PLoS One

OBJECTIVE: Different phenotypes of wheezing have been described to date but not in early life. We aim to describe wheezing phenotypes between the ages of two months and one year, and assess risk factors associated with these wheezing phenotypes in a large birth cohort. METHODS: We studied 18,041 infants from the ELFE (French Longitudinal Study of Children) birth cohort. Parents reported wheezing and respiratory symptoms at two and 12 months, and answered a complete questionnaire (exposure during pregnancy, parental allergy). RESULTS: Children with no symptoms (controls) accounted for 77.2%, 2.1% had had wheezing at two months but no wheezing at one year (intermittent), 2.4% had persistent wheezing, while 18.3% had incident wheezing at one year. Comparing persistent wheezing to controls showed that having one sibling (ORa = 2.19) or 2 siblings (ORa = 2.23) compared to none, nocturnal cough (OR = 5.2), respiratory distress (OR = 4.1) and excess bronchial secretions (OR = 3.47) at two months, reflux in the child at 2 months (OR = 1.55), maternal history of asthma (OR = 1.46) and maternal smoking during pregnancy (OR = 1.57) were significantly associated with persistent wheezing. These same factors, along with cutaneous rash in the child at 2 months (OR = 1.13) and paternal history of asthma (OR = 1.32) were significantly associated with increased odds of incident wheezing. Having one sibling (ORa = 1.9) compared to none, nocturnal cough at 2 months (OR = 1.76) and excess bronchial secretions at 2 months (OR = 1.65) were significantly associated with persistent compared to intermittent wheezing. CONCLUSION: Respiratory symptoms (cough, respiratory distress, and excessive bronchial secretion) were significantly associated with a high risk of persistent wheezing at one year. Smoking exposure during pregnancy was also a risk factor for persistent and incident wheezing

Rationales, design and recruitment for the Elfe longitudinal study

Background Many factors act simultaneously in childhood to influence health status, life chances and well being, including pre-birth influences, the environmental pollutants of early life, health status but also the social influences of family and school. A cohort study is needed to disentangle these influences and explore attribution. Methods Elfe will be a nationally representative cohort of 20 000 children followed from birth to adulthood using a multidisciplinary approach. The cohort will be based on the INSEE Permanent Demographic Panel (EDP) established using census data and civil records. The sample size has been defined in order to match the representativeness criteria and to obtain some prevalence estimation, but also to address the research area of low exposure/rare effects. The cohort will be based on repeated surveys by face to face or phone interview (at birth and each year) as well as medical interview (at 2 years) and examination (at 6 years). Furthermore, biological samples will be taken at birth to evaluate the foetal exposition to toxic substances, environmental sensors will be placed in the child's homes. Pilot studies have been initiated in 2007 (500 children) with an overall acceptance rate of 55% and are currently under progress, the 2-year survey being carried out in October this year. Discussion The longitudinal study will provide a unique source of data to analyse the development of children in their environment, to study the various factors interacting throughout the life course up to adulthood and to determine the impact of childhood experience on the individual's physical, psychological, social and professional development

Intérêts et limites des suivis de cohorte pour comprendre les situations de handicap de l'enfant

International audienceDevelopments in situational and relational perspective of disability and the emergence of the concept "special educational needs" incite taking into account the individual needs of each child since early childhood. To study and to understand the relationship between family background, socioeconomic factors and experiences, quantitative databases built in a longitudinal perspective are an opportunity. They allow considering the BEP and / or handicap situations, in a life span perspective, when they occur or when they are taken into account in the child's path. Our paper attempts to discuss the interests and the limits to use such bases to study the primary childhood of these children. Two extensive and pluridisciplinary cohorts are presented: the Millennium Cohort Study and the National Educational Panel Study. Two French cohorts are described specifically: ELFE and Epipage-2. The conclusion put in perspectives the frequent critics addressed to cohorts with their utility to study the children in situation of disability.L'évolution des compréhensions du handicap dans une perspective situationnelle et relationnelle, et l'apparition du concept « besoins éducatifs particuliers » (BEP), incitent à prendre en compte des besoins individuels de chaque enfant et ce, dès la prime enfance. Dans cette perspective, les bases de données quantitatives construites avec un recueil longitudinal sont une opportunité pour étudier et comprendre les liens entre le con-texte familial, les éléments socio-économiques et les expériences vécues. Elles permettent de considérer les BEP et/ou les situations de handicap, dans une perspective vie entière, dès leur apparition, ou dès leur prise en compte, dans le parcours de l'enfant. Notre article se propose de discuter les intérêts et limites de telles bases pour aborder la petite enfance de ces enfants. Deux cohortes pluridisciplinaires de grande envergure sont présentées : la Millennium Cohort Study et la National Educational Panel Study. Deux cohortes françaises sont décrites plus précisément : ELFE et Epipage-2. La conclusion met en perspective les critiques fréquemment adressées aux cohortes avec leur pertinence pour étudier les enfants en situation de handicap

