Abstract
Tea consumption is inversely associated with cardiovascular risk in general populations, but evidence from patients with established coronary heart disease (CHD) is limited. Whether lipoprotein(a) [Lp(a)] and C-reactive protein (CRP) modify this association has not been examined. From the UK Biobank, 25,306 participants with established CHD were identified (3,773 MACE events over a mean follow-up of 13.9 years). Cox regression with progressive adjustment was performed on 22,012 participants with complete covariate data. Restricted cubic splines (RCS), causal mediation analysis for Lp(a), and three-way interaction tests (tea × Lp(a) × CRP) were performed. A four-quadrant stratification by Lp(a) (cut-off 50 nmol/L) and CRP (cut-off 3 mg/L) was constructed. RCS analysis identified a non-linear dose-response relationship (p < 0.0001), with the lowest MACE risk at approximately 3 cups/day (HR 0.828, 95% CI 0.790-0.867, relative to 0 cups/day). Fully adjusted heavy tea consumption (≥4 cups/day) was associated with reduced risk (HR 0.895, p = 0.037). Lp(a) did not mediate the association (ACME p > 0.05). A three-way interaction was suggested at the boundary of conventional significance (p = 0.050): the low-Lp(a)/high-CRP subgroup showed the strongest benefit (HR 0.670, p < 0.001), while the high-Lp(a)/high-CRP subgroup showed none (HR 0.992, p = 0.960). In CHD patients, tea consumption of approximately 3 cups/day is associated with the lowest MACE risk. This association is jointly modified by the Lp(a)-CRP profile, with the greatest benefit in patients whose residual risk is predominantly inflammation-driven.</p>