Role of timing of exposure to pets and dampness or mold on asthma and sensitization in adolescence.

Pet and dampness or mold exposure are considered risk factors for asthma and sensitization. It is unclear whether timing of exposure to these factors is differentially associated with asthma risk and sensitization in adolescence.We investigated the role of timing of pet and dampness or mold exposure in asthma and sensitization in adolescence. Understanding this role is essential to build targeted prevention strategies.We used data from 1871 participants of the Dutch Prevention and Incidence of Asthma and Mite Allergy (PIAMA) cohort. Residential exposure to pets, dampness or mold was assessed by repeated parental questionnaires. We used asthma data from the 17-year questionnaire and sensitization data from the 16-year medical examination. We characterized timing using longitudinal exposure patterns from pregnancy till age 17 using longitudinal latent class growth modelling. We used logistic regression models to analyze associations of exposure patterns with asthma at age 17 and sensitization at age 16.For none of the time windows, exposure to pets and dampness or mold was associated with asthma at age 17, but a lower sensitization risk at age 16 was suggested, e.g. the odds ratio (95% confidence interval) for sensitization was 0.63 (0.35 to 1.11) and 0.69 (0.44 to 1.08) for early life and persistently high pet exposure,respectively, compared to very low exposure. An inverse association was also suggested for sensitization and moderate early childhood dampness or mold exposure [0.71 (0.42 to 1.19)].Different timing of pet and dampness or mold exposure was not associated with asthma, but lower risk of sensitization in adolescence was suggested, which could be partly attributable to reversed causation. Current findings are not sufficient to recommend pet avoidance to prevent allergic disease. More prospective studies are needed to obtain insights that can be used in clinical practice. This article is protected by copyright. All rights reserved.