1. Public Health and Epidemiology Research Group, School of Medicine, University of Alcala, Madrid, Spain
2. Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
3. Dornsife School of Public Health, Drexel University, Philadelphia, PA, USA
4. Department of Epidemiology and Biostatistics, Drexel University School of Public Health, Philadelphia, PA, USA