Influences on the development of allergy and asthma

A number of factors contribute to development of asthma and allergy in humans. Genetic factors clearly play a role in development, of asthma and allergy. However, recent studies suggest that westernized lifestyle, perhaps certain pollutants, and less frequent exposure to microbes may allow for allergy to develop. It is the interactions of risk genes with urbanized environments that lead to development of allergy. Recent studies suggest that the most significant period of development of allergy is in early childhood, with additional data suggesting that a tendency for mononuclear cells to produce Th2 cytokines exists in early childhood. Reviewed in this article are genetic, inflammatory and lifestyle factors which contribute to development of allergy in childhood. (C) 2002 Published by Elsevier Science Ireland Ltd.