1. Departments of Medicine and of Environmental and Occupational Medicine, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, New Brunswick, New Jersey 08903, The Cancer Institute of New Jersey, New Brunswick, New Jersey 08903, Environmental and Occupational Health Sciences Institute, Piscataway, New Jersey 08854, and Graduate Program in Nutritional Sciences, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08903