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Food Allergy studies in New Zealand Associate Professor Rohan Ameratunga

Food Allergy studies in New Zealand Associate Professor Rohan Ameratunga. Outline of talk. Case history: management of food allergy Food allergens incl cross-reactions Epidemiology of food allergy Is food allergy increasing? Consequences of lack of FA data in NZ Food allergy studies in NZ.

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Food Allergy studies in New Zealand Associate Professor Rohan Ameratunga

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  1. Food Allergy studies in New Zealand Associate Professor Rohan Ameratunga

  2. Outline of talk • Case history: management of food allergy • Food allergens incl cross-reactions • Epidemiology of food allergy • Is food allergy increasing? • Consequences of lack of FA data in NZ • Food allergy studies in NZ

  3. Case history (type 1 reaction) • Emma aged 18 months • Chronic eczema • Ate peanut butter • Within 5 minutes developed hives, angioedema and breathing difficulty • Treated appropriately-recovery

  4. Case history (type 1 reaction) • Diagnostic procedures • Management plan- reduce risk of recurrence • Is there any specific treatment? • What is her long-term prognosis? • How common is this problem? • Is this problem increasing? • What medical services are available in NZ? • Can this problem be prevented?

  5. Adverse Reactions to Food Toxic (eg. Ciguatera)Non Toxic ImmuneNon Immune (Food Allergy) (Food Intolerance) IgE Non-IgEEnzymatic Chemical Pharmacologic Unknown Food Aversion (eg eczema) (eg celiac) (lactase) (eg.salicylate) (histamine)

  6. Diagnostic procedures • Short term elimination diets • Trial of Neocate (with above) • Food challenges • Skin testing • RAST testing • Food patch testing • Novel methods incl peptide microarrays

  7. RAST testing Foodcut-off sensitivity specificity Egg6.0 U/ml 61% 92% Milk15 U/ml 51% 98% Peanut15.0 U/ml 73% 92% Fish 19.5 U/ml 40% 99% Wheat > 100 U/ml PPV 60% Soy > 100 U/ml PPV < 50%

  8. Food allergen avoidance/ Long-term elimination diets • Accurate diagnosis is critical • Paediatric dietician assessment essential • Reading food labels • Manufactured Food Database • Allergy New Zealand incl e-mail alerts

  9. Food allergy management plan • Education re foods and avoidance-dietician • Written action plan • MEDIC-ALERT emblem-velcro • ACC form • Public Health nurses to visit school/daycare • Anaphylaxis video (Allergy NZ) • Follow up RAST testing 6-12 monthly • Food challenge if RAST becomes negative

  10. Food allergens • When food allergy is confirmed, it usually proves to be restricted to 1 or 2 foods • Young children: milk, egg, peanut, tree nuts, soy, andwheat account for about 90% of cases • Adolescents and adults: peanut, fish, shellfish, and tree nuts account for about 85% • Cultural variation eg rice in Japan, increasing sesame allergy in NZ and Australia • Newly recognized allergens incl Anisakis, Lupin

  11. Treatment of food allergy • Avoidance, avoidance avoidance • Anti-IgE • Peanut desensitisation • Others incl Chinese herbs

  12. The prevalence of food allergy: A meta-analysis Rona et al JACI Sep 2007 • Papers selected from the literature • Categorised according to methodology • Cochrane methodology • Stringent criteria for inclusion • Divided according to age group • Unselected population papers, not enriched populations such as clinic patients

  13. Symptoms, testing and food challenges

  14. Is peanut allergy increasing? Grundy et al 2002 JACI 110(5) 784-789 • Isle of Wight study: • Examined sensitisation allergy • Significance (p=0.001) (p=0.2) • 1989-1994 1.1% 0.5% • 1994-1996 3.3% 1%

  15. Is food allergy increasing? • Increase in hospital admissions for anaphylaxis in Australia • Consistent methodologies needed, therefore, Uncertain…

