COcoa Supplement and

Multivitamin Outcomes Study

Study Staff



COSMOS Principal Investigators


JoAnn E. Manson, MD, DrPH

JoAnn E. Manson, MD, DrPH is a Professor of Medicine and the Michael and Lee Bell Professor of Women’s Health at Harvard Medical School. She is also Chief of the Division of Preventive Medicine at Brigham and Women’s Hospital and Professor in the Department of Epidemiology at the Harvard T.H. Chan School of Public Health. Dr. Manson is an endocrinologist, epidemiologist, and Principal Investigator (PI) or Co-PI of several research studies, including the VITamin D and OmegA-3 TriaL (; the Women’s Health Initiative Clinical Center in Boston; the cardiovascular component of the Nurses’ Health Study; and Co-PI (with Dr. Howard Sesso) of the COcoa Supplement and Multivitamin Outcomes Study (COSMOS).  Her primary research interests include clinical prevention trials evaluating nutritional and lifestyle interventions for heart disease, diabetes, and cancer, endogenous and exogenous estrogens as determinants of chronic disease outcomes, and biomarker predictors of disease. Dr. Manson has received numerous honors and has >800 peer-reviewed scientific publications.


Howard D. Sesso, ScD, MPH, FAHA

Dr. Howard D. Sesso is an Associate Professor of Medicine and Director of Nutrition Research at the Division of Preventive Medicine at Brigham and Women’s Hospital, and an Associate Professor of Epidemiology at the Harvard T.H. Chan School of Public Health. Dr. Sesso specializes in the epidemiology and prevention of cardiovascular disease and cancer, with an emphasis on dietary factors including vitamin and mineral supplements.  He was Project Director of the Physicians’ Health Study (PHS) II (, a previously completed trial that tested a multivitamin and other vitamin supplements in the prevention of cancer and cardiovascular disease, and is the Co-Principal Investigator of the COSMOS trial.


Garnet Anderson, PhD 

Dr. Garnet Anderson, is Senior Vice President and Director of the Public Health Sciences Division of Fred Hutchinson Cancer Research Center. Dr. Anderson received her Ph.D. in biostatistics from the University of Washington in 1989 and has been on the Public Health Sciences faculty in both the Biostatistics and the Cancer Prevention Programs since that time. Her primary interests are in the design and analysis of randomized trials, women's health and chronic disease prevention. She is best known for her work with Dr. Ross Prentice in the Women's Health Initiative (WHI) where she is currently the Principal Investigator of the WHI Clinical Coordinating Center. Dr. Anderson played a major role in the design, monitoring and analysis of the WHI clinical trials and was the lead statistician for the WHI hormone therapy trials. Dr. Anderson is also the Associate Director for Cancer Control and Prevention of the SWOG (Southwest Oncology Group) Statistical Center (Dr. Michael LeBlanc, PI) and an Affiliate Professor in the Department of Biostatistics at the University of Washington. She has served as statistician for the SWOG Gynecology Committee and a member of NCI's Steering Committee for gynecological cancers. Dr. Anderson has held leadership roles in other multicenter groups including as Project Director and Biostatistics Core leader in the NCI-funded Pacific Ovarian Cancer Research Consortium SPORE (Dr. Nicole Urban, PI) and a Principal Investigator (with Dr. Andrea LaCroix) of the data coordinating center for an NIA-funded clinical trials network to study alternatives therapies for menopausal symptoms (MsFLASH). She is also PI for the WHI Cancer Survivor Cohort (joint with Drs. Bette Caan and Electra Paskett). Dr. Anderson is also part of a scientific leadership team (with Drs. JoAnn Manson, MD, DrPH, and Howard Sesso, ScD, of Harvard and Brigham and Women's Hospital in Boston) conducting a five-year, large-scale randomized controlled trial (The COcoa Supplement and Multivitamins Outcomes Study - COSMOS) to test the effect of a concentrated cocoa extract and multivitamin supplements in reducing risks of CVD and cancer. Dr. Anderson has authored over 160 articles and book chapters and has served on numerous national and international panels and review groups. Dr. Anderson was named a recipient of a Fred Hutch 40th Anniversary Endowed Chair.


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