Prevalence of self-reported food allergy and IgE antibodies to food allergens in Swedish and Estonian schoolchildren

Diagnostic intervention improved health-related quality of life among teenagers with food allergy

OBJECTIVES

The aim was to examine if a diagnostic intervention set up to assess current food allergy to cow's milk, hen's egg, fish, or wheat among teenagers had an impact on generic and disease specific health-related quality of life (HRQL). The study compared HRQL scoring before and two years after the intervention, and in relation to age matched controls without reported food allergy.

METHODS

The study was performed within the Obstructive Lung Disease in Northern Sweden (OLIN) studies where a cohort study on asthma and allergic diseases among 8-year-old schoolchildren was initiated in 2006. At age 12 years, the 125/2612 (5%) children who reported allergy to cow's milk, hen's egg, fish, or wheat were invited to a diagnostic intervention including clinical examination, blood tests and evaluation by a pediatric allergist. Of 94 participants, 79 completed generic and disease specific HRQL questionnaires. Additionally, a random sample of 200 (62% of invited) children without food allergy from the OLIN cohort answered the generic HRQL questionnaire. The respondents of the HRQL questionnaires were re-examined two years later and 57 teenagers with and 154 without reported allergy participated.

RESULTS

There were no significant differences in generic HRQL scores between teenagers with and without reported food allergy at study entry, or after the intervention. Among those with reported food allergy, we found a significant improvement in disease specific HRQL after the intervention (mean values: 3.41 vs 2.80, p<0.001). Teenagers with only food allergy had better disease specific HRQL compared to those with one, two or three concomitant allergic diseases, both before and after the intervention. Children with only food allergy significantly improved their HRQL after the intervention, 1.84 vs. 2.87 (p<0.001) but this association was not seen in children with one other allergic disorder (3.16 vs. 3.65, p = 0.121) or those with two or more allergic disorders (3.72 vs. 3.90, p = 0.148).

CONCLUSION

The diagnostic intervention showed a long-term improvement of disease specific HRQL but not generic HRQL.

Prevalence estimates of eight big food allergies in Europe: Updated systematic review and meta-analysis

In 2014, the European Academy of Allergy and Clinical Immunology published prevalence estimates for food allergy (FA) and food sensitization (FS) to the so-called eight big food allergens (i.e. cow's milk, egg, wheat, soy, peanut, tree nuts, fish and shellfish) in Europe for studies published between 2000 and 2012. The current work provides 10-year updated prevalence estimates for these food allergens. A protocol was registered on PROSPERO before starting the research (reference number CRD42021266657). Six databases were searched for studies published 2012-2021, added to studies published up to 2012, resulting in a total of 93 studies. Most studies were graded as at moderate risk of bias. The overall pooled estimates for all age groups of self-reported lifetime prevalence were as follows: cow's milk (5.7%, 95% confidence interval 4.4-6.9), egg (2.4%, 1.8-3.0), wheat (1.6%, 0.9-2.3), soy (0.5%, 0.3-0.7), peanut (1.5%, 1.0-2.1), tree nuts (0.9%, 0.6-1.2), fish (1.4%, 0.8-2.0) and shellfish (0.4%, 0.3-0.6). The point prevalence of food challenge-verified allergy were as follows: cow's milk (0.3%, 0.1-0.5), egg (0.8%, 0.5-1.2), wheat (0.1%, 0.01-0.2), soy (0.3%, 0.1-0.4), peanut (0.1%, 0.0-0.2), tree nuts (0.04%, 0.02-0.1), fish (0.02%, 0.0-0.1) and shellfish (0.1%, 0.0-0.2). With some exceptions, the prevalence of allergy to common foods did not substantially change during the last decade; variations by European regions were observed.

