Association of serum surfactant protein D and SFTPD gene variants with asthma in Danish children, adolescents, and young adults

BACKGROUND

Surfactant Protein D (SP-D) is a pattern recognition molecule belonging to the family of collectins expressed in multiple human organ systems, including the lungs. Previous studies have shown that SP-D levels in bronchoalveolar lavage samples decrease and serum levels increase in patients suffering from asthma, possibly due to a combination of induced SP-D synthesis and decreased air-blood barrier integrity. The aims of this study were to investigate whether serum levels of SP-D and common variants in the SP-D gene were associated with asthma in adolescents and young adults.

METHODS

Prospective observational study including 449 adolescents and young adults (age 11-27 years) previously diagnosed with asthma during a 2-year period from 2003 to 2005 (0-16 years). At follow-up from 2016 to 2017, 314 healthy controls with no history of asthma were recruited. Serum SP-D was analyzed on samples obtained at baseline as well as samples obtained at follow-up. SP-D genotyping was performed for rs721917, rs2243639, and rs3088308.

RESULTS

No differences were found in mean levels of sSP-D and SFTPD genotype among subjects with current asthma, no current asthma, and controls. Serum SP-D and SFTPD genotype were not associated with any clinical parameters of asthma. Furthermore, baseline sSP-D was not associated with asthma at follow-up.

CONCLUSION

Serum surfactant protein D and common SP-D gene variants were not associated with asthma in Danish adolescents and young adults with mild to moderate asthma. Serum surfactant protein D did not demonstrate any value as a clinical biomarker of asthma.

Growth in Infants with Cow's Milk Protein Allergy Fed an Amino Acid-Based Formula

PURPOSE

The present study assessed the role of an amino acid-based formula (AAF) in the growth of infants with cow's milk protein allergy (CMPA).

METHODS

Non-breastfed, term infants aged 0-6 months with symptoms suggestive of CMPA were recruited from 10 pediatric centers in China. After enrollment, infants were started on AAF for two weeks, followed by an open food challenge (OFC) with cow's milk-based formula (CMF). Infants with confirmed CMPA remained on AAF until 9 months of age, in conjunction with a cow's milk protein-free complementary diet. Body weight, length, and head circumference were measured at enrollment and 9 months of age. Measurements were converted to weight-for-age, length-for-age, and head circumference-for-age Z scores (WAZ, LAZ, HCAZ), based on the World Health Organization growth reference.

RESULTS

Of 254 infants (median age 16.1 weeks, 50.9% male), 218 (85.8%) were diagnosed with non-IgE-mediated CMPA, 33 (13.0%) tolerated CMF, and 3 (1.2%) did not complete the OFC. The mean WAZ decreased from 0.119 to -0.029 between birth and enrollment (p=0.067), with significant catch-up growth to 0.178 at 9 months of age (p=0.012) while being fed the AAF. There were no significant changes in LAZ (0.400 vs. 0.552; p=0.214) or HCAZ (-0.356 vs. -0.284; p=0.705) from the time of enrollment to age 9 months, suggesting normal linear and head growth velocity.

CONCLUSION

The amino acid-based study formula, in conjunction with a cow's milk protein-free complementary diet, supported normal growth till 9 months of age in a cohort of Chinese infants with challenge-confirmed non-IgE-mediated CMPA.

The natural course of cow's milk allergy and the development of atopic diseases into adulthood

BACKGROUND

Previous studies have investigated the natural course of cow's milk allergy (CMA) and development of atopic diseases into adolescence. Studies with long-term follow-up into adulthood are lacking. The aim of this study was to investigate (a) the natural course of CMA in a 1-year birth cohort of Danish children from birth until 15 and 26 years of age and (b) the development of atopic diseases in a group of children with CMA (group A) compared to a random sample of 276 children from the same birth cohort (group B).

METHODS

A birth cohort of 1749 newborns was investigated prospectively for the development of CMA and atopic diseases. During the first year of life and at 18 months and 3, 5, 10, 15, and 26 years of age, questionnaire-based interviews, physical examination, skin prick tests, and specific IgE testing, and from 10 years also spirometry, were carried out.

RESULTS

Thirty-nine (2.2%) were diagnosed with CMA. The recovery rate was 87%, 92%, and 97% at 3, 5, and 26 years of age. Compared to group B, group A had significantly (P < .05) higher prevalence of asthma and rhinoconjunctivitis at 15 years of age, and at 26 years of age, group A had significantly higher prevalence of asthma and atopic dermatitis. The follow-up rate was 85% (A) and 70% (B).

CONCLUSION

CMA has a good prognosis regarding recovery rate. However, CMA, especially IgE-mediated, in early childhood predicts a high prevalence of atopic diseases into adulthood.

Maternal phthalate exposure and asthma, rhinitis and eczema in 552 children aged 5 years; a prospective cohort study

BACKGROUND

Prenatal phthalate exposure has been suggested to alter immune responses and increase the risk of asthma, eczema and rhinitis. However, few studies have examined the effects in prospective cohorts and only one examined rhinitis. We therefore studied associations between maternal urinary concentrations of phthalate metabolites and asthma, eczema and rhinitis in offspring aged 5 years.

METHODS

From 552 pregnant women in the Odense Child Cohort, we quantified urinary concentrations of 12 phthalate metabolites in third trimester. We assessed asthma, rhinitis and eczema in their offspring at age 5 years with a questionnaire based on the International Study of Asthma and Allergies in Childhood (ISAAC), and conducted logistic regression adjusting for relevant confounders.

RESULTS

7.4% of the children had asthma, 11.7% eczema and 9.2% rhinitis. Phthalate exposure was low compared to previous cohorts. No significant associations between prenatal phthalate exposure and asthma were found. Odds ratios (ORs) of child rhinitis with a doubling in ΣDiNP_m and di-2-ethylhexyl phthalate metabolite (ΣDEHP_m) concentrations were, respectively, 1.15 (95% confidence interval (CI) 0.97,1.36) and 1.21 (CI 0.93,1.58). The OR of eczema when doubling ΣDiNP_m was 1.24 (CI 1.00,1.55), whereas the OR of using medicine against eczema when doubling a di-ethyl phthalate (DEP) metabolite was 0.81 (CI 0.68,0.96).

CONCLUSION

The lack of association between maternal phthalate exposure and asthma in the offspring may be due to low exposure and difficulties in determining asthma in 5-year-olds. The higher odds of rhinitis may raise public concern but further research in larger cohorts of older children is warranted.

Association between prenatal exposure to perfluoroalkyl substances and asthma in 5-year-old children in the Odense Child Cohort

BACKGROUND

Asthma is the most common non-communicable disease in children. Prenatal exposure to perfluoroalkyl substances (PFASs), a group of persistent environmental chemicals with endocrine disrupting abilities, has been associated with immunomodulation and may contribute to the aetiology of asthma. We investigated the associations between prenatal exposure to five PFASs and asthma in 5-year-old children.

METHODS

We studied 981 mother-child pairs within the Odense Child Cohort (OCC), Denmark. We measured perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) in maternal serum donated in early pregnancy. A standardized questionnaire based on the International Study of Asthma and Allergies in Childhood (ISAAC) was used to assess wheeze, self-reported asthma and doctor-diagnosed asthma among children at age 5 years. Associations were examined using logistic regression analyses adjusting for parity, maternal educational level, maternal pre-pregnancy BMI, asthma predisposition and child sex.

RESULTS

Among the 5-year-old children 18.6% reported wheeze and 7.1% reported asthma. We found no association between prenatal exposure to PFAS and doctor-diagnosed asthma or wheeze. Prenatal PFAS exposure was associated with self-reported asthma, although only significant for PFNA (OR = 1.84, 95% CI 1.03,3.23).

