Efficacy of a Multi-level Intervention Designed to Promote Adherence to WCRF/AICR Dietary Guidelines for Cancer Prevention

Summary

Cancer is a leading cause of death and will affect many people in their lifetimes. Organizations such as the American Cancer Society and the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) have noted that dietary quality is a key factor influencing cancer risk, but most Americans do not meet these dietary guidelines for cancer prevention. The proposed study will enroll adults from the community (n=236 index participants, 236 household members; N = 472) who have low adherence to WCRF/AICR's four dietary guidelines. Participants will be randomized to either nutrition education or the Eatwell intervention. The Eatwell intervention content is focused on helping participants make healthier grocery shopping decisions, eat at home more often to take advantage of the optimal defaults present there, and learn how to navigate temptation when eating away from home. The findings will be relevant not only to the field of cancer prevention, but to the prevention of other diseases for which dietary quality is important.

Detailed description

The purpose of this study is to test an intervention that is designed to facilitate adherence to the dietary guidelines for cancer prevention (i.e., increase in intake of fruits, vegetables, and whole grains, and decrease in intake of processed food, red and processed meat, and sugar sweetened beverages). Using a two-arm design, participants will be randomized to receive the "Eatwell" intervention or traditional nutrition education. The Eatwell intervention content is focused on helping participants make healthier grocery shopping decisions, eat at home more often to take advantage of the optimal defaults present there, and learn how to navigate temptation when eating away from home. Aim 1: Test the hypothesis that there will be a greater increase in adherence to dietary guidelines for cancer prevention among index participants in the Eatwell condition, compared to the traditional nutrition condition. The primary outcome will be a total dietary adherence score, calculated using NCI's standardized scoring system. Grams per day of fruit, vegetables, and fiber; percentage of calorie intake from ultra-processed foods; grams per week of red meat and processed meat; and grams per day of SSBs will be examined individually as secondary outcomes. Aim 2: Test the hypothesis that there will be greater improvements in biomarkers of inflammation among index participants in the Eatwell condition, compared to the traditional nutrition condition. Aim 3: Test the hypothesis that adult household members will have greater improvements in dietary adherence (measured by total dietary adherence score, as well as change in individual components of dietary quality, as in Aim 1) when their index participant is randomized to the Eatwell condition, compared to the traditional nutrition condition. Aim 4: Examine biopsychosocial mediators and moderators of intervention effects. Aim 5: Exploratory analyses also will be conducted to, for example, examine change over time in the variables assessed as part of the study's assessment battery, understand predictors of change over time, and understand how independent or dependent variables are related to each other.

Arms & interventions

• BehavioralEatwell

  The Eatwell intervention content is focused on helping participants make healthier grocery shopping decisions, eat at home more often to take advantage of the optimal defaults present there, and learn how to navigate temptation when eating away from home. The intervention itself involves nutrition education, self-regulation, motivation, and household support. In total, it will last 18 months; index participants will attend 12 workshop sessions that are 90 minutes each. Each workshop session will include approximately 12-16 index participants. The first four sessions will be held weekly in Month 1, and subsequent sessions decrease in frequency. Each index participant will have one enrolled household member who will be asked to join four workshop sessions in a support role: sessions 3, 4, 7, and 10. In these four sessions, household members will receive education about WCRF/AIRC recommendations and training in how to provide instrumental and emotional support to index participants.

• OtherNutrition Education Control Group

  In the control condition, index participants will receive nutrition education in a series of 12 workshop sessions, following the same schedule as participants in the Eatwell condition. All of the content described under the "nutrition education" component of the Eatwell intervention will be provided. The educational material will be delivered with greater detail and with additional in-session activities, as greater time is devoted to education in the control vs. experimental condition. Participants also will receive monthly educational email messages reiterating key ideas from workshops. Specialized content and activities related to self-regulation and motivation will not be provided in the control condition. If an index participant is randomized to the control condition, their designated household member will have no intervention involvement and will only complete assessments.

Outcome measures

Eligibility criteria