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

Aims: Exposure of children to passive smoking is significantly associated with respiratory morbidity. Youngest children between 0-2 years are harmed in the most significant way, while, together with the growing age a decrease is observed of prevalence of respiratory diseases and influence of passive smoking.

Methods: During repeated investigations of children from European Longitudinal Study of Pregnancy and Childhood (ELSPAC) it was assessed, whether and how in the period from the birth to five years of age varied the rate of children exposed to environment filled with smoke and what were the differences in the frequency of diseases among the groups of children with different exposure level. Some selected characteristics of health were chosen from documentation provided in the 6th, 18th month and 5 years of children's age and processed in four children groups that differ in smoking behaviour of their mothers. The differences were statistically assessed in SPSS programme.

Results: In all compared age categories were children of smoking mothers more often exposed to stay in environment filled with smoke: children of middle and heavy smokers more, children of light smokers less. In all groups of smoking mothers, children were more often protected from exposure to passive smoking in the age of six months than after they reached 18 months and 5 years of age: differences were mostly statistically significant on the level of 1% of significance. Attending the kindergarten presents significant protecting factor for five years old children: they are more exposed during weekends than on week days (p < 0.001, resp. p < 0.01). Both respiratory symptomatology and morbidity were highly significantly increased in previous life periods of those children, whose mothers smoked. At the age of five, life in smoking household causes more frequent incidence of asthmatic symptomatology: wheezing and apnoe, and higher prevalence of allergies against home and pollen dust with breathlessness and wheezing as well (p < 0.05).

Conclusions: ELSPAC study ascertained significant influence of maternal smoking on children's health in relation to passive smoking. Consequences of exposure clinically manifest themselves especially in increased incidence of respiratory and allergic morbidity.