Introduction Des études épidémiologiques ont montré qu'une restriction nutritionnelle pendant la grossesse pouvait conduire à une réponse adaptative du fœtus conduisant à une altération durable du métabolisme. Ainsi, les enfants nés avec un petit poids de naissance sont plus à risque de développer des maladies cardiovasculaires à l'âge adulte. L'exposition à des contaminants obésogènes pourrait également jouer un rôle dans l'augmentation du risque d'obésité. L’alimentation est une des principales voies d'exposition à ces contaminants. Après une description de la qualité de l’alimentation pendant la grossesse, l’objectif était d'étudier l'association entre l'exposition prénatale aux contaminants alimentaires et la croissance des enfants.MéthodesLes données de trois cohortes de naissance ont été utilisées : deux études françaises (EDEN et ELFE), et une étude norvégienne (MoBa). Les femmes de ces cohortes, ont rempli un questionnaire de fréquence alimentaire (QFA) portant sur l’alimentation pendant la grossesse. L'évaluation des contaminants a été réalisée en combinant le QFA et des bases de données de contamination, la deuxième Etude de l’Alimentation Total (EAT2) française pour EDEN et plusieurs bases de données de contamination pour MoBa. Premièrement dans ELFE, nous avons créé un score de qualité de l'alimentation et un score spécifique à la grossesse, puis nous avons étudié les facteurs associés à une meilleure qualité alimentaire. Ensuite, nous avons examiné l’association entre la qualité de l'alimentation et la croissance prénatale. Deuxièmement, nous avons étudié la relation entre un contaminant alimentaire : l'acrylamide (AA), et la croissance prénatale, dans EDEN, et la croissance postnatale, dans MoBa. Troisièmement, nous avons étendu nos analyses à tous les contaminants alimentaires de l’EAT2, en analysant les composés pris individuellement, puis considérés en mélange.RésultatsPremièrement, nous avons montré que les recommandations générales et spécifiques étaient globalement bien suivies par les femmes enceintes. Certaines caractéristiques socioéconomiques ou démographiques étaient associées à la fois au score de qualité de l’alimentation et au score spécifique de la grossesse telles que l’âge à l’accouchement, niveau d’étude et revenu du foyer et le tabagisme. Un score élevé de qualité de l’alimentation était associé à un poids de naissance plus élevé et un risque plus faible d'avoir un enfant petit pour l’âge gestationnel (PAG).Deuxièmement, nous avons montré que plus l'exposition pendant la grossesse à l’AA est importante, plus la taille de naissance était faible et plus le risque de PAG est élevé. Dans MoBa, nous avons constaté que l'exposition prénatale à l'AA était associée à une prévalence accrue d'enfants en surpoids ou obèses et à une plus grande vitesse de croissance du poids durant l’enfance.Dans EDEN, sur les 99 composés chimiques sélectionnés, le poids de naissance était associé négativement à l’exposition à quatre contaminants alimentaires et positivement à l’exposition à quatre autres. L'IMC à 5 ans était associé négativement à un contaminant. Aucune de ces associations étaient statistiquement significative après prise en compte de la multiplicité des tests. Lorsque les composés chimiques étaient considérés en mélanges, un mélange de contaminants était positivement associé au poids de naissance et aucun mélange n’était associé à l'IMC à 5 ans.ConclusionUne qualité de l’alimentation élevée est associée à un poids de naissance plus élevé et une diminution du risque de PAG, alors que l'exposition alimentaire à l'AA est associée à une altération de la croissance fœtale. L’exposition prénatale aux contaminants alimentaires, évaluée à partir des données d’EAT, ne semble pas préoccupante vis-à-vis de la croissance prénatale et postnatale précoce car les effets retrouvés sont de faible amplitude et ne sont plus significatifs après prise en compte des tests multiples. / Introduction Maternal diet is the only prenatal source of nutrients and the major source for non-nutrients and can influence foetal growth and offspring’s long-term health. Chemicals known as “obesogens” might also play a role in increasing obesity risk and one of the main route of exposure to these chemicals is through foods. After a description of diet quality during pregnancy, the aim of this thesis was to study the association between prenatal exposure to food chemicals and prenatal and postnatal growth among children.MethodsWe used the data of three birth cohort studies: two French studies (EDEN and ELFE), and a Norwegian study (MoBa). We first described the compliance to dietary guidelines of French pregnant women and the impact of a better diet quality on birth outcomes using the data of the ELFE study. Secondly, we studied the relationship of a specific food contaminant, acrylamide, on birth size in the EDEN and postnatal growth in MoBa. Finally, we extended analyses to all available food chemicals in the second French Total Diet Study (TDS).ResultsThe nutritional guidelines for pregnant women were rather well followed in ELFE. The diet quality score was associated with higher birth weight and lower risk of having a small for gestational (SGA) baby. We showed that prenatal dietary exposure to acrylamide was associated with reduced birth size in EDEN, and to increased postnatal growth in MoBA. In EDEN, on the 99 selected food chemicals, birth weight was associated with eight chemicals (four negatively and four positively). BMI at 5 years was associated with one food chemical. These results were not significant after correction for multiple testing. When using the mixture approach, one mixture of chemical was positively associated with postnatal growth.ConclusionsThe diet quality score was associated with higher birth size. Whereas dietary exposure to acrylamide was associated with impaired foetal growth, when looking at a larger number of food chemicals, we did not find concerning association on child prenatal or postnatal growth. Exposure to food chemical assessed by TDS did not appear to be of major concern for growth but other windows of susceptibility, such as early childhood, and other outcomes, such as cognitive development, should be considered in future studies.

