Food hypersensitivity is common in Swedish schoolchildren, especially oral reactions to fruit and gastrointestinal reactions to milk

Prevalence of tree nut allergy in Europe: A systematic review and meta-analysis

In 2014, the European Academy of Allergy and Clinical Immunology (EAACI) published the first systematic review that summarized the prevalence of food allergy (FA) and food sensitization in Europe for studies published 2000-2012. However, only summary estimates for tree nut allergy (TNA) were feasible in that work. In the current update of that systematic review, we summarized the prevalence of tree nut allergy/sensitization to individual tree nuts. Six databases were searched for relevant papers published 2012-2021 and 17 eligible studies were added to the 15 studies already identified between 2000 and 2012, giving a total of 32 studies. Of the investigated tree nuts, meta-analysis was possible for hazelnut, walnut, almond, and in few cases, for cashew, and Brazil nut. The lifetime self-reported prevalence was 0.8% (95% CI 0.5-1.1) for hazelnut and 0.4% (0.2-0.9) for walnut. The point self-reported prevalence was 4.0% (2.9-5.2) for hazelnut, 3.4% (2.0-4.9) for Brazil nut, 2.0% (1.1-2.9) for almond, and 1.8% (1.1-2.5) for walnut. Point prevalence of food challenge-confirmed TNA was 0.04% (0.0-0.1) for hazelnut and 0.02% (0.01-0.1) for walnut. Due to paucity of data, we could not identify any meaningful and consistent differences across age groups and European regions.

Glutamine and lysine as common residues from epitopes on α-lactalbumin and β-lactoglobulin from cow milk identified by phage display technology

Cow milk is an important source of food protein for children; however, it could lead to allergy, especially for infants. α-Lactalbumin (α-LA) and β-lactoglobulin (β-LG) from whey protein make up a relatively high proportion of milk proteins and have received widespread attention as major allergens in milk. However, few studies have identified the epitopes of both proteins simultaneously. In this study, ImmunoCAP and indirect ELISA were first used for detection of sIgE to screen sera from allergic patients with high binding capacity for α-LA and β-LG. Subsequently, the mimotopes was biopanned by phage display technology and bioinformatics and 17 mimic peptide sequences were obtained. Aligned with the sequences of α-LA or β-LG, we identified one linear epitope on α-LA at AA 11-26 and 5 linear epitopes on β-LG at AA 9-29, AA 45-57, AA 77-80, AA 98-101, and AA 121-135, respectively. Meanwhile, the 8 conformational epitopes and their distributions of α-LA and β-LG were located using the Pepitope Server. Finally, glutamine and lysine were determined as common AA residues for the conformational epitopes both on α-LA and β-LG. Moreover, we found the addition of mouse anti-human IgE during the biopanning process did not significantly affect the identification of the epitopes.

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.

A Meta-Analysis of the Prevalence of Wheat Allergy Worldwide

Wheat allergy is a primary disease of food allergy, and its global prevalence is unclear. This study aimed to characterize the latest worldwide prevalence of wheat allergy based on five different diagnostic methods. Study searches were conducted in Web of Science, PubMed, Ovid LWW, and Cochrane database, with a time limit of 1 January 2007 to 1 September 2022. The review and screening of the articles was undertaken by two independent reviewers. The statistical analysis was conducted by R. A total of 56 articles were finally included. The prevalence of wheat allergy was 0.63% (95% CI: 0.43-0.87%) for self-reported, 0.70% (95% CI: 0.18-1.22%) for self-reported physician-diagnosed, 0.22% (95%CI: 0.07-0.65%) for skin prick test positive, 0.97% (95% CI: 0.43-2.20%) for specific immunoglobulin E positive, and 0.04% (95% CI: 0-0.16%) for food challenge. However, food challenge can be largely subjective, and the results were only based two countries, so the prevalence of wheat allergy confirmed by food challenge may be not entirely trustworthy. In conclusion, investigating the prevalence of wheat allergy in the real world as accurately as possible will contribute to the prevention, management, and risk assessment of wheat allergy.

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.

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.

Fish consumption associated with reduction of fish allergy

Purpose

This paper aims to examine the differences in the self-reported allergies to food, especially fish and shellfish, between children and adults, and to study the association between fish consumption and self-reported fish and shellfish allergy (FSA) according to age.

