EXPOSURE OF YOUNG INFANTS TO ENVIRONMENTAL TOBACCO-SMOKE - BREAST-FEEDING AMONG SMOKING MOTHERS

Objectives. This study examined the degree to which breastfeeding and cigarette smoking by mothers and smoking by other household members co ntribute to the exposure of infants to the products of tobacco smoke. Methods. The subjects were 330 mother-infant pairs derived from a coho rt of 1000 pairs enrolled in a longitudinal study of the pulmonary eff ects of prenatal and postnatal smoking. The main outcome measure was c orrected urinary cotinine levels. Results. Urinary cotinine levels wer e 10-fold higher in breast-fed infants of smoking mothers than among b ottle-fed infants of smoking mothers. Among infants of nonsmoking moth ers, urine cotinine levels were significantly increased in infants liv ing in homes with other smokers: in this group there was no significan t difference between bottle-fed and breast-fed infants. Infants whose mothers smoked in the same room as the infant had only non-significant increases in cotinine levels compared with infants whose mothers rest ricted their smoking to other rooms. Conclusions. Breast-fed infants o f smoking mothers have urine cotinine levels 10-fold higher than bottl e-fed infants whose mothers smoke, suggesting that breast-feeding, rat her than direct inhalation of environmental tobacco smoke, is the prim ary determinant of cotinine levels in infants whose mothers smoke.