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Table of Contents
Food allergy definition
Researchers from the University Medical Center Groningen developed a definition of food allergy for all Lifelines participants (adults and children) using the allergy variables from 2A. (sections: Diseases & symptoms (Allergies) and secondary & linked variables).
The Food allergy definition can be requested in the Lifelines catalogue or by mail (data@lifelines.nl).
Background
In 2020, Westerlaken-van Ginkel et al. published a paper in which an algorithm to define food allergy in adults in Lifelines is developed and described. Since the allergy variables for adults differ slightly from those of children (completed by the parents) and adolescents, this algorithm has to be adapted to defined food allergy in children/adolescents as well.
Calculation of food allergy definition
The calculation of the food allergy definition consisted of three steps: 1) coding of open text variables, 2) defining and calculating criteria to define food allergy, and 3) creating the overall food allergy variables.
1. Coding of open text variables
At the start of the process, the responses from participants on “other allergen”, “other reaction”, and “other person who diagnosed the food allergy” are coded. The allergens and reactions were coded as common, less common, and uncommon using the tables as descibed by Westerlaken-van Ginkel et al. (2020). These original coding tables were slightly changed after reachging consensus. The “other person” items have been coded into alternative practitioner, other person, and no person mentioned.
2. Defining and calculating criteria to define food allergy
Five criteria have been defined
3. Creating overall food allergy variables
Variables
| Label English | Label Dutch | Code | Variable | Assessment | Age |
| age at definition of food allergy (based on questionnaire) | leeftijd ten tijde van definitie voedselallergie (op basis van moment vragenlijst) | foodallergy_age_all_c_1 | agefa | sec * | all |
| reported product is likely allergenic? | gerapporteerd product is waarschijnlijk allergeen? | foodallergy_allergen_ach_c_1 | likelyallergen_ach | sec * | all |
| reported product is likely allergenic? | gerapporteerd product is waarschijnlijk allergeen? | foodallergy_allergen_adu_c_1 | likelyallergen_adu | sec * | all |
| reported product is likely allergenic? | gerapporteerd product is waarschijnlijk allergeen? | foodallergy_allergen_chi_c_1 | likelyallergen_chi | sec * | all |
| reported reaction is likely allergic? | gerapporteerde reactie is waarschijnlijk allergisch? | foodallergy_reaction_ach_c_1 | likelyreaction_ach | sec * | all |
| reported reaction is likely allergic? | gerapporteerde reactie is waarschijnlijk allergisch? | foodallergy_reaction_adu_c_1 | likelyreaction_adu | sec * | all |
| reported reaction is likely allergic? | gerapporteerde reactie is waarschijnlijk allergisch? | foodallergy_reaction_chi_c_1 | likelyreaction_chi | sec * | all |
| presence of food allergy according to criteria 1 and 2 (excluding criteria 3: amount of food eliciting reaction, 4: duration of symptoms, and 5: result dbpcfc) | aanwezigheid van voedselallergie volgens criteria 1 en 2 (exclusief criteria 3: hoeveelheid voedsel dat reactie uitlokt, 4: duur van symptomen, en 5: resultaat dbpcfc) | foodallergy_score_ach_c_1 | foodallergy_ach | sec * | all |
| presence of food allergy according to criteria 1 and 2 (excluding criteria 3: amount of food eliciting reaction, 4: duration of symptoms, and 5: result dbpcfc) | aanwezigheid van voedselallergie volgens criteria 1 en 2 (exclusief criteria 3: hoeveelheid voedsel dat reactie uitlokt, 4: duur van symptomen, en 5: resultaat dbpcfc) | foodallergy_score_adu_c_1 | foodallergy3_adu | sec * | all |
| presence of food allergy according to criteria 1, 2, 4, and 5 (excluding criteria 3: amount of food eliciting reaction) | aanwezigheid van voedselallergie volgens criteria 1, 2, 4, en 5 (exclusief criteria 3: hoeveelheid voedsel dat reactie uitlokt) | foodallergy_score_adu_c_2 | foodallergy2_adu | sec * | all |
| presence of food allergy according to criteria 1, 2, 3, 4, and 5 | aanwezigheid van voedselallergie volgens criteria 1, 2, 3, 4, en 5 | foodallergy_score_adu_c_3 | foodallergy_adu | sec * | all |
| presence of food allergy based on [foodallergy_score_adu_1] and [foodallergy_score_ach/chi_c_1], with the highest score shown in case of multiple scores per participant | aanwezigheid van voedselallergie gebaseerd op [foodallergy_score_adu_1] en [foodallergy_score_ach/chi_c_1], met de hoogste score weergegeven in het geval van meerdere scores per deelnemer | foodallergy_score_all_c_1 | fa3 | sec * | all |
| presence of food allergy based on [foodallergy_score_adu_2] and [foodallergy_score_ach/chi_c_1], with the highest score shown in case of multiple scores per participant | aanwezigheid van voedselallergie gebaseerd op [foodallergy_score_adu_2] en [foodallergy_score_ach/chi_c_1], met de hoogste score weergegeven in het geval van meerdere scores per deelnemer | foodallergy_score_all_c_2 | fa2 | sec * | all |
| presence of food allergy based on [foodallergy_score_adu_3] and [foodallergy_score_ach/chi_c_1], with the highest score shown in case of multiple scores per participant | aanwezigheid van voedselallergie gebaseerd op [foodallergy_score_adu_3] en [foodallergy_score_ach/chi_c_1], met de hoogste score weergegeven in het geval van meerdere scores per deelnemer | foodallergy_score_all_c_3 | fa | sec * | all |
| presence of food allergy according to criteria 1 and 2 (excluding criteria 3: amount of food eliciting reaction, 4: duration of symptoms, and 5: result dbpcfc) | aanwezigheid van voedselallergie volgens criteria 1 en 2 (exclusief criteria 3: hoeveelheid voedsel dat reactie uitlokt, 4: duur van symptomen, en 5: resultaat dbpcfc) | foodallergy_score_chi_c_1 | foodallergy_chi | sec * | all |
* The food allergy definition variables are included as assessment 'sec' because they link to different questionnaires from assessment 2A.