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Background: According to the Centers for Disease Control and Prevention (CDC), over one-third of US adults are obese. In order to assess causes of and treatments for obesity, researchers have evaluated a number of processes underlying health-related behaviors, one of which is delay discounting. Delay discounting is a cognitive process that describes the phenomenon by which individuals discount the value of a future reward compared to the value of an immediate reward. Researchers have associated delay discounting with drug addiction, alcoholism, and cigarette smoking. More recently, delay discounting has been studied with regards to health-related behaviors, such as body weight management, food intake, glucose control, and physical activity. While a number of studies have concluded that obese individuals tend to be greater discounters, the relationship between delay discounting and various health-related behaviors beyond smoking and drug use remains unclear. The purpose of this study is to evaluate the relationship between delay discounting and diet quality, glucose tolerance, physical activity, and fasting vs. non-fasting conditions. Methods: Sixty-five males (n=20) and females (n=45) were recruited for the present study. Participants completed two lab sessions: one under non-fasting conditions, and one under fasting conditions which involved measurements of body mass and composition, blood pressure, blood glucose, blood lipids, and health-related questionnaires. Delay discounting and food purchase tasks were completed at both visits. Participants were asked to complete a four-day food intake record and wear a physical activity monitor for four days. Results: Lower rates of discounting were found in those who consumed more total vegetables, and lower food reinforcement was observed in those who spent less time sedentary and more time physically active, had greater dietary Restraint, and had a lower resting heart rate. There were no significant differences between discounting rates and food reinforcement across fasting and non-fasting conditions. / Master of Science / More than one-third of US adults are obese. Obesity brings with it a number of chronic health conditions as well as the financial burden of increased healthcare costs. There are a multitude of treatment methods for obesity, and researches have evaluated many aspects of behaviors that contribute to obesity. Decision-making processes are an important factor related to management of body weight as well as general health. One field of study concerned with decision-making is called behavioral economics, and it includes the concept of delay discounting. Delay discounting is a cognitive process by which individuals tend to discount the value of future rewards in favor of more immediate rewards. This behavior has been associated with drug use and addiction, alcoholism, and cigarette smoking, as well as a number of other psychological or social parameters. More recently, research has connected delay discounting with health-related factors such as body weight management, glucose control, physical activity, and diet quality. A number of studies have concluded that obese individuals tend to be greater discounters, meaning that they prefer immediate rewards rather than delaying gratification for future rewards, however the relationship between delay discounting and various health-related behaviors remains unclear. The purpose of this study is to evaluate the relationship between delay discounting and diet quality, glucose tolerance, physical activity, and fasting vs. nonfasting conditions. Methods: Sixty-five males (n=20) and females (n=45) were recruited for the present study. Participants completed two lab sessions: one under non-fasting conditions, and one under fasting conditions which involved measurements of body mass and composition, blood pressure, blood glucose, blood lipids, and health-related questionnaires. Delay discounting and food purchase tasks were completed at both visits. Participants were asked to complete a four-day food intake record and wear a physical activity monitor for four days. Results: Lower rates of discounting were found in those who consumed more total vegetables, and lower food reinforcement was observed in those who spent less time sedentary and more time physically active, had greater dietary Restraint, and had a lower resting heart rate. There were no significant differences between discounting rates and food reinforcement across fasting and non-fasting conditions.