Does early indoor microbial exposure reduce the risk of asthma? The Prevention and Incidence of Asthma and Mite Allergy birth cohort study - 17/08/11
Reprint requests: Bert Brunekreef, PhD, Institute for Risk Assessment Sciences, Utrecht University, PO Box 80178, 3508 TD, Utrecht, The Netherlands.Utrecht, Amsterdam, Bilthoven, Groningen, and Rotterdam, The Netherlands, and Wellington, New Zealand
Abstract |
Background |
Exposure to microbial agents might inhibit the development of atopy and asthma.
Objective |
We measured the association between microbial exposure assessed at 3 months and the development of atopic sensitization and doctor-diagnosed (DD) asthma and wheeze in the first 4 years in a birth cohort study of children with atopic mothers.
Methods |
Endotoxin, fungal (1→3)-β-D-glucans, extracellular polysaccharides from the genera Penicillium and Aspergillus (EPS-Pen/Asp), and dust on living room floors were measured at 3 months of age. Serum IgE levels against common allergens were determined at 1 and 4 years, and questionnaire information about respiratory morbidity was collected yearly.
Results |
Microbial levels in mattresses were low and not associated with serum IgE levels, DD asthma, and wheeze. Floor levels of biocontaminants and dust, on the other hand, were inversely associated with DD asthma, being most pronounced for endotoxin (odds ratio [OR], 0.40; 95% CI, 0.21-0.77) and EPS-Pen/Asp (OR, 0.42; 95% CI, 0.18-0.99). Mutual adjustment for other exposures did not significantly alter the results for endotoxin and only moderately affected the results for EPS-Pen/Asp. Persistent wheeze was also consistently less common in the high-exposure group, being significant only for EPS-Pen/Asp (OR, 0.37; 95% CI, 0.15-0.96). Transient wheeze and wheeze in the past 12 months were also reduced, but effects were smaller and not significant. Relationships with serum-specific IgE levels, which could only be assessed in 41% at age 4 years, were less pronounced and statistically significant only for EPS-Pen/Asp.
Conclusions |
Early exposure to common microbial contaminants, including fungal agents, might protect against asthma.
Clinical implications |
Microbial exposure in early life might protect against asthma and might constitute a novel target for prevention.
Le texte complet de cet article est disponible en PDF.Key words : Asthma, allergy, endotoxin, (1→3)-β-D-glucan, hygiene hypothesis, infant cohort study
Abbreviations used : DD, DL, EPS-Pen/Asp, EU, OR, PIAMA
Plan
| The Prevention and Incidence of Asthma and Mite Allergy study is supported by the Netherlands Asthma Fund, Zorgonderzoek Nederland, The Ministry of the Environment, and the National Institute of Public Health and the Environment. Analyses for microbial agents in house dust were supported by The Centre for Indoor Air Research (CIAR). Jeroen Douwes has been supported by a research fellowship from the Netherlands Organization for Scientific Research (NWO) and is currently supported by a sir Charles Hercus Research Fellowship from the Health Research Council (HRC) of New Zealand. Disclosure of potential conflict of interest: The authors have declared that they have no conflict of interest. |
Vol 117 - N° 5
P. 1067-1073 - mai 2006 Retour au numéro
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