CONCLUSION

Our findings support the suggested immunomodulatory effects of PFASs, however, additional studies are warranted. In order to verify our findings, it is important to re-examine the children with postnatal measurements of serum PFAS concentrations and additional clinical diagnostic testing at an older age where an asthma diagnosis is more valid.

Microfibrillar-associated protein 4 in serum is associated with asthma in Danish adolescents and young adults

Background

Microfibrillar‐associated protein 4 (MFAP4) is an extracellular matrix protein belonging to the fibrinogen‐related protein superfamily, which plays multifaceted roles in innate immunity and normal endothelial function. It has been proposed that MFAP4 promotes the development of asthma in vivo and proasthmatic pathways of bronchial smooth muscle cells in vitro. The aim of this study was to investigate the significance of serum MFAP4 in adolescents and young adolescents with persistent asthma.

Methods

Prospective, observational study including adolescents and young adults (age 11‐27 years) previously diagnosed with asthma during childhood 2003 to 2005 (0‐15 years) at the four pediatric outpatient clinics in the Region of Southern Denmark (n = 449). Healthy controls were recruited at follow‐up (n = 314). Detection of serum MFAP4 was performed by AlphaLISA technique.

Results

Current asthma was associated to a 14% higher mean level of serum MFAP4 compared with controls (expβ 1.14, 95% confidence intervals [CI], 1.05‐1.23) and a 6% higher mean level compared with subjects with no current asthma (expβ 1.06, 95% CI, 0.99‐1.13). No association was found at follow‐up between serum MFAP4 and self‐reported atopic symptoms (other than asthma), Asthma Control Test‐score, fractional exhaled nitric oxide (FeNO), nor to flow rate at 1 second, forced vital capacity, and forced expiratory flow 25% to 75%, response to short‐acting beta 2 agonist or mannitol.

Conclusions

We found a significantly higher mean level of serum MFAP4 in adolescent and young adults with mild to moderate asthma compared with healthy controls but no association to FeNO and lung function nor to the response to short‐acting beta 2 agonist or mannitol. The result supports the hypothesis that MFAP4 plays a role in the pathogenesis of asthma although the marker did not demonstrate any obvious potential as an asthma biomarker in adolescents and young adults with asthma. To understand the possible proasthmatic functions of MFAP4, further investigation in specific asthma phenotypes and the underlying molecular mechanisms is warranted.

Probiotics in late infancy reduce the incidence of eczema: A randomized controlled trial

BACKGROUND

Allergic diseases are common and represent a considerable health and economic burden worldwide. We aimed to examine the effect of a combination of two probiotic strains administered in late infancy and early childhood on the development of allergic diseases and sensitization.

METHODS

In this double-blind, placebo-controlled intervention trial, participants were randomized to receive a daily mixture of Lactobacillus rhamnosus and Bifidobacterium animalis subsp lactis or placebo-starting prior to attending day care. The intervention period was 6 months, and the parents answered web-based questionnaires on allergic symptoms and doctor's diagnosed allergic disease monthly. IgE was measured at baseline and follow-up.

RESULTS

A total of 290 participants were randomized: 144 in the probiotic group and 146 in the placebo group. Mean age at intervention start was 10.1 months. At follow-up (mean age 16.1 months), the incidence of eczema was 4.2% in the probiotic group and 11.5% in the placebo group (P = 0.036). The incidence of asthma and conjunctivitis did not differ between groups, and no children presented with rhinitis. Sensitization was equal in the two groups at intervention start (7.5% and 9.5%, respectively), and two children in each group were sensitized during the intervention.

CONCLUSIONS

We observed a significantly lower incidence of eczema in the probiotic group compared to the placebo group. The probiotics were administered in late infancy-prior to attending day care-suggesting a broader window of opportunity using probiotics in the prevention of eczema. The incidence of asthma, rhinitis, conjunctivitis, and sensitization did not differ.

Validity of asthma diagnoses and patterns of anti-asthmatic drug use in a cohort of 2053 Danish children

BACKGROUND AND AIMS

When investigating and treating asthma in children, diagnosing must be precise and valid. There is a need for studies researching asthma in children showing how to use registry-based, epidemiological data. We examined the feasibility and validity of using anti-asthmatic drug prescription data to identify children with asthma and assessed medication patterns in children with and without confirmed asthma.

METHODS

We used population-based Danish prescription data and hospital discharge registries to identify all children aged 0 to 14 years who had redeemed at least one prescription for an inhaled anti-asthmatic drug. Individual asthma cases were validated by hospital discharge information and by their treating general practitioners according to international asthma guidelines.

RESULTS

In total, 2053 children, out of a population of 20181, had redeemed at least one prescription of any inhaled anti-asthmatic drug. The positive predictive value (PPV) of having two different asthma medications prescribed in 1 year was 80.2% for presence of true asthma, with a sensitivity of 59%. Corresponding estimates of PPV/sensitivity of at least one prescription for an inhaled corticosteroid (ICS) were 79% and 58%, respectively, while the true asthma PPV with at least one LABA prescription increased to 97%. Among children with confirmed asthma, one-third had not used Beta2-agonist therapy as part of their treatment. Conversely, among children without confirmed asthma, 40% were prescribed a minimum of two prescriptions for any kind of inhaled anti-asthmatic drug, and 12% and 9% used an ICS or Leukotriene receptor antagonist, respectively.

CONCLUSIONS

Anti-asthmatic drug prescription data could be used to identify children with true asthma, with reasonable accuracy. The observed pattern of anti-asthmatic medication usage among children with and without confirmed asthma suggests that there is room for therapeutic improvement.

Protocol for the validation of sensitivity and specificity of the Cow's Milk-related Symptom Score (CoMiSS) against open food challenge in a single-blinded, prospective, multicentre trial in infants

INTRODUCTION

The symptoms of cow's milk protein allergy (CMPA) in infancy can be non-specific which may delay a correct diagnosis and cause adverse clinical outcomes. The diagnosis of non-IgE-mediated CMPA is particularly complex as it involves a 2 to 4 week elimination diet followed by oral food challenge (OFC). The Cow's Milk-related Symptom Score (CoMiSS) is a clinical resource for primary healthcare providers which aims to increase awareness of CMPA symptoms to facilitate an earlier diagnosis. The aim of the present study is to assess if the CoMiSS can be used as a potential diagnostic tool in infants with suspected CMPA.

METHODS AND ANALYSIS

Exclusively formula-fed infants aged 0-6 months presenting with symptoms suggestive of CMPA will be included in this prospective, multicentre trial which will be conducted in 10 centres in China. All infants will commence a 2-week trial of an amino acid-based formula (AAF) while eliminating all cow milk protein from their diets. After the AAF treatment period, infants will undergo an open OFC in hospital with standard cow's milk formula, followed by an open home challenge for another 2 weeks. Clinical symptoms will be documented on standardised symptom scorecards. The CoMiSS will be determined at study entry (CoMiSS 1, before the start of the AAF), after 2 weeks (CoMiSS 2, before the OFC) and after a further period of 2 weeks or when symptoms suggestive of CMPA reappear (CoMiSS 3). Weight and length will be measured at each visit. The difference between CoMiSS 1 and 2 as a predictor of the OFC outcome will also be assessed. The diagnostic accuracy of the baseline CoMiSS will be calculated.

ETHICS AND DISSEMINATION

The study was approved by the Hunan Children's Hospital Medical Ethics Committee, Hunan, China. The findings of this trial will be submitted for publication in a peer-reviewed journal in paediatric nutrition or gastroenterology. Abstracts will be submitted to the relevant national and international conferences.

TRIAL REGISTRATION NUMBER

NCT03004729; Pre-results.

