Table I.

Frequency of sensitization with 95% confidence intervals at age 18 years by pet exposure in the first year of life.

Atopy*	No Dog or Cat Exposure	1 Dog or Cat	≥2 Dogs or Cats	P value for Chi Square test
All teens	56.1% (50.4%, 61.6%) n=314	58.2% (50.3%, 65.8%) n=165	46.5% (35.7%, 57.6%) n=86	0.19
Males only	59.3% (51.0%,67.3%) n=150	56.4% (44.7%,67.6%) n=78	53.7% (37.4%,69.3%) n=41	0.78
Females only	53.0% (45.1%,60.9%) n=164	59.8% (48.7%,70.2%) n=87	40.0% (25.7%,55.7%) n=45	0.10

^*Sensitization is defined as ≥1 allergen-specific IgE ≥ 0.35 kU/L (dog, cat, ragweed, Der f, grass, Alternaria, peanut)