A Study of Respiratory Tuberculosis in Relation to Housing Conditions in Edinburgh: I.--The Pre-War Period

In the course of the last hundred years, during which the mortality caused by tuberculosis declined considerably in many countries, it has come to be publicly recognized that this disease in modern society is not one of medical import alone, but is set in a social and economic background, the influence of which is far reaching. In particular, it has long been accepted as axiomatic that unsatisfactory housing conditions affect the prevalence of respiratory tuberculosis, that illness is more common and death more frequent where people live in the most crowded circumstances. This is not to say that bad housing is the direct cause of tubercu losis, or that any of the other social and environmental factors which may increase the prevalence of this disease can be singled out as being directly responsible for incidence or mortality, for the primary cause of tuberculosis is the tubercle bacillus. But where an association can be found between the aetiology of the disease and any environmental factor such as poor housing, and where regional and local differences in the incidence of the disease correspond with differences in that environmental factor, it is reasonable to affirm that improvement in such a factor would result in a proportional reduction in the morbidity and mortality caused by tuberculosis. In Scotland, this belief in the connexion between housing conditions and respiratory tuberculosis has been supported by the results of a number of studies carried out at various times, particularly in Glasgow. Chalmers (1913) investi gated the mortality rates in Glasgow in relation to size of house, and showed that in every age-group the rate of mortality was lower in houses of three and four apartments than in smaller houses. Peters (1933) considered incidence as well as mortality in relation to size of house and to number of persons per room, and found that mortality in the one-apartment house was 340 per cent, greater than in the four-apartment dwelling, although he considered that the specific effect of overcrowding, as measured by the average number of persons per room, was less evident than might have been expected. Laidlaw (1933) analysed all deaths of young adults which occurred in the Eastern Division of Glasgow (covering about one-fifth of the whole population of the city) in the quinquennium 1928-1932, and showed not only that a distinct difference existed between the three-apartment 143 3