Table II.

Relative risks (95% confidence intervals) of sensitization at 18 years associated with exposure to pets in the first year stratified by teen sex.^*

	Total (N=565)	Male Teens (N=269)	Female Teens (N=296)
All Teens	0.97 (0.83–1.12)	0.93 (0.76–1.15)	1.00 (0.81–1.24)
Parental History of Allergy	1.03 (0.87–1.23)	1.04 (0.81–1.33)	1.03 (0.81–1.30)
No Parental History of Allergy	0.86 (0.66–1.13)	0.80 (0.55–1.15)	0.93 (0.62–1.38)
Firstborn	0.96 (0.78–1.19)	0.97 (0.72–1.31)	0.95 (0.70–1.28)
Not Firstborn	0.96 (0.77–1.19)	0.89 (0.66–1.21)	1.04 (0.76–1.42)
Exposed to tobacco smoke in first year	0.97 (0.73–1.28)	0.83 (0.54–1.27)	1.10 (0.74–1.63)
Not exposed to tobacco smoke in first year	0.98 (0.82–1.17)	0.98 (0.78–1.25)	0.97 (0.74–1.27)

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