Bronchial obstructive phenotypes in the first year of life among Paris birth cohort infants

Wheeze trajectories are modifiable through early-life intervention and predict asthma in adolescence

BACKGROUND

The objectives of this study were to identify developmental trajectories of wheezing using data-driven methodology, and to examine whether trajectory membership differentially impacts the effectiveness of primary preventive efforts that target modifiable asthma risk factors.

METHODS

Secondary analysis of the Canadian Asthma Primary Prevention Study (CAPPS), a multifaceted prenatal intervention among children at high risk of asthma, followed from birth to 15 years. Wheezing trajectories were identified by latent class growth analysis. Predictors, intervention effects, and asthma diagnoses were examined between and within trajectory groups.

RESULTS

Among 525 children, 3 wheeze trajectory groups were identified: Low-Progressive (365, 69%), Early-Transient (52, 10%), and Early-Persistent (108, 21%). The study intervention was associated with lower odds of Early-Transient and Early-Persistent wheezing (P < .01). Other predictors of wheeze trajectories included, maternal asthma, maternal education, city of residence, breastfeeding, household pets, infant sex and atopy at 12 months. The odds of an asthma diagnosis were three-fold to six-fold higher in the Early-Persistent vs Low-Progressive group at all follow-up assessments (P = .03), whereas Early-Transient wheezing (limited to the first year) was not associated with asthma. In the Early-Persistent group, the odds of wheezing were lower among intervention than control children (adjusted odds ratio: 0.67; 95% CI: 0.48; 0.93) at 7 years.

CONCLUSIONS

Using data-driven methodology, children can be classified into clinically meaningful wheeze trajectory groups that appear to be programmed by modifiable and non-modifiable factors, and are useful for predicting asthma risk. Early-life interventions can alter some wheeze trajectories (ie, Early-Persistent) in infancy and reduce wheezing prevalence in mid-childhood.

Paving the way of systems biology and precision medicine in allergic diseases: the MeDALL success story: Mechanisms of the Development of ALLergy; EU FP7-CP-IP; Project No: 261357; 2010-2015

MeDALL (Mechanisms of the Development of ALLergy; EU FP7-CP-IP; Project No: 261357; 2010-2015) has proposed an innovative approach to develop early indicators for the prediction, diagnosis, prevention and targets for therapy. MeDALL has linked epidemiological, clinical and basic research using a stepwise, large-scale and integrative approach: MeDALL data of precisely phenotyped children followed in 14 birth cohorts spread across Europe were combined with systems biology (omics, IgE measurement using microarrays) and environmental data. Multimorbidity in the same child is more common than expected by chance alone, suggesting that these diseases share causal mechanisms irrespective of IgE sensitization. IgE sensitization should be considered differently in monosensitized and polysensitized individuals. Allergic multimorbidities and IgE polysensitization are often associated with the persistence or severity of allergic diseases. Environmental exposures are relevant for the development of allergy-related diseases. To complement the population-based studies in children, MeDALL included mechanistic experimental animal studies and in vitro studies in humans. The integration of multimorbidities and polysensitization has resulted in a new classification framework of allergic diseases that could help to improve the understanding of genetic and epigenetic mechanisms of allergy as well as to better manage allergic diseases. Ethics and gender were considered. MeDALL has deployed translational activities within the EU agenda.

Cough during infancy and subsequent childhood asthma

OBJECTIVES

Wheezing in infancy has been associated with subsequent asthma, but whether cough similarly influences asthma risk has been little studied. We sought to determine whether prolonged cough and cough without cold in the first year of life are associated with childhood asthma.

METHODS

Participants in the Infant Immune Study, a non-selected birth cohort, were surveyed 7 times in the first 9 months of life regarding the presence of wheeze and cough. Cough for more than 28 days was defined as prolonged. Parents were asked at 1 year if the child ever coughed without a cold. Asthma was defined as parental report of physician diagnosis of asthma, with symptoms or medication use between 2 and 9 years. Logistic regression was used to assess adjusted odds for asthma associated with cough characteristics.

RESULTS

A total of 24% (97) of children experienced prolonged cough and 23% (95) cough without cold in the first 9 months, respectively. Prolonged cough was associated with increased risk of asthma relative to brief cough (OR 3.57, CI: 1.88, 6.76), with the risk being particularly high among children of asthmatic mothers. Cough without cold (OR 3.13, 95% CI: 1.76, 5.57) was also independently associated with risk of childhood asthma. Both relations persisted after adjustment for wheeze and total IgE at age 1.

