Debra Kalmuss is professor of clinical public health, Andrew Davidson is professor of public health and Alwyn Cohall is associate professor of clinical public health, all at the Joseph Mailman School of Public Health, Columbia University, New York. Danielle Laraque is associate professor and chief, Department of Pediatrics, Mount Sinai Medical Center, New York. Carol Cassell is senior health scientist, Dyncorps, Atlanta.