 Manson is board certified in both internal medicine and the subspecialty of endocrinology and metabolism.Her major research interests include preventive medicine and chronic disease epidemiology, particularly risk factors for cardiovascular disease, diabetes, and cancer in women.She is principal investigator for several grants from the National Institutes of Health, including the Women's Health Initiative Vanguard Clinical Center at Brigham and Women's Hospital in Boston, Women's Antioxidant and Folic Acid Cardiovascular Trial, Biochemical and Genetic Risk Factors for CVD in Women, and the Vitamin D and Omega-3 Trial, among others.