The prevalence and temporal trends of food allergy among preschool children in Northern Thailand between 2010 and 2019()

BACKGROUND: Although recent studies suggest that the prevalence of food allergy (FA) has not changed, the data from developing countries are limited. This study aimed to investigate time trends in the prevalence of FA among preschool children in 2010 and 2019 in Northern Thailand. METHODS: Two cross-sectional studies were performed, 9 years apart (2010 and 2019), using the same methods, in children aged 3–7 years living in Chiang Mai, Thailand. Parent-reporting questionnaire surveys were conducted. Families with children reporting FA were invited to undergo further investigations with skin prick testing, serum specific IgE, and oral food challenge (OFC). The prevalence of parent-reported FA, food sensitization, and OFC-confirmed FA were compared between the 2 periods. RESULTS: A total of 1013 out of 1146 questionnaires (452/546 in 2010 and 561/600 in 2019) were returned. The response rate was 88.4%. The prevalence of parent-reported food allergy in 2019 was significantly lower than that in 2010 (5.5% vs 9.3%; p = 0.02). However, there was no significant change in the prevalence of OFC-confirmed FA (0.9% vs 1.1%; p = 0.75). Three leading causative foods of parent-reported FA were cow's milk, shrimp, and eggs. Shrimp was still the most common OFC-confirmed food allergen. Atopic dermatitis was the most significantly parent reported factor associated with FA. CONCLUSION: The overall prevalence of FA among preschool children in Northern Thailand had not increased during the past decade. There was no significant difference in the prevalence of OFC-confirmed FA between 2010 and 2019.