The South African Food Sensitisation and Food Allergy population-based study of IgE-mediated food allergy: validity, safety, and acceptability

Abstract

Background: Few studies exist on food sensitization and challenge-proven food allergy in low- and middle-income countries.

Objective: To describe the study design and methodology to recruit infants from an African population for skin prick testing and oral food challenges and the use of preliminary data to investigate the extent to which the study sample is representative of the target population.

Methods: Children 12 to 36 months old were recruited from childcare education facilities in Cape Town. Children underwent skin prick testing to foods. Those with a reactive wheal of at least 1 mm larger than the negative control and not clearly tolerant according to history to a full age-appropriate portion to at least 1 food underwent oral food challenges. Parents who chose not to participate completed a nonparticipant questionnaire. Interim analysis of at least 500 respondents was performed. Demographic features of participating children were compared with those of nonparticipants and the population demographics of the most recent Cape Town census data.

Results: The response rate was 60.1%, with high participation and completion rates of 96.5% and 97.5%, respectively. Demographics of the completed participant sample were similar to those of the Cape Town census. Use of a nonrespondent questionnaire indicated no selection bias in favor of increased participation of participants with allergy. No ethnic differences in sensitization or food allergy were evident.

Conclusion: The study was safe and feasible and the recruitment was effective and representative of the target population. Future studies will aim to increase the precision of the prevalence of food sensitization and allergy, describe environmental risk factors, and include a rural black African cohort.