1. SDH International Symposium: The Making of Health
Workshop 2: Epidemics
Measuring the socio-spatial inequalities in health: Tuberculosis and urban overpopulation in Spain in the early twentieth century Celia Miralles Buil

2. Why study overpopulation?
Introduction
Observing the link between tuberculosis and urban misery in Spanish cities.
Why study overpopulation?
Focus on the debate at the time
Production of statistics/comparable data
Let’s look into the study of social and environmental factors of the disease, and the discussions it has spawned
Overpopulation, density, overcrowding, promiscuity
Contagion factor
Insalubrity factor
Social precariousness index

3. Sources' cross-referencing as a method:
Introduction
Understanding the socio-spatial inequalities in terms of TB mortality and morbidity: a concern for doctors and demographic historians.
To understand the link between tuberculosis and population density, its construction by the actors of the time must be taken into account.
Sources' cross-referencing as a method:
Doctors' speeches and their conclusions on data
Corpus data on 5000 patients treated in free establishments in Barcelona between 1929 and 1936.

4. 1. The spread of tuberculosis in Spanish cities: urban overpopulation at the heart of the subject in the 1930s
« Mortality from tuberculosis has been historically associated with population growth in cities » *
Overpopulation as an insalubrity factor that leads to an increase of mortality according to actors of the time (diagram issued by the journal AC No. 25 of GATCPAC.)
* CLIFF, A, HAGGETT, P, SMALLMAN-RAYNOR, M, (1998) Deciphering Global Epidemics, Analytical Approaches to the Disease Records of World Cities,
The unequal distribution of TB mortality in Spanish cities, linked to overpopulation and insalubrity.

5. 1. The spread of tuberculosis in Spanish cities: urban overpopulation at the heart of the subject in the 1930s
A diagram explaining the evolution of TB mortality: the three phases of tuberculation according to Lluís Sayé.
A diagram explaining the spread of tuberculosis in space: insalubrious and densely populated districts as starting points according to actors of the time.
A diagram explaining the disease's spread in society: contagion by the Koch bacillus.

6. Distribution by district of assisted patients for 10,000 residents
Distribution by district of treated patients at the central dispensary in 1930 for 10,000 residents
2. On a neighbourhood scale: questioning the link between high population density and tuberculosis
Distribution by district of assisted patients for 10,000 residents
Tuberculosis in city districts: spatial translation of a social reality?
No correlation between density and tuberculosis for assisted patients in Barcelona
The location of patients overlaps that of Barcelona’s working-class
Visibility, proximity, social networks as factors explaining the TB patients’ location
Understanding the strong presence of patients in the Raval district
Such presence in the Raval echoes a precarious/instable situation
The densely populated and insalubrious old center as a subject of priority attention from doctors

7. Housing density: a selection criterion of patients used by doctors
3. Overcrowding and promiscuity in TB housings: an index of social precariousness or a reason for treatment?
Actors focused on the housing scale: proximity as direct contagion factor
Studies showing that the correlation between high density and TB morbidity increases when the analysis scale is reduced
Observation of promiscuity in the tuberculosis patients’ beds
The very high density in housing of assisted TB patients as a social precarity index
Cohabitation as a common reality among TB patients
Being hosted by a relative parent, a sign of spatial instability
Housing density: a selection criterion of patients used by doctors
Map of the apartment of a TB patient, written by the visiting nurses of the help desk, 1921

8. Conclusion
Deciphering the circular relationship between doctors' speeches and available data on TB mortality or morbidity.
The relationship between tuberculosis and density is built through the focus on the infection and the microbe -- put by doctors.
Reduction of observation scale on housing
Invisibility of "social factors,” underlying overcrowding and promiscuity
These medical theories and practices listed at a specific time determine the creation of a category of social assistance : TB patients.