Table 2 Exposure to maternal smoking during pregnancy or exposure to parental smoking when the infant was about 2 months old and sensitisation (IgE ⩾0.35 kU_A/l) at 4 years of age

	Any sensitisation*§			Any inhalant†§			Any food‡§
	N	n	OR (95% CI)	N	n	OR (95% CI)	N	n	OR (95% CI)
No exposure in utero or ETS	1917	399	1.00 (Referent)	1917	273	1.00 (Referent)	1917	228	1.00 (Referent)
Exposure in utero but not to ETS	98	21	1.00 (0.61 to 1.66)	98	15	1.05 (0.59 to 1.87)	98	15	1.28 (0.72 to 2.26)
Exposure to ETS but not in utero	305	76	1.26 (0.95 to 1.68)	304	45	1.06 (0.75 to 1.50)	305	56	1.61 (1.16 to 2.24)
Exposure in utero and to ETS	209	54	1.30 (0.92 to 1.82)	209	36	1.21 (0.81 to 1.81)	209	32	1.24 (0.82 to 1.89)

N, total number in the group; n, number exposed.
*Any inhalant and/or any food allergen positive.
†Any inhalant (Phadiatop and at least one single allergen positive).
‡Any food (fx5 and at least one single allergen positive).
§Adjusted for parental allergy and socioeconomic status.
ETS, environmental tobacco smoke.