Resumen:
OBJECTIVE: To determine the prevalence, risk factors for perinatal tobacco smoking, and the effects on infants' respiratory health in 12,450 mother-infant pairs from South America. METHODS: Cross-sectional population-based study in eleven centres from six countries, using a standardised questionnaire completed by parents. RESULTS: The prevalence of smoking during pregnancy was 8.4%, ranging from 1.4% in Lima to 15.3% in Montevideo; current maternal smoking was 15.3%, from 5.4% in Lima to 34.4% in Santiago; and second-hand tobacco smoke (SHS) at home was 29.8%, from 13.7% in Lima to 50.7% in Santiago. SHS and current maternal smoking were strong and independent risk factors for smoking during pregnancy (p < 0.0001). Low maternal education and monthly household income were significant risk factors for perinatal tobacco exposure. The prevalence and severity of wheezing, admissions for wheezing, pneumonia diagnosis, and admissions for pneumonia were significantly higher (p < 0.0001) in infants exposed to tobacco smoke. CONCLUSIONS: The prevalence of smoking during pregnancy, current maternal tobacco smoking, and SHS remain high in South America. Perinatal tobacco smoke exposure is strongly related to greater wheezing severity and a higher prevalence of admissions for wheezing and pneumonia during the first year of life. Low socioeconomic status and low maternal education were the most significant risk factors for smoking during pregnancy, as well as for current maternal smoking and the presence of SHS at home. Our results point to the urgent need to improve the quantity and quality of education against tobacco smoking in girls and families, starting very early in life.