New research has shed light on how treating babies with antibiotics may lead to an increased risk for asthma.
The study of over 1000 children followed from birth to 11 years, showed that a vulnerability to viral infection is more likely to be the cause of this increased asthma risk than the use of antibiotics in itself.
As reported in the The Lancet Respiratory Medicine Journal, children who had severe asthma symptoms at age 11 were indeed more likely to have been treated with antibiotics before they were one year old. However, they were also significantly more likely to have poor viral immunity as well as certain gene mutations.
“We speculate that hidden factors which increase the likelihood of both antibiotic prescription in early life and subsequent asthma are an increased susceptibility to viral infections due to impaired antiviral immunity and genetic variants on 17q21,” says lead author Professor Adnan Custovic from the University of Manchester in the UK.
Previous studies have shown that the use of antibiotics in early infancy is associated with an increased risk for childhood asthma. Some experts believe that by disrupting the child’s gut flora, the antibiotics somehow alter immune development and leave the child susceptible to allergic conditions such as asthma.
The current study did find that children with wheezing who were treated with antibiotics before the age of 1 year were more than twice as likely to have severe asthma, severe wheeze or be hospitalized for asthma symptoms by the age of 11 than children who did not receive antibiotics as babies.
However, these children also had reduced levels of cytokines, important signalling molecules that stimulate the immune system to fight against viral infection. They were also more likely to have two gene variants, specifically mutations in the chromosomal region 17q21.
“Further studies will be needed to confirm that the impaired immunity was present at the time of the early childhood respiratory symptoms and predated antibiotic prescribing rather than as a consequence of the antibiotics,” says Custovic.