Current state and future of pediatric allergology in Europe: A road map

The history of pediatric allergology (PA) in Europe is relatively youthful, dating back to 1984, when a small group of pediatricians founded the European Working Group on Pediatric Allergy and Immunology-later giving rise to ESPACI (European Society on Pediatric Allergology and Clinical Immunology). In 1990, the first dedicated journal, Pediatric Allergy and Immunology (PAI), was founded. There are striking differences across Europe, and even within European countries, in relation to the training pathways for doctors seeing children with allergic disease(s). In 2016, the EAACIClemens von Pirquet Foundation (CvP) organized and sponsored a workshop with the European Academy of Allergy and Clinical Immunology (EAACI) Pediatric Section. This collaboration focussed on the future of PA and specifically on education, research, and networking/ advocacy. The delegates representing many countries across Europe have endorsed the concept that optimal care of children with allergic diseases is delivered by pediatricians who have received dedicated training in allergy, or allergists who have received dedicated training in pediatrics. In order to meet the needs of children and families with allergic disease(s), the pediatric allergist is highly encouraged to develop several networks. Our challenge is to reinforce a clear strategic approach to scientific excellence to across our member base and to ensure and enhance the relevance of European pediatric research in allergy. With research opportunities in basic, translational, clinical, and epidemiologic trials, more trainees and trained specialists are needed and it is an exciting time to be a pediatric allergologist.

Early-life sensitization to hen's egg predicts asthma and rhinoconjunctivitis at 14 years of age

BACKGROUND

Sensitization to both inhalant and food allergens has been shown to be risk factors for development of asthma and rhinoconjunctivitis (RC). However, few studies have addressed the role of transient or persistent IgE sensitization to specific allergens in early life for later development of allergic diseases. The aim of this study was to explore the association between transient and persistent sensitization in early life and the development of asthma and RC at 6 and 14 years.

METHODS

The Danish Allergy Research Center (DARC) cohort is a prospective non-interventional birth cohort study comprising 562 children. For the purpose of this study, we examined a subgroup of the original cohort with specific IgE measured at, at least 3 of 4 follow-ups between 3 and 18 months of age (n = 366). Multiple logistic regression models were used to investigate the association between transient and persistent early-life sensitization to groups of and to individual allergens and asthma and RC at 6 and 14 years compared to a reference group with no sensitization.

RESULTS

Both transient early-life sensitization and persistent early-life sensitization to cow's milk or hen's egg proteins were associated with asthma (aOR 3.99[1.41-11.32] and 5.95[1.78-19.92]) and RC (aOR 2.94[1.19-7.28] and 6.18[1.86-20.53]) at 14 years, this association being driven mainly by sensitization to hen's egg. Transient early-life sensitization to house dust mite (HDM) had increased risk of asthma (aOR 3.80[1.17-12.41]) at 14 years.

CONCLUSIONS

Early transient IgE sensitization and persistent IgE sensitization to hen's egg were associated with asthma and RC at 14 years. Furthermore, sensitization to HDM was associated with asthma at 14 years.

Early childhood risk factors for rhinoconjunctivitis in adolescence: a prospective birth cohort study

Background

Rhinoconjunctivitis is a global health problem and one of the most common chronic conditions in children. Development of rhinoconjunctivitis depends on both genetic and environmental factors. Many studies have investigated rhinoconjunctivitis, but only few studies have evaluated the risk factors for non-allergic rhinoconjunctivitis in children finding family history of atopic diseases and gender to be of importance. The aim of this study was to investigate possible risk factors in early life for rhinoconjunctivitis, allergic as well as non-allergic, in adolescence.

Methods

The children in the Danish Allergy Research Center cohort were examined eight times from birth to 14 years of age. Visits included questionnaire-based interview, clinical examination, skin prick test and specific IgE. We used univariate and multivariate logistic regression to investigate the relationship between early-life risk factors and the development of rhinoconjunctivitis, allergic as well as non-allergic, in adolescence.

Results

Follow-up rate at 14-years was 66.2%. The prevalence of rhinoconjunctivitis was 32.8%. Family history of atopic diseases (aOR 2.25), atopic dermatitis (aOR 3.24), food allergy (aOR 3.89), early sensitization to inhalant and food allergens (aOR 2.92 and aOR 3.13) and male gender (aOR 1.90) were associated with allergic rhinoconjunctivitis but not with non-allergic rhinoconjunctivitis. Early environmental tobacco exposure was inversely associated with rhinoconjunctivitis (aOR 0.42), allergic (aOR 0.47) as well as non-allergic (aOR 0.43).

Conclusion

Different patterns of associations were revealed when stratifying rhinoconjunctivitis in allergic and non-allergic suggesting that allergic rhinoconjunctivitis and non-allergic-rhinoconjunctivitis are different phenotypes.

The prevalence of atopic diseases and the patterns of sensitization in adolescence

BACKGROUND

Atopic diseases are among the most common chronic diseases in adolescents, and it is uncertain whether the prevalence of atopic diseases has reached a plateau or is still increasing. The use of the ISAAC (International Study of Asthma and Allergy in Childhood) questionnaire has provided comparable prevalence rates from many countries, whereas studies including clinical examinations and strict diagnostic criteria are scarce. We aimed to investigate the prevalence of atopic diseases, the pattern of sensitization, and comorbidities at 14 years in a prospective birth cohort.

METHODS

The children were examined eight times from birth to 14 years. Visits included questionnaire-based interviews, clinical examination, skin prick test, and specific IgE.

RESULTS

Follow-up rate at 14 years was 66.2%. The 12-month prevalence of any atopic disease was high (40.3%) mostly due to a high prevalence of rhinoconjunctivitis (32.8%), whereas the prevalence of asthma was 12.9% and of atopic dermatitis 8.1%. In children with at least one atopic disease, 60% were sensitized, while only 16% of those without atopic diseases were sensitized. The frequency of sensitization depended on the phenotype. Among children with rhinoconjunctivitis only, rhinoconjunctivitis with concomitant asthma or atopic dermatitis or both 62.5%, 81.5%, 70%, and 100%, respectively, were sensitized, whereas it was 7.7% and 33.3% of children with only asthma or atopic dermatitis.

CONCLUSION

The prevalence of rhinoconjunctivitis was high in adolescence. Children with rhinoconjunctivitis with and without comorbidities were frequently sensitized. Children with asthma without concomitant allergic rhinoconjunctivitis were rarely sensitized.

Association between prenatal exposure to perfluorinated compounds and symptoms of infections at age 1-4years among 359 children in the Odense Child Cohort

INTRODUCTION

Perfluorinated alkylated substances (PFAS) are persistent industrial chemicals that have resulted in global environmental exposures. Previous epidemiological studies have reported possible effects on the immune system after developmental PFAS exposure, but the possible impact on childhood infectious disease is unclear.

OBJECTIVES

To investigate the association between prenatal exposure to PFAS and symptoms of infections at age 1-4years.

METHODS

The Odense Child Cohort is an on-going prospective study on children's health, where serum concentrations of perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), perfluorodecanoic acid (PFDA) and perfluorononanoic acid (PFNA) were measured in 649 pregnant women before gestational week 16. Of these women, 359 reported on symptoms of infection in their child every two weeks for a one-year period. The association between prenatal exposure to PFAS and the symptoms was estimated using a logistic regression model and a negative binomial regression model. For the latter, the outcome was reported as an incidence rate-ratio (IRR), and all models were adjusted for maternal age, educational level, parity and child age.

RESULTS

On average, the children experienced symptoms of infection 23% of the time during one year. PFOS exposure in the high tertile compared to the low tertile was associated with a statistically significant increased proportion of days with fever (IRR: 1.65 (95% CI: 1.24, 2.18), P-trend<0.001) and an increased odds of experiencing days with fever above the median (OR: 2.35 (95% CI: 1.31, 4.11). The latter tendency was also apparent for PFOA (OR: 1.97 (95% CI: 1.07, 3.62). Further, higher concentrations of PFOS and PFOA tended to increase the number of episodes of co-occurrence of fever and coughing and fever and nasal discharge during the one-year study period.

