Affiliation: | 1. Department of Dermatology, Penn State Milton S. Hershey Medical Center, Hershey, Pennsylvania, USA;2. Department of Public Health Sciences, Penn State College of Medicine, Hershey, Pennsylvania, USA;3. Department of Biostatistics, School of Public Health, Peking University, Beijing, China;4. Division of Dermatology, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California, USA |