CONCLUSIONS AND CLINICAL RELEVANCE

Prolonged cough in infancy and cough without cold are associated with childhood asthma, independent of infant wheeze. These findings suggest that characteristics of cough in infancy are early markers of asthma susceptibility, particularly among children with maternal asthma.

Childhood wheezing phenotypes influence asthma, lung function and exhaled nitric oxide fraction in adolescence

The objective of this study was to examine the associations of childhood wheezing phenotypes with asthma, lung function and exhaled nitric oxide fraction (FeNO) in adolescence.In a population-based, prospective cohort study of 6841 children, we used latent class analysis to identify wheezing phenotypes during the first 7 years of life. Physician-diagnosed asthma, spirometry and FeNO were assessed at 14-15 years.Compared with never/infrequent wheeze, intermediate-onset and persistent wheeze were consistently strongest associated with higher risk of asthma (risk ratio (95% CI) 10.9 (8.97-13.16) and 9.13 (7.74-10.77), respectively), lower forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) ratio (mean difference in standard deviation units (SDU) (95% CI) -0.34 (-0.54- -0.14) and -0.50 (-0.62- -0.38), respectively), lower forced expiratory flow at 25-75% of FVC (FEF25-75%) (mean difference in SDU (95% CI) -0.30 (-0.49- -0.10) and -0.42 (-0.54- -0.30), respectively) and increased FEV1 bronchodilator reversibility (mean difference in SDU (95% CI) 0.12 (0.02-0.22) and 0.13 (0.06-0.19), respectively). Prolonged early and persistent wheeze were associated with a decline in FEV1/FVC ratio and FEF25-75% between 8-9 and 14-15 years. Intermediate-onset, late-onset and persistent wheeze were associated with higher FeNO ratios (ratio of geometric means (95% CI) 1.90 (1.59-2.29), 1.57 (1.39-1.77) and 1.37 (1.22-1.53), respectively, compared with never/infrequent wheeze).Early-onset wheezing phenotypes persisting after 18 months of age show the strongest associations with asthma, lower lung function, even worsening from mid-childhood, and higher FeNO levels in adolescence.

Clinical relevance of cluster analysis in phenotyping allergic rhinitis in a real-life study

BACKGROUND

Disease stratification, using phenotypic characterization performed either by hypothesis- or data-driven methods, was developed to improve clinical decisions. However, cluster analysis has not been used for allergic rhinitis.

OBJECTIVE

To define clusters in allergic rhinitis and to compare them with ARIA (Allergic Rhinitis and Its Impact on Asthma), a hypothesis-driven approach.

METHODS

A French observational prospective multicenter study (EVEIL: Echelle visuelle analogique dans la rhinite allergique) was carried out on 990 patients consulting general practitioners for allergic rhinitis and treated as per clinical practice. In this study, changes in symptom scores, visual analogue scales and quality of life were measured at baseline and after 14 days of treatment. A post hoc analysis was performed to identify clusters of patients with allergic rhinitis – using Ward's hierarchical method – and to define their clinical relevance at baseline and after 14 days of treatment. The cluster approach was compared to the ARIA approach.

RESULTS

Patients were clustered into 4 phenotypes which partly followed the ARIA classes. These phenotypes differed in their disease severity including symptoms and quality of life. Physicians in real-life practice prescribed medication regardless of the phenotype and severity, with the exception of patients with ocular symptoms. Prescribed treatments were comparable in hypothesis- and data-driven analyses. The prevalence of uncontrolled patients during treatment was similar in the 4 clusters, but was significantly different according to the ARIA classes.

CONCLUSION

Cluster analysis using demographic and clinical parameters only does not appear to add relevant information for disease stratification in allergic rhinitis.

Phenotyping asthma, rhinitis and eczema in MeDALL population-based birth cohorts: an allergic comorbidity cluster

BACKGROUND

Asthma, rhinitis and eczema often co-occur in children, but their interrelationships at the population level have been poorly addressed. We assessed co-occurrence of childhood asthma, rhinitis and eczema using unsupervised statistical techniques.

