Antibiotic asthma risk to babies
17 March 2006

New research provides further evidence that babies given antibiotics may be at higher risk of developing childhood asthma.

The research from the University of British Columbia, Vancouver, analysed seven studies comparing babies who were given antibiotics and those who were not.

Of the 12,082 children included in the analysis, 1,817 cases of childhood asthma were reported. Overall researchers concluded babies exposed to at least one antibiotic were twice as likely as those unexposed to develop asthma in childhood.

In a separate analysis, the researchers pooled data from five studies to determine the effect of multiple courses of antibiotics. They concluded that for each additional course taken during the first year of life the overall chance of developing asthma increased by 16 per cent.

Lead researcher Professor Carlo Marra, said: 'Although the causal nature between antibiotics and asthma is still unclear, our overall results show that treatment with at least one antibiotic as an infant appears to be associated with the development of childhood asthma.'

How antibiotics might increase children's risk of asthma is not known. It has been suggested that early treatment with antibiotics affects the development of the immune system, making individuals more likely to respond to allergens or other asthma triggers. It has also been found that antibiotics kill off beneficial bacteria leading possibly to changes in the way the body deals with disease.

Antibiotics are commonly used to treat ear and respiratory infections and bronchitis in young children, but not every childhood infection needs antibiotics. 'Current guidelines recommend that children under age two receive an antibiotic for diagnosed ear infection. However, the majority of upper respiratory tract infections and bronchitis are viral, for which antibiotics are ineffective,' explained Dr Fawziah Marra, co-author of the study.

Asthma is the most common long-term condition among children in the UK, where every day an average of 75 children are admitted to hospital because of their asthma.

Dr Lyn Smurthwaite, Asthma UK's Research Development Manager, welcomed the research into antibiotic use as a potential risk factor: 'Identifying events in early childhood that influence asthma development is a difficult task,' she explained. 'This study shows that taking antibiotics in infancy may increase a child's risk of developing asthma and highlights that antibiotics should always be prescribed and taken responsibly.'

The study is published in Chest journal.