CONCLUSION

We found a positive association between prenatal exposure to PFOS and PFOA and the prevalence of fever, which may be a sensitive marker of infection. This finding is in agreement with an immunotoxic effect of prenatal exposure to PFAS. The wider implications for childhood infectious disease deserve attention.

Low patch test reactivity to nickel in unselected adolescents tested repeatedly with nickel in infancy

BACKGROUND

It is questionable how repeated patch tests with nickel sulfate in infancy affect nickel patch test reactivity at a later age.

METHODS

The Danish Allergy Research Center (DARC) cohort encompasses 562 infants invited to a clinical examination including patch tests with nickel sulfate six times during the first 36 months of life. At the follow-up investigation at 14 years of age (2013-2014), participants were offered re-patch tests with nickel sulfate. The Odense Adolescence Cohort Study TOACS cohort encompasses 1501 schoolchildren evaluated for the first time at 14 years of age (1995-1996) including clinical examination and nickel sulfate patch tests. The prevalence of nickel sensitization in the DARC cohort was compared to the prevalence in the TOACS cohort at 14 years of age.

RESULTS

Nickel sulfate sensitization was found in 1.2% of the participants from the DARC cohort tested repeatedly with nickel sulfate in early childhood and retested at 14 years of age compared to 8.6% of the participants from the TOACS cohort patch-tested for the first time at 14 years of age using the same patch test system and test concentration.

CONCLUSION

The significant difference in nickel patch test reactivity comparing the two cohorts may reflect an immunologic effect or the effect of nickel regulation.

Having older siblings is associated with gut microbiota development during early childhood

Background

Evidence suggests that early life infections, presence of older siblings and furred pets in the household affect the risk of developing allergic diseases through altered microbial exposure. Recently, low gut microbial diversity during infancy has also been linked with later development of allergies. We investigated whether presence of older siblings, furred pets and early life infections affected gut microbial communities at 9 and 18 months of age and whether these differences were associated with the cumulative prevalence of atopic symptoms of eczema and asthmatic bronchitis at 3 years of age. Bacterial compositions and diversity indices were determined in fecal samples collected from 114 infants in the SKOT I cohort at age 9 and 18 months by 16S rRNA gene sequencing. These were compared to the presence of older siblings, furred pets and early life infections and the cumulative prevalence of diagnosed asthmatic bronchitis and self-reported eczema at 3 years of age.

Results

The number of older siblings correlated positively with bacterial diversity (p = 0.030), diversity of the phyla Firmicutes (p = 0.013) and Bacteroidetes (p = 0.004) and bacterial richness (p = 0.006) at 18 months. Further, having older siblings was associated with increased relative abundance of several bacterial taxa at both 9 and 18 months of age. Compared to the effect of having siblings, presence of household furred pets and early life infections had less pronounced effects on the gut microbiota. Gut microbiota characteristics were not significantly associated with cumulative occurrence of eczema and asthmatic bronchitis during the first 3 years of life.

Conclusions

Presence of older siblings is associated with increased gut microbial diversity and richness during early childhood, which could contribute to the substantiation of the hygiene hypothesis. However, no associations were found between gut microbiota and atopic symptoms of eczema and asthmatic bronchitis during early childhood and thus further studies are required to elucidate whether sibling-associated gut microbial changes influence development of allergies later in childhood.

Electronic supplementary material

The online version of this article (doi:10.1186/s12866-015-0477-6) contains supplementary material, which is available to authorized users.

Determinants of house dust, endotoxin, and β-(1→3)-D-glucan in homes of Danish children

Little is known about the geographic variation and determinants of bacterial endotoxin and β-(1,3)-D-glucan in Danish house dust. In a population of 317 children, we: (i) described loads and concentrations of floor dust, endotoxin, and β-(1→3)-D-glucan and (ii) their correlations and (iii) assessed their determinants; (iv) Finally, we compared our findings with previous European studies. Bedroom floor dust was analyzed for endotoxin content by the kinetic limulus amoebocyte lysate assay and for β-(1→3)-D-glucan by the inhibition enzyme immunoassay. The parents answered questions regarding potential determinants. We found: geometric means (geometric standard deviations) 186 mg/m(2) (4.3) for dust; 5.46 × 10(3) EU/m(2) (8.0) and 31.1 × 10(3) EU/g (2.6) for endotoxin; and 142 μg/m(2) (14.3) and 0.71 × 10(3) μg/g (7.3) for β-(1→3)-D-glucan. High correlations (r > 0.75) were found between floor dust and endotoxin and β-(1→3)-D-glucan loads, while endotoxin and β-(1→3)-D-glucan concentrations were moderately correlated (r = 0.36-0.41) with the dust load. Having a carpet was positively associated with dust load and with endotoxin and β-(1→3)-D-glucan concentrations. Pet keeping, dwelling type, and dwelling location were determinants of endotoxin concentrations. No other determinants were associated with β-(1→3)-D-glucan concentrations. Compared with other European studies, we found lower β-(1→3)-D-glucan loads and concentrations but higher endotoxin loads and concentrations suggesting a geographically determined different composition of Danish floor dust compared with other European regions.

Phthalate exposure through different pathways and allergic sensitization in preschool children with asthma, allergic rhinoconjunctivitis and atopic dermatitis

Studies in rodents indicate that phthalates can function as adjuvants, increasing the potency of allergens. Meanwhile, epidemiological studies have produced inconsistent findings regarding relationships between phthalate exposures and allergic disease in humans. The present study examined phthalate exposure and allergic sensitization in a large group of 3-5 year old children: 300 random controls and 200 cases with asthma, rhinoconjunctivitis or atopic dermatitis as reported in questionnaires. The children were clinically examined to confirm their health status. Blood samples were analyzed for IgE sensitization to 20 allergens. Adjusted logistic regressions were used to look for associations between phthalate exposure indicators (mass fractions in dust from children's homes and daycares, metabolites in urine, and estimated daily indoor intakes from dust ingestion, inhalation and dermal absorption) and sensitization and allergic disease. No direct associations were found between phthalate exposures and asthma, rhinoconjunctivitis or atopic dermatitis. However, among children with these diseases, there were significant associations between non-dietary exposures to DnBP, BBzP and DEHP in the indoor environment (mass fractions in dust or daily indoor intakes from dust ingestion, inhalation and dermal absorption) and allergic sensitization. Some exposure pathways were more strongly associated with sensitization than others, although the results are not conclusive and require confirmation. A number of the associations depended on accounting for a child's exposure in more than one environment (i.e., daycare facility as well as home). Significant associations were not observed between phthalate metabolites in urine, which reflected exposure from diet as well as indoor pathways, and allergic sensitization.

Can family history and cord blood IgE predict sensitization and allergic diseases up to adulthood?

BACKGROUND

Long-term studies of the predictive value of family history and cord blood IgE level until adulthood are few, and their conclusions have been contradictory.

METHODS

Screening of total IgE in 1617 cord blood samples was performed in a Danish birth cohort. All infants with cord blood IgE (CB-IgE) ≥ 0.5 kU/l and a corresponding randomly chosen group with CB-IgE <0.5 kU/l were chosen for follow-up. Questionnaire-based interviews, physical examination, specific IgE testing, and from 10 yr also spirometry, were carried out at 1½, 5, 10, 15, and 26 yr. Predefined diagnostic criteria were used.

