BREAST-FEEDING, MATERNAL SMOKING AND LOWER RESPIRATORY-TRACT INFECTIONS

The objective of the study was to assess the relationship between brea stfeeding and lower respiratory tract infections (LRTIs) during the fi rst year of life, with special reference to maternal smoking. A cohort of 3,754 children born in 1992-1993 in the City of Oslo, Norway was r ecruited and data were collected at birth, 6 and 12 months of age. Com plete information was obtained from 3,238 children (follow-up rate 86% ). The main outcome was an episode of a LRTI, such as pneumonia, bronc hitis or bronchiolitis, based on a self-administered questionnaire add ressed to parents when the child was 6 and 12 months old, The outcome was specified as physician-diagnosed. In logistic regression analysis adjusting for confounding, maternal smoking increased the risk of LRTI s in children breastfed for 0-6 months (odds ratio (AOR) 1.7; 95% conf idence interval (95% CI) 1.2-2.4), but not essentially when the child was breastfed for more than 6 months (AOR 1.1; 95% CI 0.7-1.6). Short- term breastfeeding (0-6 months) and no maternal smoking was related to an adjusted AOR of LRTIs of 1.3 (95% CI 1.0-1.7), and short-term brea stfeeding combined with maternal smoking was related to an adjusted AO R of 2.2 (95% CI 1.6-3.1), as compared with long-term breastfeeding an d no maternal smoking. The present study indicates a protective effect of long-term breastfeeding on the risk of lower respiratory tract inf ection during the first year of life, The results suggest that the pro tective effect is strongest in children exposed to environmental tobac co smoke.