1. a Fred Hutchinson Cancer Research Center , Program in Epidemiology, Seattle, Washington
2. b Department of Epidemiology , University of Washington , Seattle, Washington
3. c Department of Environmental and Occupational Health Sciences , University of Washington , Seattle, Washington
4. d School of Public Health, Faculty of Medicine , The Chinese University of Hong Kong , Hong Kong, SAR, People's Republic of China
5. e Zhong Shan Hospital Cancer Center , Shanghai, People's Republic of China