Babies given antibiotics have higher risk of childhood food allergies

By John Murphy, MDLinx
Published September 2, 2016

Key Takeaways

Children who were prescribed antibiotics in their first year of life are 1.21 times more likely to be diagnosed with a food allergy than children who hadn’t received an antibiotic prescription as babies, according to a study in Allergy, Asthma & Clinical Immunology.

Results of the study also showed that the more antibiotics the child was prescribed, the greater their risk of a food allergy diagnosis.

These findings add to previous research suggesting that antibiotics are known to alter the composition of gut flora, which is critical for developing tolerance to foreign proteins such as food. “Our findings offer a plausible hypothesis for increasing food allergy prevalence since increased antibiotic use is common in many westernized countries,” the authors wrote.

Of note, between 1996 and 2000, American children aged 3 months to 3 years received an average of 2.2 antibiotic prescriptions per year, and between 10 and 20 courses of antibiotics by the age of 18. Also, from 1997 to 2007, the prevalence of reported food allergy increased 18% among children under 18 years old.

For this study, researchers from the University of South Carolina’s College of Pharmacy, School of Medicine, and Arnold School of Public Health in Columbia, SC, reviewed South Carolina Medicaid billing data for children from birth to age 3. Using ICD-9 codes, the researchers identified 1,504 cases of children with food allergies. Each child with food allergy was matched to four controls without food allergy—for birth month, birth year, gender, and race/ethnicity—for a total of 5,995 controls.

After adjusting for such factors as vaginal birth, breastfeeding, gestational age, maternal age, smoking status, urban residence, pre-pregnancy diabetes, and presence of asthma/wheeze/atopic dermatitis, the researchers applied conditional logistic regression to find that children prescribed antibiotics within the first year of life were 1.21 times more likely to be diagnosed with food allergy.

Dermatitis was the most commonly reported food allergy-related diagnosis (655 cases). Less common diagnoses were allergic gastroenteritis and colitis (130 cases), anaphylaxis (87 cases), and other unspecified allergies (50 cases). Specific allergies included milk (99 cases), egg (77 cases), peanut (70 cases), and seafood (29 cases), but most cases weren’t identified with a particular food allergen.

The researchers also observed a linear increase in risk of food allergy as the number of antibiotic prescriptions increased. Specifically, three prescriptions increased a child’s risk of food allergy by 1.31 times, four prescriptions by 1.43 times, and five or more prescriptions by 1.64 times.

Results also showed that children who received cephalosporins and sulfonamides had the strongest association with food allergy risk.

“We need better diagnostic tools to help identify kids who truly need antibiotics,” said study leader Bryan Love, PharmD, Clinical Associate Professor in the College of Pharmacy. “Overusing antibiotics invites more opportunity for side effects, including the potential development of food allergies, and can encourage antibacterial resistance.”

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