Background: There is a paucity of data on the prevalence, natural history and management of food allergy in most of the populous Asian countries, including China.
Objective: To determine the point prevalence of self-reported food allergy in Chinese children and teenagers in Hong Kong.
Methods: A cross-sectional population-based questionnaire survey targeted at children aged 0-14y was conducted by use of face-to-face interviews and self-administered questionnaires. Information was obtained from the parent as proxy respondent for children aged 10 and below and from both parent and child for children aged 11 to 14. Households were drawn from the Register of Quarters maintained by the Census and Statistics Department by systematic replicated sampling.
Results: A total of 7,393 land-based noninstitutionalized children aged 14 and below in Hong Kong were recruited, excluding those with non-Cantonese speaking parents and those living in non-built-up areas. The sample was representative of the 884,300 children in the target population. 352 reported having adverse reactions to foods and the estimated prevalence was 4.8% (95% CI 4.3-5.3%). The estimated prevalence of peanut allergy was 0.3-0.5% (95%CI 0.1 to 0.7%). In terms of relative frequency, shellfish, which was the top allergen, accounted for more than a third of all reactions. The second most common was hen's egg (14.5%), the third cow's milk and dairy products (10.8%) and co-fourth were peanut and combined fruits (8.5%). Out of 352 subjects who reported adverse reactions, 127 (36.1%) had urticaria and or angioedema and 79 (22.4%) had eczema exacerbations. Combined gastrointestinal symptoms accounted for 20.8 % (diarrhoea 12.8%; vomiting 5.4%; abdominal pain 2.6%). Fifty-five (15.6%) had anaphylaxis, and 7 (2%) had respiratory difficulties.
Conclusion: This survey has provided the first population based epidemiological information related to food allergy amongst children and younger teenagers in Hong Kong. The prevalence of food allergy, including that from more common subtypes, like shellfish and peanut, is highly comparable to that of most of the developed nations.