The role of passive smoking in the development of bronchial obstruction during the first 2 years of life.
We assessed the effect of exposure to environmental tobacco smoke on the risk of developing bronchial obstruction in a 2-year cohort study of 3,754 children born in Oslo, Norway, during a period of 15 months in 1992-1993. We collected questionnaire information on the child's health and environmental exposures at birth and when the child was age 6 months (follow up rate = 95%), 12 months (92%), 18 months (92%), and 24 months (81%). The outcome of interest was defined as two or more episodes of bronchial obstruction or one obstruction lasting more than 1 month, and it was verified by a specialist group evaluating data from questionnaires, clinical examinations, and health records. The risk of bronchial obstruction was increased in children exposed to environmental tobacco smoke (cumulative incidence = 0.109) compared with unexposed children (0.071), with an adjusted odds ratio of 1.6 [95% confidence interval (CI) = 1.3-2.1]. The effect was seen for maternal smoking alone (odds ratio = 1.6; 95% CI = 1.0-2.6), paternal smoking alone (odds ratio = 1.5; 95% CI = 1.1-2.2), and both parents smoking (odds ratio = 1.5; 95% CI = 1.0-2.2). There was no clear exposure-response pattern. The findings indicate that exposure to environmental tobacco smoke such as is experienced in Norwegian housing increases the risk of developing bronchial obstruction during the first 2 years of life.
Nafstad
P
P
Department of Population Health Sciences, National Institute of Public Health, Oslo, Norway.
Kongerud
J
J
Botten
G
G
Hagen
J A
JA
Jaakkola
J J
JJ
D001249:Asthma / Q000453:epidemiology / Q000209:etiology*; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D009664:Norway / Q000453:epidemiology; D016017:Odds Ratio; D012307:Risk Factors; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*
D014028:Tobacco Smoke Pollution