Abstract
IMPORTANCE: Excess salt intake is a major modifiable risk factor for hypertension and cardiovascular disease. Personalized interventions using genetic information and digital tools, such as smartphone applications, may enhance sodium reduction, but evidence remains limited. OBJECTIVE: To evaluate the effectiveness of a sodium reduction program incorporating a genetic profile and an artificial intelligence (AI)-based mobile app among adults with elevated blood pressure and a sodium-sensitive genotype. DESIGN, SETTING, AND PARTICIPANTS: A 3-arm randomized clinical trial, conducted at a Japanese electronics company from September 17 to December 16, 2024, included employees aged 20 to 65 years with elevated blood pressure and the sodium-sensitive AGT M235T genotype. INTERVENTIONS: Participants were randomized on a 1:1:0.2 basis to (1) a treatment group receiving a genetic profile and an AI-based app incorporating sodium-specific information; (2) a control group receiving no intervention; or (3) an app-only group using the app without a genetic profile or information. MAIN OUTCOMES AND MEASURES: The primary outcome was daily salt intake, estimated from spot urine samples using the INTERSALT (International Study of Electrolyte Excretion and Blood Pressure) formula. Secondary outcomes included self-reported body mass index, behavior change intentions, and systolic and diastolic blood pressure. Analysis was performed on an intention-to-treat basis. RESULTS: Of 312 randomized participants, 289 completed follow-up (mean [SD] age, 51.3 [8.3] years; 252 of 279 men [90.3%]). The mean (SD) baseline salt intake was 11.3 (2.0) g/d. At 3 months, no significant difference in salt intake was observed between the treatment and control groups (mean difference, -0.2 g/d; 95% CI, -0.7 to 0.3 g/d) or between the treatment and app-only groups (mean difference, -0.04 g/d; 95% CI, -0.9 to 0.8 g/d). No significant differences were observed between groups in any secondary outcomes. CONCLUSIONS AND RELEVANCE: In this randomized clinical trial conducted among individuals with elevated blood pressure and a sodium-sensitive genotype, a sodium reduction program combining a genetic profile and an AI-based app with sodium-specific information did not significantly reduce salt intake. These findings highlight the challenges of achieving dietary behavior change through genetic personalized plus digital interventions. TRIAL REGISTRATION: http://umin.ac.jp/ctr Identifier: UMIN000052685.