The “Atopic March”: MAS study

Abstract

Only longitudinal studies are able to dissect risk factors associated either with the new onset of a disease or with the severity of an illness. Furthermore, the timing of any relevant exposure prior to the onset of symptoms is difficult to assess in cross-sectional studies, considering the retrospective nature of the exposure assessment. Due to these inherent limitations of these types of studies, a number of prospective surveys such as the German Multicenter Birth cohort, the MAS Study have been carried out which have considerably advanced our understanding of the natural history of allergic sensitization and its relation to asthma. Whereas, house dust mite and cat allergen exposure was a risk factor for the development of sensitization towards that specific allergen, the incidence of wheeze, asthma and airway hyperresponsiveness was not affected by the level of allergen exposure. In contrast, early life infections such as repeated rhinitis episodes in the first year of life were inversely related to the development of asthma.