(P42-50-26) Dietary Assessment in the Connect for Cancer Prevention Study: A Protocol

Objectives: The Connect for Cancer Prevention Study (Connect) is a new, modern cohort, aiming to recruit 200,000 participants and focusing on cancer etiology, risk prediction, and early detection. Connect infrastructure also enables the study of a broad range of other health outcomes. Given diet’s role in disease etiologies, dietary assessment is scientifically critical to Connect’s aims.

Methods: Connect is a prospective cohort, recruiting cancer-free adults (30-70 years) through 10 integrated healthcare systems across the U.S. Recruitment began in 2021 and will continue through at least 2027. Connect integrates electronic health records with longitudinal digital surveys and serial biospecimen collection over 20+ years. Blood, urine, and saliva are currently collected; fecal collections are planned. The Diet History Questionnaire (DHQIII) was released in May 2025 to participants who reached six months of follow-up. The DHQIII includes 135 food and beverage and 26 dietary supplement items, is offered in English and Spanish, and provides back a Health Eating Index (HEI) report. The Automated Self-Administered 24-Hour (ASA24) Dietary Assessment Tool and the Activities Completed over Time in 24-hours (ACT24) tool will be released in late 2026 and will be offered four times each, interspersed, over a 12-month period.

Results: As of March 2026, 9,590 of 25,588 eligible participants (37%) completed the DHQ and 77% of those viewed their HEI report. The completion rate increased with age and was highest for white participants. The median time from survey invitation to completion was 5.6 days; 54% of participants required over an hour to complete the DHQIII. Of note, the response rate to the subsequent follow-up survey was 17% lower among those who first did the 6-month DHQIII (30%) compared to those who did not (47%), even after accounting for a comparable amount of time on study (9-12 months).

Conclusions: Because of the importance of diet in disease outcomes, ASA24 will be used to support an in-depth framework for dietary assessment in Connect. Additional support to facilitate appropriate retention is indicated based on the DHQIII completion responses. For other non-dietary analyses, the study will consider deploying additional options such as a short diet-screener.

Funding Sources: No external funding