title: Drug injection and sexual mixing patterns of drug-using male sex workers.
abstract: BACKGROUND
  Drug-using male sex workers (DUMSWs) are known to have large numbers of drug injection and sex partners.
  
  
  OBJECTIVE
  The purpose of this study was to describe the assortative and disassortative drug injection and sexual mixing patterns of DUMSWs. Implications of the high rates of disassortative mixing patterns of DUMSWs for HIV infection are discussed. Implications of disassortative mixing of DUMSWS with regard to DUMSWs bridging disparate HIV risk groups are evaluated.
  
  
  METHODS
  Data were collected from 89 DUMSWS. Data on up to six drug injection and six sex partners were collected from respondents. One hundred drug injection and 169 sex respondent/partner pairs were analyzed for the proportions of pairs that were concordant (like) or discordant (unlike) in gender, trading sex for money, race/ethnicity, and age cohort. For race/ethnicity and age, within-group differences were assessed with chi-square statistics.
  
  
  RESULTS
  Data showed high proportions of discordant respondent/partner pairs for both drug injection and sex by gender, trading sex for money, race/ethnicity, and age. Significant within-group differences in rates of discordant pairs were found for both behaviors in relation to race/ethnicity and age. Minority persons and respondents 19 years of age or younger were more likely to be in discordant pairs.
  
  
  CONCLUSIONS
  Direct assessment of HIV risk posed by the mixing patterns was not possible. Elaborating the mechanisms by which DUMSWs might act as an epidemiologic bridge is complex and involves more variables than were explored in this study. Nevertheless, such a study would be worthwhile.
authors.affiliation: Center for Health Promotion and Prevention Research, School of Public Health, University of Texas Health Science Center at Houston, Houston, Texas 77030, USA. mwilliams@sph.uth.tmc.edu
authors.forename: Mark L
authors.initials: ML
authors.lastname: Williams
authors.forename: Anne M
authors.initials: AM
authors.lastname: Bowen
authors.forename: Sandra
authors.initials: S
authors.lastname: Timpson
authors.forename: K
authors.initials: K
authors.lastname: Blair Keel
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D005006:Ethnicity; D015658:HIV Infections / Q000453:epidemiology* / Q000209:etiology; D018451:Homosexuality, Male; D006801:Humans; D008297:Male; D012307:Risk Factors; D011477:Sex Work / Q000706:statistics & numerical data*; D012725:Sexual Behavior / Q000706:statistics & numerical data*; D012747:Sexual Partners; D015819:Substance Abuse, Intravenous; D011795:Surveys and Questionnaires; D013781:Texas / Q000453:epidemiology