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Abstract(s)
Introdução: A alergia alimentar é uma epidemia crescente em todo o mundo que afeta cerca de 6-8% das crianças. É uma situação altamente stressante para crianças e suas famílias, gerando elevado nível de ansiedade, associa-se a menor qualidade de vida, por vezes pior do que em muitas outras doenças crónicas e é frequentemente motivo de bullying. Os fatores de risco ainda não são totalmente conhecidos e o diagnóstico nem sempre é exato. Não existe uma terapêutica adequada e consensual, sendo a evicção o método de eleição para prevenir reações alérgicas e a adrenalina a terapêutica mais eficaz no tratamento das reações alimentares mais graves, de anafilaxia potencialmente fatal.
É de primordial importância conhecer a realidade da nossa população quanto a aspetos de alergias alimentares, avaliar melhor a patologia envolvida, melhorar a literacia das crianças alérgicas e seus cuidadores, bem como dos profissionais de saúde, em relação a esta área de patologia clínica, com o objetivo de tornar os diagnósticos de alergia alimentar mais exatos, adequar as medidas de evicção evitando as dietas demasiado restritivas e por vezes desnecessárias, prevenir e tratar as reações potencialmente graves.
Objetivos: Construir e validar um questionário destinado a crianças com suspeita de alergia alimentar baseado nos conhecimentos científicos sobre a área, que inclua os aspetos considerados importantes para identificar o(s) alimento(s) suspeito(s) e caraterizar a reação ocorrida de modo a identificar crianças em risco de reação grave e orientar estudos adicionais.
Avaliar a prevalência de reação adversa a alimento (RAA) e alergia alimentar (AA), identificar os alimentos mais implicados e as características clínicas e laboratoriais da alergia alimentar em crianças da Beira Interior.
Avaliar o impacto dos fatores de risco mais consensuais para AA e RAA na população estudada.
Refletir sobre a implicação prática deste estudo, a nível individual, familiar e populacional, nas medidas de saúde pública e na melhoria contínua dos cuidados de saúde.
Materiais e métodos: Construímos um questionário de reações adversas a alimentos baseado em questionários validados em outros países e questionários portugueses não validados. O questionário foi revisto por imunoalergologistas e foi desenvolvida uma análise exploratória com a sua aplicação em crianças com alergia alimentar conhecida. A fiabilidade foi avaliada por teste-reteste em crianças com suspeita de reações adversas a alimentos. Para avaliar a estabilidade temporal e reprodutibilidade usámos o teste de correlação de Spearman Rho e o índice kapa de Cohen. Este questionário, designado como Q2, foi aplicado nas crianças que tinham tido resposta positiva a um curto questionário preliminar simplificado (Q1) que perguntava se havia alguma suspeita de reação adversa a algum alimento.
A prevalência de reações adversas a alimentos foi avaliada em crianças entre os 3 e 11 anos da região da Cova da Beira através do questionário de reações adversas a alimentos. Nas crianças com alimentos suspeitos, foram adicionalmente efetuados testes cutâneos por picada e determinados os níveis séricos de IgE específicas para os alimentos implicados. Foram ainda analisadas as características clínicas das reações, e recolhidos dados relativos aos antecedentes pessoais e familiares de atopia.
Os fatores de risco genéticos e ambientais foram avaliados para todas as crianças com Q2 positivo. Para além da caracterização demográfica e das reações ao(s) alimentos(s) implicados, foram analisados os antecedentes pessoais e familiares de atopia, o tempo de amamentação e idade de introdução de alimentos sólidos e reações ocorridas na diversificação alimentar. Foram ainda analisados os dados dos estudos in vivo e in vitro de atopia. Foi feita uma análise comparativa do grupo de crianças com AA provável (crianças que, em Q2, apresentavam alimento suspeito, com reação IgE-Mediada) e grupo AA possível não IgE-Med (crianças que em Q2 apresentavam alimento suspeito, com reação não IgE-mediada).
Para todos os testes estatísticos foi considerado significativo um valor de p inferior a 0,05.
Resultados: Das 4045 crianças em idade escolar, 2474 (61,2%) aceitaram responder ao questionário inicial e foram incluídas no estudo. A prevalência de reação adversa a alimentos foi de 7,1% (IC95%: 6,2-8,1), baseada no questionário inicial (Q1). Em 115 crianças manteve-se a suspeita após aplicação presencial do Questionário alargado de reações adversas a alimentos (Q2).
O questionário Q2 foi reaplicado a 50 crianças com suspeita de alergia alimentar, cerca de 3 semanas após o teste inicial. O questionário mostrou boa estabilidade temporal (coeficiente de correlação de Spearman de 0,834), e boa reprodutibilidade (apenas 2 dos 27 items apresentaram índice Kappa <0,60).
