Secondhand smoke exposure and risk of wheeze in early childhood: a prospective pregnancy birth cohort study

Table 3 Additive effect of maternal smoking during pregnancy and postnatal SHS exposure at home, Kyushu Okinawa Maternal and Child Health Study, Japan

		Wheeze in a previous year
Maternal smoking during pregnancy	Postnatal living with at least one household smoker	Risk (%)	Crude OR (95% CI)	Adjusted OR^a (95% CI)
No	No	190/732 (26.0%)	1.00	1.00
Yes	No	5/21 (23.8%)	0.89 (0.29–2.31)	0.96 (0.30–2.59)
No	Yes	140/511 (27.4%)	1.08 (0.83–1.39)	1.06 (0.81–1.39)
Yes	Yes	38/90 (42.2%)	2.09 (1.32–3.26)	2.04 (1.25–3.31)

^aAdjustment for region of residence at baseline, number of children at baseline, maternal and paternal education levels, household income, maternal and paternal history of asthma, atopic eczema, and allergic rhinitis, infant’s birth weight, infant’s sex, and breastfeeding duration
Abbreviations: CI confidence interval, OR odds ratio, SHS secondhand smoke

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