Early life exposures: impact on asthma and allergic diseaseKozyrskyj, Anita L.; Bahreinian, Salma; Azad, Meghan B.Current Opinion in Allergy & Clinical Immunology: October 2011 - Volume 11 - Issue 5 - p 400–406 doi: 10.1097/ACI.0b013e328349b166 Genetics and epidemiology: Edited by Catherine Laprise and Emmanuelle Bouzigon Abstract Author Information Purpose of review: To identify and discuss recent studies relating prenatal and early-life environmental exposures to the development of asthma and allergic disease. Recent findings: New studies show that prenatal and early-life stress can alter infant immune profiles, increasing risk for asthma and allergy. Mounting evidence implicates indoor and outdoor air pollution in the origins of allergic disease, while Vitamin D intake and a Mediterranean diet may be protective. The role of early-life fever and infection remain controversial, with recent studies yielding conflicting results and new evidence indicating that previous studies may have been confounded. New studies are increasingly focused on environmental ‘imprinting’ of the infant gut microbiota, which is a critical determinant of immune system development. Early exposures impacting the intestinal microbiota include mode of delivery, infant diet, and use of antibiotics – factors that are also associated with childhood asthma and allergic disease. Summary: This overview highlights environmental exposures during the in-utero and ex-utero time periods that are potential stimuli for the early programming of asthma and allergy. Special consideration is given for the potential role of intestinal microbiota. Future studies in this field promise to inform health policy and intervention strategies for the prevention of asthma and allergic disease. Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada Correspondence to Anita Kozyrskyj, Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, 8226a Aberhart Centre, 11402 University Avenue, Edmonton, Alberta, T6G 2J3, CanadaTel: +780 407 8672; e-mail: email@example.com Copyright © 2011 Wolters Kluwer Health, Inc. All rights reserved.