Study Organization

Study Organization

Anastassios Pittas, MD MS | Principal Investigator

Dr. Pittas is a Professor of Medicine at Tufts University School of Medicine, an Adjunct Professor of Nutrition and Policy at Tufts University Friedman School of Nutrition, Science and Policy and a Center Scientist at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University. Dr. Pittas received his B.S. degree from Massachusetts Institute of Technology and his M.D. degree from Cornell University Medical College.  After completing his Internal Medicine Residency at the New-York Presbyterian Hospital in New York City, NY and his Fellowship in Endocrinology at Tufts Medical Center, Boston, MA, he joined the staff in the Division of Endocrinology, Diabetes and Metabolism at Tufts Medical Center where he has been active in clinical care, research and teaching as they relate to the prevention and treatment of diabetes mellitus. Dr. Pittas serves as the Co-Director of the Dr. Gerald J. and Dorothy R. Friedman New York Foundation for Medical Research Diabetes Self-Education Program and as the Associate Director of the Endocrinology Fellowship Program at Tufts Medical Center.  Dr. Pittas earned his M.S. degree in Clinical Research from Sackler School of Biomedical Sciences at Tufts University in 2006. He is Diplomat of the American Board in Endocrinology and Metabolism.  Dr. Pittas’ was the recipient of a National Institutes of Health K23 Career Development Award. His work on the role of vitamin D and calcium in cardiometabolic disease has been supported by the R01, R21, U34 and U01 mechanisms of the National Institutes of Health (NIDDK and ODS) and the American Diabetes Association.  He has co-authored over 80 publications including peer-reviewed journals, books, book chapters and evidence-based reports. In 2017, he was honored to receive a Biomedical Research Exemplar Award, given to principal investigators who conduct high quality, high-impact research and exemplify professionalism and integrity. In 2017, 2018 and 2019, he was named as one of Top Docs by Boston Magazine. Need more? Visit

BessBess Dawson-Hughes, MD | Co-Investigator

Dr. Dawson-Hughes, M.D. graduated from Tufts University School of Medicine and completed her internship at St. Elizabeth’s Hospital in Brighton, MA. She became Chief Resident in Medicine at St. Elizabeth’s Hospital and went on to an endocrine fellowship at Harvard Medical School and the Brigham and Women’s Hospital. She subsequently received an Individual National Research Service Award at Harvard Medical School. Dr. Dawson-Hughes has served on the councils of several professional organizations, including the American Society for Bone and Mineral Research, the American Society of Clinical Nutrition and the International Bone and Mineral Society. Dr. Dawson-Hughes served as Principal Investigator of the NIH Osteoporosis and Related Bone Diseases Resource Center in Washington, DC from 1998-2003, served on the Advisory Council of the National Institute of Arthritis, Musculo-skeletal, and Skin Diseases from 2000-2004, and served as President of the National Osteoporosis Foundation from 2002-2005. She also served as an Associate Editor of the Journal of Bone and Mineral Research from 1994 through 2002. Dr. Dawson-Hughes has published over 350 peer-reviewed journal articles, book chapters, abstracts, and reviews. Her current research is directed at examining ways in which calcium, vitamin D influence risk of osteoporotic fractures and progression of other chronic diseases. Dr. Dawson-Hughes is frequently invited to speak to scientific and clinical groups both nationally and internationally about her research and on current advances in the diagnosis and treatment of bone diseases.

CliffClifford J. Rosen, MD | Co-Investigator

Dr. Clifford J. Rosen, M.D. is the Director of Clinical and Translational Research and a Senior Scientist at MaineMedicalCenter’s Research Institute.  He is also an Adjunct Staff Scientist at the Jackson Laboratory, and Professor of Medicine at Tufts University School of Medicine.  Dr. Rosen is the founder and Former Director of the Maine Center for Osteoporosis Research and Education.  He was the first Editor-in-Chief of the Journal of Clinical Densitometry, and he is currently the Editor-in-Chief of The Primer in Metabolic Bone Diseases, and an Associate Editor for JCEM.  His publications include more than 300 peer-reviewed manuscripts, covering both clinical and basic bone biology.

Dr.Rosen has overseen numerous phase II and III clinical trials, funded through federal (NIH) and non-federal sources.  He is currently a member of the FDA Advisory Panel on Endocrinologic and Metabolic Drugs and a former chairperson of that Panel.  He was Permanent Chair of the NIH Review Panel for Skeletal Biology and Bone Diseases for 2002-2004, and is currently a member of the NIAMS Scientific Advisory Board.  He served as president of the American Society for Bone and Mineral Research in 2002-2003.  Dr. Rosen’s research interests include the genetic regulation of insulin-like growth factor relative to skeletal metabolism, PTH as an anabolic therapy, and the relationship between marrow adipogenesis and osteoblastogenesis.

