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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Placing a Lens on the First 1000 Days of Life: Prenatal Intake, Infant Feeding, the Microbiome and Child Growth

Rana Chehab (11139342) 26 July 2021 (has links)
<div>The first 1000 days of life, from conception until the child’s second birthday, constitute a critical window for child growth and development. During infancy and early childhood, significant and rapid physical changes occur, including increases in weight, height, and brain size and organ development accompanied by cognitive and psychomotor development. Adequate infant feeding, including breastfeeding and complementary feeding, that meets the infants’ energy and nutrient requirements can help protect against growth faltering, infant and child morbidity and mortality, and delayed mental and motor development. Adequate nutrition during this critical period can also protect against adverse health outcomes and chronic diseases later in life according to the hypothesis of developmental origins of health and disease.</div><div><br></div><div>A web of factors that are country- and culture- specific influence infant feeding practices and child growth. Further, the microbiome has been suggested as a strong potential player in the association between infant nutrition and child growth. Therefore, the overarching theme of the current dissertation is to investigate hypotheses that can provide evidence to inform the paradigm linking socio-demographic, maternal, and child determinants including prenatal intake to infant feeding, the breast milk and infant gut microbiome, and child growth within the first 1000 days of life. Specifically, aims one and two examine the socio-demographic, maternal, and child determinants of child growth and breastfeeding in a cross-sectional survey of mother-child dyads in Lebanon, a middle-income country undergoing nutrition transition in the Middle East. The third aim focuses on the CHILD cohort study, a multi-center longitudinal prospective birth cohort study, to examine the associations between prenatal diet and supplement intake and the breast milk microbiome. Finally, the fourth aim is to review the evidence for the potential of the infant gut microbiome as a promising target linking complementary feeding to child undernutrition in low- and middle- income countries (LMIC) with the highest burden of undernutrition.</div><div><br></div><div>The results for aim one revealed sex-specific determinants of child growth in Lebanon. The determinants examined through a hierarchical conceptual framework included: maternal and paternal education among boys and crowding index among girls at the distal sociodemographic level, and maternal obesity among girls at the intermediate maternal level. The proximal child determinants included birth length, number of children in the household and breastfeeding duration among girls, birthweight among boys and child’s age among boys and girls.</div><div><br></div><div>In the analysis for aim two, breastfeeding practices were suboptimal in Lebanon as less than half (41.5%) of the infants were exclusively breastfed during the 40-day rest period and 12.3% were exclusively breastfed during the 6-month duration recommended by the World Health Organization. Higher socioeconomic status, as reflected by a larger number of cars owned, and C-section delivery were consistently inversely associated with lower odds of exclusive breastfeeding for 40 days and 6 months. Belonging to a family with more children was associated with higher odds of exclusive breastfeeding for 40 days; while maternal overweight and obesity were associated with lower odds of exclusive breastfeeding for 6 months.</div><div><br></div><div>Findings from aim three suggested that prenatal supplement use, but not prenatal dietary quality and patterns, modulate the breast milk microbiota composition in the CHILD cohort in Canada. This project was exploratory and utilized one of the largest birth cohort studies with available breast milk microbiome data. Specifically, use of vitamin C and D supplements plus multivitamins during any trimester in pregnancy was consistently associated with milk microbial diversity and genus composition before and after adjustment for socio-demographic, maternal, and child covariates. Use of other supplements such as fish oil, folate, and calcium was less consistently associated with the breast milk microbiome.</div><div>The fourth aim of the review chapter focused on the infant gut microbiome. The effects of complementary feeding on the infant gut microbiome are less commonly studied than those of breastfeeding, with most research conducted in high-income countries but not LMIC. In contrast, associations between inadequate complementary feeding and undernutrition have been examined in LMIC where undernutrition is most prevalent. Further, a disrupted gut microbiota has been associated with child undernutrition. Indeed, animal studies have suggested a causal association although the direction of the causality is not clear and is potentially bi-directional depending on genetic and environmental conditions. In light of the current state of knowledge described in our review supporting the potential of the gut microbiota as a key player in the relation between complementary feeding and undernutrition, the development of microbiota-directed interventions during the complementary period offers a promising route for undernutrition management.</div><div><br></div><div>Findings from the studies presented in this dissertation highlight several culture-specific determinants of child growth and breastfeeding in Lebanon. The findings also highlight the need for future research using longitudinal prospective cohorts, intervention trails and animal models to provide evidence for the proposed links to enhance the understanding of the paradigm. Such a holistic view of the determinants of and pathways between infant feeding and child growth are of great public health significance to improve the health of children throughout their lives.</div>
2

Intermediate Effects of a Social Ecological Modeled, Community-Based Intervention on the Food Security and Dietary Intake of Rural, Midwestern, Adult Food Pantry Clients

