Walter C. Willett, MD, Dr.PH

Dr. Willett is continuing an examination of the relationship between body build before menarche and physical activity during adolescence and risk of breast cancer after menopause in the Nurses' Health Study II cohort members (NHSII). This cohort of women has been followed for 20 years and now is funded by the National Cancer Institute for another five-year cycle; support from BCRF was critical in maintaining the continuity of the cohort across funding gaps. Health, lifestyle and diet information has been collected at two- and four-year intervals since the onset of the study when women were ages 25-42 years old (88% follow-up). Cohort participants have provided detailed information on diet and physical activity during high school. Mothers of cohort participants have reported exposures in utero and during early years. The researchers have found that women with a heavier build before menarche and who were physically active during adolescence have a reduced risk of breast cancer during the pre-menopausal years and are now refining analyses that demonstrates these relationships are also seen with breast cancer after menopause, and to explore possible explanations for the unexpected relation with body build.

In 2009-2010, Dr. Willett's team proposes to obtain mammograms in the Nurses' Health Study II (NHSII) cohort and ultimately examine the relationship between pre-menopausal mammographic breast density, other dietary, biomarker and lifestyle factors and risk of breast cancer in the NHSII cohort members. This cohort was recruited in 1989 when women were 25-42 years old. Every two years women are sent or complete on line, questionnaires capturing lifestyle, activity and illness or disease information. Every four years the questionnaire contains detailed questions about diet and supplement intake. Response to these follow-up questionnaires has been 88%. The investigators have also collected detailed retrospective information on diet and physical activity during high school, and exposures in utero and during early childhood have been reported by the NHSII participants' mothers. They have recently examined the relationship between mammographic density and other factors in postmenopausal women (with funding assistance from BCRF) and breast cancer risk. Completing mammogram collection in pre-menopausal women will allow the scientists to extend this work to younger women. Along with biomarker and lifestyle information, they will develop risk prediction models that have the potential to help women reduce their risk of breast cancer.

The Growing up Today Study (with funding from BCRF) has in two waves, enrolled approximately 15,000 of the NSHII participants' daughters and the Willett team proposes to continue their follow-up of this unique group of adolescent girls with a specific emphasis on diet for the next questionnaire cycle. Over the last 10-15 years these girls have complete detailed questionnaires that gather information on diet and lifestyle related to growth rates, and ultimately, breast cancer risk.

Bio:
Dr. Walter Willett is Professor of Epidemiology and Nutrition and Chairman of the Department of Nutrition at Harvard School of Public Health and Professor of Medicine at Harvard Medical School. He grew up in Madison, Wisconsin, studied food science at Michigan State University, and graduated from the University of Michigan Medical School before obtaining a Doctorate in Public Health from Harvard School of Public Health.

Dr. Willett has focused much of his work over the last 25 years on the development of methods, using both questionnaire and biochemical approaches, to study the effects of diet on the occurrence of major diseases. He has applied these methods starting in 1980 in the Nurses' Health Studies I and II and the Health Professionals Follow-up Study. Together, these cohorts that include nearly 300,000 men and women with repeated dietary assessments are providing the most detailed information on the long-term health consequences of food choices.

Dr. Willett has published over 1,200 articles, primarily on lifestyle risk factors for heart disease and cancer, and has written the textbook, Nutritional Epidemiology, published by Oxford University Press. His book for the general public, Eat, Drink and Be Healthy: The Harvard Medical School Guide to Healthy Eating, has appeared on most major bestseller lists, and he has recently published a second book, co-authored with Mollie Katzen, on weight control for a general audience, Eat, Drink, and Weigh Less, and The Fertility Diet, with Dr. Jorge Chavarro. Dr. Willett is the most cited nutritionist internationally, and is among the five most cited persons in all fields of clinical science. He is a member of the Institute of Medicine of the National Academy of Sciences and the recipient of many national and international awards for his research.