1. Slone Epidemiology Center (S.E.P., L.A.W., J.R.P.), Boston University, Boston, Massachusetts 02215
2. Division of Cancer Epidemiology and Genetics (R.T.), National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892
3. Department of Epidemiology (L.A.W., J.R.P., E.E.H.), Boston University School of Public Health, Boston, Massachusetts 02118
4. Departments of Community and Family Medicine and Pediatrics (L.T.-E.), Dartmouth Medical School and the Norris Cotton Cancer Center, Lebanon, New Hampshire 03756
5. Department of Obstetrics and Gynecology (W.C.S.), Tufts Medical Center, Boston, Massachusetts 02111