Research led by the Karolinska Institute found that exposure to antibiotics early in life is associated with an increased risk of atopic dermatitis in the general Swedish population. The study’s authors added that the risk of atopic dermatitis was partially confounded by familial factors.
The study, published online ahead of print in the journal JAMA Network Open (April 1, 2021), was led by the Department of Medical Epidemiology and Biostatistics at the Karolinska Institute in Stockholm, Sweden.
“Exposure to antibiotics in utero and the first year of life was associated with a modestly increased risk of atopic dermatitis,” the study’s authors wrote. “This risk decreased when siblings were compared, suggesting a shared familial liability.”
To assess the association of exposure to antibiotics in the prenatal period and early childhood with the risk of atopic dermatitis, the researchers conducted a cohort study using data on mother-child pairs from the Swedish Medical Birth Register linked to other national registers for information on health, socioeconomic and demographic data.
Investigators followed up with participants until an atopic dermatitis outcome, emigration, death or the end of the study on Dec. 31, 2015.
The investigators defined exposure to antibiotics as maternal exposure to systemic antibiotics during pregnancy as well as the child’s exposure to systemic antibiotics during the first year of life, as defined by a dispensed prescription in the Swedish Prescribed Drug Register.
They used time-to-event analysis to estimate the risk of outcome with attained age as a time scale. The team defined atopic dermatitis based on diagnoses in the National Patient Register and medication listed in the Swedish Prescribed Drug Register. They performed a sibling-control analysis to account for shared familial factors.
Among the 722,767 study participants, the mean age was 5.8 years and 351,589 (48.6%) were female. During the follow-up period, 153,407 children (21.2%) were exposed to antibiotics in utero and 172,405 children (23.8%) were exposed during the first year of life.
The authors write that their results showed the risk of atopic dermatitis among children exposed to prenatal antibiotics was greater than among children who were not exposed. In the sibling-control analysis, no association was observed. Exposure to antibiotics during the first year of life was associated with a greater risk of atopic dermatitis with attenuated associations in the sibling-control analysis.
The study’s authors note that additional research on how antibiotic use and other shared familial factors affect other atopic diseases is warranted.