Design/methodology/approach

This study is based on a survey conducted between April 2014 and December 2016 where children and adults were recruited from the general population of the Fez-Meknes region. The total studied population was 4,046 people.

Findings

The results show that the self-reported food allergy (FA) of the general population was more frequent among children (28.2 per cent) than adults (16.8 per cent), in which eggs, fish/shellfish, milk and cereals were the most common food cited. With regard to the self-reported FSA, the authors found a prevalence of 9.5 per cent in both children and adults, whereas fish species allergies were more frequent among adults than children. The most common clinical manifestations observed in this population were cutaneous reactions. The study of the association between fish consumption and FSA shows that people who consumed fish had a lower rate of FSA, especially in adults (p < 0.001).

Originality/value

The self-reported FA of the general population was more pronounced in children than adults. Regarding the self-reported FSA, the authors have shown a prevalence of 9.5 per cent in both children and adults, indicating an important sensitivity of their population to fish and shellfish. The authors have shown that consumption of fish was associated significantly with a lower rate of FSA, especially in adults.

Health Related Quality of Life among schoolchildren aged 12-13 years in relation to food hypersensitivity phenotypes: a population-based study

Background

While Health Related Quality of Life has been investigated among children with IgE-mediated food allergy, less is known about quality of life among children with other types of hypersensitivity to food. The aim of this study was to investigate Health Related Quality of Life (HRQL) in children with and without food hypersensitivity. Further, we compared HRQL between children with different phenotypes of food hypersensitivity.

Methods

In a large population-based cohort of schoolchildren in Northern Sweden, the parents of 2612 (96% of invited) completed a questionnaire. All 125 (5%) children who reported complete elimination of milk, egg, fish or wheat due to food hypersensitivity were invited to a clinical examination and 94 children participated. Of these, 75 children also completed a generic (KIDSCREEN-52) and a disease-specific HRQL questionnaire (FAQLQ-TF). Thereafter, these children were categorised into the different phenotypes: current food allergy, outgrown food allergy, and lactose intolerance. Additionally, 209 children with unrestricted diets answered the generic questionnaire.

Results

The median score of all KIDSCREEN-52 domains were above the population norm of 50 both in children with and without food hypersensitivity. No significant differences in distribution in generic or disease-specific HRQL were found between children with or without food hypersensitivity. There were no significant differences in HRQL between children with different phenotypes of food hypersensitivity. However, children with current food allergy tended to have the lowest HRQL. Further, poor HRQL defined as ≥75th percentile for the disease specific score was significantly more common in the current food allergy phenotype in the domain Emotional impact and the total FAQLQ, compared to the other phenotypes.

Conclusions

In this population-based study, 12–13 year old children reported good HRQL regardless of having food hypersensitivity or not. However, the children with the current phenotype reported lower HRQL than the other phenotypes.

Electronic supplementary material

The online version of this article (doi:10.1186/s13601-017-0156-9) contains supplementary material, which is available to authorized users.

Is kiwifruit allergy a matter in kiwifruit-cultivating regions? A population-based study

BACKGROUND

Although kiwifruit is known as a common cause of food allergy, population-based studies concerning the prevalence of kiwifruit allergy do not exist. We aimed to determine the prevalence and clinical characteristics of IgE-mediated kiwifruit allergy in 6-18-year-old urban schoolchildren in a region where kiwifruit is widely cultivated.

METHODS

This cross-sectional study recruited 20,800 of the randomly selected 6-18-year-old urban schoolchildren from the Rize city in the eastern Black Sea region of Turkey during 2013. Following a self-administered questionnaire completed by the parents and the child, consenting children were invited for skin prick tests (SPTs) and oral food challenges (OFCs). Children with suspected IgE-mediated kiwifruit were skin prick tested with kiwifruit (commercial allergen and prick-to-prick test with fresh kiwifruit) and a pre-defined panel of allergens (banana, avocado, latex, sesame seed, birch, timothy, hazel, cat, Dermatophagoides pteronyssinus, and Dermatophagoides farinae). All children with a positive SPT to kiwifruit were invited for an open OFC. The prevalence of IgE-mediated kiwifruit allergy was established using open OFCs.

