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

Table 2 ORs and 95% CIs for wheeze according to maternal smoking during pregnancy and postnatal SHS exposure at home, Kyushu Okinawa Maternal and Child Health Study, Japan

	Wheeze in a previous year
	Risk (%)	Crude OR (95% CI)	Adjusted OR^a (95% CI)
Maternal smoking status
None	330/1243 (26.6%)	1.00	1.00
First trimester only	21/60 (35.0%)	1.49 (0.85–2.54)	1.56 (0.87–2.74)
Second and/or third trimesters but not throughout	3/11 (27.3%)	1.04 (0.23–3.61)	1.23 (0.26–4.44)
Throughout	19/40 (47.5%)	2.50 (1.32–4.72)	2.24 (1.14–4.36)
Postnatal living with at least one household smoker
No	195/753 (25.9%)	1.00	1.00
Yes	178/601 (29.6%)	1.20 (0.95–1.53)	1.17 (0.91–1.51)

^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

ISSN: 1617-9625