STUDY OF GROWTH PATTERNS AND OBESITY, PUBERTAL DEVELOPMENT AND NEUROBEHAVIORAL DISORDERS OF 12-YEAR-OLD CHILDREN IN ASSOCIATION WITH EARLY EXPOSURES TO POLLUTANTS: THE PELAGIE BIRTH COHORT – PELAGIE12

Dès 2002, la cohorte PELAGIE a inclus près de 3500 femmes enceintes en Bretagne et suit l’environnement et la santé de leurs enfants. Aujourd’hui deux nouveaux protocoles de suivi des enfants PELAGIE sont mis en place : des questionnaires annuels « Grandir & Changer » entre les âges de 9 et 16 ans des enfants, et un examen clinique à 12 ans. Les mesures de la puberté incluent les caractères secondaires sexuels (développement de la poitrine, de la pilosité pubienne, testiculaire et la ménarche), les paramètres anthropométriques et des mesures hormonales. Le développement comportemental est évalué à l’aide d’outils auto-rapportés par l’enfant et par les parents. Les expositions prénatales et postnatales seront évaluées à partir de dosages chimiques réalisés à partir du prélèvement de sang de cordon (naissance) et de l’enfant (12 ans). Ces données seront complétées par des données de questionnaire renseignant sur les modes de vie et les activités des participants. Ce projet bénéficie de l’expertise importante de l’équipe de recherches épidémiologiques dans la mise en place et le suivi de cohortes longitudinales (Coord. INSERM-IRSET U1085, Rennes) et de la collaboration avec l’unité d’investigation clinique (CIC INSERM 1414) du Centre Hospitalier Universitaire de Rennes, qui soutient et facilite les activités de recherches en mettant à disposition le matériel, le personnel médical et les centres d’examen dans la région Bretagne.

Les suivis ont démarré à partir de septembre 2015. Malgré les contraintes pratiques fortes imposées aux familles (2 heures d’examen, à l’hôpital de Rennes, avec un parent accompagnant), le projet bénéficie d’un taux de participation des familles élevé pour le suivi par examen clinique (7/10 familles parmi celles qui sont jointes par téléphone), traduisant probablement une sensibilisation du Grand Public de plus en plus large à la santé environnementale.

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A large body of scientific evidence reports that exposure to pollutants early in life – during pregnancy and early childhood – might have an impact on development resulting in damaging effects on health across the lifespan. Pregnant women and children are exposed to a large number of environmental and occupational pollutants with the potential to act on the endocrine systems.
The mother-child PELAGIE cohort conducted in Brittany from 2002, included approximately 3500 pregnant women before 19 weeks of gestation. The women and their children were followed until birth and at ages 2 and 6. The cohort provided evidence that the early exposures to toxicants, such as solvents, current-used pesticides, polychlorinated biphenyls, may affect reproductive and developmental health, including fertility, intrauterine and postnatal growth, behavior, and asthma and allergy. It thus appears relevant to pursue the assessment of the long term impact of these toxicants on later development, in particular pubertal development.
The present project will investigate two research hypotheses. (1) Most of the persistent organic pollutants (POPs), such as organochlorine insecticides, polychlorinated biphenyls, brominated flame retardants, or perfluorinated compounds, have endocrine disrupting properties. Biomonitoring studies, including the PELAGIE cohort, have shown the presence of these POPs in biological samples in various European populations, and suggest that humans, including pregnant women, are regularly exposed to these compounds. In light of the various findings of the literature in which longitudinal studies with prospective exposure measurements are recommended, the present project aims at assessing the potential impact of the early exposure to POP compounds on growth, obesity and pubertal development. (2) Organic solvents, including glycol ethers, are present in numerous products of our domestic and occupational environments. They have well-known neurotoxic properties in adults. Our previous findings in the PELAGIE cohort reported higher levels of hyperactivity/impulsivity and aggression in 2-years-old children who were prenatally exposed to solvents; only three other studies have addressed the same issue and there is still insufficient evidence to draw firm conclusions. The present project will aim at pursuing the study of the effects of prenatal solvent exposure on neurobehavioral development in older children.
The program of the present project is to set up the follow-up of the PELAGIE children during their pubertal development. The follow-up will be conducted in two ways, using repeated self-questionnaires (every year between 9 and 16 years old), and with clinical examinations (at 12 years old). Measurements of puberty development will include the secondary sexual characteristics (breast, body and pubic hair, testicular and menarche development), anthropometric parameters (bone age, height, weight and body fat), and hormonal measurements. Neurobehavioral development, including autistic spectrum disorders, will be assessed at 12 years old of the child using self-reported and parent-reported instruments. Visual tests will be performed. Postnatal exposures will be assessed in the concurrent blood samples, and using questionnaire. This overall project will benefit from the robustness in the assessment of the early environmental exposures in the PELAGIE cohort, from the large expertise of the epidemiological research team in collecting longitudinal health data within birth cohort (Coord. epidemiological team of INSERM-IRSET U1085, Rennes), and from the collaboration with the hospital department (UIC Unité d’Investigation Clinique, CIC INSERM 1414, Rennes), which aims at facilitating the research activities by providing materials, medical personnel and examination centers in the Brittany area.