Asthma Symptoms in Pediatric Patients: Differences throughout the Seasons

Abstract

Introduction. Seasonal variation in asthma has been widely recognized. The aim of this study was to describe seasonal patterns of asthma symptoms and asthma medication use in a cohort of pediatric asthma medication users and to study determinants of seasonal childhood asthma. Methods. For this study, 602 children participating in the Pharmacogenetics of Asthma medication in Children: Medication with Anti-inflammatory effects) cohort were included. Parents were asked about their child’s respiratory symptoms and quick-reliever medication use over the past year. Logistic regression analysis was used to study determinants of seasonality in asthma control (the level of disease control based on symptoms, limitations in activities, and rescue medication use). Results. There was a decline in asthma symptoms and asthma medication use during the summer period and a peak occurred from autumn to spring. The prevalence of wheeze ranged from 32% in summer to 56% in autumn. The prevalence of respiratory symptoms and medication use was significantly lower during summer (p < .0001). Oral steroids and antibiotics use and strong parental necessity beliefs were associated with uncontrolled asthma, regardless of seasonality. Allergic rhinitis was associated with an increased risk of uncontrolled asthma during spring [odds ratio (OR): 1.9; 95% confidence interval (CI): 1.3–2.8] and summer (OR: 1.9; 95% CI: 1.2–3.0). Eczema was associated with a higher risk of uncontrolled asthma during autumn (OR: 1.5; 95% CI: 1.0–2.2) and winter (OR: 1.3; 95% CI: 1.0–1.9). Conclusion. We showed seasonal patterns in asthma symptoms and medication use. Associations were shown between allergic rhinitis and asthma control during spring/summer and eczema was associated with uncontrolled asthma during autumn/winter. Seasonality in asthma morbidity and health-care use is most likely associated with atopic constitution and viral infections, which are common during fall, winter, and spring.

• allergic rhinitis
• asthma
• children
• medication use
• PACMAN
• seasonality

Acknowledgments

The authors thank the children and parents of the PACMAN cohort study for their participation and the participating pharmacies for their cooperation. Pharmacies were selected with the help of the Utrecht University pharmacy practice research network. In addition, the authors acknowledge all the field workers: Sylvia Blind, Jorinde Berger, Karlijn Dings, Anne-Marie van Gorp, Anne Wiegink, Dionne van Dijk, Nathalie van Neijssel, Rianne Wijnands, Anne Houterman, Renee Wijsmuller, Martijn van Veen, and Hama Saeed for all their efforts.

Jan A. M. Raaijmakers is a part-time professor at the Utrecht University and vice president external scientific collaborations at GSK in Europe, and holds stock in GSK. Cornelis K. van der Ent received unrestricted grants from GSK and Grunenthal. The Division of Pharmacoepidemiology and Clinical Pharmacology employing authors Susanne J.H. Vijverberg, Ellen S. Koster, Jan A.M. Raaijmakers, and Anke-Hilse Maitland-van der Zee has received unrestricted funding for pharmacoepidemiologic research from GSK; Novo Nordisk; the private–public funded Top Institute Pharma (www.tipharma.nl; includes cofunding from universities, government, and industry); the Dutch Medicines Evaluation Board; and the Dutch Ministry of Health.