Community Health Worker Coaching, Food Insecurity, and Physical Activity in the Healthy Food First Trial: A Causal Mediation and Longitudinal Analysis

To evaluate whether change in food insecurity (ΔFI) mediated the effect of a community health worker (CHW) intervention on physical activity (PA) among food insecure (FI) hypertensive adults, we conducted a secondary analysis of the Healthy Food First randomized clinical trial of food insecure adults with hypertension recruited from 364 North Carolina clinical sites. Participants were randomized to CHW coaching or no coaching within a 2 × 2 × 2 factorial design. FI was measured at baseline and 12 months; total PA (MET-min/week) at 12 and 18 months. Mediation models estimated indirect (ACME), direct (ADE), and total effects (ATE) of CHW assignment on 12-month PA through ΔFI. Generalized estimating equations evaluated repeated PA by CHW assignment. CHW assignment was not associated with PA, and ΔFI did not mediate the relationship. Effects were small (ACME = 16.2; 95% CI −62.6, 121.8; ADE = −214.1; 95% CI −871.7, 484.5; ATE = −197.9; 95% CI −855.6, 500.8 MET-min/week). The proportion mediated was near zero (−8.2%; 95% CI −142%, 124%). GEE analyses similarly showed no association (B = 363.7 MET-min/week; SE = 302.8; P = 0.23). Modest improvements in FI alone may be insufficient to increase PA without additional PA supports. ClinicalTrials.gov Identifier: NCT05048836.