However, the study also confirmed that over-twos in daycare are no more at risk of being hospitalised with an ARI than those cared for at home.
Researchers at the Statens Serum Institut in Copenhagen compiled data from the cohort of all Danish children born between 1989 and 2004 and found that 138,821 were hospitalised for an ARI during that time. Denmark's identity registry system and state childcare registry meant that a comprehensive study of this scale was possible.
Over 95 per cent of Danish children in childcare attend subsidised state settings.
Dr Mads Kamper-J?rgensen, a public health expert and one of the authors of the report, said, 'Establishing figures on common knowledge was a positive aspect of the study. We've known that childcare attendance increases the risk of ARIs, but now we are able to study the interactions. We know that the under-two-year-olds are mainly affected and that the risk, both at home and in childcare, is the same after age two.'
Identifying the risk variation in relation to the child's time since beginning nursery was a chief goal of the study. It found that the increased risk from attending childcare is gone one year after starting.
The study also found that children with no other under-fives living at home were twice as likely, at all ages, to be at risk of hospitalisation for ARIs.
