Ancillary Studies

Although the main goal of COSMOS is to test whether cocoa flavanols or a common multivitamin can prevent heart disease, stroke, and cancer, we will also assess whether these supplements confer other health benefits on:

Memory loss or cognitive decline

Macular degeneration and cataract

Physical disability and falls

Bone fractures


Nearly 7,000 participants provided optional biospecimens (blood and urine samples), blood pressure measurements, and brief anthropometric measurements (height, weight, and waist/hip circumference) at baseline. In addition, approximately 2,000 of these participants provided follow-up biospecimens and/or measurements at 1, 2, and 3 years follow-up.

We also invited a subset of approximately 600 participants who live within driving distance of Brigham and Women’s Hospital in Boston, Massachusetts for optional clinic visits to have more detailed studies completed, including biospecimens (blood, urine, and/or fecal samples), anthropometric measurements, seated and 24-hour ambulatory blood pressure measurements, cognitive function, physical function, pulse wave velocity, bone health, and other measurements at baseline. In addition, nearly 90% of these participants returned for a 2-year follow-up clinic visit.