[Trends in respiratory morbidity of children in relation to their passive smoking exposure]

Abstract

Background: The exposure of children to passive smoking has shown significant associations to respiratory morbidity. The youngest children between 0 to 2 years of age are usually seriously affected. With increasing age of the child a decrease in respiratory illness incidence together with a decrease of the effects of passive smoking were observed. The aim of the study was to assess by repeated investigations the morbidity among children exposed to environmental tobacco smoke (at the age of 6, 18 months and 5 years) and the differences in morbidity in the groups with different exposure in children involved in the ELSPAC study (European Longitudinal Study of Pregnancy and Childhood).

Methods and results: The data about health indicators and exposure were obtained from standardized questionnaire filled by mothers and physicians in the age of 6 and 18 month and in the 5th year of age. Results were assessed for 4 groups of children with different smoking habits of their mothers. The differences were statistically evaluated in the SPSS statistical program. The children of smoking mothers were more often exposed to environmental tobacco smoke; the children of middle and heavy smokers more than the children of light smokers. In the age of six months the children were slightly more often protected from passive smoking exposure than in the age of 18 months and 5 years: the differences were statistically significant (p < 0.01). The attendance in kindergarten represents an important protective factor: the children were exposed less during the week-days than during weekends (p < 0.001, resp. p < 0.01). The respiration symptomatology and morbidity were significantly increased in the earlier periods of life of those children, whose mothers smoked. In the age of 5 years the smoking household environment influences only the higher incidence of asthmatic symptomatology (wheeze breathing, apnoe) and more frequent allergies to household dust and pollen with symptoms of dyspnoe and wheezing (p < 0.05).

Conclusion: The ELSPAC study has provided evidence of the significant influence of the mother's smoking on the child exposure to passive smoking. The consequences of such exposure are manifested especially as increased respiratory and allergic morbidity, more so in the first 18 months of life than at five years of age.