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Much attention has focused on the strong association between atopic tendency and childhood wheezing. Causal roles for atopic sensitisation 1, 2 in the pathogenesis of wheezing and asthma have been postulated as a result of numerous studies showing a higher frequency of asthmatic symptoms in atopic children than in non-atopic children. 3- 6 Consequently, interventional strategies to prevent atopic sensitisation by allergen avoidance in early life have been applied in an attempt to modify the development of childhood allergy, wheeze, and asthma. 7- 9 However, these measures have met with mixed results and have not shown definitive lasting benefit. 2, 7- 9 Given such evidence, Pearce et al 10 recently questioned the role of atopy as a causative factor in asthma. Indeed, as amply shown by Martinez et al , 11 there is growing evidence for the existence of several distinct wheezing phenotypes in childhood, not all of which are closely linked to atopy. Some forms of non-atopic wheeze such as early life transient wheeze have been well characterised, 11 with associations with impaired lung function in infancy and maternal smoking. The nature of non-atopic wheeze in later childhood, however, remains unclear. In particular, the significance of such disease in terms of associated morbidity and the similarities or differences of its characteristics with atopic wheezing need confirmation. An understanding of whether different risk factors underlie atopic and non-atopic wheeze in later childhood could also provide fresh insight into the mechanisms underlying childhood wheezing and asthma. Here we describe findings that characterise non-atopic wheeze at 10 years of age and assess whether this differs in risk factor profile from atopic disease. The results were derived from our unselected whole population birth cohort which has been prospectively followed for the first decade of life.
METHODS
A whole population birth cohort was established on the Isle of Wight in 1989 to study prospectively the natural history of childhood wheezing and to identify risk factors relevant to the development of childhood wheezing states. Approval for the study was obtained from the local research ethics committee.
Of 1536 children born between 1 January 1989 and 28 February 1990, informed consent was obtained for 1456 subjects to be enrolled. Enrolment took place at birth and information on family history of allergy...