Prenatal exposure to a farm environment modifies atopic sensitization at birth.
BACKGROUND
Previous cross-sectional surveys have suggested that maternal exposure to animal sheds during pregnancy exerted a protective effect on atopic sensitization in children lasting until school age.


OBJECTIVE
We sought to evaluate the effects of maternal exposure to animal sheds and other farm-related exposures during pregnancy on cord blood IgE levels in a prospective birth cohort.


METHODS
Pregnant women living in rural areas in Austria, Finland, France, Germany, and Switzerland were recruited in the third trimester of pregnancy. Information on maternal farm-related exposures, nutrition, and health during pregnancy was obtained by means of interviews. Specific IgE levels for food and common inhalant allergens were assessed in cord blood of 922 children and peripheral blood samples of their mothers.


RESULTS
Different sensitization patterns in cord blood of farm and nonfarm children were observed. In multivariable analysis consumption of boiled, but not unboiled, farm milk during pregnancy was positively associated with specific IgE to cow's milk independently from maternal IgE. In contrast, there was an inverse relationship between maternal exposure to animal sheds and cord blood IgE levels against seasonal allergens (adjusted odds ratio, 0.38; 95% CI, 0.21-0.70). This association was not confounded by maternal IgE levels. Maternal contact with hay enhanced the protective effect of exposure to animal sheds on IgE levels to grass pollen in cord blood.


CONCLUSIONS
Maternal exposure during pregnancy influences atopic sensitization patterns in cord blood. The (microbial) context of allergen contact possibly modifies the risk of atopic sensitization.
Ege
Markus Johannes
MJ
University Children's Hospital, Munich, Germany. markus.ege@med.uni-muenchen.de
Herzum
Ileana
I
Büchele
Gisela
G
Krauss-Etschmann
Susanne
S
Lauener
Roger P
RP
Roponen
Marjut
M
Hyvärinen
Anne
A
Vuitton
Dominique A
DA
Riedler
Josef
J
Brunekreef
Bert
B
Dalphin
Jean-Charles
JC
Braun-Fahrländer
Charlotte
C
Pekkanen
Juha
J
Renz
Harald
H
von Mutius
Erika
E
D000383:Agriculture; D000485:Allergens / Q000276:immunology*; D000818:Animals; D000829:Animals, Domestic; D015331:Cohort Studies; D004781:Environmental Exposure; D005060:Europe / Q000453:epidemiology; D005260:Female; D005312:Fetal Blood / Q000276:immunology*; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000453:epidemiology* / Q000276:immunology*; D007073:Immunoglobulin E / Q000097:blood*; D007231:Infant, Newborn; D016015:Logistic Models; D008297:Male; D018811:Maternal Exposure / Q000009:adverse effects*; D011247:Pregnancy; D011446:Prospective Studies; D011795:Surveys and Questionnaires
D000485:Allergens; D007073:Immunoglobulin E