1. Department of Epidemiology and Biostatistics, School of Public Health and National Demonstration Center for Experimental Preventive Medicine Education; Tianjin Medical University; Tianjin China
2. Center for Disease Control and Prevention of Tianjin Economic-Technological Development Area (TEDA), TEDA; Tianjin China
3. Division of General Internal Medicine, Tianjin Hospital; Tianjin China
4. Department of Nursing; Tianjin Medical College; Tianjin China
5. Department of Medicine and Therapeutics, Prince of Wales Hospital; Chinese University of Hong Kong; Hong Kong China