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Theses Doctoral

Understanding Lifestyle Behaviors and the Development of a Theory-Based Nutrition and Physical Activity Education Intervention for Latina Breast Cancer Survivors

Paul, Rachel

Lifestyle behaviors, including diet and exercise, may mediate the risk of breast cancer recurrence. Large national and international organizations, including the American Cancer Society, the American Institute for Cancer Research, and the World Research Fund, recommend consuming a diet high in plant-based foods, specifically fruits, vegetables, and whole grains, and low in dietary fat and added sugar for cancer recurrence prevention. In addition, these organizations recommend regular physical activity, typically 30 minutes of moderate to vigorous activity per day. However, many cancer survivors unfortunately fall short of meeting these recommendations. In addition, low-income, and racial/ ethnic minority populations, especially Latinas, are at increased risk of breast cancer recurrence due to a myriad of factors such as limited access to health care. Theory-based, behaviorally-focused, and culturally-tailored nutrition and physical activity education has been shown repeatedly to improve these lifestyle behaviors in other populations. Previous intervention studies by our research group have significantly improved dietary behaviors among Hispanic/ Latina breast cancer survivors. This dissertation consists of a review of the educational literature on diet and physical activity studies among breast cancer survivors, and three studies: (1) a methodological description on the development of a theory-based, behaviorally focused intervention with classroom and online education curricula, (2) an empirical validation study of a survey instrument, and (3) a cross sectional study of women’s diet and physical activity behaviors and theory-based determinants. Taken together, these studies can inform future educational interventions with this population by using our culturally-tailored, theory-based, behaviorally-focused model as a framework and by using our validated assessment tools. These studies can also inform future educational interventions by understanding diet and physical activity behaviors and related potential mediators. These dissertation activities were conducted within the context of a larger, on-going, two-by-two factorial designed National Cancer Institute (NCI) funded educational intervention study, Mi Vida Saludable (My Healthy Life), which aims to change diet and physical activity behaviors of Hispanic/ Latina breast cancer survivors. The main study will examine the separate and synergistic effects of a) online education and b) in-class education. The intervention is based upon nutrition education curricula developed by the non-profit organization Cook for Your Life, which develops recipes and cooking education for cancer patients and survivors in New York City and a previous intervention conducted by this research group, that targeted fruit, vegetable, and dietary fat intake only. The on-going larger study, Mi Vida Saludable, involves cohorts of 30-40 Hispanic/ Latina breast cancer survivors who go through the intervention arms, at intervals of every 4-8 months, depending on recruitment. As of April 2018, two of the five planned cohorts have completed the study, and four of the five cohorts have been randomized. The purpose of the initial comprehensive review of the literature was to inform the development of this Mi Vida Saludable educational intervention. Three areas relevant to the intervention were reviewed. The first area was the varying dietary and physical activity guidelines, both for cancer survivors, and also for common simultaneously occurring lifestyle-related diseases such as heart disease and diabetes. Similarities and differences were examined, and the resulting recommendations were used in the intervention development. The second area of review consisted of dietary and physical activity interventions that specifically targeted breast cancer survivors. Commonalities of successful interventions included the use of Social Cognitive Theory and the Stages of Change construct of the Transtheoretical Model. Finally, the text message literature was reviewed as it pertains to weight management, dietary, and physical activity behaviors, specifically among Hispanic/ Latina populations. Findings indicated that text message interventions were more successful if they decreased in frequency over time, included specific educational advice, and had the ability for two-way communication. The findings from these literature reviews were used to develop the Mi Vida Saludable intervention. (1). The methodological study involved the development of the content of the Mi Vida Saludable group education and electronic (“e-“)-communication programs. These programs were developed using a systematic stepwise theory-based, behaviorally-focused process, the Nutrition Education DESIGN Procedure. Briefly, DESIGN stands for: 1. Decide behaviors; 2. Explore determinants or potential mediators of change; 3. Select theory; 4. Indicate objectives; 5. Generate plans; and 6. Nail down evaluation. DESIGN was applied to help assure the curricula a) enhance motivation and b) facilitate action to change the following behaviors: 1) increase fruit and vegetable intake, specifically focused on non-starchy varieties, 2) decrease dietary fat intake operationalized as less fatty meats, decreased fat added during cooking, and smaller portions of cheese, 3) decrease added sugar intake operationalized as fewer sugar sweetened beverages and less added sugar in processed food and cooking, and 4) increase daily moderate-to-vigorous physical activity. The behavior-change theory applied was the Social Cognitive Theory. The resulting group education program consisted of 4 lessons, 4 hours each in length. Each lesson included a hands-on cooking component and facilitator-led nutrition education and discussion. Two of the four lessons included field trips to the local grocery store and farmers’ market. The resulting e-communication program included 11-months of weekly text messages, biweekly emailed newsletters, and ongoing website access. The content of the online curriculum was developed after the classroom curriculum and mirrored the classroom curriculum so that mode of education would be the key variable tested. (2). A survey instrument was developed to assess two key psychosocial potential mediators of behavior change from Social Cognitive Theory, preferences and self-efficacy, separately for each targeted behavior. This survey was tested for validity and reliability. Expert panel review assessed scale validity by Content and Face Validity. Participants from the target population assessed scale validity and reliability by 1) cognitive interviewing, 2) convergent validity, 3) internal consistency reliability, and 4) test-retest reliability. Content and face validity, and cognitive interviews successfully improved the questionnaire before quantitative analysis. Modifications from content and face validity included the addition of pictures of fruits and vegetables and the addition of examples of different food types high in fat and added sugar. Results from the cognitive interviews indicated primarily that changes should be made in the questionnaire to examples of foods with and without dietary fat and added sugar. Study findings revealed that Cronbach alpha values were sufficient for all Preferences and Self-efficacy scales except for Preferences for Added Sugar Intake. Study findings also revealed that item-total correlations were sufficient for all reduced Preferences and Self-efficacy scales, and that ICC values were sufficient for all Preferences and Self-efficacy reduced scales except for Preferences for Dietary Fat Intake. (3). Psychosocial potential mediators and measures of quality of life were examined in a cross sectional study of Mi Vida Saludable participants as they relate to women’s diet and physical activity behaviors at study entry. Outcome variables included diet, specifically servings of fruits and vegetables (both total and varieties specifically targeted by the intervention), percent dietary fat and added sugar, as well and average minutes of physical activity per week. Our study found that, among Hispanic/ Latina breast cancer survivors, decreased self-efficacy to choose lower sugar foods, increased locus of control of powerful others, and increased stress are related to increased added sugar intake. We also found that increased preferences for foods low in fat are related to decreased fat intake. Finally, we found higher mental health-related quality of life scores are related to increased fruit and vegetable intake, decreased fat intake, and increased physical activity. The results from these three studies will be used to understand behavioral outcomes of the Mi Vida Saludable study, as well as develop future interventions with this and other populations. Advancing our understanding of potential mediators and psychological variables can improve the development and success of interventions, especially among understudied populations such as Hispanic/ Latina breast cancer survivors.

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More Information

Academic Units
Behavioral Nutrition
Thesis Advisors
Contento, Isobel R.
Degree
Ph.D., Columbia University
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