Dog and cat exposure and respective pet allergy in early childhood.
BACKGROUND
The association of dog and cat exposure in early childhood with the incidence of respective allergies has remained controversial. The aim of the study was to obtain population-based evidence on the association of early exposure to dog or cat, or both, with dog and cat allergies.


METHODS
The study population was identified from the nationwide population register comprising all children aged 1-4 yr (N = 4779) born between 2001 and 2005 and living in the province of South Karelia, Finland. Cross-sectional questionnaire data on pet exposure in infancy and physician-diagnosed pet allergies were obtained from 3024 participants and merged with longitudinally accumulated data on sIgE and skin prick tests indicating allergic sensitization abstracted from all patient records in the area.


RESULTS
The adjusted relative incidence of positive test results (with 95% confidence intervals) was 2.69 (1.45-5.02) for dog and 5.03 (2.47-10.2) for cat allergens among children exposed to a respective pet alone compared with children without such exposure. The corresponding adjusted prevalence odds ratios for diagnosed dog and cat allergies were 1.75 (0.77-3.79) and 5.13 (2.30-11.4), respectively. The association between pet exposure and the incidence of positive test results was independent of parents' allergies.


CONCLUSIONS
Early exposure to dog and cat at home is associated with a higher incidence of respective pet allergy during the first four years of life. Further evidence from population-based studies with longer follow-up is required to justify any recommendation concerning early pet contacts with a view to preventing pet allergies later in life.
Centre for Lifecourse Epidemiology and Systems Medicine, University of Oulu, Oulu, Finland.|South Karelia District of Social and Health Services, Lappeenranta, Finland.
Kaisa
K
Pyrhönen
Center for Environmental and Respiratory Health Research, University of Oulu, Oulu, Finland.
Simo
S
Näyhä
Department of Mathematical Sciences, University of Oulu, Oulu, Finland.
Esa
E
Läärä
D000485:Allergens / Q000276:immunology; D000818:Animals; D002415:Cats; D002675:Child, Preschool; D015331:Cohort Studies; D004285:Dogs; D004781:Environmental Exposure / Q000009:adverse effects; D005260:Female; D005387:Finland; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology*; D007223:Infant; D008297:Male; D057805:Pets / Q000276:immunology*; D044382:Population Groups
D000485:Allergens
cat allergy; cat exposure; child; cohort; dog allergy; dog exposure; epidemiology