Com base no questionário alargado (Q2), aplicado presencialmente, a prevalência de AA autorreportada, foi de 4,6% (IC95%: 3,9-5,5). A prevalência de alergia alimentar “provável” (definição baseada em questionário Q2 positivo para algum alimento e evidência de mecanismo IgE-Mediado – Teste cutâneo por Picada (TCP) e/ou IgE elevada para esse alimento) foi de 1,4% (IC95%: 0,9-1,9). Os alimentos mais implicados foram os frutos frescos, o peixe e o ovo. O primeiro episódio ocorreu em idade mais precoce, reações mucocutâneas e anafiláticas foram mais associadas a RAA IgE-Mediadas que a Reações não IgE-Mediadas. A prevalência de alergia possível a frutos (autorreportada, baseada em Q2) foi de 1,69 (IC95%: 1,19-2,21) enquanto a alergia provável a frutos (AFr - baseada em questionário e estudos in vivo e in vitro com evidência de mecanismo IgE-Mediado) foi de 0,61% (IC95%: 0,30-0,92). Apesar de morango, citrinos e kiwi serem os frutos mais implicados na alergia a Fr possível, na AFr provável os frutos mais implicados foram o kiwi, o pêssego, a banana e o morango. Os primeiros sintomas ocorreram em idades precoces (média 2,5 anos). Na AFr provável, 47% das crianças estavam sensibilizadas a dois ou mais frutos e as manifestações clínicas foram mais frequentemente imediatas e monossintomáticas: urticária/angioedema (57.1%), síndrome alérgica oral (SAO) (64,3%). Todas as crianças alérgicas a frutos estavam sensibilizadas a pólenes e a sensibilização a látex foi positiva em 71,6% das crianças com alergia a frutos com reatividade ao látex conhecida (síndrome látex-frutos).
O sexo masculino, os antecedentes pessoais de doenças alérgicas, marcadores in vitro de atopia e a sensibilização a aeroalergénios foram significativamente mais frequentes nas crianças com AA Provável (IgE-Med) do que no Grupo com AA possível, não IgE-Mediada. Já a residência em área urbana ou rural, o nível socioeconómico, a diversificação alimentar, não mostraram diferenças estatisticamente significativas entre os dois grupos. Menor tempo de aleitamento materno foi mais associado ao Grupo não IgE-Med e a introdução de alimentos sólidos entre os 4 e os 6 meses mostrou estar significativamente menos associada à probabilidade de ter uma AA IgE-Med, comparativamente com a sua introdução após os 6 meses.
Conclusões: O questionário desenvolvido apresentou boa estabilidade temporal e reprodutibilidade, podendo ser utilizado de modo padronizado para rastreio de RAA permitindo uma abordagem uniformizada e passível de estudos comparativos futuros.
A prevalência de alergia alimentar provável em crianças portuguesas da Cova da Beira é baixa, e os pais tendem a sobrevalorizar as queixas destas, sendo a prevalência de AA significativamente mais elevada quando se baseia apenas em questionários presenciais do que nesses questionários em associação com estudos in vivo e in vitro. Os alimentos mais implicados são os frutos frescos e peixe. As reações IgE-Mediadas são mais frequentemente imediatas, polissintomáticas, mais severas e começam em idades mais precoces que as reações não IgE-mediadas.
Apesar do morango e os citrinos serem mais frequentemente reportados (alergia possível), um mecanismo IgE-Mediado demonstrado (alergia provável), bem como a manifestação clínica de SAO estão mais associados ao kiwi e ao pêssego. Nas crianças com AA provável, a sensibilização a mais do que um fruto é frequente e as manifestações são tipicamente mucocutâneas, imediatas e monossintomáticas. A reatividade cruzada com pólenes e látex é bastante frequente.O perfil de risco para AA provável, IgE-mediada, envolveu significativamente mais o sexo masculino e a presença de atopia pessoal, no nosso estudo. Pelo contrário, um menor tempo de amamentação, a presença de atopia familiar, o nível socioeconómico e o local de residência não se associaram a um risco acrescido para alergia alimentar, IgE-Mediada.
