Associations of long-term Tai Chi practice with vascular health in middle-aged and older adults: potential indirect roles of inflammation and oxidative stress - a cross-sectional study

Tai Chi is a widely practiced mind-body exercise, but its associations with vascular health and the potential involvement of inflammation and oxidative stress remain unclear. We hypothesized that, compared with irregular exercise, long-term Tai Chi practice would be associated with higher flow-mediated dilation (FMD), lower brachial-ankle pulse wave velocity (baPWV), more favorable ankle-brachial index (ABI), and lower carotid intima-media thickness (IMT). This cross-sectional study included 391 adults aged ≥45 years: 172 long-term Tai Chi practitioners, 72 conventional exercisers who regularly performed square dancing, jogging, or brisk walking, and 147 irregular exercisers. Regular exercise was defined as ≥3 sessions/week and ≥30 min/session for >1 year. Outcomes included FMD, baPWV, ABI, IMT, peak systolic velocity (PSV), wall shear stress (WSS), and resistance index (RI). Inflammatory biomarkers included high-sensitivity C-reactive protein (hs-CRP), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-10, and IL-33; oxidative-stress-related biomarkers included superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione peroxidase (GPx). Covariate-adjusted differences were estimated using targeted maximum likelihood estimation with Benjamini-Hochberg correction across the seven vascular outcomes. Exploratory indirect-association analyses were not adjusted for multiple comparisons. After correction, Tai Chi practice, compared with irregular exercise, was associated with higher FMD (1.39 percentage points; 95% confidence interval [CI], 0.84 to 1.94) and lower baPWV (-103.14 cm/s; 95% CI, -176.56 to -29.72), ABI (-0.02; 95% CI, -0.04 to -0.01), IMT (-0.09 mm; 95% CI, -0.15 to -0.03), and RI (-0.02; 95% CI, -0.05 to -0.004). Conventional exercise was associated with higher FMD than irregular exercise (0.79 percentage points; 95% CI, 0.22 to 1.37). No significant differences were detected between Tai Chi and conventional exercise after correction. Exploratory analyses identified nominal potential indirect associations involving hs-CRP, SOD, and inflammatory and oxidative-stress composites. Long-term Tai Chi practice was associated with selected vascular measures compared with irregular exercise, although no differences from conventional exercise were detected. Exploratory biomarker findings suggest possible indirect pathways but do not establish causal mediation. Prospective and randomized studies are needed to determine causality and clinical relevance. ClinicalTrials.gov NCT06307483 (Date of registration: 24/01/2024)