Associations between Dietary Phenolic Compounds and Biomarkers of Atrial Fibrillation Risk in Adults with Metabolic Syndrome: A Longitudinal Analysis.

Introduction: Phenolic compounds (PC) may reduce the risk of cardiovascular disease due to their anti-inflammatory and antioxidant effects. Examining relationships between dietary intake of total PC and atrial fibrillation (AF) risk biomarkers in a Mediterranean population with metabolic syndrome may offer new insights about AF physiopathology.

Objective: This observational study aims to analyze the relationship between total PC intake and serum levels of five AF-related biomarkers over 5 years in 566 participants from the PREDIMED-Plus trial.

Methods: In participants with metabolic syndrome (mean age: 65.1 years, 40.4% women), blood biomarkers were measured at baseline, 3, and 5 years: N-terminal pro B-type natriuretic peptide (NT-proBNP) (atrial stretch), high-sensitivity Troponin T (hs-TnT) (myocardial damage), high-sensitivity C-reactive protein (hs-CRP) (inflammation), procollagen type 1 carboxy-terminal propeptide (PICP) (fibrosis), and 3-nitrotyrosine (3-NT) (oxidative stress). PC intake was assessed using a validated 143-item food frequency questionnaire and the Phenol-Explorer database. Changes in log-transformed biomarkers levels were evaluated with multivariable-adjusted mixed linear models. Sources of between-person variability in total PC intake were also evaluated.

Results: Over 5-year, participants with moderate-high baseline PC intake (quartiles 2-4) showed a 39.5% (95%CI 27.4%;52.6%; p<0.001) increase in NT-proBNP concentrations compared to a 20.5% (95%CI% 3.4%,40.3%; p=0.03) increase in the lowest quartile, (ptime*categories =0.04). When PC intake was updated over follow-up, moderate-high intake showed a 32.2% (95%CI 19.5%;46.2%, p<0.001) increase in NT-proBNP vs. a 27.3% (95%CI 6.5%;52.1%, p=0.004) in the lowest quartile, (ptime*categories =0.02). Participants with moderate-high PC intake undergoing intensive lifestyle intervention (ILI) showed smaller increases in hs-TnT than those with lower intake. Chocolate was the main contributor to between-person variability in PC intake.

Conclusion: Our results shows that higher PC intake was associated with larger increases in NT-proBNP concentrations. In participants undergoing an ILI and higher PC intake, a lower increase in hs-TnT levels was found. Future research is warranted to better understand the role of dietary intake of PC in AF-related pathways.