[1
]
Department of Medical Statistics & Epidemiology, School of Public Health, Sun Yat-sen
University, Guangzhou, People's Republic of China.
[2
]
Division of Family Medicine and Primary Care, Jockey Club School of Public Health
and Primary Care, The Chinese University of Hong Kong, Hong Kong, China.
[3
]
Department of Medical Statistics & Epidemiology, School of Public Health, Sun Yat-sen
University, Guangzhou, People's Republic of China. Electronic address: chenyum@mail.sysu.edu.cn.