Dr. JoAnn E. Manson is an endocrinologist, epidemiologist, and Principal Investigator of several research studies, including the VITamin D and OmegA-3 TriaL (VITAL; PI with Dr. J. Buring since study inception in 2009); the COcoa Supplement and Multivitamin Outcomes Study (COSMOS, PI with Dr. H. Sesso since 2014); and others. Her primary research interests include randomized clinical prevention trials of nutritional and lifestyle factors related to heart disease, diabetes, and cancer and the role of endogenous and exogenous estrogens as determinants of chronic disease.