1. a Rollins School of Public Health , Emory University , Atlanta , GA , USA
2. b Carman and Ann Adams Department of Pediatrics , Prevention Research Center, Wayne State University School of Medicine , Detroit , MI , USA
3. c Department of Social and Behavioral Health, School of Rural Public Health , Texas A&M Health Science Center , College Station , TX , USA
4. d Department of HIV/STD Prevention , Guangxi Center for Disease Control and Prevention , Nanning , Guangxi , China