Maternal smoking during pregnancy and lactation increases the risk for atopic eczema in the offspring

Background: Maternal smoking during pregnancy has been shown to lead to immunologic changes in the offspring. However, little is known about the influence of this exposure on atopic manifestations. Objective: Our purpose was to investigate the influence of air pollutants on manifestations of atopy in preschool children. Methods: Unselected cohorts of a total of 678 5- to 6- year-old preschool children (350 boys, 328 girls) were investigated in areas with different degrees of air pollution in Bavaria. Data on the history of atopic diseases and other relevant factors were obtained by questionnaire. A skin-prick test was performed with common aeroallergens. Manifestation of atopy was defined as personal history of atopic disease or positive prick test to either grass pollen, house dust mite, or cat and analyzed multivariately. Results: Of all children, 38.9% exhibited at least one manifestation of atopy. Atopic eczema was reported in 7.9% to 15.5%, hayfever in 4.1% to 25.6%, and asthma in 3.0% to 8.1%. Of the mothers, 12.6% smoked during pregnancy or lactation or both. Analysis of the manifestation of atopy including sex, location, nitrogen oxide and sulfur dioxide exposure and maternal smoking as covariates revealed an influence of the maternal smoking during pregnancy/lactation. Of children whose mothers had smoked during pregnancy/lactation, 52.2% exhibited manifestations of atopy in contrast to 35.7% of children of nonsmoking mothers (p < 0.044). A history of atopic eczema was the only component of the variable 'manifestation of atopy' that was significantly associated with maternal smoking during pregnancy and lactation. A causal interpretation of this finding, however, was not supported by a follow-up study. Conclusion: Maternal smoking during pregnancy or lactation or both might play a role in the development of atopic eczema and should be avoided.