RESULTS

A total of 455 infants were included, 188 with CB-IgE ≥ 0.5 kU/l and 267 with CB-IgE <0.5 kU/l. Follow-up rates were high, 288 (63%) attended the 26-yr follow-up. Family history and elevated CB-IgE were significantly associated to allergic disease until 26 yr. Concerning any allergic symptoms at 1½ yr the positive and negative predictive values (PPV and NPV), the sensitivity and specificity of CB-IgE ≥ 0.5 kU/l, was 29%, 81%, 54%, and 61%, respectively. The corresponding figures at 26 yr were 46%, 62%, 43%, and 65%. Overall, family history as well as CB-IgE ≥ 0.5 kU/l was associated with high NPV and specificity, but low PPV and sensitivity.

CONCLUSION

Although family history and elevated CB-IgE were significantly associated with primarily atopic disease until 26 yr, none of these were strong predictors for subsequent sensitization and allergic symptoms from childhood until early adulthood. It appears that the predictive capacity of CB-IgE decreases in adolescence and early adulthood.

Allergy and asthma prevention 2014

Asthma and allergic diseases have become one of the epidemics of the 21st century in developed countries. Much of the success of other areas of medicine, such as infectious diseases, lies on preventive measures. Thus, much effort is also being placed lately in the prevention of asthma and allergy. This manuscript reviews the current evidence, divided into four areas of activity. Interventions modifying environmental exposure to allergens have provided inconsistent results, with multifaceted interventions being more effective in the prevention of asthma. Regarding nutrition, the use of hydrolyzed formulas in high-risk infants reduces the incidence of atopic dermatitis, while there is for now not enough evidence to recommend other dietary modifications, prebiotics, probiotics, or other microbial products. Pharmacologic agents used until now for prevention have not proved useful, while there is hope that antiviral vaccines could be useful in the future. Allergen-specific immunotherapy is effective for the treatment of allergic patients with symptoms; the study of its value for primary and secondary prevention of asthma and allergy is in its very preliminary phases. The lack of success in the prevention of these disorders lies on their complexity, which involves many genetic, epigenetic, and environmental interactions. There is a need to identify target populations, involved mechanisms and interactions, and the best interventions. These must be effective, feasible, implementable, and affordable.

EAACI food allergy and anaphylaxis guidelines: diagnosis and management of food allergy

Food allergy can result in considerable morbidity, impact negatively on quality of life, and prove costly in terms of medical care. These guidelines have been prepared by the European Academy of Allergy and Clinical Immunology's (EAACI) Guidelines for Food Allergy and Anaphylaxis Group, building on previous EAACI position papers on adverse reaction to foods and three recent systematic reviews on the epidemiology, diagnosis, and management of food allergy, and provide evidence-based recommendations for the diagnosis and management of food allergy. While the primary audience is allergists, this document is relevant for all other healthcare professionals, including primary care physicians, and pediatric and adult specialists, dieticians, pharmacists and paramedics. Our current understanding of the manifestations of food allergy, the role of diagnostic tests, and the effective management of patients of all ages with food allergy is presented. The acute management of non-life-threatening reactions is covered in these guidelines, but for guidance on the emergency management of anaphylaxis, readers are referred to the related EAACI Anaphylaxis Guidelines.

Associations between selected allergens, phthalates, nicotine, polycyclic aromatic hydrocarbons, and bedroom ventilation and clinically confirmed asthma, rhinoconjunctivitis, and atopic dermatitis in preschool children

Previous studies, often using data from questionnaires, have reported associations between various characteristics of indoor environments and allergic disease. The aim of this study has been to investigate possible associations between objectively assessed indoor environmental factors and clinically confirmed asthma, rhinoconjunctivitis, and atopic dermatitis. The study is a cross-sectional case-control study of 500 children aged 3-5 years from Odense, Denmark. The 200 cases had at least two parentally reported allergic diseases, while the 300 controls were randomly selected from 2835 participating families. A single physician conducted clinical examinations of all 500 children. Children from the initially random control group with clinically confirmed allergic disease were subsequently excluded from the control group and admitted in the case group, leaving 242 in the healthy control group. For most children, specific IgE's against various allergens were determined. In parallel, dust samples were collected and air change rates were measured in the children's bedrooms. The dust samples were analyzed for phthalate esters, polycyclic aromatic hydrocarbons (PAH), nicotine, and various allergens. Among children diagnosed with asthma, concentrations of nicotine were higher (P < 0.05) and cat allergens were lower (P < 0.05) compared with the healthy controls; air change rates were lower for those sensitized (specific IgE+) compared with those not sensitized (specific IgE-, P < 0.05); and dust mite allergens were higher for specific IgE+ cases compared with healthy controls (P < 0.05). When disease status was based solely on questionnaire responses (as opposed to physician diagnosis), significant associations were found between di(2-ethylhexyl) phthalate (DEHP) and dog allergens in dust and current wheeze.

Phthalate metabolites in urine and asthma, allergic rhinoconjunctivitis and atopic dermatitis in preschool children

Phthalate esters are among the most ubiquitous of indoor pollutants and have been associated with various adverse health effects. In the present study we assessed the cross-sectional association between eight different phthalate metabolites in urine and allergic disease in young children. As part of the Danish Indoor Environment and Children's Health study, urine samples were collected from 440 children aged 3-5 years, of whom 222 were healthy controls, 68 were clinically diagnosed with asthma, 76 with rhinoconjunctivitis and 81 with atopic dermatitis (disease subgroups are not mutually exclusive; some children had more than one disease). There were no statistically significant differences in the urine concentrations of phthalate metabolites between cases and healthy controls with the exception of MnBP and MECPP, which were higher in healthy controls compared with the asthma case group. In the crude analysis MnBP and MiBP were negatively associated with asthma. In the analysis adjusted for multiple factors, only a weak positive association between MEP in urine and atopic dermatitis was found; there were no positive associations between any phthalate metabolites in urine and either asthma or rhinoconjunctivitis. These findings appear to contradict earlier studies. Differences may be due to higher exposures to certain phthalates (e.g., BBzP) via non-dietary pathways in earlier studies, phthalates serving as surrogates for an agent associated with asthma (e.g., PVC flooring) in previous studies but not the present study or altered cleaning habits and the use of "allergy friendly" products by parents of children with allergic disease in the current study in contrast to studies conducted earlier.

Prevalence of IgE sensitization in Danish children with suspected asthma

OBJECTIVE

The aim of this article was to estimate the prevalence of IgE sensitization in Danish children with suspected asthma and to characterize the pattern of sensitization.

STUDY DESIGN

We performed a cross-sectional study including 1744 children from 0 to 15 yr suspected of asthma who were referred to pediatric outpatient clinics in the region of southern Denmark from 2003 to 2005. The children were subjected to an extensive questionnaire-based interview, clinical examination, and both skin prick testing (SPT) and IgE measurements for 17 allergens.

RESULTS

Asthma was confirmed in 1024 of the 1744 children. Among the children in whom the asthma diagnosis was confirmed, sensitization to one or more of the 17 allergens tested was found in 67.5% by either SPT or s-IgE ≥ class 2. Sensitization to any food allergen was found in 31.1%, to any outdoor allergen in 36.2%, and to any indoor allergen in 51.8%. Sensitization to cockroach and latex was rare. We found a weak correlation between SPT and s-IgE among food allergens and a more distinct correlation among inhalant allergens. Surprisingly, 30.1% of children in whom the asthma diagnosis was disproven used inhaled corticosteroids (ICS). On the contrary, 32.5% of the children for whom the asthma diagnosis was verified were not treated with ICS.

CONCLUSION

We have found a high prevalence of sensitization among children with verified asthma. Our study supports relevant allergy testing in all children with verified asthma and emphasizes the importance of a thorough asthma diagnosis before prescribing continuous inhaled corticosteroids to children.