Introduction: Food allergy is a growing worldwide epidemic affecting about 6-8% of children. It is a highly stressful situation for children and their families, generating high levels of anxiety, being associated with poorer quality of life, sometimes worse than in many other chronic diseases, and is often the object of bullying. Risk factors are not yet fully known and the diagnosis is not always accurate. There is no adequate and consensual therapy, and avoidance is the method of choice to prevent allergic reactions and epinephrine is the most effective therapy for treating the most severe food-associated reactions of potentially fatal anaphylaxis. It is of prime importance to know the reality of our population regarding aspects of food allergies, to better evaluate the pathology involved, to improve the literacy of allergic children and their caregivers, as well as health professionals, in relation to this area of clinical pathology. The aim should be to make food allergy diagnoses more accurate, to adapt avoidance measures to avoid overly restrictive and sometimes unnecessary diets, to prevent and treat potentially serious reactions. Objectives: To construct and validate a questionnaire for children with suspected food allergies based on scientific knowledge of the area, including aspects considered important to identify the suspected food (s) and characterize the reaction that occurred identify children at risk of severe reaction and guide further studies. To evaluate the prevalence of adverse food reaction (AFR) and food allergy (FA), to identify the most frequently implicated foods as well as the clinical and laboratory characteristics of food allergy in children of the Beira Interior. To evaluate the impact of the most consensual risk factors for FA and AFR on the population studied. To elaborate on the practical implications of this study, at individual, family and population level, on public health measures and the continuous improvement of health care. Materials and methods: We constructed a food adverse reaction questionnaire based on validated questionnaires in other countries and on non-validated Portuguese questionnaires. The questionnaire was reviewed by immunoallergologists and an exploratory analysis was developed with its application in children with known food allergy. Reliability was assessed by test-retest in children with suspected adverse food reactions. To assess temporal stability and reproducibility we used the Spearman Rho correlation test and Cohen's kappa index. This questionnaire was called Q2and was applied to children who had a positive reply to a short simplified preliminary questionnaire (Q1), which asked if there was any suspicion of adverse reaction to any food. The prevalence of adverse food reactions was assessed in children aged 3 to 11 years-old children from Cova da Beira region, by applying the adverse food reaction questionnaires. In children reporting episodes with suspicious foods, skin prick tests were additionally performed and specific IgE serum levels were determined for the involved foods. Clinical features of the reactions were analysed, and data related to personal and family history of atopy were collected. Genetic and environmental risk factors were assessed for all children with positive Q2. In addition to demographic characterization, and reactions to the food (s) involved, personal and family history of atopy, breastfeeding time, age of introduction of solid foods and reactions occurring in food diversification were analysed. Data from in vivo and in vitro atopy studies were also analysed. A comparative analysis was carried out between the group of children with probable FA (children who had suspicious food in Q2, with an IgE-Mediated reaction) and the group with possible non-IgE-Med FA (children who had suspicious food in Q2, with a non-IgE-Mediated reaction). For all statistical tests a p value of less than 0.05 was considered significant. Results: Of the 4045 school-age children, 2474 (61.2%) agreed to answer the initial questionnaire and were included in the study. The prevalence of self-reported adverse reaction to food was 7.1% (95% CI: 6.2-8.1), based on the initial questionnaire (Q1). In 115 children, the suspicion remained after face-to-face application of the Extended Adverse Food Reaction Questionnaire (Q2). The Q2 questionnaire was re-applied to 50 children with suspected food allergy about 3 weeks after the initial test. The questionnaire showed good temporal stability (Spearman's correlation coefficient of 0.834), and good reproducibility (only 2 of 27 items had a Kappa index <0.60). Based on the extended questionnaire (Q2), applied in person, the final prevalence of self-reported FA was 4.6% (95% CI: 3.9-5.5). The prevalence of “probable” food allergy (definition based on Q2 positive questionnaire for some food and evidence of an IgE-mediated mechanism – positive SPT and/or high serum IgE levels specific for this food) was 1.4% (95% CI: 0.9-1 9). The most implicated foods were fresh fruits, fish and egg. The first episode occurred at an earlier age, and mucocutaneous and anaphylactic reactions were more frequently associated with IgE-Mediated AFR than with non-IgE-Mediated reactions. The prevalence of possible fruit allergy (self-reported, based on Q2) was 1.69 (95% CI: 1.19-2.21) while probable fruit allergy (FrA - based on questionnaire and on in vivo and on in vitro studies with evidence of IgE-mediated mechanism) was 0.61% (95% CI: 0.30-0.92). Although strawberry, citrus and kiwi were the most frequently implicated fruits in possible allergy to fruits, in probable FrA the most implicated fruits were kiwi, peach, banana and strawberry. The first