Incidence and natural history of hen's egg allergy in the first 2 years of life-the EuroPrevall birth cohort study.

BACKGROUND: Parents and health staff perceive hen's egg allergy (HEA) as a common food allergy in early childhood, but the true incidence is unclear because population-based studies with gold-standard diagnostic criteria are lacking. OBJECTIVE: To establish the incidence and course of challenge-confirmed HEA in children, from birth until the age of 24 months, in different European regions. METHODS: In the EuroPrevall birth cohort study, children with a suspected HEA and their age-matched controls were evaluated in 9 countries, using a standardized protocol including measurement of HE-specific immunoglobulin E-antibodies in serum, skin prick tests, and double-blind, placebo-controlled food challenges (DBPCFC). RESULTS: Across Europe, 12 049 newborns were enrolled, and 9336 (77.5%) were followed up to 2 years of age. In 298 children, HEA was suspected and DBPCFC was offered. HEA by age two was confirmed in 86 of 172 challenged children (mean raw incidence 0.84%, 95% confidence interval (95% CI) 0.67-1.03). Adjusted mean incidence of HEA was 1.23% (95% CI 0.98-1.51) considering possible cases among eligible children who were not challenged. Centre-specific incidence ranged from United Kingdom (2.18%, 95% CI 1.27-3.47) to Greece (0.07%). Half of the HE-allergic children became tolerant to HE within 1 year after the initial diagnosis. CONCLUSIONS: The largest multinational European birth cohort study on food allergy with gold-standard diagnostic methods showed that the mean adjusted incidence of HEA was considerably lower than previously documented, although differences in incidence rates among countries were noted. Half of the children with documented HEA gained tolerance within 1 year postdiagnosis.

Incidence and natural history of challenge-proven cow's milk allergy in European children--EuroPrevall birth cohort.

BACKGROUND: Cow's milk allergy (CMA) is one of the most commonly reported childhood food problems. Community-based incidence and prevalence estimates vary widely, due to possible misinterpretations of presumed reactions to milk and differences in study design, particularly diagnostic criteria. METHODS: Children from the EuroPrevall birth cohort in 9 European countries with symptoms possibly related to CMA were invited for clinical evaluation including cows' milk-specific IgE antibodies (IgE), skin prick test (SPT) reactivity and double-blind, placebo-controlled food challenge. RESULTS: Across Europe, 12 049 children were enrolled, and 9336 (77.5%) were followed up to 2 years of age. CMA was suspected in 358 children and confirmed in 55 resulting in an overall incidence of challenge-proven CMA of 0.54% (95% CI 0.41-0.70). National incidences ranged from 1% (in the Netherlands and UK) to <0.3% (in Lithuania, Germany and Greece). Of all children with CMA, 23.6% had no cow's milk-specific IgE in serum, especially those from UK, the Netherlands, Poland and Italy. Of children with CMA who were re-evaluated one year after diagnosis, 69% (22/32) tolerated cow's milk, including all children with non-IgE-associated CMA and 57% of those children with IgE-associated CMA. CONCLUSIONS: This unique pan-European birth cohort study using the gold standard diagnostic procedure for food allergies confirmed challenge-proven CMA in <1% of children up to age 2. Affected infants without detectable specific antibodies to cow's milk were very likely to tolerate cow's milk one year after diagnosis, whereas only half of those with specific antibodies in serum 'outgrew' their disease so soon.

Dietary habits and supplement use in relation to national pregnancy recommendations: data from the EuroPrevall birth cohort.

Assessing maternal dietary habits across Europe during pregnancy in relation to their national pregnancy recommendations. A collaborative, multi-centre, birth cohort study in nine European countries was conducted as part of European Union funded EuroPrevall project. Standardised baseline questionnaire data included details of food intake, nutritional supplement use, exposure to cigarette smoke during pregnancy and socio-demographic data. Pregnancy recommendations were collected from all nine countries from the appropriate national organisations. The most commonly taken supplement in pregnancy was folic acid (55.6 % Lithuania-97.8 % Spain) and was favoured by older, well-educated mothers. Vitamin D supplementation across the cohort was very poor (0.3 % Spain-5.1 % Lithuania). There were significant differences in foods consumed in different countries during pregnancy e.g. only 2.7 % Dutch mothers avoided eating peanut, while 44.4 % of British mothers avoided it. Some countries have minimal pregnancy recommendations i.e. Lithuania, Poland and Spain while others have similar, very specific recommendations i.e. UK, the Netherlands, Iceland, Greece. Allergy specific recommendations were associated with food avoidance during pregnancy [relative rate (RR) 1.18 95 % CI 0.02-1.37]. Nutritional supplement recommendations were also associated with avoidance (RR 1.08, 1.00-1.16). Maternal dietary habits and the use of dietary supplements during pregnancy vary significantly across Europe and in some instances may be influenced by national recommendations.

Exclusively breastfed infants at risk for false negative double blind placebo controlled milk challenge.

The double blind placebo controlled food challenge (DBPCFC) is the gold standard for diagnosing cow's milk allergy (CMA). However, false-negative DBPCFC have been reported. We present 2 cases with a false negative DBPCFC in exclusively breastfed infants suspected of CMA. These cases highlight the occurrence of severe allergic reactions of infants who were exclusively breastfed. Several reported causes of a false negative DBPCFC will be discussed. However, there is currently no clear understanding of the cause of a false negative DBPCFC. This paper highlights that a negative outcome of a DBFCFC must be interpreted with caution, because a severe allergic reaction might occur upon re-introduction of cow's milk. Therefore, an additional open food challenge under medical supervision is recommended in exclusively breastfed infants with a negative DBPCFC.

