1. Department of Dermatology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
2. Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, AL 35294, USA
3. Center for Preventive Ophthalmology & Biostatistics (CPOB), School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
4. School of Biomedical Informatics, University of Texas Health Sciences Center at Houston, Houston, TX 77030, USA
5. Hudson Alpha Institute for Biotechnology, Huntsville, AL 35806, USA
6. College of Public Health, University of Kentucky, Lexington, KY 40508, USA