Air pollution, birth outcomes and early respiratory health - taking gene environmental interactions into account

The relationship between ambient air pollution and a number of health conditions has been studied extensively, but there are still uncertainties. This is particularly the case for the relationships between ambient air pollution exposure during pregnancy and maternal health during pregnancy, pregnancy outcomes and respiratory health in early life. The present study will use data from about 20 000 participants of the Norwegian Mother and Child Cohort (MoBa), who lived in or in the vicinities of Oslo and Bergen during pregnancy. The aim is to investigate the associations between pregnancy outcomes and respiratory symptoms/diseases in early life and estimated levels of air pollution at participants? home addresses. For estimating ambient air pollution levels we used a similar approach as in the European Study of Cohort for Air Pollution (ESCAPE), an EU financed study including 29 research centers and cohorts in Europe. Another aim of the project is to address associations between indicators of air pollution exposure and DNA methylation for a smaller subsample of the MoBa cohort. The Project has been carried out mainly according to the project plan with the exception of the delays described earlier. Air pollution exposures have been measured and exposure models have been developed and the participants have been assigned exposures levels based on the developed model ((LUR-model). Associations between exposure estimates and the chosen health related outcomes have been assessed and papers are under preparation but still not publishing at the moment.

This project is based on the Norwegian Mother and Child Cohort Study (MoBa). Pregnancy is a critical time period determining disease susceptibility not only in childhood, but also later in life. Air pollution exposure during pregnancy has been associated with adverse birth outcomes. Early exposure to outdoor air pollution even in pregnancy may also have an effect upon the development of respiratory diseases, such as asthma related phenotypes. The aim of this project is to build up new knowledge on the pat hogenesis of respiratory diseases by focusing on fetal exposure to air pollution during pregnancy. There is a great need to develop a new paradigm of disease pathogenesis that takes advantages of applied molecular approaches to asthma as it occurs in huma ns at different stages of development. The MoBa cohort has a large sample size and will be able to address more sensitive groups due to the use of genetic factors that influence individual susceptibility to air pollution. In addition, we are participating in the EU project European Study of Cohorts for Air Pollution Effects (ESCAPE) and this enables us to have better spatial and temporal understanding of the air pollution exposure, thus being able to address more trimester-specific exposure for each pregn ancy. The international collaboration will enhance Norway's position in playing a key role in epigenetics and research into respiratory diseases by building national competence in these fields. This study will advance knowledge of the mechanisms whereby o utdoor air pollution exposure during pregnancy influences gene expression and risk of atopic diseases. Further, we will examine whether methylation of these genes is associated with the development of asthma-related phenotypes, and this could provide us w ith great insights in how environmental factors in pregnancy and early childhood can influence methylation and DNA regulation. Results from this study will form the basis of the project and future studies.