[Epidemiologic study of Alnus sieboldiana Matsumura (alder) pollinosis in Ashiya city].

Alnus sieboldiana has been planted widely on denuded sites in the Rokko mountains. Its pollination season is in the latter half of that of Japanese cedar. This epidemiologic study was carried out in Ashiya in the 1991 spring hay fever season. The subjects were 532 female residents chosen at random, who had been living there more than ten years. There was an evident relation between the airbone alder pollen count and the prevalence of alder pollinosis. In the mountain town most severely inundated with alder pollen (977/sq. cm/year), the prevalence rate of alder pollinosis alone or both alder and cedar pollinosis was 26.1%. In the flat area 5 km far from south of the mountain town, where aribome pollen count was 386/sq.cm/year, the prevalence rate of alder pollinosis was 4.3%. The heavy traffic main road pass through the flat area, thus the air pollution was significantly strong in the flat area more than in the mountain town. However, we couldn't find adjuvant effect of air pollution on the alder pollinosis, which was often reported about Japanese cedar pollinosis.