Frequency of food allergy in Europe: An updated systematic review and meta-analysis

Food allergy (FA) is increasingly reported in Europe, however, the latest prevalence estimates were based on studies published a decade ago. The present work provides the most updated estimates of the prevalence and trends of FA in Europe. Databases were searched for studies published between 2012 and 2021, added to studies published up to 2012. In total, 110 studies were included in this update. Most studies were graded as moderate risk of bias. Pooled lifetime and point prevalence of self-reported FA were 19.9% (95% CI 16.6-23.3) and 13.1% (95% CI 11.3-14.8), respectively. The point prevalence of sensitization based on specific IgE (slgE) was 16.6% (95% CI 12.3-20.8), skin prick test (SPT) 5.7% (95% CI 3.9-7.4), and positive food challenge 0.8% (95% CI 0.5-0.9). While lifetime prevalence of self-reported FA and food challenge positivity only slightly changed, the point prevalence of self-reported FA, sIgE and SPT positivity increased from previous estimates. This may reflect a real increase, increased awareness, increased number of foods assessed, or increased number of studies from countries with less data in the first review. Future studies require rigorous designs and implementation of standardized methodology in diagnosing FA, including use of double-blinded placebo-controlled food challenge to minimize potential biases.

Gut microbiota and atopic dermatitis in children: a scoping review

Background

Gut microbiota plays an important role in the development of atopic dermatitis (AD). We aimed to elucidate research trends in gut microbiota and AD in children, to provide evidence and insights to the clinical prevention and treatment of AD in children.

Methods

A scoping literature review on the studies of gut microbiota and AD were conducted. Two authors independently searched Pubmed et al. databases for studies focused on gut microbiota and AD in children up to January 15, 2022. The literatures were screened and analyzed by two reviewers.

Results

A total of 44 reports were finally included and analyzed. Current researches have indicated that abnormal human microecology is closely associated with AD, and the disturbance of intestinal microbiota plays an important role in the occurrence and development of AD. Probiotics can correct the microbiota disorder, have the functions of regulating immunity, antioxidant, and help to restore the microecological homeostasis. However, there is still a lack of high-quality research reports on the efficacy and safety of probiotics in the prevention and treatment of AD in children.

Conclusions

The changes of gut microbiota are essential to the development of AD in children, which may be an effective target for the prevention and treatment of AD. Future studies with larger sample size and rigorous design are needed to elucidate the effects and safety of probiotics in AD.

Late introduction of solids into infants' diets may increase the risk of food allergy development

Background

This study investigated risk factors associated with food allergy or food intolerance among school children in two Swedish towns.

Methods

Questionnaires were used to collect data on self-reported food allergy or intolerance (SRFA) in children aged 7–8 years from Mölndal in southwestern Sweden and Kiruna in northern Sweden. It included questions about specific food allergy or intolerance to cows’ milk, hens’ eggs, fish, peanuts, tree nuts, and cereals and also age of onset, type of symptoms and age of cessation. Information was also gathered on family allergy history, dietary habits, and certain lifestyle aspects.

Results

Of 1838 questionnaires distributed, 1029 were returned: 717/1354 (53%) from Mölndal and 312/484 (64%) from Kiruna. The cumulative incidence of SRFA was 19.6% with a significantly higher cumulative incidence in Kiruna (28.5%) than in Mölndal (15.7%), P < .001. Solids were introduced at a later age in Kiruna. Introduction of solids into a child’s diet from the age of 7 months or later, and maternal history of allergic disease, were both risk factors associated with a higher risk of food allergy or intolerance.

Conclusion

Late introduction of solids into an infant’s diet may be one risk factor for developing food allergy or intolerance. Later introduction of solids in Kiruna may be one explanation for the higher cumulative incidence of SRFA in that region.

Immunoglobulin E-Mediated Food Allergies Differ in East Mediterranean Children Aged 0-2 Years

OBJECTIVE

Precise diagnosis of allergy requires knowledge of the population's food allergy (FA) spectrum and predictors.

METHODS

Medical charts of Turkish children aged 0-2 years with FA and/or atopic dermatitis (AD) were reviewed.

