[1] Univ Penn, Sch Med, Dept Dermatol, Philadelphia, PA 19104 USA
[2] Univ Penn, Sch Med, Ctr Clin Epidemiol & Biostat, Philadelphia, PA 19104 USA
[3] Univ Penn, Sch Med, Dept Epidemiol & Biostat, Philadelphia, PA 19104 USA
[4] Univ Rochester, Dept Dermatol, Rochester, NY 14627 USA
[5] Sabinsa Corp, Piscataway, NJ USA