symptoms occurred at early ages (average 2.5 years). In probable FrA, 47% of children were sensitised to two or more fruits and clinical manifestations were most often immediate and monosymptomatic: urticaria / angioedema (57.1%), oral allergic syndrome (OAS) (64.3%). All fruit-allergic children were sensitised to pollens and latex sensitisation was positive in 71.6% of children with fruit allergy with known latex reactivity (latex-fruit syndrome). Being a male, having a personal history of allergic diseases, and having positive in vitro markers of atopy, and aeroallergen sensitisation were significantly more frequent in children with Probable FA (IgE-Med) than in the possible non-IgE-Mediated FA group. Residence in urban or rural areas, socioeconomic status, and food diversification did not show statistically significant differences between the two groups. Shorter breastfeeding time was more frequently associated with the non-IgE-Med group and the introduction of solid foods between 4 and 6 months was significantly less associated with the likelihood of having an IgE-Med FA compared to its introduction after 6 months. Conclusions: The developed questionnaire presented good temporal stability and reproducibility and could be used in a standardised way for AFR screening, thereby allowing a uniform approach which may facilitate future comparative studies. The prevalence of probable food allergy in Portuguese children in Cova da Beira is low, children's parents have a tendency to overestimate their complaints, and the prevalence of FA is significantly higher when based only on face-to-face questionnaires than on these questionnaires associated with in vivo and in vitro studies. The most frequently implicated foods are fresh fruits and fish. IgE-Mediated reactions are more often immediate, polysymptomatic, more severe, and begin at earlier ages than non-IgE-Mediated reactions. Although strawberry and citrus fruits are most frequently reported (possible allergy), a demonstrated IgE-mediated mechanism (probable allergy) as well as the clinical manifestation of OAS are more frequently associated with kiwi and peach. In children with probable FA, sensitisation to more than one fruit is frequent and manifestations are typically mucocutaneous, immediate and monosymptomatic. Cross reactivity with pollen and latex is quite common. The risk profile for probable, IgE-Mediated FA involved in our study, was significantly more frequently associated with being male and having personal atopy. In contrast, shorter breastfeeding time, the presence of family atopy, socioeconomic status, and place of residence were not associated with an increased risk for IgE-Mediated food allergy.
Introduction: Food allergy is a growing worldwide epidemic affecting about 6-8% of children. It is a highly stressful situation for children and their families, generating high levels of anxiety, being associated with poorer quality of life, sometimes worse than in many other chronic diseases, and is often the object of bullying. Risk factors are not yet fully known and the diagnosis is not always accurate. There is no adequate and consensual therapy, and avoidance is the method of choice to prevent allergic reactions and epinephrine is the most effective therapy for treating the most severe food-associated reactions of potentially fatal anaphylaxis. It is of prime importance to know the reality of our population regarding aspects of food allergies, to better evaluate the pathology involved, to improve the literacy of allergic children and their caregivers, as well as health professionals, in relation to this area of clinical pathology. The aim should be to make food allergy diagnoses more accurate, to adapt avoidance measures to avoid overly restrictive and sometimes unnecessary diets, to prevent and treat potentially serious reactions. Objectives: To construct and validate a questionnaire for children with suspected food allergies based on scientific knowledge of the area, including aspects considered important to identify the suspected food (s) and characterize the reaction that occurred identify children at risk of severe reaction and guide further studies. To evaluate the prevalence of adverse food reaction (AFR) and food allergy (FA), to identify the most frequently implicated foods as well as the clinical and laboratory characteristics of food allergy in children of the Beira Interior. To evaluate the impact of the most consensual risk factors for FA and AFR on the population studied. To elaborate on the practical implications of this study, at individual, family and population level, on public health measures and the continuous improvement of health care. Materials and methods: We constructed a food adverse reaction questionnaire based on validated questionnaires in other countries and on non-validated Portuguese questionnaires. The questionnaire was reviewed by immunoallergologists and an exploratory analysis was developed with its application in children with known food allergy. Reliability was assessed by test-retest in children with suspected adverse food reactions. To assess temporal stability and reproducibility we used the Spearman Rho correlation test and Cohen's kappa index. This questionnaire was called Q2and was applied to children who had a positive reply to a short simplified preliminary questionnaire (Q1), which asked if there was any suspicion of adverse reaction to any food. The prevalence of adverse food reactions was assessed in children aged 3 to 11 years-old children from Cova da Beira region, by applying the adverse food reaction questionnaires. In children reporting episodes with suspicious foods, skin prick tests were additionally