Measurement and Determinants of Diet Quality in Older Adults

Poor dietary quality is a major contributor to chronic disease risk among older adults and is associated with age-related conditions including obesity, cardiovascular disease, type 2 diabetes, cognitive decline, and chronic inflammation. Older adults experiencing food insecurity often face additional barriers to healthy eating, including limited access to nutritious foods, language and literacy challenges, unfamiliarity with available produce, and logistical barriers to participating in food assistance programs. Understanding these barriers is critical for developing culturally relevant and sustainable nutrition interventions that can improve dietary quality and health outcomes in vulnerable populations.

This mixed-methods study will evaluate dietary quality among older adults participating in the Los Angeles County Food Rx Produce Distribution Program and explore participant perspectives regarding healthy eating, food access, and produce distribution services. The study has two primary aims.

Aim 1: Validation and Comparison of Dietary Quality Assessment Tools

The first aim is to assess dietary quality among adults aged 60 years and older who regularly participate in Food Rx produce distribution events. Participants will complete two dietary assessment instruments:

The Mediterranean Diet Adherence Screener (PREDIMED Mediterranean Diet Scale [MDS]), a widely used and validated measure of adherence to a Mediterranean dietary pattern.

The Global Diet Quality Questionnaire (GDQQ), a country-specific dietary quality assessment tool developed to rapidly evaluate alignment with global dietary recommendations across diverse cultural populations.

The GDQQ generates a Global Dietary Recommendations (GDR) score based on dietary factors associated with protection from and risk for noncommunicable diseases. The study will examine the relationship between GDQQ-GDR scores and PREDIMED MDS scores and evaluate whether the GDQQ performs comparably to or better than the PREDIMED MDS in predicting self-reported body mass index (BMI).

Approximately 125 older adults will complete dietary quality assessments and demographic questionnaires. Survey data will be collected electronically using REDCap and analyzed using descriptive statistics, correlation analyses, and multivariable regression models. Analyses will evaluate associations among dietary quality, demographic characteristics, food security status, comorbidities, and participation in produce distribution programs.

Aim 2: Qualitative Assessment of Barriers and Facilitators to Healthy Eating

The second aim will explore participant experiences, perceptions, and barriers related to healthy eating and participation in produce distribution programs. A randomly selected subset of participants from Aim 1 will be invited to participate in semi-structured qualitative interviews.

The qualitative component is informed by a Community Advisory Board (CAB) consisting of Food Rx stakeholders and community members with expertise in food access and nutrition programming. Interview questions were developed collaboratively with CAB input to ensure cultural relevance and responsiveness to participant experiences.

Interviews will examine:

Understanding of dietary quality and healthy eating Knowledge of the relationship between diet and chronic disease Experiences accessing nutritious foods Perceived barriers to improving dietary quality Experiences with produce distribution events Perceived benefits and challenges of Food Rx participation Attitudes toward unfamiliar or culturally relevant produce items Recommendations for improving food distribution services and nutrition interventions

A minimum of 20 and up to 30 interviews will be conducted, with recruitment continuing until thematic saturation is achieved. Interviews will be conducted by trained bilingual interviewers in English or Spanish. Interview data will undergo thematic analysis using a grounded theory approach, with coding performed independently by multiple researchers and reviewed for consensus.

Community-Engaged Research Approach

This study utilizes a community-based participatory research framework through collaboration with the National Health Foundation and the Food Rx Community Advisory Board. Community stakeholders contribute to study design, development of interview guides, interpretation of findings, and dissemination of results. This approach is intended to enhance cultural appropriateness, participant engagement, and the practical relevance of study findings.

Significance

This study addresses an important gap in understanding dietary quality assessment among diverse older adult populations experiencing food insecurity. Findings will provide evidence regarding the validity and feasibility of using the GDQQ in community-based nutrition programs and will identify barriers and facilitators that influence healthy eating among older adults. Results are expected to inform future culturally tailored nutrition interventions, improve produce prescription programs, and support strategies aimed at reducing nutrition-related chronic disease risk in underserved populations.

Inclusion criteria

• Participants eligible for enrollment in either the survey or interview component must meet the following criteria:

• Be 60 years of age or older
• Be a regular attendee (i.e., more than one visit) at L.A. County Food Rx produce distribution events
• Be able to communicate in English or Spanish, as these are the languages in which study materials and interviews are available
• Be able to provide informed consent and complete the brief study activities These criteria reflect the study's focus on older adults at increased risk for chronic disease due to food insecurity and poor diet quality. English and Spanish were selected based on the primary languages spoken at Food Rx distribution sites and the capacity of the study team to support accurate, culturally sensitive data collection.

Exclusion criteria

• Individuals will be excluded if they:

• Are younger than 60 years old
• Are first-time attendees at the produce distribution site (i.e., not familiar with program operations)
• Are unable to understand or communicate in English or Spanish
• Are unable to provide informed consent or complete the questionnaires or interview due to cognitive or physical limitations Language and participation history were included as exclusion criteria to ensure participant familiarity with the setting and the ability to engage meaningfully in data collection. ose who cannot provide informed consent will be excluded in accordance with ethical research protections for vulnerable adults.