Abstract Body: Backgrounds: Cocoa flavanols have potential blood pressure (BP)-lowering effects in shorter-term, smaller-scale randomized clinical trials (RCTs), but its effect on incident hypertension has not been examined in a large-scale RCT. The COcoa Supplement and Multivitamin Outcomes Study (COSMOS) evaluated whether longer-term cocoa extract supplementation had an effect on incident hypertension in older adults.
Methods: COSMOS is a 2x2 factorial, double-blind, placebo-controlled RCT testing cocoa extract (including 500 mg/day cocoa flavanols, with 80 mg/day (-)-epicatechin) and a multivitamin among 21,442 women aged ≥65y and men aged ≥60y. In 8,905 COSMOS participants free from baseline self-reported hypertension, we investigated the effect of cocoa extract on incident hypertension using Cox proportional hazards models. Incident hypertension was defined as self-reported first-time physician diagnosis, initiation of anti-hypertensive medications, or self-reported elevated systolic BP (SBP) ≥ 140 mmHg or diastolic BP (DBP) ≥ 90 mmHg.
Results: Mean age at baseline was 71.1 years (SD: 6.2) and 58.8% of the participants were women. 48.6% had baseline SBP < 120 mmHg, corresponding to the normal range. Baseline characteristics were balanced between the cocoa extract and placebo groups. Over a median follow-up of 3.4 years, in intention-to-treat analyses cocoa extract supplementation had no significant effect on incident hypertension, with the incidence rates (IRs) of 71.2 and 73.8 per 1000 person-years in cocoa and placebo groups, respectively (hazard ratio [HR]: 0.96 [95% confidence interval: 0.88, 1.05]). A significant interaction was observed between treatment assignment and baseline SBP (p=0.002). Cocoa extract supplementation reduced the incidence of hypertension among participants with baseline SBP < 120 mmHg (IR: 38.2 vs. 50.3 per 1000 person-years; HR: 0.76 [0.64, 0.90]), but not among those with SBP of 120-139 mmHg (IR: 101.4 vs. 96.8 per 1000 person-years; HR: 1.05 [0.93, 1.18]; Figure). Consistent results were obtained in sensitivity analyses using different definitions of hypertension: physician diagnosis, initiation of anti-hypertensive medications, or elevated BP alone. Per-protocol analysis using inverse probability weighting to account for non-adherence also supported the effect in SBP < 120 mmHg.
Conclusion: In older adults, years-long supplementation of cocoa extract may reduce the risk of incident hypertension among those with normal BP levels.