The natural course of sensitization and allergic diseases from childhood to adulthood

BACKGROUND

Longitudinal prospective population-based birth cohort studies of the natural history of sensitization and allergic diseases from childhood to adulthood are few. The aim of the present prospective study was to investigate the natural course of sensitization and allergic diseases in a random population-based sample of 276 children from a 1-year birth cohort of unselected Danish children followed from birth to 26 years of age.

METHODS

Questionnaire-based interviews, physical examination, skin prick tests, specific IgE testing, and from 10 years also spirometry, were carried out at 1.5, 5, 10, 15 and 26 years of age. Predefined diagnostic criteria were used.

RESULTS

Follow-up rates were high, 193 (70%) attended the 26-year follow-up. The prevalence of current eczema was stable during childhood; 13% (1.5 yrs.), 9.2% (5 yrs.), 10.8% (10 yrs.), and 9.8% (15 yrs.), and 5.7% at 26 yrs. From birth to 26 years the cumulative prevalence of eczema, food allergy, asthma, and rhinoconjunctivitis was 23.5%, 13.8%, 17%, and 27.9% respectively. More than half of the participants had one or more allergic disease in the period between birth and 26 years of age. The rates of sensitization (S-IgE = 0.35 kU/l) were 8%, 23%, 26%, 32%, and 31% at 1.5, 5, 10, 15, and 26 years of age, respectively. Sensitization to food allergens was most prevalent in early infancy, whereas sensitization to inhalant allergens dominated later on.

CONCLUSION

The results support the concept of the allergic march. Allergic diseases are not only occurring in childhood but persist into adulthood.

Testing children for allergies: why, how, who and when: an updated statement of the European Academy of Allergy and Clinical Immunology (EAACI) Section on Pediatrics and the EAACI-Clemens von Pirquet Foundation

Allergic diseases are common in childhood and can cause a significant morbidity and impaired quality-of-life of the children and their families. Adequate allergy testing is the prerequisite for optimal care, including allergen avoidance, pharmacotherapy and immunotherapy. Children with persisting or recurrent or severe symptoms suggestive for allergy should undergo an appropriate diagnostic work-up, irrespective of their age. Adequate allergy testing may also allow defining allergic trigger in common symptoms. We provide here evidence-based guidance on when and how to test for allergy in children based on common presenting symptoms suggestive of allergic diseases.

The history of pediatric allergy in Europe - from a working group to ESPACI and SP-EAACI

A Working Group on Pediatric Allergology was formed in 1984, which rapidly developed to become the European Society on Pediatric Allergology and Clinical Immunology (ESPACI) in 1988 with its own journal, Pediatric Allergology and Immunology. ESPACI worked together with the European Academy of Allergology and Clinical Immunology (EAACI) to form a Section of Pediatrics within EAACI (SP-EAACI) in 1996. The ESPACI and the SP-EAACI formally merged in 2001. Within the EAACI organization, the Pediatric Section has continued to grow. The Pediatric Section is working to develop pediatric allergology across Europe, focusing on postgraduate education, facilitating the research agenda and advocating for children and adolescents with allergies.

Positive nickel patch tests in infants are of low clinical relevance and rarely reproducible

BACKGROUND

We have previously reported patch test reactivity to nickel sulphate in a cohort of unselected infants tested repeatedly at 3-18 months of age. A reproducible positive reaction at 12 and 18 months was selected as a sign of nickel sensitivity provided a patch test with an empty Finn chamber was negative. A reproducible positive reaction was seen in 8.6% of the infants. The objective of this study is to follow-up on infants with alleged nickel sensitivity.

METHODS

A total of 562 infants were included in the cohort and patch tested with nickel sulphate (ICDRG guidelines). The 26 children with a positive patch test reaction to nickel sulphate at 12 and 18 months were offered repeated patch tests at 3 and 6 yr.

RESULTS

Among the 21 children tested at both 12 months, 18 months and at 3 and 6 yr only 2 of 21 had reproducible nickel reactions (one clinically relevant), 13 of 21 were negative and 6 of 21 were negative at 3 or 6 yr.

CONCLUSIONS

Only 9.5% of the children had reproducible nickel sulphate reactivity, while 62% became negative. The results are noteworthy and can be interpreted in different ways: Repeated nickel patch tests did not cause patch test sensitization. The test reactions in infancy are probably of irritant or non-specific nature. Hence, nickel patch tests should only be performed in small children if there is a clinical suspicion of nickel-induced allergic contact dermatitis.

Children's health and its association with indoor environments in Danish homes and daycare centres - methods

The principle objective of the Danish research program 'Indoor Environment and Children's Health' (IECH) was to explore associations between various exposures that children experience in their indoor environments (specifically their homes and daycare centers) and their well-being and health. The targeted health endpoints were allergy, asthma, and certain respiratory symptoms. The study was designed with two stages. In the first stage, a questionnaire survey was distributed to more than 17,000 families with children between the ages of 1 and 5. The questionnaire focused on the children's health and the environments within the homes they inhabited and daycare facilities they attended. More than 11,000 questionnaires were returned. In the second stage, a subsample of 500 children was selected for more detailed studies, including an extensive set of measurements in their homes and daycare centers and a clinical examination; all clinical examinations were carried out by the same physician. In this study, the methods used for data collection within the IECH research program are presented and discussed. Furthermore, initial findings are presented regarding descriptors of the study population and selected characteristics of the children's dwellings and daycare centers.

PRACTICAL IMPLICATIONS

This study outlines methods that might be followed by future investigators conducting large-scale field studies of potential connections between various indoor environmental factors and selected health endpoints. Of particular note are (i) the two-stage design - a broad questionnaire-based survey followed by a more intensive set of measurements among a subset of participants who have been selected based on their responses to the questionnaire; (ii) the case-base approach utilized in the stage 2 in contrast to the more commonly used case-control approach; (iii) the inclusion of the children's daycare environment when conducting intensive sampling to more fully capture the children's total indoor exposure; and (iv) all clinical examinations conducted by the same physician. We recognize that future investigators are unlikely to fully duplicate the methods outlined in this study, but we hope that it provides a useful starting point in terms of factors that might be considered when designing such a study.

Does pet ownership in infancy lead to asthma or allergy at school age? Pooled analysis of individual participant data from 11 European birth cohorts

OBJECTIVE

To examine the associations between pet keeping in early childhood and asthma and allergies in children aged 6-10 years.

DESIGN

Pooled analysis of individual participant data of 11 prospective European birth cohorts that recruited a total of over 22,000 children in the 1990s. EXPOSURE DEFINITION: Ownership of only cats, dogs, birds, rodents, or cats/dogs combined during the first 2 years of life. OUTCOME DEFINITION: Current asthma (primary outcome), allergic asthma, allergic rhinitis and allergic sensitization during 6-10 years of age.

DATA SYNTHESIS

Three-step approach: (i) Common definition of outcome and exposure variables across cohorts; (ii) calculation of adjusted effect estimates for each cohort; (iii) pooling of effect estimates by using random effects meta-analysis models.

RESULTS

We found no association between furry and feathered pet keeping early in life and asthma in school age. For example, the odds ratio for asthma comparing cat ownership with "no pets" (10 studies, 11489 participants) was 1.00 (95% confidence interval 0.78 to 1.28) (I(2) = 9%; p = 0.36). The odds ratio for asthma comparing dog ownership with "no pets" (9 studies, 11433 participants) was 0.77 (0.58 to 1.03) (I(2) = 0%, p = 0.89). Owning both cat(s) and dog(s) compared to "no pets" resulted in an odds ratio of 1.04 (0.59 to 1.84) (I(2) = 33%, p = 0.18). Similarly, for allergic asthma and for allergic rhinitis we did not find associations regarding any type of pet ownership early in life. However, we found some evidence for an association between ownership of furry pets during the first 2 years of life and reduced likelihood of becoming sensitized to aero-allergens.

