2010 Annual Report
1a.Objectives (from AD-416)
The long-term objective of this project is to develop improved understanding of how genes influence obesity-related behaviors through experiences of food intake and physical activity, and whether these experiences mediate the gene to behavior relationships. We will focus on the following objectives that will be studied concurrently within the same experiments.
Objective 1: Determine the extent to which relationships between appetite-related genetic factors and dietary intake are mediated by subjective feelings of hunger, satiety, and other psychosocial variables in children.
Subobjective 1A: Generate a questionnaire that assesses food and physical activity related experiences in middle school students.
Subobjective 1B: Test whether food and physical activity related experiences mediate the gene to dietary intake and physical activity relationships.
Objective 2: Determine the extent to which relationships between activity-related genetic factors and physical activity are mediated by subjective feelings of enjoyment and related psychosocial variables in children.
1b.Approach (from AD-416)
Children's Nutrition Research Center researchers will conduct a literature review of possible experiential aspects of genes in regard to diet and physical activity (e.g., satiety, enjoyment of physical activity). Knowledge gained from these reviews will permit the researchers to conduct focus group discussions to generate items that reflect these possible gene experiences, and convert the statements to items in a questionnaire. Our scientific team will conduct cognitive interviewing with children to ensure the items are understood by the children. We will distribute the questionnaires for completion by large numbers of children on which to conduct the psychometric analyses. The accretion of adiposity among 3rd and 4th grade students over the summer will be studied. The above questionnaires and the genetic variables will be used, and associated relationships will be evaluated.
Obesity is a complex phenomenon reflecting many diverse behavioral and biological influences. Since cross-sectional studies can lead to flawed inferences, the naturalistic study of the influences on obesity/adiposity are best studied in longitudinal designs. However, sufficient changes must occur over time in the dependent variable to have something to predict, and more cost-effective research can be conducted if these changes occur over short time intervals. Several recent studies have indicated that among children, greater increases in adiposity occurred during the few summer months than during the much longer school year. While schools have been blamed for being substantial contributors to the obesity epidemic, the summer months studied suggest that the home environment may be a bigger contributor. This might include differences in influences from the local neighborhood, the home environment, parenting practices, or how child psychosocial variables interact with these environmental influences.
A complex picture is also emerging wherein a large number of genes have been related to adiposity, each in several studies. These genes appear to be influencing adiposity in diverse pathways including hunger/satiety, physical activity, and metabolic mechanisms. This large number of genes influencing adiposity suggest there are a large number of pathways of influence, with any specific case of obesity having an individualized etiology. Part of this individualized etiology may include differences in psychosocial and behavioral influences. During FY2010, we generated an initial conceptual model that encompasses these possible behavioral, personal, ecological and genetic influences.
The ADODR monitors activities for the project by routine site visits, and review of major purchases of supplies/equipment, use of SCA funds for foreign travel, and submission of grant applications by investigators funded through the SCA.