RESULTS

A total of 1,389 patients, 912 with FA and 1,140 with AD, were included. In the FA group, the most frequently diagnosed FAs were egg white (75.9%), cow's milk (55.7%), tree nuts (31.5%) and sesame (20.6%). The detection of FA in 99% of children with any kind of FA necessitate testing with egg white, cow's milk, hazelnut, sesame, walnut, cashew, and pistachio. In the FA group, 72.7 and 56.8% had AD and multiple FA respectively. Multiple FA (56.8 vs. 49.8%) and hen's egg allergy (85.5 vs. 50.2%, p < 0.005) were more common and cow's milk allergy (51.4 vs. 67.1%, p < 0.005) less common in the AD subgroup of the FA group than in the non-AD subgroup. Multiple FA likelihood increases parallel to the severity of AD (p < 0.05). In the AD group, 58.2% had an immunoglobulin E-mediated FA. The risk of concomitant FA increased as the age at symptom onset of AD decreased (OR 0.800 [95% CI 0.731-0.875]; p < 0.001) and the severity of AD increased (OR 2.350 [95% CI 1.898-2.911]; p < 0.001).

CONCLUSION

Although severe and early-onset AD is a predictor of the presence and magnitude of FA in infancy, the spectrum of FA is a reflection of cultural characteristics. The clinical presentations of both AD and FA may in fact be an expression of the extent of the immune dysregulation underlying atopy and allergy.

Development of a tool for screening adverse food reactions and food allergy in Portuguese children

INTRODUCTION AND OBJECTIVES

A standardised questionnaire may be an excellent tool for epidemiological studies aiming at screening children with suspected food allergies. Thus, the aim of the present study was to develop a screening questionnaire for assessing children with suspected food allergy and to analyse its reproducibility.

MATERIALS AND METHODS

A questionnaire of adverse food reactions was developed by literary review of similar questionnaires validated in other countries as well as less well defined, non-validated Portuguese questionnaires. Peer review of the questionnaire by a panel of specialists and subsequent exploratory analysis was carried out by applying the questionnaire in children with confirmed food allergy. Test-retest analysis was performed by giving a face-to-face questionnaire to 159 children with suspected adverse food reactions, aged between three and 11 years. Temporal stability using Spearman Rho correlation test and reproducibility was studied using Cohen's Kappa index.

RESULTS

115 children confirmed adverse food reactions that occurred with one or more foods. Retest was given about three weeks after the test, to 50 of these children who were randomly selected. The questionnaire showed good temporal stability (Spearman correlation coefficient of 0.834), and good reproducibility (only two of the 27 items had a Kappa index <0.60).

CONCLUSIONS

This questionnaire showed good temporal stability and reproducibility. Its validation for screening children with suspected food allergy will allow a standardised approach to diagnosis and comparison of results obtained in different centres.

Medical certification reduces the number of children requiring allergen elimination diets for school lunches

Background

Following the increase in the number of children with food allergies, support systems are now required for school lunches, but a large-scale factual investigation has not been carried out.

Objective

We evaluated the features of elimination diet due to food allergy and the support system in kindergartens and schools.

Methods

A prefecture-based questionnaire survey regarding measures for food allergies in school lunches of all kindergartens, public elementary schools, and public junior high schools (631 facilities) was conducted in Oita Prefecture, Japan.

Results

The recovery rate of the questionnaire was 99.5%, which included 106,008 students in total. A total of 1,562 children (1.5%) required elimination diets. The rate of children on elimination diets in kindergartens and elementary/junior high schools that required medical certification by a physician was 1.2% (324 among 27,761 children), which was significantly lower than the 1.8% of children (1,227 among 68,576 students) on elimination diets at the request of guardians without the need for medical certification (p < 0.0001). A total of 43.9% of the kindergartens and schools said that they would contact guardians if symptoms were observed after accidental ingestion, while a low 8.1% stated that they provided support to children themselves, including the administration of adrenaline auto-injectors.

Conclusion

Medical certification reduces the number of children requiring elimination diets, but it has not been adequately implemented. Furthermore, waiting to contact guardians after symptoms are observed may lead to the delayed treatment of anaphylaxis. Cooperation between physicians and teachers is desired to avoid the overdiagnosis and undertreatment of children with food allergies.

High incidence and remission of reported food hypersensitivity in Swedish children followed from 8 to 12 years of age - a population based cohort study

BACKGROUND

Few population-based cohort studies have examined reported food hypersensitivity longitudinally. We investigated prevalence, incidence and remission of perceived food hypersensitivity among schoolchildren from 8 to 12 years of age, and risk factors associated with incidence and remission.