PattyPatricia Sheehan, RN MPH MS | (Former) Project Manager

Patricia (Patty) Sheehan is Assistant Professor at Tufts University School of Medicine.  She received her BSN from Villanova University, a MPH with a concentration in epidemiology from Johns Hopkins University followed by a MS in Community Health (Family Nurse Practitioner) from the University of Massachusetts.  She started her career as a clinical research nurse at the National Institutes of Health Clinical Center.  Ms. Sheehan has organized, directed and completed large multicenter trials for both academia and industry, most recently as the Associate Director for the NHLBI sponsored IMMEDIATE Trial.  In addition to her research experience, she has worked in public and community health nursing and provided primary and specialized care as a nurse practitioner.   She is a member of the Society for Clinical Trials and held certification as a Clinical Research Associate by the Association of Clinical Research Professionals.

PaulPaul Fuss | (Former) Research Associate

Paul Fuss received his B.A. degree from the University of Michigan and has over 20 years of experience as a research coordinator and project manager in nutrition-based clinical research, including multi-center clinical trials, conducted at the Human Nutrition Research Center on Aging at Tufts University. He served as the site Project Manager for the multi-center CALERIE Study, a large and very complex trial on calorie restriction and the aging process. Most recently, he completed a field study on the effectiveness of a new micronutrient-rich supplemental food on improving the health and nutritional status of primary school-aged children in the West African country of Guinea-Bissau. Mr. Fuss joined the research team in the Division of Endocrinology at Tufts Medical Center in 2012.

EllenEllen Vickery, MS | Research Associate

Ellen Vickery received her B.A. in Environmental Studies from New York University and her M.S. in Nutritional Epidemiology from the Tufts University Friedman School of Nutrition Science and Policy. Prior to joining the team in the Division of Endocrinology, Ms. Vickery served for six years as a member of the Coordinating Center staff for the multi-center NHLBI-funded IMMEDIATE Trial, first as a research assistant and then as a research coordinator. The study examined the efficacy of an intravenous solution of glucose, insulin and potassium for improving outcomes in patients experiencing acute coronary syndromes and was completed in 2012.

Picture2Cindy Haviet, MS | (Former) Research Assistant

Cindy Haviet received her B.A. in Biology with a minor in Public Health from Regis College in 2013 and after two remaining courses will receive her M.S. in Regulatory and Clinical Research Management, a program geared towards working in an academic research environment or regulatory affairs. During her undergraduate study, Cindy was the co-founder & President of the Regis College Science Association & a member of The National Biological Honor Society. In her graduate studies she has taken courses that are complementary to the work she will be doing as part of the D2d research team.  Samples of the courses include clinical research methodology, pharmaceutical regulations, biostatistics, and quality systems and risk management.

Danielle Riggs | Director of Research Administration

Danielle Riggs received her B.S. in Biology from Stonehill College, and has worked within Research Administration at Tufts Medical Center since 2000, most recently joining the leadership team for the Department of Medicine in 2008 as the Director of Administration and Finance.  She oversees the pre- and post-award administration for all federal, foundation, and industry grants and clinical trials throughout the Divisions of Medicine.  In this role, she helped to build the budget management model for D2d, and continues to work with D2d to develop and oversee internal systems for monitoring D2d’s complex budget across sites.

OliviaOlivia Lovegreen | (Former) Research Administrator

Olivia Lovegreen received her B.S. in Health Policy and Management from Providence College in 2012. During her undergraduate study she interned at Rhode Island Primary Care Physicians Corporation and Butler Hospital in the Risk Management department. Following graduation she spent a short time working at Joslin Diabetes Center which fostered her interest in grant management. Olivia began working in the Research Administration department at Tufts Medical Center in March 2014 and is enjoying the opportunity to work on such a large study with multiple sites across the country.

JasonJason Nelson, MPH | Study Analyst

Mr. Nelson is a statistician in the Biostatistics Research Center in the Institute for Clinical Research and Health Policy Studies (ICRHPS). Since 2007, through the Biostatistics Research Center, Mr. Nelson has provided statistical research support and data management to clinical researchers throughout the Tufts Medical Center community as well as to collaborators at other institutions. His primary research interest includes spatial analysis of geographic information.  Mr. Nelson received his MPH in biostatistics and epidemiology from Tufts University School of Medicine.