Maternal smoking during pregnancy increases the risk of recurrent wheezing during the first years of life (BAMSE)

Respiratory Research

Table 2 Recurrent wheezing, doctor's diagnosed asthma and any wheezing up to two years of age in relation to exposure to maternal smoking during pregnancy⁶ and ETS⁷ with or without maternal smoking during pregnancy.

	N	n	OR crude	95% CI	OR adj⁸	95 % CI
Recurrent wheezing up to two years of age
No maternal smoking during pregnancy and no exposure to ETS⁹	3222	246	1		1
Maternal smoking during pregnancy but no exposure to ETS	135	21	2.2	1.4 – 3.6	2.2	1.3 – 3.6
Exposure to ETS with or without smoking during pregnancy	422	54	1.8	1.3 – 2.4	1.6	1.2 – 2.3
Doctor's diagnosed asthma up to two years of age
No maternal smoking during pregnancy and no exposure to ETS	3224	191	1		1
Maternal smoking during pregnancy but no exposure to ETS	134	16	2.2	1.3 – 3.7	2.1	1.2 – 3.7
Exposure to ETS with or without smoking during pregnancy	424	37	1.5	1.1 – 2.2	1.4	0.95 – 2.1
Any wheezing up to two years of age
No maternal smoking during pregnancy and no exposure to ETS	3207	855	1		1
Maternal smoking during pregnancy but no exposure to ETS	135	50	1.6	1.1 – 2.3	1.7	1.2 – 2.4
Exposure to ETS with or without smoking during pregnancy	422	142	1.4	1.1 – 1.7	1.3	1.0 – 1.6

⁶ Maternal smoking of one cigarette a day or more.
⁷ Maternal tobacco smoking during the first months of life and/or at one year of life.
⁸ Adjusted for heredity, defined as asthma and/or allergic rhino- conjunctivitis diagnosed by a doctor and in combination with reported allergy to furred pets and/or pollen in one or both parents (reported asthma medication was required for asthma diagnosis), maternal age and length of exclusive breast feeding.
⁹ Reference category: no maternal smoking during pregnancy and no exposure to ETS.

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