METHODS

We included 17 209 children at 4 years and 14 585 at 8 years from seven European population-based birth cohorts (MeDALL project). At each age period, children were grouped, using partitioning cluster analysis, according to the distribution of 23 variables covering symptoms 'ever' and 'in the last 12 months', doctor diagnosis, age of onset and treatments of asthma, rhinitis and eczema; immunoglobulin E sensitization; weight; and height. We tested the sensitivity of our estimates to subject and variable selections, and to different statistical approaches, including latent class analysis and self-organizing maps.

RESULTS

Two groups were identified as the optimal way to cluster the data at both age periods and in all sensitivity analyses. The first (reference) group at 4 and 8 years (including 70% and 79% of children, respectively) was characterized by a low prevalence of symptoms and sensitization, whereas the second (symptomatic) group exhibited more frequent symptoms and sensitization. Ninety-nine percentage of children with comorbidities (co-occurrence of asthma, rhinitis and/or eczema) were included in the symptomatic group at both ages. The children's characteristics in both groups were consistent in all sensitivity analyses.

CONCLUSION

At 4 and 8 years, at the population level, asthma, rhinitis and eczema can be classified together as an allergic comorbidity cluster. Future research including time-repeated assessments and biological data will help understanding the interrelationships between these diseases.

Determinants of allergic rhinitis in young children with asthma

Background

In the preschool period, allergic rhinitis (AR) is infrequent and thus under-diagnosed. However, recent works have highlighted the occurrence of AR in toddlers although the causes of AR in this young population remain unknown. The objective of this study was to identify determinants of AR in young children with asthma.

Methods

We carried out a case-control study of 227 children with active asthma and enrolled in the Trousseau Asthma Program. AR and other allergic diseases (asthma, food allergy and eczema) were diagnosed by medical doctors using standardized questionnaires. Parental history of AR and asthma, biological markers of atopy (total IgE, blood eosinophilia, allergic sensitization towards food and aeroallergens) and environmental parameters were also collected.

Results

Forty one of the children (18.1%) had AR. By univariate logistic regression analysis, AR was mainly associated with peanut sensitization (OR = 6.75; p = 0.002); food allergy (OR = 4.31; p = 0.026); mold exposure (OR = 3.81 p<0.01) and parental history of AR (OR = 1.42; p = 0.046). Due to the strong link between food allergy and peanut sensitization three models of multivariate logistic regression were performed and confirmed that AR is associated with peanut sensitization but also food allergy and mold exposure. A random forest analysis was also performed to explain AR. The results reinforced the logistic analysis that peanut sensitization and mold exposure were the principal determinants of AR.

Conclusions & Clinical Relevance

These results stress the importance of investigating AR in young children with asthma to potentially diagnose a particularly severe allergic asthmatic phenotype. Moreover, these data evoke the hypothesis that peanut could be an aeroallergen.

Feasibility of aerosol drug delivery to sleeping infants: a prospective observational study

OBJECTIVES

Delivery of inhaled medications to infants is usually very demanding and is often associated with crying and mask rejection. It has been suggested that aerosol administration during sleep may be an attractive alternative. Previous studies in sleeping children were disappointing as most of the children awoke and rejected the treatment. The SootherMask (SM) is a new, gentle and innovative approach for delivering inhaled medication to infants and toddlers. The present pilot study describes the feasibility of administering inhaled medications during sleep using the SM.

DESIGN

Prospective observational study.

SETTING

Out patients.

PARTICIPANTS

13 sleeping infants with recurrent wheezing who regularly used pacifiers and were <12 months old.

INTERVENTION

Participants inhaled technetium99mDTPA-labelled normal saline aerosol delivered via a Respimat Soft Mist Inhaler (SMI) (Boehringer-Ingelheim, Germany) and SM + InspiraChamber (IC; InspiRx Inc, New Jersey, USA).

OUTCOMES

The two major outcomes were the acceptability of the treatment and the lung deposition (per cent of emitted dose).

RESULTS

All infants who fulfilled the inclusion criteria successfully received the SM treatment during sleep without difficulty. Mean lung deposition (±SD) averaged 1.6±0.5% in the right lung.

CONCLUSIONS

This study demonstrated that the combination of Respimat, IC and SM was able to administer aerosol therapy to all the sleeping infants who were regular pacifier users with good lung deposition. Administration of aerosols during sleep is advantageous since all the sleeping children accepted the mask and ensuing aerosol therapy under these conditions, in contrast to previous studies in which there was frequent mask rejection using currently available devices.

CLINICAL TRIAL REGISTRY

NCT01120938.

