title: HIV-, HCV-, and co-infections and associated risk factors among drug users in southwestern China: a township-level ecological study incorporating spatial regression.
abstract: BACKGROUND
  The human immunodeficiency virus (HIV) and hepatitis C virus (HCV) are major public health problems. Many studies have been performed to investigate the association between demographic and behavioral factors and HIV or HCV infection. However, some of the results of these studies have been in conflict.
  
  
  RESULTS
  The data of all entrants in the 11 national methadone clinics in the Yi Autonomous Prefecture from March 2004 to December 2012 were collected from the national database. Several spatial regression models were used to analyze specific community characteristics associated with the prevalence of HIV and HCV infection at the township level. The study enrolled 6,417 adult patients. The prevalence of HIV infection, HCV infection and co-infection was 25.4%, 30.9%, and 11.0%, respectively. Prevalence exhibited stark geographical variations in the area studied. The four regression models showed Yi ethnicity to be associated with both the prevalence of HIV and of HIV/HCV co-infection. The male drug users in some northwestern counties had greater odds of being infected with HIV than female drug users, but the opposite was observed in some eastern counties. The 'being in drug rehabilitation variable was found to be positively associated with prevalence of HCV infection in some southern townships, however, it was found to be negatively associated with it in some northern townships.
  
  
  CONCLUSIONS
  The spatial modeling creates better representations of data such that public health interventions must focus on areas with high frequency of HIV/HCV to prevent further transmission of both HIV and HCV.
authors.affiliation: Department of Epidemiology, School of Public Health, Fudan University, Shanghai, China; Key Laboratory of Public Health Safety, Ministry of Education, Fudan University, Shanghai, China; Tropical Disease Research Center, Fudan University, Shanghai, China.
authors.forename: Yi-Biao
authors.initials: YB
authors.lastname: Zhou
authors.affiliation: Center for Disease Prevention and Control of Liangshan Prefecture, Sichuan, China.
authors.forename: Qi-Xing
authors.initials: QX
authors.lastname: Wang
authors.affiliation: Department of Environmental and Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, Florida, United States of America; Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America.
authors.forename: Song
authors.initials: S
authors.lastname: Liang
authors.affiliation: Center for Disease Prevention and Control of Liangshan Prefecture, Sichuan, China.
authors.forename: Yu-Han
authors.initials: YH
authors.lastname: Gong
authors.affiliation: Xuhui Center for Disease Prevention and Control, Shanghai, China.
authors.forename: Mei-xia
authors.initials: MX
authors.lastname: Yang
authors.affiliation: Department of Epidemiology, School of Public Health, Fudan University, Shanghai, China; Key Laboratory of Public Health Safety, Ministry of Education, Fudan University, Shanghai, China; Tropical Disease Research Center, Fudan University, Shanghai, China.
authors.forename: Shi-Jiao
authors.initials: SJ
authors.lastname: Nie
authors.affiliation: Center for Disease Prevention and Control of Liangshan Prefecture, Sichuan, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Nan
authors.affiliation: Department of Epidemiology, School of Public Health, Fudan University, Shanghai, China; Key Laboratory of Public Health Safety, Ministry of Education, Fudan University, Shanghai, China; Tropical Disease Research Center, Fudan University, Shanghai, China.
authors.forename: Ai-Hui
authors.initials: AH
authors.lastname: Yang
authors.affiliation: Center for Disease Prevention and Control of Liangshan Prefecture, Sichuan, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Liao
authors.affiliation: Department of Environmental and Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, Florida, United States of America; Department of Biostatistics, University of Florida, Gainesville, Florida, United States of America.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Epidemiology, School of Public Health, Fudan University, Shanghai, China; Key Laboratory of Public Health Safety, Ministry of Education, Fudan University, Shanghai, China; Tropical Disease Research Center, Fudan University, Shanghai, China.
authors.forename: Xiu-Xia
authors.initials: XX
authors.lastname: Song
authors.affiliation: Department of Epidemiology, School of Public Health, Fudan University, Shanghai, China; Key Laboratory of Public Health Safety, Ministry of Education, Fudan University, Shanghai, China; Tropical Disease Research Center, Fudan University, Shanghai, China.
authors.forename: Qing-Wu
authors.initials: QW
authors.lastname: Jiang
mesh_terms: D000328:Adult; D002681:China / Q000453:epidemiology; D060085:Coinfection / Q000453:epidemiology* / Q000821:virology*; D055030:Drug Users; D005260:Female; D006678:HIV; D015658:HIV Infections / Q000453:epidemiology* / Q000821:virology; D016174:Hepacivirus; D006526:Hepatitis C / Q000453:epidemiology* / Q000821:virology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D015819:Substance Abuse, Intravenous / Q000821:virology; D019966:Substance-Related Disorders / Q000821:virology*