1. Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA, USA
2. Community Medicine and Public Health Department, Faculty of Medicine, Menoufia University, Shebin El-Kom, Egypt
3. Department of Biostatistics, College of Public Health, University of Iowa, Iowa City, IA, USA
4. Department of Epidemiology and Environmental Health, State University of New York, Buffalo, NY, USA
5. Department of Pharmacology and Toxicology, State University of New York, Buffalo, NY, USA
6. Department of Clinical Pathology, National Liver Institute, Menoufia University, Shebin El-Kom, Egypt