Breastfeeding for longer than six months helps protect babies and children from problematic chest infections, new research has claimed.
The research also showed how young children living in damp homes were twice as likely to need treatment with an inhaler to relieve respiratory symptoms.
Living in areas with dense traffic also increased the risk of chest infections in kids, and exposure to tobacco smoke increased their risk of coughing and wheezing.
The research, presented at a respiratory conference of doctors in Europe, tracked 1344 mothers and their children living in Scotland and England over a period of years.
Researchers documented the children at ages one and then two, monitoring chest infections, coughing and wheezing symptoms, respiratory medication, and exposure to potential environmental risk factors.
Analysis revealed that children who were breastfed for more than six months suffered fewer chest infections, while attending day care increased the risk.
Dr Tom Ruffles said the research provided "some important evidence" about how to reduce chest infections in babies and toddlers.
"The benefits of breastfeeding are well-established, and we should continue to support mothers who want to breastfeed their babies."
Another study presented at the conference revealed city kids suffer more chest infections than those in rural areas.
Researchers followed 663 children and their mothers from pregnancy until the children were three years old, recording how many respiratory infections they developed.
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The study found children in urban neighbourhoods had an average of 17 respiratory infections, such as coughs and colds, before the age of three compared to 15 for those growing up in the countryside.
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 urban children had differences in their immune systems compared to rural kids.
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.
"Our results suggest that the environment children live in can have an effect on their developing immune system before they are exposed to coughs and colds," Dr Nicklas Brustad said.
