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Antibiotics in the first year of life linked to more food allergies

NEW YORK (Reuters Health) – Babies who are exposed to antibiotics in the first year of life appear to have an increased risk of food allergies, researchers say.

Dr. Bryan Love, from the University of South Carolina in Columbia, whose data were presented this week at the 2013 Annual Meeting of the American Academy of Allergy, Asthma & Immunology (AAAAI) in San Antonio, Texas, told Reuters Health that a normal gut immune response, including the interaction with a diverse microbiome, is essential for development of food tolerance.

He and his team suspected that altering the normal gut flora in infants with early use of antibiotics might be a factor in the increasing prevalence of childhood food allergy.

“Our team became aware of other studies showing an association between antibiotic use and the development of clinical diseases believed to be due to disruption in the normal flora and food allergy seemed like a logical extension of these prior works,” Dr. Love told Reuters Health. “As a father of two young children, this study also had a personal appeal.”

The researchers analyzed data obtained from South Carolina Medicaid for children born between 2007 and 2009, noting any antibiotic exposures in the first year of life.

They identified 1,105 cases if food allergy diagnoses made before age three and matched them with 6,433 controls.

The mean number of antibiotic courses was 2.65 for children with food allergy diagnoses and 1.84 for controls (p<0.001). Among those receiving antibiotics, the mean time to receiving the first antibiotic course was 181.5 days for cases and 190.1 days for controls (p = 0.009).

The controls were also less likely to receive any antibiotic. The analysis showed that 33% of controls never received an antibiotic, compared with 24% of cases (p<0.001).

The likelihood of having a food allergy was highest with exposure between days 183- 365 (odds ratio 1.98).

Multiple courses of antibiotics presented a greater risk. Three or more courses increased the odds of food allergy, but more than five courses seeming to have the greatest impact on risk (OR 2.25).

“While antibiotics are beneficial for certain disease states, they also can have side effects. Some of these, like diarrhea, are short lived but emerging data like ours suggest that early antibiotic use may be associated with long-term side effects in some patients,” Dr. Love said.

“We’d like to see more research in this area to validate our findings,” he added. “Ultimately, our hope is that our study and others like it will lead to new treatments or methods to prevent food allergy from occurring.”

Reuters Health invited Dr. Sakina Bajowala, from the Kaneland Allergy & Asthma Center, North Aurora, IL, to comment on this study.

“There is growing evidence to support the concept that environmental factors influence the expression of our genetic code at critical points during development, a concept that is known as epigenetics,” Dr. Bajowala said.

Of these environmental factors, one of the most important is the microbiome. “This is a collection of various microorganisms residing in our bodies. Because a diverse microbiome is associated with the development of immune tolerance, it is noteworthy that disturbing the balance of microbes with antibiotics in early life may have long-lasting effects on a child’s health,” she said.

Dr. Bajowala added that this study gives physicians another reason to take pause when considering the prescription of an antibiotic to infants. “Children with multiple courses of antibiotics in the first year of life were found to be more likely to develop food allergy. We must always ask ourselves, ‘Is this medication truly necessary and does the benefit justify the potential risks?”