A robust numerical model for the pre-design of composite reinforcement by expanded bonded bushing (EB²)

For many years now, composite materials have been used for aeronautical and space structures. In order to join composite parts together or with metallic parts, classical bolted assembly technologies are generally employed, after being slightly adapted to these new configurations. Thus, for composite bolted joints the load transfer is mainly performed through the contact between the fastener’s pin and the composite hole. This type of contact generates high local stress concentration around the hole, which then requires to be reinforced. One solution consists in adding a metallic ring inside the hole, which allows reducing the load along a part of the composite hole. Different processes can be used: expansion, bonding or simple setting.CapAero developed EB² (Expanded Bonded Bushing), an innovative technique for ring reinforcement by expansion and bonding. This process provides the advantage of not requiring any specific device for bonding, since the adhesive lies in its microencapsulated form and is already part of the semi-product. The expansion of the pre-coated ring, with a mandrel, mainly aims at crushing the capsules inside the adhesive and mixing the two components together, but also at setting up a light radial preload inside the composite. The combination of expansion and bonding gives the joint better stiffness and failure strength for bearing loads, since the presence of the adhesive allows the load reduction all around the hole, and not only along a part of it.For the metallic case, the ring design usually relies on hardening criteria but for composite joints, a damage initiation is not desirable. Consequently, the design rules are totally different. For now, no design tools dedicated to composite yet exist. A particular design method has then to be defined, and its application requires the control of the expansion rate applied. Indeed, a low expansion does not allow improving mechanical performance, but a too high expansion can lead to premature bearing damage in the composite. Given the potential combination of manufacturing tolerances in stakes in the joint, only taking into consideration the nominal optimal geometry is not enough.The present study first introduces the development of an axisymmetric finite element model, for a robust predesign. This model is used to run a high number of simulations, which takes into account different manufacturing variabilities. According to specifications, the analysis of residual stresses and circumferential strains allows the choice of proper ring geometries. The finite element model is then numerically validated by a previously developed 3D finite element model which reproduces accurately the expansion process. Finally, the model predictions are compared to the results of experimental tests, for several values of expansion rate.The experimental test run has two objectives: the first one is to validate the numerical model, by measuring the expansion load and strains around the hole, for numerous geometries of specimens and for different variations of processes. The second one is to identify which expansion rate generates the best adhesive activation. Thus, after expansion, push-out tests are run on specimens, in order to estimate the joint quality by comparison of push-out loads between all configurations.The study brings conclusions about the relevance of such a tool and its limitations, and also the perspectives for this work, which could ultimately allow the study of bolted structures

Rationales, design and recruitment for the Elfe longitudinal study

Abstract Background Many factors act simultaneously in childhood to influence health status, life chances and well being, including pre-birth influences, the environmental pollutants of early life, health status but also the social influences of family and school. A cohort study is needed to disentangle these influences and explore attribution. Methods Elfe will be a nationally representative cohort of 20 000 children followed from birth to adulthood using a multidisciplinary approach. The cohort will be based on the INSEE Permanent Demographic Panel (EDP) established using census data and civil records. The sample size has been defined in order to match the representativeness criteria and to obtain some prevalence estimation, but also to address the research area of low exposure/rare effects. The cohort will be based on repeated surveys by face to face or phone interview (at birth and each year) as well as medical interview (at 2 years) and examination (at 6 years). Furthermore, biological samples will be taken at birth to evaluate the foetal exposition to toxic substances, environmental sensors will be placed in the child's homes. Pilot studies have been initiated in 2007 (500 children) with an overall acceptance rate of 55% and are currently under progress, the 2-year survey being carried out in October this year. Discussion The longitudinal study will provide a unique source of data to analyse the development of children in their environment, to study the various factors interacting throughout the life course up to adulthood and to determine the impact of childhood experience on the individual's physical, psychological, social and professional development.</p

Couverture vaccinale et déterminants socioéconomiques de la vaccination BCG chez l'enfant avant 3 mois : résultats de la cohorte Elfe, 2011

