How much of a role do genes play in the onset of diseases and how much of a role does an individual’s environment play? It’s a question that has long intrigued epidemiologists. “It’s really the core question we’ve been asking in epidemiology,” said David Hunter, Richard Doll Professor of Epidemiology and Medicine at the University of Oxford and Vincent L. Gregory Professor in Cancer Prevention, Emeritus at Harvard T.H. Chan School of Public Health.
On Dec. 12, 2018, Hunter delivered the 168th Cutter Lecture on Preventive Medicine to an auditorium packed with students, faculty, and colleagues. “If you told me when I was a student here that one day I might be given this honor I would have never believed it,” he said.
Hunter trained as a medical doctor in Australia before coming to Harvard Chan School to study epidemiology. His thesis focused on sun exposure and skin cancer. “Perhaps I didn’t realize it then, but we were actually studying gene-environment interactions.”
Hunter spent time discussing large observational studies, such as the Nurses’ Health Studies, that are designed to help determine how social environments and individual behavior, including diet and exercise habits, influence disease risk. Observational studies present many challenges, including relatively small sample sizes and a reliance on self-reported data, which may not always be accurate, he said.
But he noted that questionnaires can provide accurate information on many associations, for example, between diet and the risk of cardiovascular disease or diabetes. For revealing links between diet and cancer, though, such studies suggest that adult’s diets are not a major determinant of short-term risk of most cancers. “That’s something that has emerged rather painfully over the past 30 or 40 years,” he said.