ABSTRACT
Asthma is a complex disease of largely unknown etiology but with a rela-
tively well-defined and effective clinical management strategy (1,2). The
high, but variable, prevalence of asthma in many countries (3,4), together
with substantial impacts of the disease on quality of life (5,6), health-care costs, (7) and mortality (8-11), have led to substantial public interest in
the disease. There is evidence that a range of environmental factors influ-
ence the course of asthma, by triggering exacerbations (12-16), and possi-
bly by inducing longer-term changes (17,18). Clinical management has a
major impact on the course of the disease: usually beneficial, but occasion-
ally adverse (19-21). There is evidence that utilization of beneficial clinical
management strategies for asthma (22,23) is sub-optimal.