Exposure to paracetamol and antibiotics in early life and elevated risk of asthma in childhood.

Prospective studies on increased risk of childhood asthma due to exposure to paracetamol and antibiotics in early life have yielded contradictory results. Therefore, the aim of the present study was to investigate the association between administration of paracetamol and antibiotics in the first 12 months of life and delayed asthma symptoms later in childhood. This is a cross-sectional study that included 1,063 children from the primary schools in Coimbra, Portugal. ISAAC-based environmental and core asthma and rhinitis questionnaires were used to obtain information about children's respiratory health and administration of paracetamol and antibiotics. We found that early paracetamol use significantly increased the risk of asthma ever (at least one episode in life) (OR = 2.9; 95 %CI:1.8-4.5), current asthma (OR = 2.4; 95 %CI:1.5-3.6), wheezing ever (OR = 2.5; 95 %CI:1.8-3.4), rhinitis ever (OR = 2.4; 95 %CI:1.7-3.3), and current rhinitis (OR = 2.8; 95 %CI:2.0-3.9). Antibiotic exposure showed a similar effect with the risk for current asthma (OR = 1.6; 95 %CI:1.0-2.5), asthma ever (OR = 2.0; 95 %CI:1.3-3.1), wheeze ever (OR = 2.3; 95 %CI:1.7-3.2), and rhinitis symptoms (OR = 1.8; 95 %CI:1.3-2.6, OR = 1.8; 95 %CI:1.3-2.6, OR = 1.9; 95 %CI:1.2-3.0 for rhinitis ever, current rhinitis, and tearing, respectively). We further found that increased frequency of paracetamol use during the last 12 months preceding the study facilitated the appearance of allergic symptoms, suggesting a dose-dependent associations. In conclusion, the study shows a significant association between exposure to paracetamol and antibiotics in the first 12 months of life and both prevalence and severity of asthma and rhinitis symptoms in children 5-9 years old.