OBJECTIVE: The debate continues on the effect of passive smoking on nonsmokers. The effect of parental smoking on the lung function of children varies considerably according to geographic area, source of passive smoking, and sex. The objective of this study was to evaluate the effect of parental smoking on the lung function of children. POPULATION AND METHODS: A cross-sectional study was performed on a sample of the population of healthy children and adolescents between 6 and 18 years of age in Galicia. Subjects were selected by means of 2-stage cluster sampling grouped by sex and age. RESULTS: Approximately 56% of the children were exposed to the tobacco smoke of one of their parents. Children whose fathers were smokers presented a 40% higher risk of reduced forced expiratory flow at 75% of forced vital capacity (FEF75%) and a 30% higher risk of reduced FEF25%-75%. Children whose mothers were smokers presented a 30% higher risk of reduced forced expiratory volume in the first second and a 40% higher risk of reduced FEF50%. There was a 60% increase in risk of reduced FEF75%. The fact that both parents smoked did not appear to increase the risk of reduced lung function. CONCLUSIONS: Parental smoking has a considerable effect on the lung function of children and adolescents. Smoking by either the mother or the father has a decisive influence. The fact that this effect is independent of the growth of the child and that the obstructive effect is located principally in the distal airways appears to confirm the hypothesis that this effect is produced after birth.
OBJECTIVE: The debate continues on the effect of passive smoking on nonsmokers. The effect of parental smoking on the lung function of children varies considerably according to geographic area, source of passive smoking, and sex. The objective of this study was to evaluate the effect of parental smoking on the lung function of children. POPULATION AND METHODS: A cross-sectional study was performed on a sample of the population of healthy children and adolescents between 6 and 18 years of age in Galicia. Subjects were selected by means of 2-stage cluster sampling grouped by sex and age. RESULTS: Approximately 56% of the children were exposed to the tobacco smoke of one of their parents. Children whose fathers were smokers presented a 40% higher risk of reduced forced expiratory flow at 75% of forced vital capacity (FEF75%) and a 30% higher risk of reduced FEF25%-75%. Children whose mothers were smokers presented a 30% higher risk of reduced forced expiratory volume in the first second and a 40% higher risk of reduced FEF50%. There was a 60% increase in risk of reduced FEF75%. The fact that both parents smoked did not appear to increase the risk of reduced lung function. CONCLUSIONS: Parental smoking has a considerable effect on the lung function of children and adolescents. Smoking by either the mother or the father has a decisive influence. The fact that this effect is independent of the growth of the child and that the obstructive effect is located principally in the distal airways appears to confirm the hypothesis that this effect is produced after birth.