Association of sedentary behavior with atrial fibrillation-related biomarkers in a population with overweight or obesity.

Background: Blood biomarkers can characterize the atrial substrate, helping to elucidate mechanisms of atrial fibrillation (AF) development. Understanding whether sedentary behavior affects AF-related biomarkers is key for future prevention strategies.

Methods: We studied 252 participants in PREDIMED-Plus, a multicenter randomized trial in Spain for the primary prevention of cardiovascular disease. A wrist-worn accelerometer was used to measure physical activity (PA) in a week at baseline and at least once during follow-up at years 3 and 5. Blood samples were collected at each time point to measure selected cardiovascular biomarkers: propeptide of procollagen type I, high-sensitivity (hs) troponin T (hsTnT), hs C-reactive protein, 3-nitrotyrosine, and N-terminal propeptide of B-type natriuretic peptide (NT-proBNP). Sedentary time was assessed as inactive time (< 1.5 METs in waking time). Using isotemporal substitution, we analyzed the impact of replacing 30-min sedentary time per day with low-intensity PA (LPA, 1.5-3 METs), moderate to vigorous PA (MVPA, > 3 METs) and time in bed (time difference between going to bed and getting up) on log-transformed biomarkers cross-sectionally and longitudinally, using linear regression and mixed models.

Results: At baseline, 252 eligible participants averaged 65 years of age (SD 4.9), and BMI 32.2 kg/m (SD 3.3), and 40% were female. Cross-sectionally, replacing 30-min sedentary time with LPA, MVPA, or time in bed had no significant association with biomarkers. After 5 years, replacing baseline 30-min of sedentary time per day with LPA or MVPA was associated with lower hs-TnT concentrations compared to baseline (-4%, 95% CI -8%, -1%; -2%, 95% CI -7%, 4%, respectively). Substituting 30-min sedentary time with LPA or MVPA showed nonsignificant reductions in NT-proBNP (-3%, 95% CI -11%, 5%; -8%, 95% CI -20%, 5%, respectively), but not a consistent association with other biomarkers.

Conclusion: In overweight/obese individuals, prolonged sedentary time, when compared to engaging in PA, was associated with unfavorable changes of hs-TnT over 5 years, but no significant impact on other AF-related biomarkers.