title: Historical declines in tuberculosis in England and Wales: improving social conditions or natural selection?
abstract: OBJECTIVE
  A reinvestigation of the relationship between the decline of tuberculosis and improvement in social conditions in England and Wales during Victorian times.
  
  
  METHODS
  A retrospective study using data published in the annual reports of the Registrar General from 1853 to 1910. MEASURES ASSESSED: 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.
  
  
  RESULTS
  Tuberculosis mortality declined at an annual average rate of 1.71% (95% confidence interval [Cl] 0.77-2.63), 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% (95% CI 0.29-1.81).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Tuberculosis Research Unit, Cardiothoracic Centre, Liverpool, United Kingdom. p.d.o.davies@liverpool.ac.uk
authors.forename: R P
authors.initials: RP
authors.lastname: Davies
authors.forename: K
authors.initials: K
authors.lastname: Tocque
authors.forename: M A
authors.initials: MA
authors.lastname: Bellis
authors.forename: T
authors.initials: T
authors.lastname: Rimmington
authors.forename: P D
authors.initials: PD
authors.lastname: Davies
mesh_terms: D002423:Cause of Death; D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D008297:Male; D009026:Mortality / Q000639:trends; D012189:Retrospective Studies; D012924:Social Conditions; D012959:Socioeconomic Factors; D014397:Tuberculosis, Pulmonary / Q000401:mortality*; D014852:Wales / Q000453:epidemiology