Prenatal dog and cat exposure decrease production of total IgE throughout infancy
Published Online: August 8, 2011
In an upcoming issue of The Journal of Allergy and Clinical Immunology (JACI), Havstad and colleagues report novel results showing that the presence of dog(s) and/or cat(s) in the home affects the development of total IgE throughout infancy in a large, racially diverse cohort. Total IgE tends to be higher in asthmatics. The relationship between pet exposure and total IgE was found to vary by delivery type (caesarean-section vs. vaginal) and mother’s race.
Using the population-based Wayne County Health, Environment Allergy and Asthma Longitudinal Study (WHEALS) birth cohort from southeastern Michigan, they analyzed 1,187 infants with anywhere from one to four measurements of total IgE collected from birth to 2 years of age. Effects of prenatal dog and cat exposure on the shape and pattern of IgE throughout early life were assessed using an improved statistical approach that accounted for multiple measurements of IgE as well as missing data and varying time points of sample collection. In this type of analysis the term trajectory is used to describe the rise and fall of IgE values plotted over time for each child. Trajectory analyses overcome inherent limitations of traditional repeated measures analysis along with offering additional benefits, flexibility, and information that could prove important in other birth cohort studies.
Results suggest that total IgE has an accelerated increase in the first 6 months of life, with a smaller rate of increase through 2 years of age. Overall, children from homes with pets had a total IgE trajectory that was an estimated 28% lower then children from pet-free homes. This protective effect of pet exposure was stronger within children born via caesarean section (43% lower vs. 16% lower for children born vaginally). There was also some evidence of racial difference in the effect of pet exposure on IgE. Those with non-African American mothers had an estimated 33% lower IgE trajectory as compared to a 10% decrease in children of African American mothers. Further work investigating the mechanism(s) underlying the pet effect, such as the impact of pets on home ecology and subsequent infant health, could eventually translate into preventive interventions.
The Journal of Allergy and Clinical Immunology (JACI) is the official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.