The EuroPrevall birth cohort study on food allergy: baseline characteristics of 12,000 newborns and their families from nine European countries.

It is unclear why some children develop food allergy. The EuroPrevall birth cohort was established to examine regional differences in the prevalence and risk factors of food allergy in European children using gold-standard diagnostic criteria. The aim of this report was to describe pre-, post-natal and environmental characteristics among the participating countries. In nine countries across four major European climatic regions, mothers and their newborns were enrolled from October 2005 through February 2010. Using standardized questionnaires, we assessed allergic diseases and self-reported food hypersensitivity of parents and siblings, nutrition during pregnancy, nutritional supplements, medications, mode of delivery, socio-demographic data and home environmental exposures. A total of 12,049 babies and their families were recruited. Self-reported adverse reactions to food ever were considerably more common in mothers from Germany (30%), Iceland, United Kingdom, and the Netherlands (all 20-22%) compared with those from Italy (11%), Lithuania, Greece, Poland, and Spain (all 5-8%). Prevalence estimates of parental asthma, allergic rhinitis and eczema were highest in north-west (Iceland, UK), followed by west (Germany, the Netherlands), south (Greece, Italy, Spain) and lowest in central and east Europe (Poland, Lithuania). Over 17% of Spanish and Greek children were exposed to tobacco smoke in utero compared with only 8-11% in other countries. Caesarean section rate was highest in Greece (44%) and lowest in Spain (<3%). We found country-specific differences in antibiotic use, pet ownership, type of flooring and baby's mattress. In the EuroPrevall birth cohort study, the largest study using gold-standard diagnostic criteria for food allergy in children worldwide, we found considerable country-specific baseline differences regarding a wide range of factors that are hypothesized to play a role in the development of food allergy including allergic family history, obstetrical practices, pre- and post-natal environmental exposures.

The multinational birth cohort of EuroPrevall: background, aims and methods.

BACKGROUND/AIM: The true prevalence and risk factors of food allergies in children are not known because estimates were based predominantly on subjective assessments and skin or serum tests of allergic sensitization to food. The diagnostic gold standard, a double-blind placebo-controlled food provocation test, was not performed consistently to confirm suspected allergic reactions in previous population studies in children. This protocol describes the specific aims and diagnostic protocol of a birth cohort study examining prevalence patterns and influential factors of confirmed food allergies in European children from different regions. METHODS: Within the collaborative translational research project EuroPrevall, we started a multi-center birth cohort study, recruiting a total of over 12 000 newborns in nine countries across Europe in 2005-2009. In addition to three telephone interviews during the first 30 months, parents were asked to immediately inform the centers about possible allergic reactions to food at any time during the follow-up period. RESULTS: All children with suspected food allergy symptoms were clinically evaluated including double-blind placebo-controlled food challenge tests. We assessed sensitization to different food allergens by measurements of specific serum immunoglobulin E and skin prick tests, collect blood, saliva or buccal swabs for genetic tests, breast milk for measurement of food proteins/cytokines, and evaluate quality-of-life and economic burden of families with food allergic children. CONCLUSIONS: This birth cohort provides unique data on prevalence, risk factors, quality-of-life, and costs of food allergies in Europe, leading to the development of more informed and integrated preventative and treatment strategies for children with food allergies.

Infant feeding and allergy prevention: a review of current knowledge and recommendations. A EuroPrevall state of the art paper.

The relationship between infant feeding patterns and the later development of food allergies has been the focus of much debate and research over the last decade. National recommendations have been made by many countries on how to feed infants to reduce the risk of food allergy but due to the lack of firm evidence the recommendations differ widely. This review has been developed as part of EuroPrevall, a European multicentre research project funded by the European Union, to document the differing feeding recommendations made across Europe, to investigate the current evidence base for any allergy prevention feeding recommendations and to identify areas where further research is needed. This review will also provide information which, when combined with the infant feeding data collected as part of EuroPrevall, will give an indication of compliance to national feeding guidelines which can be utilised to assess the effectiveness of current dissemination and implementation strategies.

Treatment variables and intellectual outcome in children with classic phenylketonuria. A single-center-based study.

Records of 46 patients with classic phenylketonuria (PKU) were used to determine treatment variables associated with intellectual outcome. Patients comprised three groups: phenylalanine-restricted diet started 1) after 3 months and loss of diet control at a mean age of 7 years, 2) before age 3 months and loss of diet control at a mean age of 5 years, and 3) before age 3 months and through a mean age of 11 years. All underwent IQ testing during the diet; groups 1 and 2 were retested at a mean of six years off the diet. On the diet, groups 2 and 3 had higher IQs than group 1; group 3 IQ was also higher than IQ off diet in groups 1 and 2. After discontinuing the diet, group 2 IQs decreased significantly. Predictors of IQ in group 1 were age at loss of diet control and percentage of phenylalanine concentrations > 15 mg/dL; in group 2, mean phenylalanine concentrations and age at loss of diet control. Predictors of changes in group 1 IQs were global degree of dietary control and percentage of phenylalanine concentrations > 15 mg/dL; in group 2, phenylalanine concentrations of < 3 mg/dL and age at start of diet. Group 1 patients with phenylalanine concentrations < 3 mg/dL or > 15 mg/dL achieved no IQ gain by continuing the diet after age 7 years. Thus, intellectual prognosis is best for PKU patients who start a phenylalanine-restricted diet early and continue through age 12 years.