Prenatal, postnatal antibiotic use may be associated with food allergy development

Key takeaways:

• The strongest association was seen in infants born preterm and/or with low birth weight.
• Factors such as maternal BMI, smoking status and type of infant feeding influenced the risk for developing food allergy.

Researchers found a moderate association in early life antibiotic use and childhood food allergy in South Korea, according to a study published in Pediatric Allergy and Immunology.

Both prenatal and postnatal antibiotic use showed a 5% increase in subsequent food allergy in children, Jiyeon Oh, MD, of the department of medicine, Kyung Hee University College of Medicine in Seoul, South Korea, and colleagues wrote.

Methods

This study used data from the National Health Insurance service in South Korea on infants born between Jan. 1, 2010, and Dec. 31, 2017. The index date consisted of the birth date of the child, and follow-up ended on Dec. 31, 2020, on the date of a first diagnosis of food allergy or in the case of a death of a child. The observation period occurred between Jan. 1, 2009, and Dec. 31, 2020.

The entire cohort included 3,161,858 children (2,333,618 children with antibiotic exposure and 828,240 without). The study included four different designs including a full unmatched cohort, a propensity-matched cohort, a sibling comparison cohort and a health screening cohort.

The propensity-matched cohort was score-matched 1:1 based on maternal age at delivery, infant sex, residence region, season of birth, income, nulliparity, year of delivery, maternal food allergy history, atopic dermatitis, asthma, Severe Maternal Morbidity score, mode of delivery, preterm birth, low birthweight, number of antibiotic prescriptions a year prior to pregnancy, and inpatient admissions and outpatient visits of the mother within a year prior to pregnancy.

The propensity-matched cohort included a total of 1,639,408 children (819,704 both with and without antibiotic exposure).

The health screening cohort included participants who had BMI scores available within 3 years of pregnancy as well as smoking status and infant feeding type. This cohort consisted of 523,417 children (130,086 with antibiotic exposure and 393,331 without). The sibling comparison cohort included discordant sibling pairs with fetal and postnatal antibiotic exposure (284,806 with antibiotic exposure and 274,587 without).

Fetal antibiotic exposure was defined as the mother receiving antibiotics for at least 3 days during pregnancy. These mothers were classified into four groups: antibiotics use in the first trimester, second trimester, third trimester and more than one trimester. Mothers were also classified into another four groups according to the duration of antibiotic exposure including no antibiotic exposure and exposure for 3 to 29 days, 30 to 59 days and 60 days or more.

Antibiotics were categorized into four groups: penicillin, cephalosporins, macrolides and other. Postnatal antibiotic exposure was defined as the infant receiving antibiotics for at least 3 days within 6 months after birth.

Results

Among the 3,161,858 infants (median follow-up period, 6.92 years; 52.6% boys) in the birth cohort, 29,973 (1.9%) were diagnosed with food allergies.

Within the 1:1 propensity score-matched cohort, an association was found between prenatal and postnatal antibiotic exposure and food allergy development (prenatal, adjusted HR = 1.05; 95% CI, 1.02-1.09; postnatal, aHR = 1.05; 95% CI, 1.01-1.1).

Specifically, 17% of the prenatal group and 15% of the postnatal group in the health screening cohort developed a food allergy.

This association was stronger with short term antibiotic use of 30 days or less (aHR = 1.05; 95% CI, 1.02 - 1.09) and 60 days or more (aHR = 0.55; 95% CI, 0.26-1.16), and with a smaller number of antibiotics used, including zero (aHR = 1.1; 95% CI, 1.05-1.16) and three or more (aHR = 1.01; 95% CI, 0.97-1.05).

Within the health screening cohort, an association was found in the prenatal (aHR = 1.75; 95% CI, 1.10-1.23) and postnatal (aHR = 1.15; 95% CI, 1.09-1.23) antibiotic exposure groups when maternal BMI, smoking status and type of infant feeding were considered. The most significant association was found among infants who were born preterm along with a low birthweight (aHR = 1.16; 95% CI, 1.04-1.29).

In the sibling comparison analysis, prenatal and postnatal exposure to antibiotics were also associated with a higher risk for developing food allergies (aHR = 1.06; 95% CI, 1.02-1.12).

Researchers noted that the results of the study showed a moderate but consistent association between antibiotic exposure during prenatal and postnatal periods with the subsequent development of food allergies in childhood. They further suggested that health care providers should take the results of the study into account when considering prescribing antibiotics.