Affiliation: | 1. Dermatoepidemiology Unit, VA Medical Center, Providence, Rhode Island, USA;2. Department of Dermatology, Rhode Island Hospital and Brown University, Providence, Rhode Island, USA;3. College of Arts and Sciences, Brown University, Providence, Rhode Island, USA;4. Cooperative Studies Program, VA Maryland Health Care System, Perry Point, Maryland, USA;5. Department of Epidemiology, Brown University, Providence, Rhode Island, USA |