A reinvestigation of the relationship between the decline of tuberculosis and improvement in social conditions in England and Wales during Victorian times.
Design: A retrospective study using data published in the annual reports of the Registrar General from 1853 to 1910. The diseases studied, in addition to tuberculosis were, dysentery and cholera including their total and infant mortality. Social conditions were evaluated from earnings and population density per house. Tuberculosis mortality declined at an annual average rate of 1.71% (95%CI 0.77 to 2.63) whereas total mortality, infant mortality and mortality from cholera and dysentery and house population density showed no statistically significant decline over the same period. Real earnings increased by 1.05% (C10.29 to 1.81). Improving social conditions do not provide the total explanation for the decline in tuberculosis during Victorian times. Other factors, principally natural selection, probably played a role. Part of the current increase in tuberculosis may be caused by effective drug therapy eliminating natural selection.