Position du problème L’obligation de vaccination par le Bacille Calmette et Guérin (BCG) a été remplacée en 2007 par une recommandation forte de vaccination des enfants les plus exposés à la tuberculose mais les données de couverture vaccinale (CV) sont insuffisantes. Nous avons estimé la CV à l’âge d’environ deux mois et identifié des déterminants socioéconomiques de vaccination. Méthodes L’étude longitudinale française depuis l’enfance (Elfe) a porté sur un échantillon aléatoire d’environ 18 000 enfants nés en 2011 sélectionnés à la naissance dans 320 maternités de France métropolitaine. Les informations ont été recueillies par questionnaire et par entretien téléphonique réalisés environ deux mois après l’accouchement. Les CV ont été estimées en Île-de-France (IDF) et hors IDF, et pour différents niveaux de risque de tuberculose, approché par l’origine géographique des parents. Des régressions de Poisson ont permis d’étudier les associations entre variables socioéconomiques et statut vaccinal BCG, exprimées par des rapports de prévalence (RP). Résultats La CV était plus élevée en IDF (59,5 %) comparée à celle des enfants à risque hors IDF (46,7 %) (p<0,001). Chez les enfants ayant deux parents originaires d’un pays de forte endémie tuberculeuse, elle était de 80,5 % en IDF et de 60,4 % hors IDF. Dans le modèle multivarié, le fait d’avoir un ou des parents originaires d’un pays de forte endémie tuberculeuse (RP autour de 1,40) ou d’avoir consulté un pédiatre libéral (RP autour de 1,15) ou un centre de PMI (RP autour de 1,40) après la sortie de maternité étaient associés à des CV plus élevées alors que des études supérieures chez la mère étaient associées à des CV plus faibles (RP=0,80). Conclusion La vaccination par le BCG est précoce après la sortie de la maternité. Les enfants ayant consulté en premier un pédiatre ou un médecin de PMI sont les mieux vaccinés. Les enfants à plus fort risque de tuberculose sont probablement bien identifiés par les médecins et mieux vaccinés

Cohort Profile: The French National cohort of children ELFE: birth to 5 years

ELFE is the first French national birth cohort. Its objective is to study determinants of the development, health and socialization of children from birth to adulthood through a multidisciplinary approach. A total of 18 329 children were recruited at birth in a random sample of maternity units in metropolitan France during 25 selected days of 2011 spread over the year. Follow-up in the first 5 years consisted of telephone interviews of both parents of the child at age 2 months and 1 year and 2 years, and of one parent at age 3.5 years; a home visit at age 3.5 years; questionnaires to the child’s physician at age 2 years, the child’s nursery school doctor at age 3 to 4 years, and the child’s nursery schoolteacher at age 4 years. Participation rates at the age 2-month, 1- and 2-year and 3.5-year parental interviews were 92%, 86%, 82% and 80%, espectively, of contacted participants. The main categories of data collected concern: sociodemographic characteristics; family life; parental health, behaviour and life values; child development and health; child school performance, behaviour, and socialization; day care and school; and childhood environmental exposures. The ELFE has an open-data policy after an 18-month exclusivity period following each release of new data. The data-access policy, study protocols, questionnaires and data catalogue can be found online: [https://www.ELFE-france.fr/en/

Constructing a Cohort: Experience with the French Elfe Project

The project to construct a multidisciplinary study cohort of 20,000 children to be monitored from birth to adulthood was launched in France in 2005. It was designed to address the concerns of various public bodies, especially those concerned with the environment, and researchers from a variety of disciplines. The result was the formation of the Elfe (Étude longitudinale française depuis l’enfance) longitudinal cohort of children, scheduled to commence in March/April 2011. The authors describe the origins of the project. The approach was deliberately intended to be multidisciplinary, and a large number of research teams were associated in designing the project, suggesting research questions in three major fields: social sciences, health and the links between health and the environment. To make the most of the life course approach, observations will be frequent (annually during the early years). A major place is given to fathers, who play an increasing role in children’s upbringing and socialization. The sample will be representative of births in 2011 throughout metropolitan France. The vast quantity of information to be collected and its highly personal nature require particular caution in the creation and management of data files, for which an innovative procedure will be used. The results of a pilot cohort study launched in 2007 are also presented. They cover several hundred families, whose children are now three years old

La construction d’une cohorte : l’expérience du projet français Elfe

Le projet de mise en place d’une cohorte pluridisciplinaire de 20 000 enfants suivis depuis la naissance jusqu’à l’âge adulte a été lancé en France en 2005. Il résulte de préoccupations de diverses instances publiques – notamment dans le domaine de l’environnement – comme de chercheurs de disciplines variées. L’aboutissement en a été la constitution de la cohorte Elfe, Étude longitudinale française depuis l’enfance, dont le démarrage est prévu en mars/avril 2011. Les auteurs retracent la genèse du projet. La démarche s’est voulue résolument pluridisciplinaire, et un grand nombre d’équipes de recherche ont été associées à l’élaboration du projet, en proposant des questions de recherche dans trois grands domaines : sciences sociales, santé et relations entre santé et environnement. Pour bénéficier au maximum de la puissance de la Life course approach, les observations seront fréquentes (annuelles pendant les premières années). Une place importante est faite aux pères, qui jouent un rôle croissant dans l’éducation et la socialisation des enfants. L’échantillon sera représentatif des naissances de l’année 2011 sur l’ensemble du territoire de France métropolitaine. La grande quantité d’informations collectées et leur caractère très personnel exigent une prudence particulière dans la constitution et la gestion des fichiers pour laquelle une procédure originale est mise en œuvre. Les résultats du suivi d’une cohorte pilote lancée en 2007 sont aussi présentés. Ils concernent plusieurs centaines de familles, dont les enfants ont maintenant 3 ans

EUROCONTROL Experimental Centre

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