Table IV.

Pet exposure in the first year of life and total IgE at 18 years.

Pet exposure	N	Mean IgE IU/mL (95% CI)
All Teens
No cat or dog	314	44.6(37.6, 53.0)
1 cat or dog	165	33.4(26.3, 42.3)
≥2 cats or dogs	86	28.9(21.2, 39.4)
test for group differences*		p=0.053
test for trend†		p=0.017
Not Sensitized at 18 Years‡
No cat or dog	138	14.7(12.0, 18.0)
1 cat or dog	69	10.6(7.6, 15.0)
≥2 cats or dogs	46	13.5(9.3, 19.6)
test for group differences*		p=0.47
test for trend†		p=0.48
Sensitized at 18 Years‡
No cat or dog	176	106.6(89.7, 127.5)
1 cat or dog	96	75.9(61.5, 93.6)
≥ 2 cats or dogs	40	69.2(48.0, 99.8)
test for group differences*		p=0.029
test for trend†		p=0.007

^*Test for group differences is Kruskal-Wallis.

^†Test for trend is Jonckheere-Terpstra.

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