What drives prescribing of asthma medication to preschool wheezing children? A primary care study

There is limited information on which data primary care pediatricians (PCPs) use to decide whether to prescribe or not asthma maintenance treatment, and what drives prescribing a specific therapy. The study aim was to investigate how prescribing anti-asthma maintenance treatment to preschool wheezing children is influenced by patient, family, environmental, and PCP characteristics. We conducted a cross-sectional study at 32 PCPs sites in Campania, Italy. Medical, family, and environmental information of 376 preschool wheezy children, and characteristics of the enrolled PCPs were collected. Main outcome measures of multilevel multivariate logistic regression analyses were the prescribing of maintenance treatment, and the prescription of a combined therapy as opposed to monotherapy. Variables significantly associated with long-term inhaled corticosteroids (ICS) and/or leukotriene modifiers prescription included frequent wheezing (OR = 7.19), emergency department (ED) visits (OR = 2.21), personal allergic diseases (OR = 8.49), day-care/kindergarten attendance (OR = 2.67), a high PCP prescribing volume (OR = 2.74), and a low proportion of 0- to 5-year-old patients with wheezing diagnosis (OR = 1.16). Leukotriene modifiers plus ICS were much more likely prescribed than ICS or leukotriene modifiers alone to older children (OR = 1.06) and to patients experiencing frequent wheezing (OR = 3.00), ED visits (OR = 3.12), or tobacco smoke exposure during the first 2 years of life (OR = 2.04). Finally, PCP's characteristics significantly associated with ICS plus leukotriene modifiers prescription were group practice (OR = 4.16) and a high prescribing volume (OR = 1.45). Our findings suggest that child characteristics alone are not sufficient to explain how PCPs decide to prescribe maintenance treatment and which therapy to assign, but variables associated to PCPs are crucial as well.

Does consideration of larger study areas yield more accurate estimates of air pollution health effects? An illustration of the bias-variance trade-off in air pollution epidemiology

BACKGROUND

Spatially-resolved air pollution models can be developed in large areas. The resulting increased exposure contrasts and population size offer opportunities to better characterize the effect of atmospheric pollutants on respiratory health. However the heterogeneity of these areas may also enhance the potential for confounding. We aimed to discuss some analytical approaches to handle this trade-off.

METHODS

We modeled NO2 and PM10 concentrations at the home addresses of 1082 pregnant mothers from EDEN cohort living in and around urban areas, using ADMS dispersion model. Simulations were performed to identify the best strategy to limit confounding by unmeasured factors varying with area type. We examined the relation between modeled concentrations and respiratory health in infants using regression models with and without adjustment or interaction terms with area type.

RESULTS

Simulations indicated that adjustment for area limited the bias due to unmeasured confounders varying with area at the costs of a slight decrease in statistical power. In our cohort, rural and urban areas differed for air pollution levels and for many factors associated with respiratory health and exposure. Area tended to modify effect measures of air pollution on respiratory health.

CONCLUSIONS

Increasing the size of the study area also increases the potential for residual confounding. Our simulations suggest that adjusting for type of area is a good option to limit residual confounding due to area-associated factors without restricting the area size. Other statistical approaches developed in the field of spatial epidemiology are an alternative to control for poorly-measured spatially-varying confounders.

Onset and persistence of respiratory/allergic symptoms in preschoolers: new insights from the PARIS birth cohort

BACKGROUND

The natural course of childhood asthma and allergy is complex and not fully understood. We aimed to identify phenotypes based upon the time course of respiratory/allergic symptoms throughout preschool years.

METHODS

As part of the PARIS cohort, symptoms of wheezing, dry night cough, rhinitis and dermatitis were collected annually from birth to age 4 years. K-means clustering was used to group into phenotypes children with similar symptoms trajectories over the study period. Associations of phenotypes with IgE sensitization and risk factors were studied using multinomial logistic regression.

RESULTS

Besides a group with low prevalence of symptoms considered as reference (n = 1236, 49.0%), four distinct respiratory/allergic phenotypes were identified: two transient [transient rhinitis phenotype (n = 295, 11.7%), transient wheeze phenotype (n = 399, 15.8%)], without any relation with IgE sensitization, and two persistent [cough/rhinitis phenotype (n = 284, 11.3%), dermatitis phenotype (n = 308, 12.2%)], associated with IgE sensitization. Transient rhinitis phenotype was only associated with tobacco smoke exposure, which could irritate the airways. Transient wheeze phenotype was related to male sex and contact with other children (older siblings, day care attendance). Lastly, risk factors for both IgE-associated phenotypes encompassed parental history of allergy, potential exposure to allergens and stress, known to be associated with the development of allergic diseases.

