Revision of threshold levels for evoking pollinosis to oak, pine, Japanese hop, and ragweed in the metropolitan area Seoul, Korea

Abstract

Purpose: The threshold levels for symptom development of pollinosis vary among studies and countries. This study aimed to determine currently used threshold levels for it. Methods: Oak, pine, Japanese hop, and ragweed pollen samples were collected daily for 8 years from the Seoul and Guri areas. A total of 792 subjects with allergy to these pollens were recruited. The symptom index (SI) was assessed through telephone interviews and allergy questionnaires, and data were analyzed using decision tree. Results: The risk index for oak pollen allergy was "mild" when the pollen count was 0-2 grains/m(3), "moderate" when it was 3-11 grains/m(3), "severe" when it was 12-28 grains/m(3), and "dangerous" when it was >= 29 grains/m(3). The risk level for pine pollen allergy was "mild"when the pollen count was 0-4 grains/m(3), "moderate" when it was 5-42 grains/m(3), "severe" when it was 43-66 grains/m(3), and "dangerous" when it was >= 67 grains/m(3). For Japanese hop pollen allergy, the risk level was "mild" when the pollen count was 0-8 grains/m(3), "moderate" when it was 9-10 grains/m(3), "severe" when it was 11-19 grains/m(3), and "dangerous" when it was >= 20 grains/m(3). Finally, for ragweed, the risk level was "mild" when the pollen count was 0-1 grains/m(3), "moderate" when it was 2-6 grains/m(3), "severe"when it was 7-33 grains/m(3), and"dangerous" when it was >= 34 grains/m(3). Conclusions: Revising the threshold levels for the risk index for pollen allergies may be useful for developing pollen prediction models for patients with pollen allergies in Korea.