CONCLUSIONS

Pet ownership in early life did not appear to either increase or reduce the risk of asthma or allergic rhinitis symptoms in children aged 6-10. Advice from health care practitioners to avoid or to specifically acquire pets for primary prevention of asthma or allergic rhinitis in children should not be given.

[Sublingual immunotherapy in children with grass pollen induced allergic rhinoconjunctivitis]

Specific immunotherapy is the only current treatment that may modify the disease process in allergic rhinoconjunctivitis. Recent studies have evidenced that sublingual administration of grass extract tablets is an efficacious, safe and convenient form of specific immunotherapy in children with grass pollen induced allergic rhinoconjunctivitis. It is recommended that daily treatment is initiated four months before the pollen season begins and continued through three years, though paediatric studies of long-term and potential asthma and allergy prevention effects are still awaited.

Identifying parents with risky alcohol consumption habits in a paediatric unit--are screening and brief intervention appropriate methods?

BACKGROUND

There is no systematic identification of parents with excessive alcohol use who have a child admitted to hospital. Children in families with excessive alcohol issues form a high risk group as substantial alcohol consumption has a damaging influence on a child emotionally, cognitively, socially and physically. Alcohol consumption is a sensitive issue, and health staff needs knowledge, qualifications and adequate training in communicating with parents about this taboo.

AIM

• To identify specific patterns in subgroups of parents by comparing results from screening and demographic variables • To identify systematic patterns in staff members by demographic variables to decide whether these factors influence the screening results.

METHODS

During 1 year, screening and brief intervention (SBI) was accomplished, including health staff conducting dialogues with parents of a hospitalized child using motivational interviewing (MI) and screening for risky alcohol behaviour by Cut down, Annoyance from others, feel Guilty, Early-morning Craving (CAGE)-C. Data were analysed by descriptive statistics, and relationships were tested with a statistical significance level of 0.05, using SPSS (version 16.0).

RESULTS

Motivational dialogues with 779 parents were conducted by 43 staff members, and 11% of the parents were screened positive for risky alcohol behaviour. Drinking alcohol 4 days a week or more and drinking alcohol outside mealtimes were main risk factors. Parents' gender was the strongest predictor of screening positive and OR was 6.8 for men (CI 4.03-11.74) compared to women, p<0.0001. An OR of 1.2 for parents' age (CI 1.02-1.42) indicates the risk of screening positive increases with age, p=0.027.

CONCLUSIONS

Brief intervention using CAGE-C and MI has proven successful in mapping parents' alcohol consumption patterns and in identifying parents with risky alcohol consumption habits. Health staff is able to manage health promotion and prevention when having the right competences and when being supervised.

Development of atopic dermatitis in the DARC birth cohort

The aim was to describe the relapsing pattern, sensitization and prognosis of atopic dermatitis (AD) in the first 6 yr in a population-based, prospective birth cohort. The DARC cohort includes 562 children with clinical examinations, specific-IgE and skin prick test at all follow-ups. All children were examined for the development of AD using Hanifin-Rajka criteria and for food hypersensitivity by oral challenges. Severity of AD was measured by objective SCORing Atopic Dermatitis (SCORAD). Point-prevalence of AD peaked at 18 months of age (10%) and decreased at 36 and 72 months to slightly below 7%. The 6-yr cumulative incidence was 22.8% and sensitization was found in 43% of children with AD. It was predominately sensitization to foods, however shifting toward inhalant allergens with age. Sensitization at >or=2 follow-ups affected severity, whereas short-term sensitization at one follow-up does not. Children with early, non-IgE mediated (intrinsic) AD outgrew more often their eczema; however if they develop persistent AD, they remain intrinsic. Early long-term sensitization worsens the prognosis, but 38% of all children have a debut later than 18 months of age. Boys had earlier onset of AD than girls. The large number of follow-ups gives a detailed picture of the relapsing pattern and shows that the relapses occur independently of time of onset. We could not establish any clear correlation between elimination diets and AD duration nor severity.

The association between early sensitization patterns and subsequent allergic disease. The DARC birth cohort study

Prevention of allergic diseases depends on early identification of clinical markers preceding such disorders. This study describes the natural course of sensitization as measured by skin prick test (SPT) and specific immunoglobulin E (S-IgE) and analyses the association between early sensitization patterns and subsequent allergic disease at 6 yr of age. In an ongoing population-based birth cohort study of 562 children, follow-up visits were performed at 0, 3, 6, 9, 12, 18, 36, and 72 months. Visits included an interview, physical examination, SPTs, and S-IgE measurements for 12 food and inhalant allergens. The frequency of S-IgE sensitization to > or = 1 inhalant allergen was constant from 0 to 6 months (9-10%), decreased at 12-18 months before increasing from 36 months onwards. S-IgE sensitization to at least one food allergen remained constant from 0 to 6 yr. SPT sensitization to food and inhalant allergens appeared from 3 and 12 months, respectively. Early food sensitization (S-IgE) between 3 and 18 months was found to be significantly (p < 0.05) associated with atopic dermatitis (OR: 4.0 [1.6-9.9]) and asthma (OR 4.0 [1.1-12.5]) at the age of 6 yr. Children with atopic dermatitis, asthma, or rhinoconjunctivitis, and sensitization at 6 yr, were sensitized to food allergens to a large extent (53%, 42%, and 47%, respectively) already at 6 months. Early inhalant sensitization (S-IgE) did not increase the risk of later allergic disease. Early atopic dermatitis (0-18 months) was also highly associated with subsequent allergic disease. Children with early food sensitization and/or atopic dermatitis would be a proper target group for future interventional studies.

Food allergy and food sensitization in early childhood: results from the DARC cohort

BACKGROUND

The prevalence of food hypersensitivity (FHS) and the relationship with atopic dermatitis (AD) is controversial. The aim of this study was to determine the development of FHS and to correlate this with AD in relation to sensitization and symptoms.

METHODS

This study combines new data from birth to 18 months of age with previous published results from 3 and 6 years. The Danish Allergy Research Centre cohort, including 562 children, is a unique, population-based, prospective birth cohort, with clinical examinations at all follow-ups. All children were examined for the development of AD using Hanifin-Rajka criteria and for FHS using interviews, skin prick test (SPT), specific immunoglobulin E (IgE), and food challenge according to EAACI guidelines.

RESULTS

Twenty children were confirmed with FHS to milk, egg, and peanut. FHS peaked at 18 months (3.6%) and then decreased to 1.2% at 72 months of age. No new cases were found after 3 years. Self-reporting could only be confirmed in 31% of cases. Among the 122 children with AD, 18 had FHS (14.8%). FHS was IgE-mediated in 95% of the cases but 16 of 20 children were additionally sensitized to other foods which they tolerated. Children with AD were neither more IgE-sensitized nor had higher levels of IgE when compared with healthy children but they were more persistently sensitized.

CONCLUSIONS

Sensitization to foods in young children without food allergy seems to be a normal phenomenon. The discrepancy between sensitization, self-reported food-related symptoms and confirmed FHS illustrates the need to perform standardized oral challenges in order to confirm the diagnosis of FHS.