CONCLUSION

This study provides evidence for the existence of different respiratory/allergic phenotypes before school age. The fact that they differ in terms of sensitization and risk factors reinforces the plausibility of distinct phenotypes, potentially linked to irritation and infections for the transient phenotypes and to allergy for the persistent phenotypes.

Dry night cough as a marker of allergy in preschool children: the PARIS birth cohort

BACKGROUND

Early detection of children at risk for developing allergy is an important challenge. Our first analyses in infants from the Pollution and Asthma Risk: an Infant Study (PARIS) birth cohort suggested that dry night cough was associated with parental-reported allergic disorders. The aim of the present study was to refine this finding by investigating the time course of dry night cough from birth to age 4 yr in relation to blood markers of atopy and allergic morbidity.

METHODS

Health outcomes were regularly assessed by parental self-administered questionnaires. Blood markers of atopy were measured at age 18 months. Children with similar patterns of dry night cough over the first 4 yr of life were grouped together using k-means clustering. Associations with atopy/allergy were studied using multinomial logistic regression.

RESULTS

Three trajectories of dry night cough were identified in 1869 children. Besides the never/infrequent pattern (72.4%), the transient pattern (8.8%) was composed of children who coughed in the first year and recovered by age 4 yr, while the rising pattern (18.8%) included all symptomatic children at age 4 yr, whether they were persistent or late coughers. Compared with the never/infrequent pattern, the rising pattern was significantly associated with elevated total immunoglobulin E (IgE) level (odds ratio [OR] = 1.70, 95% confidence interval [CI] = 1.21-2.39) and inhalant allergens sensitization (OR = 2.66, 95% CI = 1.26-5.61) at age 18 months, and with doctor-diagnosed allergic diseases over the first 4 yr such as hay fever (OR = 2.52, 95% CI = 1.49-4.26) and eczema (OR = 1.29, 95% CI = 1.00-1.66).

CONCLUSIONS

This study provides evidence that persistent/late dry night cough may indicate allergy in preschool children.

Cough and dyspnoea may discriminate allergic and infectious respiratory phenotypes in infancy

Asthma symptoms are non-specific during infancy, making the identification of different subgroups among preschool children with early respiratory manifestations an important challenge. We previously used a clustering approach to identify bronchial obstructive phenotypes in 1-yr-old infants from the Pollution and Asthma Risk: an Infant Study (PARIS) birth cohort. In the present study, we examined whether these phenotypes were stable at 3 yr and studied their comorbidity and risk factors. Partitioning around medoids (PAM) method was applied at 1 and 3 yr of age to cluster children according to wheezing, dry night cough, dyspnoea with sleep disturbance and breathlessness. The resulting groups were used to derive phenotypes in 2084 children during their first 3 yr of life. Analysis of associated comorbidity and risk factors was conducted using multinomial logistic regression. PAM groups were similarly defined at both ages so that two respiratory phenotypes were identified between birth and 3 yr: cough phenotype (CP) and dyspnoea phenotype (DP) including 14.1% and 30.7% of children, respectively. CP infants experienced more often allergic features than DP, dominated by respiratory infections. Parental history of allergy, potential allergen exposure and psychosocial factors were associated with CP. Day care centre attendance was more frequent in DP as well as exposure to domestic chemical pollution, suggesting a greater vulnerability to pathogens. Finally, dry night cough and dyspnoea disturbing the sleep appear to be markers of two respiratory profiles potentially allergic and infectious before 3 yr old.

Novel severe wheezy young children phenotypes: boys atopic multiple-trigger and girls nonatopic uncontrolled wheeze

BACKGROUND

Recurrent wheezing during infancy is a heterogeneous disorder that has been associated with early-onset asthma.

OBJECTIVE

To identify phenotypes of severe recurrent wheezing and therapeutic approaches.

METHODS

We performed cluster analysis with 20 variables of 551 children with active asthma, younger than 36 months old, and enrolled in the Trousseau Asthma Program.

