Doctor of Philosophy / Department of Human Nutrition / David A. Dzewaltowski / Consumption of fruits and vegetables (FV) contributes to healthy growth and development among youth. For effective intervention development, an understanding of the underlying casual influences on consumption is needed. The current dissertation is intended to identify whether influences on youth fruit and vegetable consumption (FVC) vary by age, gender, ethnicity and socioeconomic status (SES). The series of four chapters focus on self-efficacy for FVC and proxy efficacy to influence other adults to provide supportive FV environments. Chapter One reviews studies examining the influences on youth FVC. Consistently across studies, FV preferences and FV availability influenced youth FVC. Chapter Two and Chapter Three report studies documenting that children's confidence (proxy efficacy) to influence parents to make FV available and to influence other adults (after-school staff) to make FV available are independent but related constructs to self-efficacy to eat fruits and self-efficacy to eat vegetables. Differences were found in these constructs according to school demographic variables and youth demographic variables. Chapter Two reports that youth attending elementary schools with lower concentrations of racial/ethnic diversity and higher concentrations of high SES were more confident in influencing their parents to make FV available than youth attending schools with higher concentrations of racial/ethnic diversity and higher concentrations of low SES. Although analyses of cross sectional data collected on elementary-aged youth presented in Chapter 3 showed no demographic differences at the school level, Chapter Four examined longitudinal data across sixth-, seventh- and eighth-grade and found demographic differences using youth level variables. Across the middle school years, youth declined in proxy efficacy and racial/ethnic minority youth declined at a significantly faster rate than white youth. Each year, male and lower SES youth were significantly lower in proxy efficacy than females and higher SES youth, respectively. Thus, school or youth demographic differences in self-efficacy and proxy efficacy may contribute to the understanding of why males and lower SES youth eat less FV than females and higher SES youth.

Individuals who are disadvantaged by low-income and/ or minority status face a number of barriers to experiencing optimal health and eating well. Twenty Aboriginal and 29 non-Aboriginal participants (N = 49) from Ottawa, Canada took part in a cross-sectional, mixed methods study and completed one questionnaire and single in-depth interview that verified: 1) food security status and household eating habits, 2) fruit and vegetable purchase and consumption, and 3) knowledge about or participation in the Good Food Box [GFB] Program. Ottawa GFB staff (n = 5), site coordinators (n = 6) and steering committee members (n = 3) took part in separate discussion groups to identify challenges and strengths related to program coordination, management and delivery. Within an ecological framework, qualitative data is discussed using a social phenomenological and thematic approach. Using χ2 analyses, results suggest a medium effect size and association between food security status and Aboriginal identity (χ2(1) = 8.04, p < 0.01; φ = 0.4) and satisfaction with how stores meet household food needs and gender (χ2(1) = 5.86, p < 0.05; φ = 0.36). A relationship between participation in the GFB Program and food security status (χ2(1) = 11.13, p < 0.01; φ = 0.48) is also shown where estimates suggest that GFB customers are 9.9 times more likely to be food secure compared to non-affiliates. ANOVA results and post-hoc tests demonstrate a significant mean difference in frequency of fruit consumption between GFB customers and non-program users (F(2, 46) = 11.29, p = 0.00) where 29.6% of the variance (ω2 = 0.296) is explained by program participation. Results-based and community-driven recommendations to improve access to healthy food, food security and the GFB Program are discussed as shared responsibilities between different levels of government across sectors and the community since these are public and social health issues, determinants of health and economic concerns. Implications of findings are also discussed.

Due to the short time the updated National School Lunch Program standards have been in place since fall of 2012, few research studies have explored what effect these new standards have had on fruit and vegetable (F/V) consumption, particularly among elementary school students. Because the new standards require schools to offer students more F/V than before, researchers are interested to know if F/V consumption has indeed increased. The participants in the study were enrolled in a program to motivate students to eat more F/V – the Food Dudes program. The results of the data analysis found that most students, regardless of grade, were eating less F/V initially after the new standards were in place. However, the group of students receiving prizes from the Food Dudes program actually ate more F/V over time instead of less. Also, F/V consumption for the first spring under the new standards did not decrease as much as it had during the spring under the old standards. These results indicate that, despite initial declines in F/V consumption, students could be adjusting to the updated standards. Also, students who have participated in the incentives group of the Food Dudes program did not show a drop in F/V consumption, even during the first semester the new standards were in place. Future studies should look at the current F/V intake of students under the updated guidelines now that they have been in place for several school years, as well as at additional intervention programs to increase F/V consumption among this population.

Rowe and Kahns theory of successful aging identifies three main components of aging successfully: reducing the risk of disease and disability, maintaining high cognitive and physical function, and engagement with life. While there is compelling evidence that suggests the legitimacy of this concept in the 50-75 year old community dwelling population, three areas of expansion are necessary: 1.) programmatic research; 2.) extending the existing research samples to include older samples and those living in continuing care retirement communities (CCRCs); and 3.) the integration of data collection and analysis to move beyond investigation of just one successful aging outcome to include elements of all three components of successful aging. Longitudinal analysis utilizing hierarchical linear modeling (HLM) was conducted on a convenience sample of 136 older adults (mean age = 80.8 years at baseline) participating in a pilot community-wide successful aging program over a 26-month period. Results indicate the sample reported exercising frequently, ate recommended levels of fruits and vegetables, had healthy BMIs, had positive ratings of health, were highly involved in productive activities, and were satisfied with their ability to give and receive social support at baseline. High levels of mobility were measured in the sample. Participants maintained this picture of successful aging over time for the majority of outcome variables, though significant declines in self-reported health were observed. Participants also reported improvements in their satisfaction with receiving social support. Results support four major conclusions: 1.) The three criteria of successful aging identified by Rowe and Kahn (1997) were observed among older adults living in CCRCs who were enrolled in a successful aging program. 2.) Stability was observed on a number of the outcomes over 26 months in this convenience sample, which has implications for intervention/programmatic research. Despite the traditional improvement-oriented focus of programmatic research, stability or maintenance of well-being over time should be viewed as a positive outcome in older age, particularly when compared to national data depicting trends of decline. 3.) The interdependence of current results support the notion that successful aging programming needs to include multi-disciplinary intervention strategies, as supported by the finding that modifiers of physical, social, and intellectual well-being include constructs from each of the components of successful aging. 4.) Participants of the current study were largely in the precontemplation and contemplation stages of change. Readiness to change needs to be factored into the design of any successful aging program, as the Transtheoretical Model could be a powerful tool for the identification of readiness to change and the development of appropriate and effective successful aging programming.

The purpose of this non-experimental quantitative correlational study was to investigate the relationship between academic achievement and health in a national sample of college students using quantitative data analysis. Specifically, the researcher analyzed the relationship between three health-promoting behaviors (physical activity, strength training, and fruit and vegetable consumption), three negative health behaviors (cigarette, e-cigarette, and opioid use) and obesity with GPA. Cross-sectional data on student health collected from the American College Health Association’s National College Health Assessment II (ACHA-NCHA-II) and completed by 426,650 college students from 650 U.S. colleges during the semesters between 2015 and 2019 formed the foundation for this research. Nine research questions were addressed using a series of chi square tests. Results showed there was a significant positive relationship between health behaviors and grade average. Students who met the recommendations for fruit and vegetable consumption, moderate activity and vigorous physical activity were more likely to have GPAs than those who did not. Students who used cigarettes, opioids, or were obese were more likely to have GPAs.