RESULTS

The response rate to the questionnaire was 75.9% (15783/20800). The estimated prevalence of parental-perceived IgE-mediated kiwifruit allergy was 0.5% (72/15783) (95% CI, 0.39-0.61%). Of the 72 children, 52 (72.2%) were skin tested, and 17 (32.7%) were found to be positive to kiwifruit with both commercial extract and kiwifruit. The most frequently reported symptoms in kiwifruit SPT-positive children were cutaneous (n = 10, 58.8%) followed by gastrointestinal (n = 6, 35.3%) and bronchial (n = 4, 23.5%). Oral symptoms were reported in six (35.3%) children. All children who were kiwifruit positive by SPT were found positive during the oral challenge. The confirmed prevalence of IgE-mediated kiwifruit allergy by means of open OFC in 6-18-year-old urban schoolchildren living in Rize city was 0.10% (95% CI, 0.06-0.16).

CONCLUSION

Prevalence of parental-perceived and clinically confirmed kiwifruit allergy is not consistent. In contrast to expectations, kiwifruit allergy prevalence was low in a city where it is cultivated and highly consumed.

Reintroduction failure is common among adolescents after double-blind placebo-controlled food challenges

AIM

There has been a lack of research on adolescents who undergo double-blind placebo-controlled food challenges. The aim of this study was to investigate food allergic adolescents' experiences and consequences of double-blind placebo-controlled food challenges.

METHODS

This qualitative, descriptive interview study included 17 adolescents aged 14-15 years with total elimination of cows' milk, hens' eggs or cod due to food allergies. The participants, who were initially identified from a large population-based cohort study, were interviewed 18 months after completing their challenges.

RESULTS

The double-blind placebo-controlled food challenge proved to be a complex experience for the adolescents, involving fear of potential reactions and the hope that the food could be reintroduced. Experiences during the challenge were described in three themes: facing fears in a secure environment, being hesitant but curious about unknown tastes and waiting for unknown food reactions. Experiences after the challenge were described in two themes: gaining control and freedom and continuing old habits. A negative challenge was not consistently associated with the reintroduction of the challenged food.

CONCLUSION

This study highlighted the importance of considering the adolescents' expectations and experiences of the challenge and the reintroduction process to ensure desirable changes in their dietary habits. Follow-ups should be performed regardless of the outcome of challenges.

Allergic rhinoconjunctivitis continued to increase in Swedish children up to 2007, but asthma and eczema levelled off from 1991

AIM

This study investigated whether allergies among schoolchildren increased in Sweden between 1979 and 2007 and whether the geographical differences observed in previous studies remained.

METHODS

We collected questionnaire data on asthma, allergic rhinoconjunctivitis (ARC) and eczema in children aged seven to eight years from Mölndal, Gothenburg, in south-western Sweden and Kiruna in northern Sweden in 1979 (n = 4682), 1991 (n = 2481) and 2007 (n = 1029). The same regions and questions were used in all three studies, and extra questions on food allergy or intolerance were added in 2007.

RESULTS

In 1979, 1991 and 2007, the total prevalence of asthma was 2.5%, 5.7% and 7.1%, ARC was 5.5%, 8.1% and 11.1% and eczema was 7.1%, 18.3% and 19.7%, respectively. Asthma prevalence remained higher in Kiruna, but no significant regional differences were seen for ARC and eczema. Almost 20% reported a history of food allergy or intolerance, with a higher prevalence in Kiruna. The allergy risk was reduced if both parents were born outside Sweden.

CONCLUSION

The prevalence of ARC continued to increase between 1991 and 2007, but increases in asthma and eczema started to level off in 1991. Some geographical differences remained, but total allergy rates were similar in Kiruna and Mölndal in 2007.

Food-Related Symptoms and Food Allergy in Swedish Children from Early Life to Adolescence

Background

Risk factors for persistence of food-related symptoms (FRS) and food allergy (FA) from early life to adolescence are incompletely understood. The aim of this study was to identify risk factors for FRS and FA in adolescence amongst children with FRS or FA in the first four years of life (early life).

