Young children growing up in towns and cities suffer from more respiratory infections than those who live in rural areas, according to a study.
Another research, published in the journal Pediatric Pulmonology, shows that factors such as attending day care, living in a damp home or near dense traffic increase the risk of chest infections in young children, while breastfeeding reduces the risk.
Both the studies were presented on Monday at the European Respiratory Society International Congress in Milan, Italy.
The first study, presented by Nicklas Brustad, from the University of Copenhagen, Denmark, included 663 children and their mothers who took part in the research from pregnancy until the children were three years old.
The team recorded whether the children were growing up in urban or rural areas and how many respiratory infections they developed.
They found that children living in urban areas had an average of 17 respiratory infections, such as coughs and colds, before the age of three compared to an average of 15 infections in children living in rural areas.
The researchers also carried out detailed blood tests on the mothers during pregnancy and on their new-born babies, and analysed the children's immune systems when they were four weeks old.
They found that children living in urban areas had differences in their immune systems compared to those living in rural areas.
There were also differences in the blood samples from the mothers and babies that correlated with the difference in living environment and number of respiratory infections, the researchers said.
«Our findings suggest that urban living is an independent risk factor for developing infections in early life when taking account of several related factors