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Research Project: Epidemiology of Childhood Diet and Obesity

Location: Children's Nutrition Research Center

2021 Annual Report


Objectives
Objective 1: The National Health and Nutrition Examination Survey (NHANES) (2001-2014 and later releases) will be used to identify diet-related risk factors for obesity, and other health outcomes in children, adolescents, and adults specifically: Objective 1A: Identify eating patterns in children, adolescents and adults by gender and ethnicity, Objective 1B: Examine the association between eating patterns and obesity and related health risk factors, Objective 1C: Examine the impact of individual foods, nutrients, and food-specific patterns on obesity and health outcomes in children, adolescents, and adults. Objective 1D: Identify the impact of eating patterns on dietary intake, nutrient adequacy, and diet quality. Objective 2: Examine the rural-urban differences in and associations between food security status, food availability, participation in Federal nutrition assistance programs, dietary intake, and obesity among children across the different age groups, i.e., 2-5 years, 6-11 years, 12-15 years and 16-18 years old. Subobjective 2A: Examine the rural-urban differences in food security status (FSS) of children across the various age groups. Subobjective 2B: Determine the association of FSS with food availability and participation in federal nutrition assistance programs (FNAP) among children, based on rural-urban residence. Subobjective 2C: Determine the association of FSS with dietary intake and diet quality among children, based on rural-urban residence. Subobjective 2D: Determine the association between FSS and weight status of children, based on rural-urban residence. Objective 3: Determine the relationship between children’s physical activity, diet, sedentary behavior, and sleep, on summer weight gain in children and the impact of parenting on these behaviors using data from the Early Childhood Longitudinal Kindergarten 2011 Cohort, the Family Life, Activity, Sun, Health, and Eating study and others as appropriate. Subobjective 3A: Conduct a systematic review and meta-analysis of interventions for obesity prevention and treatment among school-age children targeting the summer months when children are not in school, and assessing their impact on BMI, PA, diet, sedentary behavior, and sleep. Subobjective 3B: Determine the number and types of distinct categorical body mass index (BMI) percentile trajectories in a longitudinal early childhood cohort and examine whether children's physical activity (PA), diet, sedentary behavior, sleep timing, child care arrangements, and medication usage predict developmental trajectory membership in order to inform obesity prevention interventions. Subobjective 3C: Examine the relationship between adolescents' BMI, physical activity, sedentary behavior, sleep and diet during in-school and out-of-school times and the impact of parenting practices on these behaviors.


Approach
Today, an estimated 16% of US children and adolescents are overweight and 17% are obese, and the prevalence continues to rise. Obesity is the result of energy imbalance, and dietary behaviors associated with overweight need to be examined. The long-term objective of this project is to better understand eating patterns, impact of food security status, rural/urban differences, and seasonal differences in weight-related behaviors that influence obesity and other health risk factors in children, adolescents, and adults. Few attempts have been made to identify broader eating patterns and their association with weight status and other chronic disease risk factors. This project aims to identify eating patterns--in terms of food sources, food group consumption, and nutrient intake--that may be associated with obesity and other health risk factors in children, adolescents, and adults using extant datasets. Also, food insecurity is related to poor dietary behaviors that can lead to net positive energy balance and obesity. Thus, we aim to assess the impact of food security status on dietary intake and quality, food availability, participation in federal food assistance programs, and weight status based on rural/urban residence. Finally, we will examine other behavioral predictors of children’s weight gain (i.e., sleep, physical activity, sedentary behavior) using the school-summer paradigm. Together this research will facilitate a better understanding of how to behaviorally target interventions to prevent obesity during childhood.


