Table 3

Unadjusted relative risks associated with parental smoking: case-control studies

Reference		Age		Cases		Controls		Odds ratios (95% CI) for smoking by:		Dose-response	Cotinine3-150
Reference		Age		Cases		Controls		Either parent	Mother	Dose-response	Cotinine3-150	Father
21	2–16	400	213	1.30 (0.93 to 1.83)			—	−
22	1–12	302	433	1.00 (0.70 to 1.42)			No3-151	−
23	0–17	137	246	—	1.43 (0.92 to 2.23)	0.71 (0.44 to 1.15)	—	−
24	3–15	49	77	1.97 (0.90 to 4.35)	2.56 (1.23 to 5.32)	0.87 (0.42 to 1.80)	Yes	+
25	3–14	107	121	1.13 (0.67 to 1.90)	2.00 (1.16 to 3.48)		Yes	+
26	c. 9	102	105	1.43 (0.75 to 2.71)			—	−
27	3–4	457	457	—	1.16 (0.89 to 1.51)	0.81 (0.62 to 1.06)	—	−
28	c. 5.5	140	140	2.12 (1.32 to 3.42)			—	−
29	5–11	115	96	0.76 (0.44 to 1.31)			—	−
30	5–7	19	43	0.71 (0.22 to 2.22)			—	+
31	3–15	300	100	0.90 (0.57 to 1.42)	(few smoke)	0.95 (0.60 to 1.50)	—	−
32	0–5	158	201	1.80 (1.20 to 2.70)			—	−
33	1.5–4	75	137	1.46 (0.83 to 2.58)	1.70 (0.93 to 3.14)	1.02 (0.42 to 2.46)	No	+
34	1–4	193	318	1.62 (1.13 to 2.32)			—	−
35	12–18	486	475	—	1.38 (1.18 to 1.61)	0.96 (0.69 to 1.34)	Yes	−
36	7–12	193	149	2.00 (1.22 to 3.27)			—	+
37	7–9	348	272	1.57 (1.06 to 2.33)	1.70 (1.23 to 2.34)	1.23 (0.90 to 1.70)	Yes	+
38	6–18	203	203	—	(few smoke)	1.03 (0.63 to 1.70)	—	−
39	4–9	131	131	—	2.79 (1.66 to 4.67)	—	Yes	−

↵3-150 Urinary cotinine measured (not all such studies reported on dose-response relationships).
↵3-151 Dose-response relationship only evident for skin prick negative subjects.