performed and specific IgE serum levels were determined for the involved foods. Clinical features of the reactions were analysed, and data related to personal and family history of atopy were collected. Genetic and environmental risk factors were assessed for all children with positive Q2. In addition to demographic characterization, and reactions to the food (s) involved, personal and family history of atopy, breastfeeding time, age of introduction of solid foods and reactions occurring in food diversification were analysed. Data from in vivo and in vitro atopy studies were also analysed. A comparative analysis was carried out between the group of children with probable FA (children who had suspicious food in Q2, with an IgE-Mediated reaction) and the group with possible non-IgE-Med FA (children who had suspicious food in Q2, with a non-IgE-Mediated reaction). For all statistical tests a p value of less than 0.05 was considered significant. Results: Of the 4045 school-age children, 2474 (61.2%) agreed to answer the initial questionnaire and were included in the study. The prevalence of self-reported adverse reaction to food was 7.1% (95% CI: 6.2-8.1), based on the initial questionnaire (Q1). In 115 children, the suspicion remained after face-to-face application of the Extended Adverse Food Reaction Questionnaire (Q2). The Q2 questionnaire was re-applied to 50 children with suspected food allergy about 3 weeks after the initial test. The questionnaire showed good temporal stability (Spearman's correlation coefficient of 0.834), and good reproducibility (only 2 of 27 items had a Kappa index <0.60). Based on the extended questionnaire (Q2), applied in person, the final prevalence of self-reported FA was 4.6% (95% CI: 3.9-5.5). The prevalence of “probable” food allergy (definition based on Q2 positive questionnaire for some food and evidence of an IgE-mediated mechanism – positive SPT and/or high serum IgE levels specific for this food) was 1.4% (95% CI: 0.9-1 9). The most implicated foods were fresh fruits, fish and egg. The first episode occurred at an earlier age, and mucocutaneous and anaphylactic reactions were more frequently associated with IgE-Mediated AFR than with non-IgE-Mediated reactions. The prevalence of possible fruit allergy (self-reported, based on Q2) was 1.69 (95% CI: 1.19-2.21) while probable fruit allergy (FrA - based on questionnaire and on in vivo and on in vitro studies with evidence of IgE-mediated mechanism) was 0.61% (95% CI: 0.30-0.92). Although strawberry, citrus and kiwi were the most frequently implicated fruits in possible allergy to fruits, in probable FrA the most implicated fruits were kiwi, peach, banana and strawberry. The first symptoms occurred at early ages (average 2.5 years). In probable FrA, 47% of children were sensitised to two or more fruits and clinical manifestations were most often immediate and monosymptomatic: urticaria / angioedema (57.1%), oral allergic syndrome (OAS) (64.3%). All fruit-allergic children were sensitised to pollens and latex sensitisation was positive in 71.6% of children with fruit allergy with known latex reactivity (latex-fruit syndrome). Being a male, having a personal history of allergic diseases, and having positive in vitro markers of atopy, and aeroallergen sensitisation were significantly more frequent in children with Probable FA (IgE-Med) than in the possible non-IgE-Mediated FA group. Residence in urban or rural areas, socioeconomic status, and food diversification did not show statistically significant differences between the two groups. Shorter breastfeeding time was more frequently associated with the non-IgE-Med group and the introduction of solid foods between 4 and 6 months was significantly less associated with the likelihood of having an IgE-Med FA compared to its introduction after 6 months. Conclusions: The developed questionnaire presented good temporal stability and reproducibility and could be used in a standardised way for AFR screening, thereby allowing a uniform approach which may facilitate future comparative studies. The prevalence of probable food allergy in Portuguese children in Cova da Beira is low, children's parents have a tendency to overestimate their complaints, and the prevalence of FA is significantly higher when based only on face-to-face questionnaires than on these questionnaires associated with in vivo and in vitro studies. The most frequently implicated foods are fresh fruits and fish. IgE-Mediated reactions are more often immediate, polysymptomatic, more severe, and begin at earlier ages than non-IgE-Mediated reactions. Although strawberry and citrus fruits are most frequently reported (possible allergy), a demonstrated IgE-mediated mechanism (probable allergy) as well as the clinical manifestation of OAS are more frequently associated with kiwi and peach. In children with probable FA, sensitisation to more than one fruit is frequent and manifestations are typically mucocutaneous, immediate and monosymptomatic. Cross reactivity with pollen and latex is quite common. The risk profile for probable, IgE-Mediated FA involved in our study, was significantly more frequently associated with being male and having personal atopy. In contrast, shorter breastfeeding time, the presence of family atopy, socioeconomic status, and place of residence were not associated with an increased risk for IgE-Mediated food allergy.
Description
Keywords
Doenças do sistema imunitário - Hipersensibilidade alimentar - Fisiopatologia Hipersensibilidade alimentar - Técnicas e procedimentos diagnósticos - Crianças 3 a 11 anos - Cova da Beira Hipersensibilidade alimentar - Inquéritos e questionários - Crianças 3 a 11 anos - Cova da Beira