The prevalence of allergic diseases in an unselected group of 6-year-old children. The DARC birth cohort study

This study determines the prevalence of atopic dermatitis, asthma, rhinoconjunctivitis, food hypersensitivity and urticaria and the frequency of sensitization in children with and without clinical allergic disease. In an ongoing prospective non-interventional birth cohort study of 562 unselected children, 404 children were subjected to interview, clinical examination, lung function measurements and allergy testing at 6 yr of age. Sensitization measured by skin prick test (SPT) and specific immunoglobulin E (S-IgE) was determined for 24 different allergens. The 1-yr period prevalence of atopic dermatitis, asthma and rhinoconjunctivitis was 14.4%, 6.2% and 13.6%. 25.7% of the children suffered from at least one of the three diseases. The frequency of sensitization in children with no disease (controls), any allergic disease, atopic dermatitis, asthma and rhinoconjunctivitis was 17%, 45%, 47%, 56% and 55% (defined as SPT >or=3 mm and/or S-IgE >or=0.35 kU/l for at least one allergen). Symptoms were linked to sensitization for 44% in the asthma group and 42% in the rhinoconjunctivitis group, whereas sensitization could not be linked to worsening of the eczema in any cases of atopic dermatitis. Overlap between the three diseases was significantly more frequent in sensitized children than in non-sensitized (19/46 = 41% vs. 9/58 = 16%, p = 0.004). The prevalence of food hypersensitivity and urticaria was 1.2% and 5.4% respectively. In unselected 6 yr old children, approximately half of the children with atopic dermatitis, asthma or rhinoconjunctivitis are IgE-sensitized. Sensitization tends to link these diseases to each other.

Meta-analysis of determinants for pet ownership in 12 European birth cohorts on asthma and allergies: a GA2LEN initiative

BACKGROUND

Studies on pet ownership as a risk or protective factor for asthma and allergy show inconsistent results. This may be on account of insufficient adjustment of confounding factors.

AIM

The objective of this study was to describe determinants of cat and dog ownership in European families with and without allergies.

METHODS

Within the EU-funded network of excellence GA(2)LEN, we performed meta-analyses with data from 12 ongoing European birth cohort studies on asthma and allergy. Each of the birth cohort studies enrolled between 485 and 4089 children. Pet ownership, allergic status (asthma, allergic rhinitis, eczema) of parents and siblings, parental education, access to ground floor, and number of people living at home were assessed by questionnaires.

RESULTS

Among the 25 056 families from seven European countries cats (14.9%) were more common than dogs (12.0%). Allergic family history significantly reduced the odds to own a cat (adjusted combined random-effect OR 0.91; 95% CI 0.85-0.99), or dog (0.90; 0.86-0.94). A higher parental educational level had even more pronounced effects on cat (0.84; 0.71-0.98), and dog ownership (0.61; 0.54-0.70). Elder siblings reduced the odds to own cats, but not dogs. Convenient ground access significantly increased the odds, whereas crowding at home was not associated with cat or dog ownership.

CONCLUSIONS

The chances to own a cat or dog were significantly reduced in allergic families, in parents with a higher educational level, and in homes without convenient ground access. In addition to parental allergies, social and housing factors should be considered as potential confounders in studies on pet exposure and allergic diseases.

Spirometry in an unselected group of 6-year-old children: the DARC birth cohort study

This study presents reference equations for spirometric parameters in 6-year-old children and evaluates the ability of spirometry to discriminate healthy children from children with asthma. Baseline spirometry and respiratory symptoms were assessed in 404 children participating in a longitudinal birth cohort study. Children with known asthma, possible asthma and a control group also performed bronchodilator measurements. At least two acceptable flow-volume curves at baseline were obtained by 368/404 children (91%). The two best values for FEV1 and FVC were within 5% of each other in 88% and 83% of children, respectively. Linear regression analyses for 242 children included in the reference population demonstrated height to be the main predictor of all spirometric indices except FEV1/FVC. FEV1, FEV75, and FVC correlated reasonably to anthropometric data in contrast to flow parameters. Gender differences were found for FEV1, FVC, and FEV75, but not for flow parameters. Asthma was diagnosed in 25/404 children. Baseline lung function in healthy children and children with asthma overlapped, although asthmatic children could be discriminated to some extent. Bronchodilator tests showed a difference in Delta FEV1(mean) between healthy children and children with asthma (3.1% vs. 6.1%, P < 0.05). At a cut-off point of Delta FEV1 = 7.8%, bronchodilator tests had a sensitivity of 46% and a specificity of 92% for current asthma. Spirometry including bronchodilator measurements was demonstrated to be feasible in 6-year-old children and reference values were determined. Spirometry aids the diagnosis of asthma in young children, but knowledge on sensitivity and specificity of these measurements is a prerequisite.

Dietary prevention of allergic diseases in infants and small children

Because of scientific fraud four trials have been excluded from the original Cochrane meta-analysis on formulas containing hydrolyzed protein for prevention of allergy and food intolerance in infants. Unlike the conclusions of the revised Cochrane review the export group set up by the Section on Paediatrics, European Academy of Allergology and Clinical Immunology (SP-EAACI) do not find that the exclusion of the four trials demands a change of the previous recommendations regarding primary dietary prevention of allergic diseases. Ideally, recommendations on primary dietary prevention should be based only on the results of randomized and quasi-randomized trials (selection criteria in the Cochrane review). However, regarding breastfeeding randomization is unethical, Therefore, in the development of recommendations on dietary primary prevention, high-quality systematic reviews of high-quality cohort studies should be included in the evidence base. The study type combined with assessment of the methodological quality determines the level of evidence. In view of some methodological concerns in the Cochrane meta-analysis, particularly regarding definitions and diagnostic criteria for outcome measures and inclusion of non peer-reviewed studies/reports, a revision of the Cochrane analysis may seem warranted. Based on analysis of published peer-reviewed observational and interventional studies the results still indicate that breastfeeding is highly recommended for all infants irrespective of atopic heredity. A dietary regimen is effective in the prevention of allergic diseases in high-risk infants, particularly in early infancy regarding food allergy and eczema. The most effective dietary regimen is exclusively breastfeeding for at least 4-6 months or, in absence of breast milk, formulas with documented reduced allergenicity for at least the first 4 months, combined with avoidance of solid food and cow's milk for the first 4 months.

Specific immunotherapy has long-term preventive effect of seasonal and perennial asthma: 10-year follow-up on the PAT study

BACKGROUND

3-year subcutaneous specific immunotherapy (SIT) in children with seasonal allergic rhinoconjunctivitis reduced the risk of developing asthma during treatment and 2 years after discontinuation of SIT (5-year follow-up) indicating long-term preventive effect of SIT.

OBJECTIVE

We evaluated the long-term clinical effect and the preventive effect of developing asthma 7-years after termination of SIT.

METHODS

One hundred and forty-seven subjects, aged 16-25 years with grass and/or birch pollen allergy was investigated 10 years after initiation of a 3-year course of SIT with standardized allergen extracts of grass and/or birch or no SIT respectively. Conjunctival provocations were performed outside the season and methacholine bronchial provocations were performed during the season and winter. Asthma was assessed by clinical evaluation.

RESULTS

The significant improvements in rhinoconjunctivitis and conjunctival sensitivity persisted at the 10-year follow-up. Significantly less actively treated subjects had developed asthma at 10-year follow-up as evaluated by clinical symptoms [odds ratio 2.5 (1.1-5.9)]. Patients who developed asthma among controls were 24/53 and in the SIT group 16/64. The longitudinal treatment effect when adjusted for bronchial hyper-responsiveness and asthma status at baseline including all observations at 3, 5 and 10 years follow-up (children with or without asthma at baseline, n = 189; 511 observations) was statistically significant (P = 0.0075). The odds ratio for no-asthma was 4.6 95% CI (1.5-13.7) in favor of SIT.

CONCLUSION

A 3-year course of SIT with standardized allergen extracts has shown long-term clinical effects and the potential of preventing development of asthma in children with allergic rhinoconjunctivitis up to 7 years after treatment.

CLINICAL IMPLICATION

Specific immunotherapy has long-term clinical effects and the potential of preventing development of asthma in children with allergic rhino conjunctivitis up to 7 years after treatment termination.