METHODS

A population-based cohort including all 7-8 year-old children in three Swedish towns was recruited in 2006. A total of 2,585 (96% of invited) children participated in a parental questionnaire. The children in two of the towns, n = 1,700 (90% of invited) also participated in skin-prick-testing with airborne allergens. The cohort was followed using the same methods at 11-12 years of age. At study follow up, specific IgE to foods was analyzed in a randomized subset of children (n = 652).

RESULTS

The prevalence of perceived food hypersensitivity increased from 21% at 8 years to 26% at 12 years of age. During this four-year-period, the cumulative incidence of food hypersensitivity was high (15%), as was remission (33%). This pattern was particularly evident for hypersensitivity to cow´s milk, while the incidence of hypersensitivity to other foods was lower. Female sex, allergic heredity, current rhinitis and allergic sensitization were associated with the incidence of food hypersensitivity and allergic sensitization was negatively associated with remission. Risk-factor-patterns for both incidence and remission were different for hypersensitivity to milk compared with hypersensitivity to other foods. Generally, the agreement between reported food hypersensitivity and IgE-sensitization to the implicated food was poor.

CONCLUSIONS

In this longitudinal, population-based cohort-study perceived food hypersensitivity was common among children between ages 8 and 12, often transient and not well correlated with food-specific IgE. While these findings suggest an overestimated prevalence of food hypersensitivity, the public-health-significance remains high as they reflect the perceived reality to which the children adapt their life and food intakes.

Prevalence of common food allergies in Europe: a systematic review and meta-analysis

Allergy to cow's milk, egg, wheat, soy, peanut, tree nuts, fish, and shellfish constitutes the majority of food allergy reactions, but reliable estimates of their prevalence are lacking. This systematic review aimed to provide up-to-date estimates of their prevalence in Europe.Studies published in Europe from January 1, 2000, to September 30, 2012, were identified from searches of four electronic databases. Two independent reviewers appraised the studies and extracted the estimates of interest. Data were pooled using random-effects meta-analyses. Fifty studies were included in a narrative synthesis and 42 studies in the meta-analyses. Although there were significant heterogeneity between the studies, the overall pooled estimates for all age groups of self-reported lifetime prevalence of allergy to cow's milk, egg, wheat, soy, peanut, tree nuts, fish, and shellfish were 6.0% (95% confidence interval: 5.7-6.4), 2.5% (2.3-2.7), 3.6% (3.0-4.2), 0.4% (0.3-0.6), 1.3% (1.2-1.5), 2.2% (1.8-2.5), and 1.3% (0.9-1.7), respectively. The prevalence of food-challenge-defined allergy to cow's milk, egg, wheat, soy, peanut, tree nuts, fish, and shellfish was 0.6% (0.5-0.8), 0.2% (0.2-0.3), 0.1% (0.01-0.2), 0.3% (0.1-0.4), 0.2% (0.2-0.3), 0.5% (0.08-0.8), 0.1% (0.02-0.2), and 0.1% (0.06-0.3), respectively. Allergy to cow's milk and egg was more common among younger children, while allergy to peanut, tree nuts, fish, and shellfish was more common among the older ones. There were insufficient data to compare the estimates of soy and wheat allergy between the age groups. Allergy to most foods, except soy and peanut, appeared to be more common in Northern Europe. In summary, the lifetime self-reported prevalence of allergy to common foods in Europe ranged from 0.1 to 6.0%. The heterogeneity between studies was high, and participation rates varied across studies reaching as low as <20% in some studies. Standardizing the methods of assessment of food allergies and initiating strategies to increase participation will advance this evidence base.

