title: Estimating the size of HIV key affected populations in Chongqing, China, using the network scale-up method.
abstract: OBJECTIVE
  To estimate the average social network size in the general population and the size of HIV key affected populations (KAPs) in Chongqing municipality using the network scale-up method (NSUM).
  
  
  METHODS
  A general population survey was conducted in 2011 through a multistage random sampling method. Participants aged between 18 and 60 years were recruited. The average social network size (c) was estimated and adjusted by known population method. The size of HIV KAP in Chongqing municipality was estimated using the adjusted c value with adjustment for the transmission effect using the scaled respect factor.
  
  
  RESULTS
  3,026 inhabitants of Chongqing agreed to the survey, and 2,957 (97.7%) completed the questionnaire. The adjusted c value was 310. The estimated size of KAP was 28,418(95% Confidence Interval (CI):26,636∼30,201) for female sex workers (FSW), 163,199(95%CI:156,490∼169,908) for clients of FSW, 37,959(95%CI: 34,888∼41,030) for drug users (DU), 14,975(95%CI:13,047∼16,904) for injecting drug users (IDU) and 16,767(95%CI:14,602∼18,932) for men who have sex with men (MSM). The ratio of clients to FSW was 5.74∶1, and IDU accounted for 39.5% of the DU population. The estimates suggest that FSW account for 0.37% of the female population aged 15-49 years in Chongqing, and clients of FSW and MSM represent 2.09% and 0.21% of the male population aged 15-49 years in the city, respectively.
  
  
  CONCLUSIONS
  NSUM provides reasonable population size estimates for FSW, their clients, DU and IDU in Chongqing. However, it is likely to underestimate the population size of MSM even after adjusting for the transmission effect.
authors: National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.
authors: Wei
authors: W
authors: Guo
authors: Shuilian
authors: S
authors: Bao
authors: Wen
authors: W
authors: Lin
authors: Guohui
authors: G
authors: Wu
authors: Wei
authors: W
authors: Zhang
authors: Wolfgang
authors: W
authors: Hladik
authors: Abu
authors: A
authors: Abdul-Quader
authors: Marc
authors: M
authors: Bulterys
authors: Serena
authors: S
authors: Fuller
authors: Lu
authors: L
authors: Wang
mesh_terms: D000328:Adult; D000465:Algorithms; D002681:China / Q000453:epidemiology; D005260:Female; D015658:HIV Infections / Q000453:epidemiology* / Q000635:transmission; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D011159:Population Surveillance; D012307:Risk Factors; D014505:Urban Population
references: Int J Prev Med. 2012 Jul;3(7):471-6
references: 22891148
references: AIDS. 2008 Dec;22 Suppl 5:S137-48
references: 19098474
references: Sex Transm Infect. 2006 Jun;82 Suppl 3:iii26-33
references: 16735289
references: Zhonghua Liu Xing Bing Xue Za Zhi. 2007 Sep;28(9):848-50
references: 18251264
references: PLoS One. 2012;7(1):e31184
references: 22563366
references: J Acquir Immune Defic Syndr. 2009 Sep 1;52(1):79-85
references: 19448559
references: Eval Rev. 1998 Apr;22(2):289-308
references: 10183307
references: Soc Networks. 2011 Jan 1;33(1):70-78
references: 21318126
references: Zhonghua Liu Xing Bing Xue Za Zhi. 2010 Jun;31(6):666-9
references: 21163100
references: Sex Transm Infect. 2006 Jun;82 Suppl 3:iii18-25
references: 16735288
references: Am J Epidemiol. 2011 Nov 15;174(10):1190-6
references: 22003188
references: Zhonghua Yu Fang Yi Xue Za Zhi. 2010 Nov;44(11):969-74
references: 21215121
references: Sex Transm Infect. 2010 Dec;86 Suppl 2:ii11-5
references: 21106509