PURPOSE OF THE STUDY.
To analyze risk factors and protective factors for allergic rhinitis in school age children in a Swedish birth cohort.
Birth cohort of 8341 children born in western Sweden in 2003. Questionnaires were distributed at age 8, and 4051(49%) were returned.
Data were collected by questionnaires at ages 6 months and 1, 4.5, and 8 years and from the Swedish Medical Birth Registrar. The 8-year questionnaire addressed health, family, environment, feeding habits, and specifically allergic rhinitis. To be considered positive for allergic rhinitis, children had to have both symptoms and medication use. Information regarding antibiotic use in the first week of life, farm living, eczema, and food allergy were collected on earlier questionnaires.
Allergic rhinitis symptoms were reported in 14% of the children at age 8, with 10.9% reporting both symptoms and medication use. Mean age of onset of symptoms was 5.7 years. Multivariate analysis showed positive associations between allergic rhinitis and antibiotic use during the first week of life (odds ratio 1.75; 95% confidence interval 1.03–2.97), paternal allergic rhinitis (2.73; 2.12–3.52), doctor-diagnosed food allergy in the first year (2.45; 1.61–3.73), eczema in the first year (1.97; 1.50–2.59), and male gender (1.35; 1.05–1.74). Living on a farm with animals at preschool age was associated with a decreased risk of allergic rhinitis (0.31; 0.13–0.78). Tree and grass pollen were reported as the most common triggers.
The major findings of this study are that antibiotic exposure in the first week of life is associated with an increased risk of allergic rhinitis at age 8 and that living on a farm with animals while in preschool is associated with a decreased risk of allergic rhinitis at age 8. Both of these findings are in accordance with the hygiene hypothesis.
This large birth cohort study describes known associations between eczema and food allergy in early childhood and allergic rhinitis at school age but also points to antibiotic use the first week of life as an independent risk factor for allergic rhinitis and farm living during preschool as an independent protective factor for allergic rhinitis. These findings are consistent with previous studies that have found an increased risk of childhood allergic disease associated with early antibiotic use. Together, these findings lend further support to the notion that perturbations in microbial exposures during early life influence the risk of allergic disease. Although judicious use of early antibiotics could be a possible means to help prevent future allergic rhinitis, it is also possible that early antibiotic use is simply a marker for children with perinatal distress or infection. Future studies should aim to determine if the risk conferred by antibiotic exposure appears to be independent of infection or perinatal distress and is instead mediated by antibiotic-induced changes to the infant’s microbiota.
- Copyright © 2015 by the American Academy of Pediatrics