Breanne N. Wright (5930408) 14 May 2019 (has links)
<p>Food insecurity, or limited access to enough foods for an active, healthy life, characterizes the situation of 65% of US food pantry clients. Food insecurity is associated with poor dietary intake of key food groups and nutrients, diet-related chronic disease, poor physical and mental health, and reduced quality of life. Although food pantry clients are prevalently food insecure, there is a sizeable proportion of clients who are classified as food secure (FS), or report having adequate access to healthy foods. Previous studies suggest that food secure pantry clients may use pantry resources differently, and have diets that differ in quality and intake, compared to food insecure clients (including low food secure [LFS] and very low food secure [VLFS] clients). </p><p>Food pantries may be an important venue for interventions to improve food security and dietary outcomes. Since dietary intake and use of food pantries may differ by food security status, the efficacy of such interventions may also differ by food security status. A social ecological modeled (SEM), community-based intervention in the food pantry setting is promising in sustaining local change efforts and may facilitate long-term implementation of strategies to improve diet-related outcomes among food pantry clients. Therefore, the aims of this dissertation were to 1) characterize differences in diet quality and intake between FS, LFS and VLFS pantry clients; 2) explore associations between the nutritional quality of the pantry food environment (foods in stock and foods distributed to clients) and client diet quality by food security status; and 3) evaluate the intermediate effects of a SEM, community-based intervention to improve diet-related outcomes among pantry clients with comparison by food security status.</p><p>Aim 1 was addressed by examining associations between food security and both diet quality and usual intake (in separate mixed multiple linear regression models) in a cross-sectional analysis of adult food pantry clients at baseline. FS status was associated with a higher Healthy Eating Index-2010 (HEI-2010) whole grains score, as well as a higher mean usual intakes of whole grains and iron, compared to LFS status. FS status was also associated with higher mean usual intakes of dark green vegetables and total dairy compared to LFS and VLFS status.</p><p>Aim 2 was addressed by evaluating the relationship between the quality of the mix of foods in stock (pantry inventories) and distributed (client food bags) at food pantries with client diet quality, and investigating how these relationships varied by food security status, in a cross-sectional analysis of adult food pantry clients at baseline. Client food bag HEI-2010 scores were positively associated with client diet scores for the total vegetables, total fruit, total protein foods, and sodium components, while pantry inventory HEI-2010 scores were negatively associated with client diet scores for the total score and for the total fruit and fatty acids components. VLFS clients consumed more whole grains from client food bags compared to FS clients, and consumed more greens and beans from pantry inventories compared to LFS clients.</p><p>Aim 3 was addressed by evaluating longitudinal changes in adult food security, diet quality and usual intake over the first two years (baseline to midpoint) of a three-year SEM, community-based food pantry intervention‒ Voices for Food (Clinical Trial Registry: NCT0356609). Adult food security score improved in the intervention group, while HEI-2010 total score and several component scores improved in the comparison group. When comparing the change in main outcomes over time between the intervention and comparison groups, no favorable differences were observed at this intermediate time point.</p><p> </p><p>Food pantries do not comprise a homogeneous population of clients. Pantry clients have different quality diets and rely on pantries to acquire different types of foods depending on their food security status. Food pantries may be an important venue to target interventions that improve diet-related outcomes, with consideration for the complex interplay between food security status, the pantry food environment and availability of resources to prepare healthy foods. Evaluation of the final study time point, as well as further investigation of the dose-dependent effect of each intervention component and other individual community characteristics, may elucidate the relationship between the intervention and client outcomes.</p><p></p>
3

Novel School-Based Strategies to Improve Participation in the School Breakfast Program, Diet Quality, and Cognitive Performance in Adolescents

Steve M. Douglas (6619109) 15 May 2019
<p>Observational evidence links breakfast skipping, a behavior frequently observed among adolescents, with other poor health related behaviors that perpetuates a lifestyle associated with poor weight management and decreased cognitive performance. Furthermore, evidence suggests that both the consumption of breakfast and the quality of breakfast consumed may influence both weight and cognitive performance related outcomes. In an effort to improve the prevalence of breakfast consumption and the quality of breakfasts consumed among adolescents, recent initiatives have sought to increase participation in the federal School Breakfast Program (SBP). </p><p>The main objectives of this dissertation were to determine: 1) whether the habitual consumption of breakfast influences perceived appetite following the consumption of breakfast and whether habitual breakfast consumption influences post prandial appetitive sensations following the consumption of breakfasts varying in macronutrient distribution; 2) the feasibility of consuming an egg-based, ‘Breakfast in the Classroom’ (BIC) program in 8th grade students and whether the daily consumption of egg-based breakfasts improve School Breakfast Program participation, the quality of breakfasts consumed, and snacking behavior in 8th grade students; and 3) whether differences in cognitive performance exist between 6th-8th grade students who consume school breakfast, students who consume breakfast at home only, and students who skip breakfast following the initiation of a higher-protein Breakfast in the Classroom program. </p><p>This dissertation is organized into chapters that consist of published manuscripts or manuscripts formatted for submission to peer-reviewed journals. Chapter 2 consists of comprehensive review of the evidence linking breakfast consumption and composition to obesity and cognitive performance with an emphasis on the recent advances in school breakfast programs and future directions. Chapter 3 evaluates whether the habitual consumption of breakfast influences perceived appetite following the consumption of breakfast and whether habitual breakfast consumption influences postprandial appetitive sensations following the consumption of breakfasts varying in macronutrient distribution. Chapter 4 examines the feasibility of implementing an egg-based BIC program and subsequent effects on SBP participation, the quality of breakfasts consumed, and evening snacking in 8th grade students. Chapter 5 examines differences in cognitive performance between 6th-8th grade students who consume school breakfast, students who consume breakfast at home only, and students who skip breakfast following a higher-protein BIC. Chapter 6 summarizes the main findings and presents considerations for future research.</p><p>Collectively, the findings from this dissertation demonstrate:1) consuming 30 grams of protein at breakfast improves appetite and satiety compared to a breakfast containing 15 grams of protein, independent of habitual breakfast consumption in overweight adolescent females; 2) implementing a universally-free ‘Breakfast in the Classroom’ program that serves two additional eggs to a traditional school breakfast served via a traditional SBP is feasible and improves SBP participation, the quality of breakfast consumed, and reduces unhealthy evening snacking; and 3) students who consume breakfast at school, as part of a higher-protein BIC program, perform better on tasks assessing cognitive flexibility and executive function in middle school students when compared to students who skip breakfast, regardless of key behavioral and/or socioeconomic factors. Thus, this work suggests increasing protein content of school breakfasts using a universally-free distribution program is feasible and may provide benefits on overall diet quality and cognitive performance for 6th-8th grade students. <br></p>

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