Factors Affecting Estimates of the Prevalence of Asthma and Wheezing in Childhood

: Nine recent studies of the prevalence of asthma and wheezing in childhood are reviewed. Sample prevalences are found to range from 5 to 31% and possible reasons for this are considered; it is shown that the prevalence of asthma found is highly dependent on the criteria used for diagnosis. Some clinical and research implications are discussed.