Neonatal respiratory morbidity at term and the risk of childhood asthma

• Published in: Archives of disease in childhood Vol. 89; no. 10; pp. 956 - 960
• Main Authors: Smith, G C S, Wood, A M, White, I R, Pell, J P, Cameron, A D, Dobbie, R
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd and Royal College of Paediatrics and Child Health 01-10-2004; BMJ; BMJ Publishing Group Ltd
• Subjects: Adult; Asthma; Asthma - epidemiology; Asthma - etiology; Biological and medical sciences; caesarean section; Child; Chronic obstructive pulmonary disease, asthma; Complications; Epidemiologic Methods; Gestational Age; hazard ratio; Humans; ICD; Infant, Newborn; inter-quartile range; International Classification of Disease; IQR; Maternal Age; Medical sciences; Original; Pneumology; RDS; Respiration Disorders - complications; Respiration Disorders - epidemiology; Respiratory distress syndrome; Risk factors; Scotland - epidemiology; Scottish Morbidity Record; SMR; transient tachypnoea; transient tachypnoea of the newborn; TTN; Scotland; United Kingdom; British Isles, Scotland; Human; Pediatrics; Neonatal; Prognosis; Respiratory disease; Birth; Respiratory system; Epidemiology; Morbidity; Asthma; Newborn; Risk factor; Evolution; Obstructive pulmonary disease; Child; Public health
• ISSN: 0003-9888; 1468-2044
• DOI: 10.1136/adc.2003.045971

Objective: To determine whether neonatal respiratory morbidity at term is associated with an increased risk of later asthma and whether this may explain previously described associations between caesarean delivery and asthma. Design: Retrospective cohort study using Scottish Morbidity Record (SMR) data of maternity (SMR02), neonatal (SMR11), and acute hospital (SMR01) discharges. Setting: Scotland. Participants: All singleton births at term between 1992–1995 in 23 Scottish maternity hospitals. Main outcome measures: Hospital admission with a diagnosis of asthma in the principal position between 1992 and 2000. Results: Children who had a diagnosis of transient tachypnoea of the newborn or respiratory distress syndrome were at increased risk of being admitted to hospital with a diagnosis of asthma (hazard ratio (HR) 1.7, 95% confidence interval (95% CI) 1.4 to 2.2, p<0.001). This association was observed both among children delivered vaginally (HR 1.5, 95% CI 1.1 to 2.0, p = 0.007) and among those delivered by caesarean section (HR 2.2, 95% CI 1.6 to 3.0, p<0.001). In the absence of neonatal respiratory morbidity, delivery by caesarean section was weakly associated with the risk of asthma in childhood (HR 1.1, 95% CI 1.0 to 1.2, p = 0.004). The strengths of the associations were similar whether the caesarean delivery was planned or emergency and were not significantly altered by adjustment for maternal, obstetric, and other neonatal characteristics. Conclusions: Neonatal respiratory morbidity at term is associated with an increased risk of asthma in childhood which may explain previously described associations between caesarean delivery and later asthma.