Theses and Dissertations
This collection includes both ASU Theses and Dissertations, submitted by graduate students, and the Barrett, Honors College theses submitted by undergraduate students.
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Description
Vitamin D is a nutrient that is obtained through the diet and vitamin D supplementation and created from exposure to Ultraviolet B (UVB) radiation. While there are many factors that determine how much serum 25-hydroxyvitamin D (25(OH)D) concentration is in the body, little is known about how genetic variation in vitamin D-related genes influences serum 25(OH)D concentrations resulting from daily vitamin D intake and exposure to direct sunlight. Previous studies show that common genetic variants rs10741657 (CYP2R1), rs4588 (GC), rs228678 (GC), and rs4516035 (VDR) act as moderators and alter the effect of outdoor time and vitamin D intake on serum 25(OH)D concentrations. The objective of this study is to analyze the associations between serum 25(OH)D concentrations resulting from outdoor time and vitamin D intake, and genetic risk scores (GRS) established from previous studies involving single nucleotide polymorphisms (SNP) located on or near genes involving vitamin D synthesis, transport, activation, and degradation in 102 Hispanic and Non-Hispanic adults in the San Diego County, California. This study is a secondary analysis of data from the Community of Mine study. Global Positioning System (GPS) data collected by the Qstarz GPS device worn by each participant was used to measure outdoor time, a proxy measurement for sun exposure time. Vitamin D intake was assessed using two 24-hour dietary recalls. Blood samples were measured for serum 25(OH)D concentrations. DNA was provided to assess each participant for the various genetic variants. Adjusted analyses of the GRS and serum 25(OH)D concentrations showed that individuals with high GRS (3-4) had lower serum 25(OH)D concentrations than individuals with low GRS (0-2) for both Nissen GRS and Rivera-Paredez GRS.
ContributorsAnderson, Heather Ray (Author) / Sears, Dorothy (Thesis advisor) / Alexon, Christy (Committee member) / Dinu, Valentin (Committee member) / Jankowska, Marta (Committee member) / Arizona State University (Publisher)
Created2022
Description
The Adequate Intake (AI) level for total fiber for adults is 14 grams per 1,000 kilocalories per day; however, only 12.9% of Americans met their total fiber needs according to the 2015-2016 National Health and Nutrition Examination Survey (NHANES). A lower frequency of home-cooked meals and a higher frequency of restaurant meals have been cited as a possible explanation for the low dietary fiber intake among Americans, and according to the Social-Ecological Model, the retail food environment can influence our food choices such as the choice to eat at home or eat out. The objective of this study is to examine the relationship between a dynamic measurement of exposure to the retail food environment and fiber intake (total fiber, soluble fiber, insoluble fiber, and pectin). This is a secondary analysis of data from the Community of Mine study, a cross-sectional study of 602 adults residing in San Diego County, California. Dynamic exposure to the retail food environment was assessed using Global Positioning Systems (GPS) data collected by the Qstarz GPS device worn by each participant. Fiber intake was assessed using two 24-hour dietary recalls. Multivariate regression analysis was used to assess correlations. Descriptive results showed no significant differences in dynamic exposure to the retail food environment by sex, Hispanic ethnicity, and income. There were significant differences in fiber intake by sex and ethnicity. The results of the multivariate regression analysis suggest that exposure to the retail food environment is not associated with fiber intake among a subset of American adults.
ContributorsHarb, Amanda A (Author) / Sears, Dorothy (Thesis advisor) / Alexon, Christy (Committee member) / Jankowska, Marta (Committee member) / Ohri-Vachaspati, Punam (Committee member) / Arizona State University (Publisher)
Created2020