Environment and development of atopy.
OBJECTIVE
Asthma and other atopic disorders are the result of complex interactions between genetic predisposition and multiple environmental influences. However, the marked increase in asthma prevalence over recent decades is unlikely to be due to genetic changes, highlighting the contribution of environmental factors to the process of allergic sensitization.


RESULTS
This article reviews recent information on environmental influences on the development of atopy in children. Both observational and interventional studies continue to shed new light on the critical influence of early life events--such as events in pregnancy, exposure to allergens and endotoxin, pet ownership, infections, family size--and have highlighted important gene-environment interactions that modify the relationships between environmental exposures and atopic outcomes.


CONCLUSIONS
The future is likely to see a concerted effort to further define the role that these environmental exposures play in allergic sensitization and the expression of atopic diseases, in order to provide a rational platform on which to develop new methods of allergy prevention that can be targeted at high-risk children.
Upham
John W
JW
Division of Cell Biology, Telethon Institute for Child Health Research, Centre for Child Health Research, The University of Western Australia, Perth, Western Australia, Australia. johnu@ichr.uwa.edu.au
Holt
Patrick G
PG
D002648:Child; D004781:Environmental Exposure / Q000009:adverse effects*; D006801:Humans; D006967:Hypersensitivity / Q000209:etiology*