Methods

In children enrolled in a Swedish birth cohort and followed to 16 years (n = 2572), we defined children with early life FRS in the absence of FA, and FA. Corresponding phenotypes were defined at 16 years. Associations between potential risk factors at 4 years and FRS and FA at 16 years were investigated using logistic regression.

Results

Early life FRS and FA prevalences were 12.2% and 6.8%, respectively. Amongst children with early life FRS, 35.7% had FRS or FA at 16 years, whereas 74.3% of the children with early life FA had FA at 16 years. For each of the early life phenotypes, parental allergy, early life allergic multimorbidity, early life reactions to peanuts/tree nuts and IgE reactivity at 4 years were statistically significantly associated with FRS or FA at 16 years. In contrast, male sex was associated with an increased risk of FA at 16 years among children with early life FA only.

Conclusions

In early life, food-related symptoms are twice as common as food allergy. Unlike food allergy, food-related symptoms often remit by adolescence. Yet, these phenotypes have many common risk factors for persistence to adolescence.

Burden of allergy diets in Finnish day care reduced by change in practices

BACKGROUND

Nonessential allergy diets in children with mild symptoms may harm the development of immunological tolerance and impose a burden on families and day care. We aimed to reduce the high prevalence of allergy diets in day care by reforming the practices for inquiring about need of special diets from parents.

METHODS

We developed a new special diet form and an information leaflet based on the new allergy guidelines. The new form was implemented into 40 Finnish day care centres in the capital region in 2013-2015. The questionnaires on practices concerning special diets in day care centres and allergy knowledge were collected from the personnel.

RESULTS

After 2 years, the new special diet form was used by 64% of families with food-allergic children, and the prevalence of allergy diets in day care centres decreased by 43% to 4.3% (IQ range 3.05-5.96). A significant decrease was found in the prevalence of all basic (milk, grains, egg) and most other allergy diets (P for trend < 0.01). The new practice was well accepted by day care and kitchen personnel. Lack of updated allergy knowledge was noted among day care personnel.

CONCLUSIONS

The burden of allergy diets in day care settings could be decreased by simple pragmatic changes based on current allergy guidelines. Old allergy attitudes persisted among day care personnel, indicating the need for continuous education.

Self-reported prevalence and risk factors associated with food hypersensitivity in Mexican young adults

BACKGROUND

Food hypersensitivity (FH) is defined as any unfavorable reaction after the ingestion, contact, or inhalation of a food. Few FH prevalence studies have been performed in the Mexican adult population.

OBJECTIVE

To determine the prevalence of self-reported FH and probable food allergy (FA) among a sample of Mexican young adults and to determine the most commonly involved foods, associated symptoms, and risk factors.

METHODS

We designed an observational, cross-sectional study in which 1,253 young adults (aged 18-25 years) born in the State of Mexico answered a questionnaire concerning FH. We obtained information on personal and familial histories of allergic diseases, the involved foods, and the subsequent adverse reactions to their consumption.

RESULTS

The prevalence of FH was 30.1% and was significantly higher in women than in men (P < .001). The prevalence of probable FA was 5.9% and was also higher in women (P = .02). Gastrointestinal symptoms were reported in 83.1% of FH cases, whereas cutaneous symptoms and oral allergy syndrome were reported in FA cases. The food groups most associated with FH were dairy products (13.2%), vegetables (10.0%), and fruits (8.0%). The food groups most associated with FA were fruits (3.0%) and seafood (1.8%). Female sex, personal history of allergic diseases, maternal history of atopic dermatitis, and parental history of urticaria were significantly associated (P < .05) with the presence of FH.

CONCLUSION

FH in young adults might be more common than previously thought, especially in women. However, further studies are needed to confirm this situation in the Mexican population.

Milk allergy is a minor cause of milk avoidance due to perceived hypersensitivity among schoolchildren in Northern Sweden

AIM

We investigated phenotypes of milk hypersensitivity among schoolchildren aged 11-12 in Northern Sweden.

METHODS

In a population-based cohort, 1824 (98%) children aged 11-12 participated in a questionnaire survey, skin prick testing, interviews on food hypersensitivity and assessment of body mass index (BMI). Of the 265 children reporting milk hypersensitivity, milk avoidance and no coeliac disease, 236 (89%) participated in a structured interview and blood samples for analyses of milk-specific Immunoglobulin E. The children were then categorised into milk hypersensitivity phenotypes according to preset criteria.

