title: Antibiotic exposure in the first year of life and later treated asthma, a population based birth cohort study of 143,000 children.
abstract: Several epidemiological studies reported an association between antibiotic consumption in the first year of life and later asthma, but results are conflicting and affected by potential biases. We examined this controversial issue in a population-based birth cohort. Using administrative data, we identified 143,163 children born in 1995-2011 in Friuli-Venezia Giulia (Italy) (median follow-up 5.25 years, 927,350 person-years). Antibiotic prescriptions in the first year of life and subsequent treated asthma (defined as ≥2 anti-asthmatic drug prescriptions within a 12-month period) were retrieved from drug prescription records. We estimated incidence rate ratios (IRR) using Poisson regression models, adjusted for perinatal variables and for hospitalizations for infections in the first year of life. We identified 34,957 new-onset asthma cases. Antibiotic consumption in the first year of life increased the risk of new-onset asthma [IRR 1.51, 95% confidence interval (CI) 1.48-1.54] with a dose-response relationship (p-trend <0.001). The risk was highest for asthma identified at 13-35 months of life (IRR 2.07, 95% CI 2.00-2.14), but remained statistically significant for asthma identified at 36-71 months (IRR 1.17, 95% CI 1.14-1.21) and at ≥72 months (IRR 1.15, 95% CI 1.08-1.22). Antibiotics increased the risk of current asthma at ≥6 years (IRR 1.35, 95% CI 1.30-1.41) and at ≥13 years of age (IRR 1.19, 95% CI 1.08-1.33). Antibiotic exposure in infancy is associated with an increased risk of asthma up to adolescence. The association detected at older ages is not explained by reverse causation; however, confounding by respiratory infections not leading to hospital admission cannot be excluded.
authors.affiliation: Laboratory of Public Health and Population Studies, Department of Molecular Medicine, University of Padua, Via Loredan, 18, 35131, Padua, Italy.
authors.forename: Gisella
authors.initials: G
authors.lastname: Pitter
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, 17177, Stockholm, Sweden.|Department of Pediatrics, Örebro University Hospital, 70185, Örebro, Örebro, Sweden.
authors.forename: Jonas Filip
authors.initials: JF
authors.lastname: Ludvigsson
authors.affiliation: Friuli-Venezia Giulia Regional Health Information System, Informatica per il Sistema degli Enti Locali (INSIEL) S.p.A., Udine, Italy.
authors.forename: Pierantonio
authors.initials: P
authors.lastname: Romor
authors.affiliation: Epidemiological Service, Health Directorate, Friuli Venezia-Giulia Region, Udine, Italy.
authors.forename: Loris
authors.initials: L
authors.lastname: Zanier
authors.affiliation: Laboratory of Public Health and Population Studies, Department of Molecular Medicine, University of Padua, Via Loredan, 18, 35131, Padua, Italy.
authors.forename: Renzo
authors.initials: R
authors.lastname: Zanotti
authors.affiliation: Laboratory of Public Health and Population Studies, Department of Molecular Medicine, University of Padua, Via Loredan, 18, 35131, Padua, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Simonato
authors.affiliation: Laboratory of Public Health and Population Studies, Department of Molecular Medicine, University of Padua, Via Loredan, 18, 35131, Padua, Italy. cristina.canova@unipd.it.
authors.forename: Cristina
authors.initials: C
authors.lastname: Canova
mesh_terms: D000293:Adolescent; D000900:Anti-Bacterial Agents / Q000009:adverse effects / Q000627:therapeutic use*; D001249:Asthma / Q000175:diagnosis / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004305:Dose-Response Relationship, Drug; D011307:Drug Prescriptions / Q000706:statistics & numerical data*; D005260:Female; D005500:Follow-Up Studies; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007223:Infant; D007558:Italy; D008297:Male; D008498:Medical Record Linkage; D016017:Odds Ratio; D011159:Population Surveillance; D011247:Pregnancy; D012141:Respiratory Tract Infections / Q000188:drug therapy*; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D000900:Anti-Bacterial Agents
keywords: Antibiotics; Asthma; Birth cohort; Childhood asthma; Record-linkage study