RESULTS

We identified 3 independent clusters of children with wheezing. Cluster 1, mild episodic viral wheeze (n= 327), consisted of children with wheezing related only to colds (71%), mild disease (76%), and mainly normal chest x-ray results. Cluster 2, nonatopic uncontrolled wheeze (n = 157), was characterized by moderate to severe disease (91%), uncontrolled wheezing despite high doses of inhaled corticosteroids (55%), parents with asthma, and increased levels of ferritine. Cluster 3, atopic multiple-trigger wheeze (n = 67), included more children with multiple-trigger wheeze (68%) than did clusters 1 or 2; eczema (75%); a positive result from the Phadiatop Infant test (90%); increased levels of IgE, IgA, and IgG; and abnormal results from chest x-rays. In separate analysis, 1 parameter for boys (increased total level of IgE) and 2 parameters for girls (wheezing severity and increased total level of IgE) properly classified 90% of boys and 83% of girls in the appropriate cluster. Significant associations were found between overcrowding, molds and cockroaches at home, and atopic multiple-trigger wheeze and between day-care attendance and nonatopic uncontrolled wheeze in other parts.

CONCLUSION

We identified different phenotypes of recurrent wheezing in young children by using cluster analysis with usual variables. These phenotypes require confirmation in longer, follow-up studies.

Understanding the complexity of IgE-related phenotypes from childhood to young adulthood: a Mechanisms of the Development of Allergy (MeDALL) seminar

Mechanisms of the Development of Allergy (MeDALL), a Seventh Framework Program European Union project, aims to generate novel knowledge on the mechanisms of initiation of allergy. Precise phenotypes of IgE-mediated allergic diseases will be defined in MeDALL. As part of MeDALL, a scientific seminar was held on January 24, 2011, to review current knowledge on the IgE-related phenotypes and to explore how a multidisciplinary effort could result in a new integrative translational approach. This article provides a summary of the meeting. It develops challenges in IgE-related phenotypes and new clinical and epidemiologic approaches to the investigation of allergic phenotypes, including cluster analysis, scale-free models, candidate biomarkers, and IgE microarrays; the particular case of severe asthma was reviewed. Then novel approaches to the IgE-associated phenotypes are reviewed from the individual mechanisms to the systems, including epigenetics, human in vitro immunology, systems biology, and animal models. The last chapter deals with the understanding of the population-based IgE-associated phenotypes in children and adolescents, including age effect in terms of maturation, observed effects of early-life exposures and shift of focus from early life to pregnancy, gene-environment interactions, cohort effects, and time trends in patients with allergic diseases. This review helps to define phenotypes of allergic diseases in MeDALL.

MeDALL (Mechanisms of the Development of ALLergy): an integrated approach from phenotypes to systems medicine

The origin of the epidemic of IgE-associated (allergic) diseases is unclear. MeDALL (Mechanisms of the Development of ALLergy), an FP7 European Union project (No. 264357), aims to generate novel knowledge on the mechanisms of initiation of allergy and to propose early diagnosis, prevention, and targets for therapy. A novel phenotype definition and an integrative translational approach are needed to understand how a network of molecular and environmental factors can lead to complex allergic diseases. A novel, stepwise, large-scale, and integrative approach will be led by a network of complementary experts in allergy, epidemiology, allergen biochemistry, immunology, molecular biology, epigenetics, functional genomics, bioinformatics, computational and systems biology. The following steps are proposed: (i) Identification of 'classical' and 'novel' phenotypes in existing birth cohorts; (ii) Building discovery of the relevant mechanisms in IgE-associated allergic diseases in existing longitudinal birth cohorts and Karelian children; (iii) Validation and redefinition of classical and novel phenotypes of IgE-associated allergic diseases; and (iv) Translational integration of systems biology outcomes into health care, including societal aspects. MeDALL will lead to: (i) A better understanding of allergic phenotypes, thus expanding current knowledge of the genomic and environmental determinants of allergic diseases in an integrative way; (ii) Novel diagnostic tools for the early diagnosis of allergy, targets for the development of novel treatment modalities, and prevention of allergic diseases; (iii) Improving the health of European citizens as well as increasing the competitiveness and boosting the innovative capacity of Europe, while addressing global health issues and ethical issues.

Does allergic rhinitis exist in infancy? Findings from the PARIS birth cohort

BACKGROUND

  Early onset of allergic rhinitis (AR) is poorly described, and rhinitis symptoms are often attributed to infections. This study analyses the relations between AR-like symptoms and atopy in infancy in the PARIS (Pollution and Asthma Risk: an Infant Study) birth cohort.