The epidemiology of food allergy in Europe: a systematic review and meta-analysis

Food allergy (FA) is an important atopic disease although its precise burden is unclear. This systematic review aimed to provide recent, up-to-date data on the incidence, prevalence, time trends, and risk and prognostic factors for FA in Europe. We searched four electronic databases, covering studies published from 1 January 2000 to 30 September 2012. Two independent reviewers appraised the studies and qualified the risk of bias using the Critical Appraisal Skills Programme tool. Seventy-five eligible articles (comprising 56 primary studies) were included in a narrative synthesis, and 30 studies in a random-effects meta-analysis. Most of the studies were graded as at moderate risk of bias. The pooled lifetime and point prevalence of self-reported FA were 17.3% (95% CI: 17.0-17.6) and 5.9% (95% CI: 5.7-6.1), respectively. The point prevalence of sensitization to ≥1 food as assessed by specific IgE was 10.1% (95% CI: 9.4-10.8) and skin prick test 2.7% (95% CI: 2.4-3.0), food challenge positivity 0.9% (95% CI: 0.8-1.1). While the incidence of FA appeared stable over time, there was some evidence that the prevalence may be increasing. There were no consistent risk or prognostic factors for the development or resolution of FA identified, but sex, age, country of residence, familial atopic history, and the presence of other allergic diseases seem to be important. Food allergy is a significant clinical problem in Europe. The evidence base in this area would benefit from additional studies using standardized, rigorous methodology; data are particularly required from Eastern and Southern Europe.

A global survey of changing patterns of food allergy burden in children

While food allergies and eczema are among the most common chronic non-communicable diseases in children in many countries worldwide, quality data on the burden of these diseases is lacking, particularly in developing countries. This 2012 survey was performed to collect information on existing data on the global patterns and prevalence of food allergy by surveying all the national member societies of the World Allergy Organization, and some of their neighbouring countries. Data were collected from 89 countries, including published data, and changes in the health care burden of food allergy. More than half of the countries surveyed (52/89) did not have any data on food allergy prevalence. Only 10% (9/89) of countries had accurate food allergy prevalence data, based on oral food challenges (OFC). The remaining countries (23/89) had data largely based on parent-reporting of a food allergy diagnosis or symptoms, which is recognised to overestimate the prevalence of food allergy. Based on more accurate measures, the prevalence of clinical (OFC proven) food allergy in preschool children in developed countries is now as high as 10%. In large and rapidly emerging societies of Asia, such as China, where there are documented increases in food allergy, the prevalence of OFC-proven food allergy is now around 7% in pre-schoolers, comparable to the reported prevalence in European regions. While food allergy appears to be increasing in both developed and developing countries in the last 10-15 years, there is a lack of quality comparative data. This survey also highlights inequities in paediatric allergy services, availability of adrenaline auto-injectors and standardised National Anaphylaxis Action plans. In conclusion, there remains a need to gather more accurate data on the prevalence of food allergy in many developed and developing countries to better anticipate and address the rising community and health service burden of food allergy.

Prevalence and sensitization of atopic allergy and coeliac disease in the Northern Sweden Population Health Study

Background

Atopic allergy is effected by a number of environmental exposures, such as dry air and time spent outdoors, but there are few estimates of the prevalence in populations from sub-arctic areas.

Objective

To determine the prevalence and severity of symptoms of food, inhalation and skin-related allergens and coeliac disease (CD) in the sub-arctic region of Sweden. To study the correlation between self-reported allergy and allergy test results. To estimate the heritability of these estimates.

Study design

The study was conducted in Karesuando and Soppero in Northern Sweden as part of the Northern Sweden Population Health Study (n=1,068). We used a questionnaire for self-reported allergy and CD status and measured inhalation-related allergens using Phadiatop, food-related allergens using the F×5 assay and IgA and IgG antibodies against tissue transglutaminase (anti-tTG) to indicate prevalence of CD.

Results

The prevalence of self-reported allergy was very high, with 42.3% reporting mild to severe allergy. Inhalation-related allergy was reported in 26.7%, food-related allergy in 24.9% and skin-related allergy in 2.4% of the participants. Of inhalation-related allergy, 11.0% reported reactions against fur and 14.6% against pollen/grass. Among food-related reactions, 14.9% reported milk (protein and lactose) as the cause. The IgE measurements showed that 18.4% had elevated values for inhalation allergens and 11.7% for food allergens. Self-reported allergies and symptoms were positively correlated (p<0.01) with age- and sex-corrected inhalation allergens. Allergy prevalence was inversely correlated with age and number of hours spent outdoors. High levels of IgA and IgG anti-tTG antibodies, CD-related allergens, were found in 1.4 and 0.6% of participants, respectively. All allergens were found to be significantly (p<3 e–10) heritable, with estimated heritabilities ranging from 0.34 (F×5) to 0.65 (IgA).

