With longstanding interest in the causes and prevention of chronic disease, particularly among women, Dr. Colditz has evaluated numerous lifestyle factors, documenting that current use of postmenopausal hormone therapy increases the risk of breast cancer. He has developed statistical models to more accurately classify levels of risk for several cancers. Other areas of his expertise include tobacco and obesity in relation to cancer. He also documented that smoking increases risk of stroke and total mortality among women and that weight gain increases the risk of diabetes. He has focused extensively on the validation of self-report information for use in large-scale epidemiologic studies and refined diet assessment tools for use in public health settings such as WIC. He has devoted much effort to the application of scientific advances in cancer prevention to broader population programs working with the American Cancer Society and the Massachusetts Cancer Control Program. He also developed the website, Your Disease Risk, to communicate tailored prevention messages to the public. He leads a team writing the Cancer News in Context blog. He continues to pursue approaches to the translation of epidemiologic data to improve risk stratification and tailor prevention messages and screening strategies.

Dr. Colditz sits on multiple committees to further cancer prevention efforts internationally. He chaired the National Academies of Sciences, Engineering, and Medicine work group, Improving Health Research on Small Populations; chaired the International Agency for Research on Cancer Working Group; was an adviser to the National Cancer Moonshot Initiative led by former Vice President Joe Biden; and currently serves on the NIH Council of Councils.