Maternal atopy and parity

Authors


: Dr Jordi Sunyer, Unitat de Recerca Respiratòria i Ambiental, Institut Municipal d'Investigació Mèdica (IMIM), Doctor Aiguader 80, E-08003 Barcelona, Spain. E-mail: jsunyer@imim.es¶Members of the AMICS (Asthma Multi-centre Infants Cohort Study) Group: Ashford: Paul Cullinan, Jessica Harris, Warwick Atkinson, Pamela Mills, Susan Moffat, Carol White, Meinir Jones, Anthony Newman-Taylor; Barcelona: Goncal Figueras, Oriol Vall, Oscar Garcia, Carme Puig, Eva Sanchez, Josep M Antó, Jordi Sunyer, Xavier Basagaña; Menorca: Maties Torrent, M̂ Victoria Estraña, Mireia García. The AMICS study is coordinated by Maria Barnes. Funding: Ashford: the COLT Foundation; Barcelona: FIS 95/0314; Menorca: FIS 97/0588.

Abstract

Background Family size and high birth order were related to the prevalence of hayfever and positive skin prick test. However, this association may be explained by maternal atopy. We examined the relationship between maternal atopy and the number of offspring in three European cohorts of pregnant women.

Methods The mothers and their children (n = 1487) were recruited for the Asthma Multi-centre Infants Cohort Study (AMICS). The three concurrent cohorts (Ashford, Kent (UK); Menorca island (Spain) and Barcelona city (Spain) followed the same research protocol. Maternal and paternal atopy was identified by skin prick tests at different times at the three centres.

Results Maternal atopy was inversely related to the number of offspring, an association which occurred in each of the three cohorts and remained when atopy was defined separately for individual allergens (a positive response to testing with either Der p 1 or grass pollen) and which was not confounded by maternal age, smoking nor social class (the adjusted odds ratios were 0.71, 0.79 and 0.26 for increasing number of offspring, P = 0.002). Neither maternal asthma (P = 0.43) nor paternal atopy (P = 0.58) were associated with the number of offspring. Maternal atopy was not related to reproductive outcomes.

Conclusions The association between maternal atopy and parity challenges the role of family size on child atopy, which should be studied in other populations.

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