Senior Epidemiologist Murdoch Children’s Research Institute Murdoch Childrens Research Institute Melbourne , Victoria, Australia
Background: The consumption of antibiotics is increasing worldwide, leading to concern around the increasing prevalence of antibiotic resistance and potential long-term adverse environmental and health effects. One in four women receive at least one antibiotic during pregnancy and the majority of prescribed medicines are antibiotics, with unknown effects on a foetus and on the infant’s acquired microbiome. Otitis media represents the most common reason for childhood physician sick visits and for antibiotic prescription in early childhood. In this study we examine longitudinal trajectories of propensity to ear infections, requiring collection of both an indicator of antibiotic use during pregnancy and repeated measurement of ear infection rates at multiple time points in the context of a national birth cohort study.
Objective: This study investigates associations between in utero antibiotic exposure and ear infection trajectories over the first decade of life, hypothesising effects result in early or persistent, rather than later-developing, ear infections.
Design/Methods: Design & Participants: The Longitudinal Study of Australian Children (LSAC) birth cohort recruited a nationally-representative sample of 5107 infants in 2004. Measures: Mothers reported antibiotic use in pregnancy when a child was 3-21 months old (wave 1), and ongoing problems with ear infection every 2 years spanning ages 0-1 to 10-11 years (waves 1 to 6). Analysis: Latent class models identified ear infection trajectories, and univariable and multivariable multinomial logistic regression determined odds of adverse trajectories by antibiotic exposure.
Results: 4500 (88.1% of original sample) children contributed (mean baseline age 0.7 years; 51.3% boys); 10.4% of mothers reported antibiotic use in pregnancy. Four probability trajectories for ear infection emerged: “consistently low” (86.2%), “moderate to low” (5.6%), “low to moderate” (6.7%) and “consistently high” (1.4%). Antibiotic use in pregnancy was associated with children following “consistently high” (aOR 2.04, 95% CI 1.08 to 3.88, p=0.03) and “moderate to low” (aOR 1.78, 95% CI 1.25 to 2.53, p=0.001) trajectories. Conclusion(s): Antibiotic use in pregnancy is associated with an increased risk of persistent and early childhood ear infections. This highlights the wisdom of cautious antibiotic use during pregnancy, and the need for study of potential mechanisms underlying these associations.
Authors/Institutions: Yanhong J. Hu, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia; Jing Wang, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia; Joseph I. Harwell, Brown University Warren Alpert Medical School, Providence, Rhode Island, United States; Melissa Wake, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia