title: A population-based questionnaire survey on the prevalence of peanut, tree nut, and shellfish allergy in 2 Asian populations.
abstract: BACKGROUND
  There has been a substantial increase in the prevalence of peanut and tree nut allergy in Western populations in the last 2 decades. However, there is an impression that peanut and tree nut allergy is relatively uncommon in Asia.
  
  
  OBJECTIVE
  To evaluate the prevalence of peanut, tree nut, and shellfish allergy in schoolchildren in 2 Asian countries (Singapore and Philippines).
  
  
  METHODS
  A structured written questionnaire was administered to local and expatriate Singapore (4-6 and 14-16 years old) and Philippine (14-16 years old) schoolchildren.
  
  
  RESULTS
  A total of 25,692 schoolchildren responded to the survey (response rate, 74.2%). Of these, 23,425 responses fell within the study protocol's 4 to 6 and 14 to 16 year age groups and were included in the analysis. The prevalence of convincing peanut and tree nut allergy were similar in both local Singapore (4-6 years, 0.64%, 0.28%; 14-16 years, 0.47%, 0.3%, respectively) and Philippine (14-16, 0.43%, 0.33%, respectively) schoolchildren, but was higher in the Singapore expatriates (4-6 years, 1.29%, 1.12%; 14-16 years, both 1.21%, respectively; 4-6 years, expatriates vs local Singaporeans: peanut, P = .019; tree nut, P = .0017; 14-16 years, P > .05). Conversely, shellfish allergy was more common in the local Singapore (4-6 years, 1.19%; 14-16 years, 5.23%) and Philippine (14-16 years, 5.12%) schoolchildren compared with expatriate children (4-6 years, 0.55%; 14-16 years, 0.96%; P < .001). When data were pooled, respondents born in Western countries were at higher risk of peanut (adjusted odds ratios [95% CIs]: 4-6 years, 3.47 [1.35-8.93]; 14-16 years, 5.56 [1.74-17.76]) and tree nut allergy (adjusted odds ratios [95% CIs]: 4-6 years, 10.40 [1.61-67.36]; 14-16 years, 3.53 [1.00-12.43]) compared with those born in Asia.
  
  
  CONCLUSIONS
  This study substantiates the notion that peanut and tree nut allergy is relatively low in Asian children, and instead shellfish allergy predominates. Environmental factors that are yet to be defined are likely to contribute to these differences.
authors.affiliation: National University Health System, Singapore.
authors.forename: Lynette Pei-Chi
authors.initials: LP
authors.lastname: Shek
authors.forename: Elizabeth Ann
authors.initials: EA
authors.lastname: Cabrera-Morales
authors.forename: Shu E
authors.initials: SE
authors.lastname: Soh
authors.forename: Irvin
authors.initials: I
authors.lastname: Gerez
authors.forename: Pau Zhing
authors.initials: PZ
authors.lastname: Ng
authors.forename: Fong Cheng
authors.initials: FC
authors.lastname: Yi
authors.forename: Stefan
authors.initials: S
authors.lastname: Ma
authors.forename: Bee Wah
authors.initials: BW
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000367:Age Factors; D044466:Asian People; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D021184:Nut Hypersensitivity / Q000453:epidemiology*; D021183:Peanut Hypersensitivity / Q000453:epidemiology*; D010679:Philippines / Q000453:epidemiology; D015995:Prevalence; D012307:Risk Factors; D012758:Shellfish / Q000009:adverse effects*; D012846:Singapore / Q000453:epidemiology; D011795:Surveys and Questionnaires