  16. The changing face of food hypersensitivity in an Asian community Chiang et al Clin Exp Allergy 2007 • Very little data on food allergy in Asia • Different diets • Ethnic makeup Chinese, Indian, Malays, Eurasian • Melting pot: Rapidly changing lifestyle • Increasing westernisation of diet • Previous data indicates Chinese have major issues with fish and shellfish

  17. The changing face of food hypersensitivity in an Asian community • Study centre Kerdang Kerbau children's Hospital outpatient centre • Methods prospective data on children referred with suspected food allergy • Spt data collected 2003-2006 • Inclusion compatible history and + spt • Other allergies documented eczema and allergic rhinitis, asthma

  18. The changing face of food hypersensitivity in an Asian community • Spt positive results • Egg 40% • Shellfish 39% • Peanuts 27% • Fish 13% • Cow’s milk 12% • Sesame 9% • Wheat 6% • Soy 3%

  19. The changing face of food hypersensitivity in an Asian community • Food introduction • Egg 8.6mo • Fish 6.6mo • Shellfish 12.2mo • Fish introduced at the same time or earlier as eggs in 83% of children

  20. The changing epidemiology of food allergy Food allergy studies in NZ

  21. Lack of food allergy data in New Zealand • Currently no data • May be similar to overseas?? • However ethnic makeup different • Ethnic makeup rapidly changing • Role of genetics • Feeding practices may be different • Available foods are different eg shellfish

  22. Food allergy studies: unanswered questions • What is the burden of food allergy? • What services are utilised by patients • What are the gaps in services • What is the response of Gov’t agencies? • Are there any unusual food allergies in NZ? • What is the natural history of food allergy? • Can food allergy be prevented?

  23. Agencies involved in food allergy • Ministry of health • ARPHS • DHBNZ • Ministry of Education • PHARMAC • MEDSAFE • ACC • Ministry of Trade and Industry • FSANZ • NZFSA • IGA

  24. Lack of food allergy Research in New Zealand • Lack of data is hindering medical services • No paediatric allergy specialist in south Island • Epipens unfunded

  25. Lack of food allergy Research in New Zealand • Ad hoc approach in schools • Issues with preschools

  26. Lack of food allergy Research in New Zealand • Risk management issues for food industry and hospitality industry • Important for food export industry • Public not aware of the problem • Impact on quality of life not appreciated

  27. Is there an ideal method to determine food allergy prevalence? • Large scale unselected cohort • Regular clinical review and testing • DBPCFC for patients with Sx or +ve tests • But...

  28. Is there an ideal method? • Time dependent data • Risk of food challenges • Expense of studies • No data on adults • Change in demographics • Change in feeding practices • Changes in available foods • Therefore likely to be different in others parts of NZ

  29. Difficulties with food allergy Epidemiology • Symptoms vary according to age • Symptoms not confined to one organ system • Delayed reactions • Patients may not be aware a food is triggering symptoms • Survey instruments are not well established • The need for lab tests • Need for food challenges- expense and risks • Studies are therefore expensive

  30. Difficulties with FA studies in NZ • Funding agencies- low priority • Food industry unaware/ denial of risk

  31. Advantages of working with Plunket clinics • Up to 90% of New Zealand’s infants/young children are monitored through Plunket clinics • Conducting our studies through Plunket is likely to give us a relatively unbiased sample for community studies of FA in NZ • This work may increase the awareness of immune-mediated FA symptoms and encourage patients to seek medical help.

