Association between first airborne cedar pollen level peak and pollinosis symptom onset: a web-based survey

Abstract

Cedar pollinosis in Japan affects nearly 25 % of Japanese citizens. To develop a treatment for cedar pollinosis, it is necessary to understand the relationship between the time of its occurrence and the amount of airborne cedar pollen. In the spring of 2009, we conducted daily Internet-based epidemiologic surveys, which included 1453 individuals. We examined the relationship between initial date of onset of pollinosis symptoms and daily amount of airborne cedar pollen to which subjects were exposed. Approximately 35.2 % of the subjects experienced the onset of pollinosis during a one-week interval in which the middle day coincided with the peak pollen count. The odds ratio for this one-week time interval was 4.03 (95 % confidence interval: 3.34–4.86). The predicted date of the cedar pollen peak can be used to determine the appropriate date for initiation of self-medication with anti-allergy drugs and thus avoid development of sustained and severe pollinosis.

Keywords:

• seasonal allergic rhinitis
• web-based survey
• population surveillance
• pollinosis
• cedar

Acknowledgments

Financial support for this study was provided by a grant from the Ministry of Health, Labor and Welfare, Japan [grant number H21-food, general -002]. We thank many members of CO-OP for their cooperation with this survey. We also thank Yoshiko Miyake and Mamiko Yoshimura (Department of Public Health, Health Management and Policy, Nara Medical University School of Medicine) for the data analyses, and the Tokyo Metropolitan Government for providing data on the cedar pollen levels.