1 Department of Family Medicine, University of California Los Angeles, Los Angeles, CA 90024, USA. Electronic address: sshoptaw@mednet.ucla.edu.
2 Fielding School of Public Health, University of California Los Angeles, Los Angeles, CA 90024, USA; School of Preventive Medicine and Public Health, Hanoi Medical University, Hanoi, Vietnam.
3 School of Preventive Medicine and Public Health, Hanoi Medical University, Hanoi, Vietnam.