1. Food Safety and Health Research Center, School of Public Health; Southern Medical University; Guangzhou 510515 Guangdong P.R. China
2. Department of Preventive Medicine, School of Public Health; Sun Yat-sen University; Guangzhou 510080 Guangdong P.R. China
3. JC School of Public Health and Primary Care; The Chinese University of Hong Kong; Hong Kong SAR China
4. Upper Gastrointestinal Surgery, Department of Molecular Medicine and Surgery, Karolinska Institute; Karolinska University Hospital; NS 67, 2nd Floor 17176 Stockholm Sweden
5. Hong Kong Occupational and Environmental Health Academy; Hong Kong SAR China