 cases per 100 000 inhabitants aged less than 15 years in 2013, 14.71 in 2014 and 8.54 in 2015 (Table 1). The maximum differences in the calculated incidence between districts in 2014 (using the distribution of the population by subdistrict of 2013) and in 2015 was of +/- 3 cases per 100 000 inhabitants, and we found no changes in incidence in the subdistricts with ANSTs or the subdistricts without ANSTs in 2014.

The IR comparing subdistricts of Seville with areas with structural poverty and the subdistricts without such areas revealed significant differences, with the incidence being up to nearly 9 times greater in the most disadvantaged areas (IR 2013 = 8.73; IR 2014 = 3.13; IR 2015 = 4.47) (Fig. 1).

Figure 1.

Quintile distribution of subdistricts of the city of Seville by incidence of tuberculosis in children aged less than 15 years from 2013 to 2015.

We generated this chart using the software application gvSIG, and data on the geographical distribution of the population aged <15 years of year 2013 for calculating the incidence of tuberculosis in this 3-year period.

(0.18MB).

Our findings join the already considerable body of evidence on the association between poverty and tuberculosis (including in the paediatric population) and reveal the considerable health inequalities that exist in relation to TB based on the SES of the area of residence of the inhabitants of Seville. To meet the WHO objectives toward tuberculosis elimination, we must prioritise efforts on the part of welfare and health care organizations for the active search of cases in the most disadvantaged areas of our cities and to raise the awareness of both the public and policy-makers on the need to implement a multidisciplinary strategy to address social determinants of health and the inequalities that they generate.