Language

English

Publication Date

1-1-2026

Journal

Contemporary Clinical Trials

DOI

10.1016/j.cct.2025.108143

PMID

41232753

PMCID

PMC12668361

PubMedCentral® Posted Date

4-10-2026

PubMedCentral® Full Text Version

Author MSS

Abstract

Background: Understanding the impact of nutrition on human aging requires long-term trials in young, healthy, unmedicated adults. As part of the Dietary Approaches for Longevity and Health (DiAL Health) pilot project, we evaluated strategies for recruiting this population for aging-related dietary intervention studies.

Methods: We analyzed recruitment costs to enroll 70 participants (ages 25-49, BMI 22.0-29.9 kg/m2) across two DiAL Health sites and used NHANES data (2017-March 2020) to estimate the proportion of U.S. adults meeting partial trial eligibility. Additionally, a formative study surveyed 492 U.S. adults (≥18 years) to assess interest in aging-focused dietary trials.

Results: Of 2049 applicants screened, 70 were enrolled (3.4 %), with recruitment costs of $1572 per participant at site 1 and $625 at site 2. NHANES data revealed only 3.6 % (555/15,560) of adults met partial eligibility criteria, while 2.2 % (11/492) of formative survey respondents met full eligibility. DiAL Health eligible participants were willing to participate in dietary interventions like time-restricted eating or caloric restriction, but willingness declined for longer or more burdensome trials.

Conclusions: Recruiting young, healthy, unmedicated individuals for aging-focused dietary intervention trials is challenging due to low rates of eligibility and enrollment (∼3-4 % of initial applicants enrolled). Longer trials with stricter eligibility are likely to face greater recruitment barriers, highlighting the need for targeted strategies to engage, recruit, and retain this population effectively.

Keywords

Humans, Pilot Projects, Male, Adult, Female, Middle Aged, Longevity, Patient Selection, Nutrition Surveys, United States, Diet, Aging, Aging, Calorie Restriction, Time-Restricted Eating, Intermittent Fasting, Dietary Interventions

Published Open-Access

yes

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