Conclusions

Self-reported allergy correlated well with the antibody measurements. The prevalence of allergy was highest in the young and those working inside. Heritability of atopy and sensitization was high. The prevalence of CD-related autoantibodies was high and did not coincide with the self-reported allergy.

Prevalence of confirmed IgE-mediated food allergy among adolescents in Turkey

BACKGROUND

Although food allergy is an important health problem in Western countries, the prevalence varies among geographic regions. There is limited data on the prevalence of food allergy especially for adolescent age group, and the data from Turkey and Mediterranean region are even scarce.

METHODS

The study is a cross-sectional survey including a questionnaire followed by phone survey with families that have reported food allergy and clinical evaluation of children having a history compatible with food allergy after phone survey. The sample number of students has been calculated 9096 of a total of 210.000 students at the second stage (6th, 7th, and 8th grades) of state elementary schools in the metropolitan counties of Ankara province with the assumption of food allergy prevalence (P) = 1% and a δ value = 0.2 (α < 0.05, β = 0.8).

RESULTS

Of 11,233 questionnaires distributed at 34 schools, 10,096 (89.4%) have been returned. The number of reported food allergy was 1139 (11.2%), and it was reduced to 133 (1.3%) after phone survey. After clinical evaluation by skin test, specific IgE and double-blind placebo-controlled food challenge (DBPCFC), proven IgE-mediated food allergy was determined in 15 (0.15%) children. The foods most commonly resulting food allergy were peanut 0.05% and treenuts 0.05%.

CONCLUSION

The prevalence of food allergy among adolescent age group has been confirmed to be comparatively low in Turkey. Peanuts and treenuts were determined to be the most common causes of IgE-mediated food allergy.

Prevalence of food allergy in Taiwan: a questionnaire-based survey

AIM

Food allergy is common in children and adults, and could be potentially fatal in minor groups. It is important for physicians to identify the prevalence of food allergies and to recognise common food allergens to make precise diagnosis and choose correct therapeutic approaches.

METHODS

We used a nationwide, cross-sectional, random questionnaire-based survey to estimate the self-reported and expert-screened prevalence of food allergies and to identify the common food allergens in Taiwan. In this study, the perceptional diagnosis of food allergies was screened by physicians according to descriptions of convincing symptoms and medical recordings; in the meantime, non-allergic adverse reactions to foods, including food intolerance or food avoidance, were clarified.

RESULTS

A total of 30 018 individuals who met the inclusion criteria was evaluated, and 6.95% of them were diagnosed as victims of food allergies. The prevalence was 3.44% in children under 3 years of age, 7.65% in children aged 4-18 years and 6.40% in adults respectively. About 77.33% of the food allergy population had experienced recurrent allergic attacks. Systemic reactions happened about 4.89% in food allergies group. The most commonly reported food allergen in Taiwan is seafood, including shrimp, crab, fish and mollusc. In addition, mango, milk, peanuts and eggs were also important food allergens in the general population; while milk, shellfish, peanuts and eggs were common in children.

CONCLUSIONS

Less than 10% of the Taiwan population suffers from food allergy with different allergic symptoms to variable food allergens in different age groups.

Experiences of double-blind, placebo-controlled food challenges (DBPCFC): a qualitative analysis of mothers' experiences

Fear and anxiety are recurring problems for parents of food-allergic children. However, no study has described parents' experiences of introducing food to their children after double-blind provocation. Therefore the aim of this study was to investigate mothers' experiences during their child's negative Double-Blind, Placebo-Controlled Food Challenge (DBPCFC) and the following reintroduction of food. Eight mothers were interviewed and a qualitative content analysis displayed two themes and six subthemes. The first theme, 'living with fear of the unknown', included the subthemes of 'fear of losing control', 'having faith even though fear prevails', 'reintroducing despite fear' and 'fear of causing harm'. In the second theme, the mothers described the challenging process of 're-evaluating earlier experiences' through the sub-themes of 'daring to take new challenges' and 'refraining from new challenges'. Our study indicates that the maternal perspective--not only the professional perspective--needs to be taken into account if mothers are to succeed in the challenging process of reintroducing foods.