RESULTS

In all, 14.5% reported milk hypersensitivity. Of these, 3% were categorised as current milk allergy, 23% as outgrown milk allergy, 40% as probable lactose intolerance and 11% as nondefinable. Furthermore, 23% had discontinued their elimination diet. Milk allergy was associated with other atopic disorders and lower BMI, with an odds ratio of 0.82 and 95% confidence interval of 0.80-0.98. Only 2% had previously undergone an oral challenge.

CONCLUSION

The most common symptom phenotypes among Swedish children aged 11-12 with self-reported milk hypersensitivity and milk avoidance were probable intolerance and outgrown milk allergy, while current milk allergy was uncommon. Children with milk allergy had a lower BMI and most lacked a challenge-proven diagnosis.

Self-reported adverse reactions and IgE sensitization to common foods in adults with asthma

Background

There is very few data available on the prevalence of food hypersensitivity among adults with asthma. The aim of this study was to explore the prevalence of self-reported adverse reactions and IgE sensitization to the different foods and to determine the spectrum and the prevalence of food-related gastrointestinal symptoms in adults with and with no asthma.

Methods

A cross sectional study based on interviews and questionnaire responses from 1527 subjects, aged 18–75 years of age, from Västra Götaland in Sweden, as part of the larger West Sweden Asthma Study. IgE analyses were performed in sera from all subjects.

Results

Fifty three percent of adults with asthma reported adverse reactions to foods compared to 30 % of non-asthmatics. Most asthmatics reported symptoms from eating hazelnut, followed by other nuts, birch-related foods, milk, peanut and shellfish. Furthermore, adults with asthma experienced significantly more often gastrointestinal symptoms from hazelnut, apple and milk and were found to significantly more often be sensitized to the most common foods compared to the non-asthmatic subjects. The asthmatics showed a significant correlation between IgE to both hazelnut and birch and self-reported symptoms after ingestion of hazelnut and to a lesser extent to almonds.

Conclusions

The prevalence of self-reported adverse reactions and sensitization to the most common foods was much higher among the asthmatic subjects. Hazelnut was the food that asthmatics most frequently experienced adverse reactions from, and the strong correlation between IgE to hazelnut and birch indicate that the observed adverse reactions are partly due to sensitization to allergens from the PR-10 family.

Electronic supplementary material

The online version of this article (doi:10.1186/s13601-015-0067-6) contains supplementary material, which is available to authorized users.

Assessment of Allergy to Milk, Egg, Cod, and Wheat in Swedish Schoolchildren: A Population Based Cohort Study

Objectives

Knowledge about the prevalence of allergies to foods in childhood and adolescence is incomplete. The purpose of this study was to investigate the prevalence of allergies to milk, egg, cod, and wheat using reported data, clinical examinations, and double-blind placebo-controlled food challenges, and to describe the phenotypes of reported food hypersensitivity in a cohort of Swedish schoolchildren.

Methods

In a population-based cohort of 12-year-old children, the parents of 2612 (96% of invited) completed a questionnaire. Specific IgE antibodies to foods were analyzed in a random sample (n=695). Children reporting complete avoidance of milk, egg, cod, or wheat due to perceived hypersensitivity and without physician-diagnosed celiac disease were invited to undergo clinical examination that included specific IgE testing, a celiac screening test, and categorization into phenotypes of food hypersensitivity according to preset criteria. Children with possible food allergy were further evaluated with double-blind challenges.

Results

In this cohort, the prevalence of reported food allergy to milk, egg, cod, or wheat was 4.8%. Food allergy was diagnosed in 1.4% of the children after clinical evaluation and in 0.6% following double-blind placebo-controlled food challenge. After clinical examination, children who completely avoided one or more essential foods due to perceived food hypersensitivity were categorized with the following phenotypes: allergy (29%), outgrown allergy (19%), lactose intolerance (40%), and unclear (12%).

Conclusions

There was a high discrepancy in the prevalence of allergy to milk, egg, cod and wheat as assessed by reported data, clinical evaluation, and double-blind food challenges. Food hypersensitivity phenotyping according to preset criteria was helpful for identifying children with food allergy.

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.