Niki Mitselou1, Jenny Hallberg2,3,4, Olof Stephansson5,6, Catarina Almqvist7,8, Erik Melén2,3,4, Jonas F Ludvigsson1,7,9,10. 1. Department of Pediatrics, Örebro University Hospital, Örebro, Sweden. 2. Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden. 3. Sachs' Children and Youth Hospital, Södersjukhuset, Stockholm, Sweden. 4. Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, Stockholm, Sweden. 5. Department of Medicine, Solna, Clinical Epidemiology Division, Karolinska Institutet, Stockholm, Sweden. 6. Department of Women's Health, Karolinska University Hospital, Stockholm, Sweden. 7. Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden. 8. Pediatric Allergy and Pulmonology Unit, Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden. 9. Division of Epidemiology and Public Health, School of Medicine, University of Nottingham, Nottingham, UK. 10. Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY, USA.
Abstract
BACKGROUND: Perinatal conditions may be associated with future allergic disease; however, data are conflicting and incomplete for childhood allergic rhinitis (AR). The aim of this study was to examine pregnancy outcome (cesarean delivery, preterm birth, low birthweight) and offspring AR as defined by national registers. METHODS: Nationwide longitudinal cohort study using prospectively recorded register data from 1 059 600 singleton livebirths born in Sweden in 2001-2012. Cox regression adjusted for infant sex and maternal factors (age at delivery, country of birth, parity, smoking, body mass index, and asthma/pulmonary disease) estimated hazard ratios (HRs) for AR during childhood. RESULTS: During the study period 2001-2013, 22 386 (2.11%) children were diagnosed with AR. AR was more common in infants born through cesarean delivery (2.34%) than in those born vaginally (2.10%) (HR = 1.12; 95% confidence interval [95% CI] = 1.08-1.16). This was equivalent to one extra case of AR in 383 children followed up in our study. AR was also associated with moderately preterm birth (≥32-36 weeks of gestation: HR = 1.12, 95% CI = 1.04-1.20), large for gestational age (HR = 1.05, 95% CI = 1.01-1.10), and low (<7) 5-minute Apgar score (HR = 1.15, 95% CI = 1.02-1.30). Similar risk estimates were obtained when we restricted the outcome to ≥2 hospital-based records of AR. No association was observed between very preterm birth, post-term birth, low birthweight, or small for gestational age and AR. CONCLUSION: Our study indicates an association between pregnancy outcomes and childhood AR, although observed effect sizes were generally modest.
BACKGROUND: Perinatal conditions may be associated with future allergic disease; however, data are conflicting and incomplete for childhood allergic rhinitis (AR). The aim of this study was to examine pregnancy outcome (cesarean delivery, preterm birth, low birthweight) and offspring AR as defined by national registers. METHODS: Nationwide longitudinal cohort study using prospectively recorded register data from 1 059 600 singleton livebirths born in Sweden in 2001-2012. Cox regression adjusted for infant sex and maternal factors (age at delivery, country of birth, parity, smoking, body mass index, and asthma/pulmonary disease) estimated hazard ratios (HRs) for AR during childhood. RESULTS: During the study period 2001-2013, 22 386 (2.11%) children were diagnosed with AR. AR was more common in infants born through cesarean delivery (2.34%) than in those born vaginally (2.10%) (HR = 1.12; 95% confidence interval [95% CI] = 1.08-1.16). This was equivalent to one extra case of AR in 383 children followed up in our study. AR was also associated with moderately preterm birth (≥32-36 weeks of gestation: HR = 1.12, 95% CI = 1.04-1.20), large for gestational age (HR = 1.05, 95% CI = 1.01-1.10), and low (<7) 5-minute Apgar score (HR = 1.15, 95% CI = 1.02-1.30). Similar risk estimates were obtained when we restricted the outcome to ≥2 hospital-based records of AR. No association was observed between very preterm birth, post-term birth, low birthweight, or small for gestational age and AR. CONCLUSION: Our study indicates an association between pregnancy outcomes and childhood AR, although observed effect sizes were generally modest.