The prevalence of oral symptoms caused by Rosaceae fruits and soybean consumption in children; a Japanese population-based survey.

Background: Pollen food Syndrome (PFS) to Rosaceae fruits and soybean, related to Bet v 1 homologue sensitization has been reported increasingly throughout Japan, possibly due to the wide distribution of alder.

Methods: In 2015, we conducted a school-based questionnaire survey among two age groups; students in primary school (Years 1-2) and secondary school (Years 8-9) from each of the 47 prefectures of Japan. We analyzed the prevalence, demographic and clinical characteristics of children with oral symptoms to Rosaceae fruits/soybean; defined as oral symptoms occurring shortly after ingesting apple, peach, cherry or soybean. Additionally, we assessed the correlation between the prevalence and external data on alder sensitization rates by prefecture.

Results: Responses from 41,264 primary and 35,302 secondary school students were analyzed. The prevalence of oral symptoms to Rosaceae fruits/soybean was 0.99%, 95%CI: 0.89-1.09% and 2.75%, 95%CI: 2.59-2.93% among each age group, respectively. Children with oral symptoms were more likely to have parental and personal history of allergic disease compared to those without symptoms. Oral symptoms were experienced more often in children with severe spring allergic rhinitis or have both allergic rhinitis and wheeze. There was a strong correlation between the prevalence of oral symptoms and alder sensitization rates by prefecture among both age groups (r = 0.63, p < 0.001 and r = 0.76, p < 0.001, respectively).

Conclusions: Oral symptoms to Rosaceae fruits/soybean, which is suggestive of PFS was reported by 1-3% Japanese school children. It was associated with the geographic alder sensitization rate, supporting the underlying sensitization to Bet v 1.