food allergy studies in new zealand associate professor rohan ameratunga
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Food Allergy studies in New Zealand Associate Professor Rohan Ameratunga. Outline of talk. Food allergy outline Epidemiology of food allergy Consequences of lack of FA data in NZ Food allergy studies in NZ. Adverse Reactions to Food. Toxic (eg. Ciguatera) Non Toxic - PowerPoint PPT PresentationTRANSCRIPT
Food Allergy studies in New ZealandAssociate Professor Rohan Ameratunga
Outline of talk
• Food allergy outline
• Epidemiology of food allergy
• Consequences of lack of FA data in NZ
• Food allergy studies in NZ
Adverse Reactions to Food
Toxic (eg. Ciguatera) Non Toxic
Immune Non Immune (Food Allergy) (Food Intolerance)
IgE Non-IgE Enzymatic Chemical Pharmacologic
Unknown Food Aversion
(lactase) (histamine)(eg eczema) (eg celiac) (eg.salicylate)
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
Lack of food allergy Research in New Zealand
• Lack of data is hindering medical services
• No paediatric allergy specialist in south Island
• Epipens unfunded
Lack of food allergy Research in New Zealand
• Ad hoc approach in schools
• Issues with preschools
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
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...
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
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
Difficulties with FA studies in NZ
• Funding agencies- low priority
• Food industry unaware/ denial of risk
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.
Study 1: Pilot study of Plunket Clinics in AucklandInterviewer assisted food allergy questionnaire
• Clinics Manurewa, Tuakau, Sylvia Park
• Participation rate 62% (68/102)
• Total number of interviews 68
• Total number of children 96
Pilot study of Plunket Clinics in AucklandFA 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)
Study 1: Pilot study of Plunket Clinics in AucklandInterviewer assisted food allergy questionnaire
• Which health professional made Dx?
• Type of testing undertaken
• Treatments given
• Demographic questions including ethnicity, education level etc
Pilot study of Plunket Clinics in AucklandFA symptoms: hives
Pilot study of Plunket Clinics in AucklandFA symptoms: eczema
Pilot study of Plunket Clinics in AucklandEthnicities 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%
Pilot study of Plunket Clinics in AucklandResults: FA symptoms
• FA symptoms11/96
• 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
Pilot study of Plunket Clinics in AucklandFA 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
Pilot study of Plunket Clinics in AucklandFA 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
Pilot study of Plunket Clinics in AucklandConsulted GP but not investigated 6/8
Age Symptoms Suspected food
4/14 eczema milk formula
7/12 vomiting wheat, milk
17/12 hives kiwifruit
4/12 vomit/aspirate milk formula
9/12 angioedema wheat, milk, egg
30/12 hives/vomiting strawberries, tomato
Pilot study of Plunket Clinics in AucklandResults: 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
Pilot study of Plunket Clinics in AucklandResults: FA and family history of allergies
FA Sx No FA Sx
• FH allergies 55% 16%
• No FH allergies 45% 84%
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
Pilot study of Plunket Clinics in AucklandLimitations
• Limitations of using Plunket
• No testing was undertaken
• No food challenges were undertaken
• Small sample size
• Geographic variation
• Questionnaire needs to be validated
Pilot study of Plunket Clinics in AucklandConclusions 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
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???
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
Study protocol
pregnancy birth 6/12 1 yr
enrol RAST RAST RAST
FFQ FFQ FFQ FFQ FFQ FFQSx Sx Sx SxSx
Study 3 Breast feeding and FA preventionEligibility
• Have an older child with proven FA
• Pregnant- 34/40+
• Regular FA questionnaire
• Regular dietary assessment
• RAST testing cord blood and 5 and 12 months
• Prelude to a longer cohort study
Funding: unrestricted grants
• Nutricia
• ADHB Charitable trust
• Allergy New Zealand
• ASCIA
• Australian Laboratory Sciences
• William and Lois Manchester trust
Food Allergy Research Group
• Christine Crooks (LabPlus)
• Maia Brewerton (Wellington Hospital)
• Steve Buetow (UoA)
• Penny Jorgensen (Allergy New Zealand)
• Elizabeth Robinson (UoA)
• Shannon Brothers (Starship)
• Clare Wall (UoA)
• Allen Liang Allergy Specialist
• Rohan Ameratunga (LabPlus, Chair)
Paediatric food allergy/ eczema clinic JHU
Prof Robert Wood
Prof Hugh Sampson
Prof Ken Schurberth