Progress Report
Three objectives (1B, 1C and 1D) were addressed to examine the impact of individual foods, nutrients and food specific patterns on adequacy, food group consumption and obesity and health outcomes in children (and infant/toddlers), adolescents and adults. Researchers conducted secondary data analyses using the national data set (National Health and Nutrition Examination Survey) [NHANES] for three of the studies. The most notable results showed that although 100% orange juice (OJ) consumption by Americans has declined over time, those who consumed 100% OJ had higher intakes of nutrients of public health concern compared to non-consumers. Thus, consumption of OJ should be encouraged for children and adults as part of an overall healthy diet since it improves nutrient intake and diet quality and contributes to dietary guidance for total fruit intake. The fourth study provided detailed information on adolescents' nutrition knowledge, perceptions, and definitions of nutrition terms. These findings could partially explain why approximately 80% of adolescents do not meet the Dietary Guidelines for Americans. Objectives 2A and 2B aimed to assess the rural-urban differences in food security status and assess its association with food availability and participation in federal nutrition assistance programs among the different age groups of children. However, the data on rural-urban residence from the National Health and Nutrition Examination Survey (NHANES) are not freely available and are considered restricted use data. We received approval from the Centers for Disease Control and Prevention (CDC) National Center for Health Statistics (NCHS) Research Data Center (RDC) in March 2021 to access restricted data on rural-urban residence. The merged data is created and the data creation syntax provided by NCHS have been reviewed. Currently, we are developing the analytic syntax to be conducted in the RDC. In the interim we conducted two ancillary studies related to the COVID-19 pandemic. The first study assessed the impact of COVID-19 on overall operations of emergency food assistance organizations such as food pantries. For this qualitative study, we recruited 18 food pantries in the Houston, Texas Metropolitan Area and conducted interviews with their staff. These interviews inquired about their operations during COVID-19 and how they were altered due to the pandemic including food procurement and distribution, safety measures taken, clientele served, assistance received/obtained, etc. Overall, the findings indicate that the food pantries developed diverse ways to cope with the increased demands during the pandemic. There were major changes that occurred in their operations including food procurement and distribution processes, safety measures undertaken, number of staff and volunteers, the clientele that was served (number and demographics) as well as in the funding/assistance they received. However, they also illustrated that there are several susceptibilities we must further research and seek to alter in order to more effectively manage the next national food insecurity crisis. The second study is an online survey to assess the impact of COVID-19 on food access and food security in the state of Texas. The online survey was rolled out in May, 2021 and will be open until the end of August, 2021. Objective 3A, has focused on conducting a systematic review and meta-analysis of interventions for obesity prevention and treatment among school-age children targeting the summer months when children are not in school, and assessing their impact on body mass index (BMI), physical activity, diet, sedentary behavior, and sleep. A total of 45 studies were identified for inclusion in the systematic review, and this year researchers focused on the extraction and preliminary analysis of the data. Data extracted from articles included participant characteristics, treatment setting (day camp, clinic, residential camp, etc.), descriptions of the intervention, theoretical orientation (cognitive behavioral, non-theory, etc.), study design, behaviors targeted (e.g., diet, sleep, physical activity), and length of the intervention. All studies were assessed for risk of bias. Behavioral strategies used by each intervention were assessed using Michie's taxonomy which is a hierarchical classification of behavior modification strategies. We began preliminary data analyses and plan to submit these as an abstract presentation next year.


Accomplishments
1. Orange juice consumption improves diet quality. Americans are under-consuming vitamins A, D, E, and C, folate, calcium, magnesium, potassium, and fiber relative to the current Dietary Guidelines for Americans recommendations. 100% orange juice (OJ) is the most commonly consumed fruit juice and contributes a variety of vitamins A, D, E, and C, folate, calcium, magnesium, potassium, and fiber in the diet. Researchers in Houston, Texas, found that the consumption of 100% OJ was associated with higher intakes of dietary fiber, folate, calcium, magnesium, potassium and vitamin C without an association with an increase in weight. Decreasing consumption of 100% OJ has reduced intakes and adequacy of key nutrients; thus, affecting the individuals' overall diet quality. Consumption of OJ should be encouraged for children and adults as part of a healthy diet in an effort to move Americans to meeting current dietary recommendations.

2. Perceptions about health, nutrition knowledge and the Dietary Guidelines food groups. Adolescents tend to have poor dietary practices and for this reason they have been a common target for the 2015 Dietary Guidelines for Americans (DGA)recommendations to enhance their diet and overall health. The words used by the DGA to describe aspects of the diet and the food categories may be unclear to adolescents. To assess this, researchers from Houston, Texas, surveyed adolescents to define terms commonly used in the dietary guidelines and to categorize 20 of the foods most consumed by adolescents using the most recent DGA food categories. Researchers found that adolescents defined "healthy" in terms of behaviors performed (e.g. diet and physical activity) but had difficulty in defining other commonly used guideline terms (e.g. energy-dense, processed foods). Adolescents were able to accurately classify 72% of the commonly consumed foods but had difficulty with complex foods (e.g. pizza, chicken soup) which required the use of multiple categories, and foods that had both desirable and undesirable characteristics (e.g. potato chips and chocolate chip cookies). More research is needed on clarifying the terms and categories used in the Dietary Guidelines to enhance adolescents understanding, compliance, and health.

3. Added sugars intakes and physiologic factors in adults. Studies have shown that the consumption of added sugars is associated with an increased risk for liver disease and risk factors for cardiovascular disease. Researchers in Houston, Texas, conducted a study using existing datasets to confirm these findings and to better understand the relationship of added sugars intake with liver enzymes and risk factors for cardiovascular disease. Our findings showed that higher intakes of added sugars were not consistently associated with increased liver enzymes and increased cardiovascular disease biomarkers including blood pressure, lipid levels, and glucose levels, or with elevated uric acid levels. Additional studies with more rigorous designs are needed to confirm the above findings.