Comparative study of food allergies in children

Comparative study of food allergies in children from China, India and Russia: The EuroPrevall-INCO surveys:

Publication date: Available online 16 December 2019

Source: The Journal of Allergy and Clinical Immunology: In Practice

Author(s): Jing Li, Ludmila M. Ogorodova, Padukudru Anand Mahesh, Maggie Haitian Wang, Olga Sergeevna Fedorova, Ting Fan Leung, Montserrat Fernandez-Rivas, EN Clare Mills, James Potts, Ischa Kummeling, Serge A. Versteeg, Ronald van Ree, Maria Yazdanbakhsh, Peter GJ. Burney, Gary WK. Wong

Abstract

Background

A clear understanding of the differences of the epidemiology of food allergy between rural and urban populations may provide insights to the causes of increasing prevalence of food allergy in the developed world.

Objective

We used a standardized methodology to determine the prevalence and types of food specific allergic sensitisation and food allergies in schoolchildren from urban and rural regions of China, Russia, and India.

Methods

The current study is a multicentre epidemiological survey of children recruited from five cities in China (Hong Kong, Guangzhou), Russia (Tomsk), India (Bangalore, Mysore), and one rural county in Southern China (Shaoguan). A total of 35,549 children aged 6 to 11 years from three countries participated in this survey. Random samples of children from three countries were first screened by the Europrevall screening questionnaire. Children with and without history of adverse reactions to foods were then recruited for the subsequent case-control comparative studies. We determined the prevalence rates of food specific IgE sensitization and food allergies using the pre-defined criteria.

Results

The prevalence rates of food-specific IgE sensitisation (≥0.7kU/L) to at least one food were 16.6% in Hong Kong, 7.0% in Guangzhou, 16.8% in rural Shaoguan, 8.0% in Tomsk, and 19.1% in India. Using a definition of probable food allergy as reporting allergic symptoms within 2 hours of ingestion of a specific food plus the presence of allergic sensitization to the specific food (positive IgE and/or positive skin-prick-test), the prevalence of food allergy was highest in Hong Kong (1.50%), intermediate in Russia (0.87%), lowest in Guangzhou (0.21%), Shaoguan (0.69%) and India (0.14%). For children recruited from Hong Kong, both sensitization and food allergy were significantly higher in children who were born and raised in Hong Kong when compared to those who were born in mainland China and migrated to Hong Kong highlighting the importance of early life exposures in affecting the subsequent development of food sensitization and food allergy.

Conclusions

There are wide variations in the prevalence of food specific IgE sensitization and food allergy in the three participating countries. Food allergy appears to be less common when compared to developed countries. The variations of the prevalence of food allergen sensitization cannot be explained by the differences in the degree of urbanization. Despite the high prevalence of food-specific IgE sensitization in India and rural China, food allergy is still extremely uncommon. In addition to IgE sensitization, other factors must play important roles resulting in the clinical manifestations of food allergies.