For many years Wilbur worked for the Centers for Disease Control at the National Center for Health Statistics. He worked on National Health Examination Surveys and on innovative research projects. While at CDC he consulted with the Pakistan Medical Research Council on the National Health Survey of Pakistan and follow-up projects. After leaving the CDC he worked briefly with the National Institute on Aging and then taught at the Aga Khan University in Karachi and the Nanjing University of Science and Technology in Nanjing, China. His research interests are in social inequalities in health, population health status and how it changes with social and economic development, and the development of institutions that promote population health.