Risk factors of adverse reactions to food in German adults

BACKGROUND

Allergic diseases have been increasing during the last decades. Previous studies suggest an impact of a variety of risk factors on the prevalence of food hypersensitivity.

OBJECTIVE

Data of a cross-sectional population-based survey were analysed to study the prevalence of food hypersensitivity in females and males adjusted for age and education.

METHODS

A population aged 18-79 years from a representative, randomly sampled survey studying 13,300 inhabitants from Germany (Berlin) was analysed. The Berlin study data were weighted with regard to age, sex, education and allergic diseases such as atopic dermatitis, rhinoconjunctivitis and asthma. Instruments for evaluation included mailed questionnaires, structured telephone interviews, physical examinations, detection of total IgE, skin prick tests and double-blind, placebo-controlled food challenge tests (DBPCFC).

RESULTS

Three thousand two hundred and twenty-seven questionnaires were evaluated. The data show a significantly higher risk of self-reported symptoms in the female group, among persons with higher education and in the age group of 18-39 years. Among individuals with clinical symptoms, females were at lower risk of having positive skin prick tests [aOR=0.32; 95% CI (0.21-0.50); P<0.01] and having a raised total IgE [aOR=0.37; 95% CI (0.24-0.56); P<0.01], but showed a higher risk of non-IgE and IgE-mediated food hypersensitivity [aOR=2.27; 95% CI (1.31-3.93); P<0.01] than males. Based on weighted data, the point prevalence of adverse reactions to food resulted in 3.3% [95% CI (2.4-4.5%)] for women and 1.8% [95% CI (1.2-2.7%)] for men after DBPCFC.

CONCLUSION

From a general population survey conducted in Germany, we determined that women are at greater risk of having symptoms of food allergy and also at greater risk of having DBPCFC-confirmed symptomatic food allergy. However, among individuals with symptoms of food allergy, men have a higher prevalence of food-specific IgE-sensitization and of raised total IgE than women.

Does hapten exposure predispose to atopic disease? The hapten-atopy hypothesis

Contact allergy data indicates that atopics have heightened oral tolerance to haptens (chemical allergens). We speculate here, that artificially increased oral exposure to chemicals compete with dietary proteins for the development of oral tolerance, predisposing to the acquisition of food protein allergy and representing one driver for the increasing prevalence of protein allergy and/or atopy. Hapten exposure via other surfaces such as the skin and airways might also be important in promoting atopic disease. Consistent with this hypothesis it is notable that over 40 years, with the huge increase in atopic disease, there has also been an increase in dietary hapten exposure through processed food, formula milk and oral antibiotic and drug use.

Review and discussion of the body's normal microorganisms

Nurses need to be constantly vigilant in their hygiene practices, yet not ignore the role of normal microbes in the maintenance of health: we have more microorganisms living on us and in us than any other type of cell, and they have a role in preventing colonisation by harmful pathogens, and also in regulating the immune system. This article reviews the types of microorganisms normally found in and on individuals, and how these can contribute to health.

Health-related quality of life in food hypersensitive schoolchildren and their families: parents' perceptions

BACKGROUND

About 20% of schoolchildren and adolescents in Sweden suffer from perceived food hypersensitivity (e.g. allergy or intolerance). Our knowledge of how child food hypersensitivity affects parents HRQL and what aspects of the hypersensitivity condition relate to HRQL deterioration in the family is limited. Thus the aim of this study was to investigate the parent-reported HRQL in families with a schoolchild considered to be food hypersensitive. The allergy-associated parameters we operated with were number of offending food items, adverse food reactions, additional hypersensitivity, allergic diseases and additional family members with food hypersensitivity. These parameters, along with age and gender were assessed in relation to child, parent and family HRQL.

