Thorax 60:87-88 doi:10.1136/thx.2004.038331
  • Editorial

The ebb and flow of asthma

  1. B G Toelle1,
  2. G B Marks1,2
  1. 1Woolcock Institute of Medical Research, Sydney, NSW 2050, Australia
  2. 2University of Sydney, Sydney, NSW 2006, Australia
  1. Correspondence to:
    Dr B Toelle
    Woolcock Institute of Medical Research, P O Box M77, Missenden Road Post Office, NSW 2050, Australia;

    More studies reporting international time trends will put us in a better position to explain the changing prevalence of asthma

    Without ever fully understanding the reasons for the global increase in the prevalence of asthma during the later part of the 20th century, we are now faced with the challenge of explaining an apparent decrease in prevalence. A challenge indeed! During the 1980s and early 1990s several repeat cross sectional studies, conducted in widely varying regions of the world, reported an increase in the prevalence of symptoms of asthma, diagnosed asthma, and medication use for asthma.1,2 Although most studies relied on self-reported symptoms and diagnoses—and hence could be subject to reporting bias—at least one3 observed substantial changes in airway hyperresponsiveness, lending credence to the view that this was not simply related to changes in disease classification and labelling. Parallel increases in hospitalisation rates4 and mortality rates5 also were consistent with a true rising tide of asthma. This trend led to major national and international initiatives to control the disease.6–9