1. Yale University School of Medicine, Epidemiology and Public Health, Division of Environmental Health Sciences, New Haven, Connecticut, USA
2. Harvard School of Public Health, Department of Environmental Health, Boston, Massachusetts, USA
3. Dhaka Community Hospital, Dhaka, Bangladesh
4. School of Medicine, Department of Public Health, Taipei Medical College, Taipei, Taiwan
5. Harvard School of Public Health, Department of Biostatistics, Boston, Massachusetts, USA