Editor,—The article recently published by van Cleemput has made a valuable contribution to the health care needs of travellers and has drawn attention to a very deprived section of our community.1 However, the assertion that childhood asthma is more common in travellers is not based on sound evidence. This suggestion was based on a study by Anderson, who reported on the health concerns and needs of traveller families.2 The selection criterion for Anderson's study was families with children of less than 5 years of age. The traveller families had a mean of six children aged 1 to 15 years. The control affluent families had a mean of 1.7 children aged 1 to 3 years, and the control inner city families had a mean of 1.9 children aged 1 to 4 years. Anderson reported that asthma was a concern to 30% of travellers compared with 11% of inner city families and 4.5% of affluent families, using a questionnaire that seemed to tackle parental concerns only, and was not validated for asthma incidence. Yet, van Cleemput extrapolated a high incidence of asthma in travellers' children from this study, and did not comment on questionnaire validation or the confounding factors of age and transient early wheezing.

We used the ISAAC (International Study of Asthma and Allergies in Childhood) questionnaire to compare the prevalence of asthma in schoolboys, aged 6 to 12 years, from travellers' families with settled controls.3 The parent reported prevalence of wheezing and related symptoms were all more common in schoolboys from the control group than in traveller schoolboys. The values were significant for wheeze in the last year (31.3% v 14.8%, OR 5.6, p=0.025), and for doctor diagnosed asthma (25.6%v 11.1%, OR 5.1, p=0.04). We concluded that the experience of the travelling lifestyle may be a protective factor in the development of asthma.