  32. Study 1: Pilot study of Plunket Clinics in Auckland Interviewer assisted food allergy questionnaire • Clinics Manurewa, Tuakau, Sylvia Park • Participation rate 62% (68/102) • Total number of interviews 68 • Total number of children 96

  33. Pilot study of Plunket Clinics in Auckland FA symptoms-associated with foods • Hives • Swelling in the skin • Itchy skin • Eczema (skin inflammation) • Stomach upset (nausea, vomiting, pain) • Mouth and or throat swelling • Eye and nose problems (hay-fever) • Throat tightness • Breathing difficulties (not wheeze) • Wheeze (asthma) • Life threatening reaction (anaphylaxis) • Other symptom (please list)

  34. Study 1: Pilot study of Plunket Clinics in Auckland Interviewer assisted food allergy questionnaire • Which health professional made Dx? • Type of testing undertaken • Treatments given • Demographic questions including ethnicity, education level etc

  35. Pilot study of Plunket Clinics in Auckland FA symptoms: hives

  36. Pilot study of Plunket Clinics in Auckland FA symptoms: eczema

  37. Pilot study of Plunket Clinics in Auckland Ethnicities of participants study 2006 census • NZ European 62% (60.4%) • Maori 20.8% (14.3%) • Chinese 9.4% (3.7%) • Samoan 8.3% (3.3%) • Indian 11.5% (2.7%) • Cook Island 5.2% (1.5%) • Tongan 5.2% (1.3%) • Niuean 4%

  38. Pilot study of Plunket Clinics in Auckland Results: FA symptoms • FA symptoms 11/96 • Males: females 4:7 • Diagnosed by allergy specialist 3/11 • Consulted GP 8/11 • FA suspected by GP (no testing) 2/8 • Consulted GP: FA not considered 6/8 • Ethnicities: NZE, Maori, Indian, Chinese, Niuean

  39. Pilot study of Plunket Clinics in Auckland FA symptoms: Allergy specialist • 39/12 male infant: hives with baby cereal: peanuts, milk allergy • 36/12 female twins: hives with formula: milk, egg peanut, soy

  40. Pilot study of Plunket Clinics in Auckland FA suspected by GP- not tested • FA symptoms - not investigated 8/11 • FA suspected by GP 2/8 • 14/12 Hives with strawberry yoghurt • 60/12 Worsening eczema after cow’s milk • Advised “too young” to do skin tests • Neither tested

  41. Pilot study of Plunket Clinics in Auckland Consulted GP but not investigated 6/8

  42. Pilot study of Plunket Clinics in Auckland Results: Eczema • Eczema 29/96 (30%) • Treated by GP 17/96 (18%) • NZ Health survey 14% with eczema • Some mothers (4/29) changed own diet while breast feeding- eczema improved. • Nutritional risks of ad hoc diets

  43. Pilot study of Plunket Clinics in Auckland Results: FA and family history of allergies FA Sx No FA Sx • FH allergies 55% 16% • No FH allergies 45% 84%

  44. Disadvantages of working with Plunket clinics • Parents of children > 2yrs stop attending Plunket clinics • May not attend frequently with second child • Ethnic issues Language, transport • Other providers eg Tamariki ora

  45. Pilot study of Plunket Clinics in Auckland Limitations • Limitations of using Plunket • No testing was undertaken • No food challenges were undertaken • Small sample size • Geographic variation • Questionnaire needs to be validated

  46. Pilot study of Plunket Clinics in Auckland Conclusions from preliminary findings • FA probably at least as common in NZ • Eczema is a major issue • Under recognised • Under investigated • Under treated • Affects all ethnicities • Lactating mothers are running significant health risks with ad hoc diets

  47. Study 2 Larger cross-sectional study of FA • Larger study of FA symptoms in Auckland • Practical issues • Interview room ? Mobile office • Languages • Cost of testing • Food challenges • Funding • Value???

  48. Study 3 Breast feeding and FA prevention • Currently no data on the role of elimination diets and breast feeding • Mothers are given conflicting advice on early vs delayed introduction of allergenic foods • Nutritional risks in ad hoc diets

  49. Dietary prevention recommendations (Sicherer and Burks, 2008)

  50. Study 3 Breast feeding and FA prevention Aim: To determine whether dietary exposure (the mother’s dietary intake while breastfeeding, formula feeding and the introduction of solids) influences allergen sensitisation in infants at high risk of FA up to one year

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