Study: No significant long-term benefits found in cocoa extract for AMD

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An ancillary segment of the COSMOS randomized clinical trial (NCT03205202) found that cocoa extract supplementation over an extended period did not affect the overall occurrence of age-related macular degeneration (AMD) in older patients,¹ according to first author William G. Christen, ScD, for the COSMOS Research Group. He is from the Division of Preventive Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston.

This large study sought to determine if daily supplementation with cocoa extract, a source of flavanols, reduces the occurrence or progression of AMD.

“Although the pathophysiology remains unclear, the consistent observation of decreased choroidal circulation in eyes with AMD^2-4 supports a vascular basis for the disease and has led some investigators to hypothesize that AMD and cardiovascular disease (CVD) may share common underlying mechanisms and risk factors.^5-8 Consistent with this possibility, epidemiologic studies have shown that the risk of AMD is higher in those with CVD compared to those without^9-12 and in those with CVD risk factors, such as elevated blood pressure,^10,12-14 dyslipidemia,^8,12,15-18 higher body mass index,^19,20 and smoking,^21,22 the research team explained.

In addition, nutrition has been thought to contribute to AMD^23,24 and CVD.^25,26 “An area of growing interest is the potential cardiovascular benefits of moderate consumption of cocoa products, with a focus on cocoa flavanols, a group of flavonoids present in the cocoa bean,²⁷” they explained.

Study methods

A total of 21,442 US adults (12,666 women, mean age, 72.1 years) aged 60 years and older were included. They received a cocoa extract supplement and a multivitamin supplement (500 mg/day cocoa flavanols, including 80 mg (−)-epicatechin, a bioactive component in dark chocolate) or placebo to determine if CVD and cancer were prevented. This intervention phase was performed from June 2015 through December 2020.

The primary end point was a composite of incident cases of AMD plus cases of progression to advanced AMD (geographic atrophy, neovascular membrane, retinal pigment epithelium detachment, or disciform scar) among participants with AMD at baseline, the investigators explained.

Ancillary study results

During a median treatment period of 3.6 years, the authors reported that 344 participants (1.6%) had a confirmed AMD event, ie, 316 had incident AMD, 28 progressed to advanced AMD); of these, 159 cases (1.5%) were in the cocoa extract group and 185 cases (1.7%) were in the placebo group ((hazard ratio [HR], 0.87; 95% confidence interval [CI], 0.71-1.08; P =0 .21).

Separate Cox models fitted because of evidence of nonproportional hazards (P = 0.048) indicated a 23% decreased risk in the cocoa extract group during the first 2 years of treatment (HR, 0.77; 95% CI, 0.59-1.01), with no added benefit for treatment beyond 2 years (HR, 1.06; 95% CI, 0.76-1.50). Similar time-dependent findings were observed for visually significant AMD and advanced AMD, the study found.

While cocoa extract supplementation for a median period of 3.6 years did not significantly affect incident AMD and AMD progression, the study could not rule out a possible benefit of supplementation during the first 2 years of treatment. The researchers suggested that further research is warranted to clarify whether long-term cocoa extract supplementation may reduce AMD events.

References

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