Effect of Secondary Cigarette Smoke from Household Members on Breastfeeding Duration: A Prospective Cohort Study.

OBJECTIVE Maternal smoking and exposure to tobacco smoke is one modifiable risk factor that affects breastfeeding initiation and duration. We prospectively examine the effects of maternal and paternal smoking and other family members' smoking status on the duration of breastfeeding. MATERIALS AND METHODS A cohort of 1,277 mother-infant pairs admitted to the postpartum units of four major public hospitals in Hong Kong. Demographic data, maternal, paternal and household smoking habits, and other potential confounding variables were collected via self-reported questionnaires during the postnatal hospitalization. Breastfeeding status after hospital discharge was assessed through telephone follow-up up to 12 months postpartum, or until participants were no longer breastfeeding. If the participant had weaned during that follow-up interval, she was asked to report the total duration (in weeks) of both any and exclusive breastfeeding. RESULTS A total of 1,240 (97%) mother-infant pairs completed followed up, 2.5% were smokers, 29.2% of their partners smoked, and 11.3% had another smoker living in their home. Maternal and other family members' smoking predicted breastfeeding cessation. When compared with mothers in nonsmoking family, those exposed to two or more family members who smoked had approximately a 30% increased risk of breastfeeding cessation (adjusted hazard ratio [aHR] = 1.31; 95% CI 1.01-1.68). CONCLUSION Mothers who were exposed to two or more smokers in the household had a significantly shorter duration of any breastfeeding at 12-month follow-up.