METHODS

  Data on AR-like symptoms (runny nose, blocked nose, sneezing apart from a cold) were collected using a standardized questionnaire administered during the health examination at age 18 months included in the follow-up of the PARIS birth cohort. Parental history of allergy and children's atopy blood markers (blood eosinophilia ≥470 eosinophils/mm(3) , total immunoglobulin E ≥45 U/ml and presence of allergen-specific IgE) were assessed. Associations were studied using multivariate logistic regression models adjusted for potential confounders.

RESULTS

  Prevalence of AR-like symptoms in the past year was 9.1% of the 1850 toddlers of the study cohort. AR-like symptoms and dry cough apart from a cold were frequent comorbid conditions. Parental history of AR in both parents increased the risk of suffering from AR-like symptoms with an OR 2.09 (P=0.036). Significant associations were found with the presence of concurrent biological markers of atopy, especially blood eosinophilia and sensitization to house dust mite (OR 1.54, P=0.046 and OR 2.91, P=0.042) whereas there was no relation with sensitization to food.

CONCLUSIONS

  These results support the hypothesis that AR could begin as early as 18 months of life. Suspicion of AR should be reinforced in infants with parental history of AR or biological evidence of atopy, particularly blood eosinophilia and sensitization to inhalant allergens.

Phenotypes of childhood asthma: are they real?

It has been suggested that there are several distinct phenotypes of childhood asthma or childhood wheezing. Here, we review the research relating to these phenotypes, with a focus on the methods used to define and validate them. Childhood wheezing disorders manifest themselves in a range of observable (phenotypic) features such as lung function, bronchial responsiveness, atopy and a highly variable time course (prognosis). The underlying causes are not sufficiently understood to define disease entities based on aetiology. Nevertheless, there is a need for a classification that would (i) facilitate research into aetiology and pathophysiology, (ii) allow targeted treatment and preventive measures and (iii) improve the prediction of long-term outcome. Classical attempts to define phenotypes have been one-dimensional, relying on few or single features such as triggers (exclusive viral wheeze vs. multiple trigger wheeze) or time course (early transient wheeze, persistent and late onset wheeze). These definitions are simple but essentially subjective. Recently, a multi-dimensional approach has been adopted. This approach is based on a wide range of features and relies on multivariate methods such as cluster or latent class analysis. Phenotypes identified in this manner are more complex but arguably more objective. Although phenotypes have an undisputed standing in current research on childhood asthma and wheezing, there is confusion about the meaning of the term 'phenotype' causing much circular debate. If phenotypes are meant to represent 'real' underlying disease entities rather than superficial features, there is a need for validation and harmonization of definitions. The multi-dimensional approach allows validation by replication across different populations and may contribute to a more reliable classification of childhood wheezing disorders and to improved precision of research relying on phenotype recognition, particularly in genetics. Ultimately, the underlying pathophysiology and aetiology will need to be understood to properly characterize the diseases causing recurrent wheeze in children.

Exposure to traffic exhaust and night cough during early childhood: the CCAAPS birth cohort

Though studies have investigated the association between air pollution and respiratory health outcomes in children, few have focused on night cough. The study objective was to simultaneously evaluate family factors (i.e., race, gender, maternal and paternal asthma, and breastfeeding), health (allergen sensitization and wheezing symptoms), home factors (dog, cat, mold, endotoxin, and dust mite), and other environmental exposures (traffic exhaust and second-hand tobacco smoke) for associations with recurrent dry night cough (RNC) during early childhood. A structural equation model with repeat measures was developed assessing RNC at ages one, two, and three. The prevalence of RNC was relatively large and similar at ages, one, two, and three at 21.6%, 17.3%, and 21.1%, respectively. Children exposed to the highest tertile of traffic exhaust had an estimated 45% increase in risk of RNC compared with children less exposed (adjusted OR 1.45, 95% CI: 1.09, 1.94). Also, wheezing was associated with a 76% higher risk of RNC (adjusted OR 1.76, 95% CI: 1.36, 2.26). A protective trend for breastfeeding was found with a 27% reduction in risk associated with breastfeeding (adjusted OR 0.73, 95% CI: 0.53, 1.01). No other factors were significant. These results suggest that traffic exhaust exposure may be a risk factor for night cough in young children.