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Study downplays asthma link with antibiotics

By Christian Duffin

Early exposure to antibiotics may increase the risk of childhood asthma, but to a lesser extent than previously thought, a systematic review and meta-analysis shows.

US researchers identified 22 studies assessing prenatal and childhood antibiotic exposure children aged up to 18.

For exposure in the first year of life, the pooled odds ratio for all studies was 1.52. The pooled odds ratios estimates for studies that adjusted for respiratory infection, or asthma onset at or after two years, were both 1.16 but remained significant.

If a baseline incidence of 10% is assumed, the number needed to harm would be 87, though the authors caution that this number is ‘highly uncertain' as it is sensitive to a number of assumptions used.

On the basis of this, the authors suggested there is a 'significant but weak association between antibiotic use in early life and childhood asthma'.

Study leader Dr Kari Risnes, a paediatrician at the Yale University school of public health, concluded: 'Antibiotics seem to slightly increase the risk of childhood asthma.'

Pediatrics 2011, line 23 May

The link between antibiotics and childhood asthma may be weaker than first thought