TABLE 5.

JOINT EFFECTS OF ACTIVE SMOKING AND EXPOSURE TO MATERNAL SMOKING DURING PREGNANCY AND CHILDHOOD ON NEWLY DIAGNOSED ASTHMA, RELATIVE RISK AND 95% CONFIDENCE INTERVAL, CHILDREN'S HEALTH STUDY 1993–2003

		Maternal Smoking during Pregnancy and Childhood
		Unexposed	During Pregnancy Only	Both
Frequent regular smoking*	No	1 (—)	1.1 (0.6–2.0)	0.7 (0.4–1.2)
	Yes	1.6 (0.6–4.3)	9.9 (2.3–42.5)	6.9 (1.9–25.3)

Relative risks (Hazard ratios) and corresponding 95% confidence intervals were obtained from Cox's proportional hazard model with separate baseline hazard for sex and age (in yr) at study entry. All models are adjusted for race/ethnicity and community.

^*Smoking at least seven cigarettes in the last week.