METHODS

In May 2004, a postal questionnaire was distributed to parents of 220 schoolchildren with parent-reported food hypersensitivity (response rate 74%). Two questionnaires were used: CHQ-PF28 and a study-specific questionnaire including questions on allergy-associated parameters. In order to find factors that predict impact on HRQL, stepwise multiple linear regression analyses were carried out.

RESULTS

An important predictor of low HRQL was allergic disease (i.e. asthma, eczema, rhino conjunctivitis) in addition to food hypersensitivity. The higher the number of allergic diseases, the lower the physical HRQL for the child, the lower the parental HRQL and the more disruption in family activities. Male gender predicted lower physical HRQL than female gender. If the child had sibling(s) with food hypersensitivity this predicted lower psychosocial HRQL for the child and lower parental HRQL. Food-induced gastro-intestinal symptoms predicted lower parental HRQL while food-induced breathing difficulties predicted higher psychosocial HRQL for the child and enhanced HRQL with regards to the family's ability to get along.

CONCLUSION

The variance in the child's physical HRQL was to a considerable extent explained by the presence of allergic disease. However, food hypersensitivity by itself was associated with deterioration of child's psychosocial HRQL, regardless of additional allergic disease. The results suggest that it is rather the risk of food reactions and measures to avoid them that are associated with lower HRQL than the clinical reactivity induced by food intake. Therefore, food hypersensitivity must be considered to have a strong psychosocial impact.

Prevalence of sensitization reported and objectively assessed food hypersensitivity amongst six-year-old children: a population-based study

There is a paucity of information on food hypersensitivity (FHS) in young children and there are even fewer population-based studies in this area. The aim of the study was to determine the prevalence of parentally reported FHS, and objectively diagnosed FHS amongst six-year-old children and to establish the rates of sensitization to key allergens. This population-based cohort study recruited 798 6-year-olds resident on the Isle of Wight (UK). Sensitization rates, reported rates of FHS and objectively assessed FHS was established using food challenges. A total of 94 (11.8%) 6 yr olds reported a problem with a food or food ingredient. The rate of sensitization to the pre-defined panel of food allergens was 25/700 (3.6%). Based on open food challenge and/or suggestive history and skin tests, the prevalence of FHS was 2.5% (95% CI 1.5-3.8). Based on double-blind challenges, a clinical diagnosis or suggestive history and positive skin tests, the prevalence was 1.6% (95% CI 0.9-2.7). The rates of perception of FHS are higher than the prevalence of sensitization to main food allergens and the prevalence of FHS based on food challenges. Milk, peanut and wheat were the key food allergens amongst those with positive challenges.

Risk assessment in elderly for sensitization to food and respiratory allergens

For elderly people, epidemiological data are rare for respiratory allergies and completely missing for food allergies. The aim of this study was to examine the prevalence and risk factors for sensitizations in 109 people with a mean age of 77 years, who are living in a geriatric nursing home. The cross-sectional study included a detailed interview, skin prick tests, and serum tests for specific and total IgE, IFN-gamma, and ST2, a marker for Th2-lymphocyte activity. Almost all study subjects (n=101) suffered from co-morbidity, 14 from type I allergy, 25 from gastrointestinal disorders treated with anti-ulcer drugs, 25 were chronic alcoholics and 21 were smokers. The total IgE levels were significantly higher in men (P=0.025), and not affected by smoking or alcohol consumption. Skin prick tests were positive in 41.7% of tested patients. Specific IgE to respiratory allergens was found in 40.4% of all patients and was elevated in men (P=0.013), with a significant correlation to smoking (P=0.029). Specific IgE to food allergens was detected in 24.8%, apparently without connection to the investigated risk factors. However, positive skin prick tests with food allergens could be correlated with chronic alcohol consumption (P=0.036). The intake of anti-ulcer medication was significantly correlated with elevated ST2 levels as an indirect readout for Th2-cell activity (P<0.001). The risk factors for sensitization in elderly to respiratory allergens were chronic damage of respiratory epithelia due to smoking, and for sensitization to food allergens chronic alcohol consumption.