A Population-Based Study of Fish Allergy in the Philippines, Singapore and Thailand

Abstract

Background: Fish allergy is the third most common food allergy after milk and egg in parts of Europe, but there is little data about prevalence in South East Asia where it is an important part of regular diets. Objective: We aimed to obtain an estimate of the population prevalence of fish allergy among older children in the Philippines, Singapore and Thailand. Methods: The population prevalence of fish allergy in 14- to 16-year-old children in the 3 countries was evaluated using a structured written questionnaire which was distributed to students of randomly selected secondary schools. An extended questionnaire to determine convincing fish allergy on the basis of typical clinical manifestations within 2 h of ingestion was administered to those with positive responses. Results: From acohort of 25,842 students, responses were 81.1% in the Philippines (n = 11,434), 67.9% in Singapore (n = 6,498) and 80.2% (n = 2,034) in Thailand. Using criteria for convincing food allergy, fish allergy was much higher in the Philippines [2.29%, 95% confidence interval (CI) 2.02–2.56] than in Singapore (0.26%, 95% CI 0.14–0.79) and Thailand (0.29%, 95% CI 0.06–0.52). Weighted multiple logistic regression analyses showed that compared to the Philippines, prevalence rates were lower in Singapore [odds ratio (OR) 0.40, 95% CI 0.27–0.60, p < 0.0001] and Thailand (OR 0.13, 95% CI 0.05–0.33, p < 0.0001). Females were more likely to have fish allergy compared to males for all children combined (OR 1.32, 95% CI 1.11–1.58, p = 0.002). Most allergies appeared mild, as only 28% of cases sought medical consultation at the time of the reaction and 31.2% of cases reported continued exposure despite allergic symptoms. Conclusion: Fish allergy in late childhood is more common in the Philippines compared to Singapore and Thailand. Differences in food processing, dietary habits and other cultural practices might be important risk factors for the development of fish allergy in these populations.

Food allergy in Singapore: opening a new chapter

“…Comparing with other Southeast Asian countries, our prevalence rate is similar to that of Thailand (0.29% based on convincing history). (12) The low prevalence in some countries was initially thought to be associated with early introduction of fish to the diet as compared to the West. (32) However, in Connet et al's study, the rate of fish allergy in the Philippines, where fish is similarly introduced to the diet at an early age, was found to be surprisingly high at 2.29%.…”

“…(32) However, in Connet et al's study, the rate of fish allergy in the Philippines, where fish is similarly introduced to the diet at an early age, was found to be surprisingly high at 2.29%. (12) In addition, the allergic profile of the Filipino group demonstrated a late-onset-type of fish allergy, unlike in Singapore where fish allergy usually occurs in the first year of life. (33) It was proposed by the authors that this entity in the Philippines could be due to differences in fish preparation methods, with the high availability of dried and salted fish as opposed to cooked fish, possibly promoting immunogenicity.…”

“…(33) It was proposed by the authors that this entity in the Philippines could be due to differences in fish preparation methods, with the high availability of dried and salted fish as opposed to cooked fish, possibly promoting immunogenicity. (12) Outside the Southeast Asian region, the prevalence rates of fish allergy in ethnically similar countries are also variable.…”

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“…Higher rates of self-reported allergic reactions were observed in some Asian countries, both for adults (24.5 %; China) (Sai et al, 2011) and children (8.7 % and 11.6 %, respectively; Philippines) (Connett et al, 2012). However, the only study which used OFC to confirm diagnosis reported a prevalence of clinical allergy to crab and shrimp of 0.2 % and 0.9 %, respectively, among three-to seven-year-olds in Thailand (Lao-araya and Trakultivakorn, 2011).…”

Which Foods Cause Food Allergy and How Is Food Allergy Treated?

“…In children from Spain, fish allergy starts in the second year of life and is the third most prevalent food allergy after egg and milk [48]. A recent population-based study in southeast Asia in children 14e16 years old has shown a prevalence of fish allergy of 2.29% in the Philippines, whereas in Singapore and Thailand it is 10 times lower [49].…”