The association between antibiotic use in infancy and the use of inhaled corticosteroids later in childhood

Abstract

Background: It has been postulated that infants who are given antibiotics for respiratory illnesses are more likely to develop wheezing illnesses requiring inhaled corticosteroids (ICS) later in childhood. Aim: To investigate the association between dispensing of antibiotics among infants aged ≤1 year and dispensing of ICS over the next two years, using data from the infant cohort of the Longitudinal Study of Australian Children (LSAC). Methods: The infant cohort was recruited in 2004 at age 0-1 years (response rate 57%) and re-assessed two years later (response rate 90%). A face-to-face interview was conducted with the primary carer. Information on dispensing of oral antibiotics and/or ICS came from Pharmaceutical Benefit Scheme linked data (consent rate 93%). Odds ratios were calculated using a logistic regression model accounting for the survey design. Results: 4,328 infants were surveyed at both baseline and follow-up, and had parental consent for PBS information to be linked to their survey data. Infants who had any ICS dispensed before baseline were excluded from analysis (n=15). Of the remaining 4,313 infants, 447 (12.7%) had been dispensed antibiotics before baseline. Of these infants, 8% were subsequently dispensed ICS between baseline and 2-year follow-up, compared with only 3% of children who had not been dispensed any antibiotics before baseline (OR= 2.5 (95% CI 1.7-3.9)). The odds of ICS use by age 2–3 years among infants dispensed antibiotics by age 0–1 years remained significantly higher even after excluding infants who were reported as having wheezing illness or eczema at baseline (OR=2.8 (95% CI 1.5-5.1)). Conclusions: The findings indicate that antibiotic use during the first years of life can predict ICS use later in childhood. Use of ICS could be a marker of the severity of respiratory conditions such as asthma or wheeze. Support: ACAM is a collaborating unit of the AIHW and is funded by the Australian Government Department of Health and Ageing.