title: Analysis of duration of risk behaviour for key populations: a literature review.
abstract: BACKGROUND
  The objective of this paper is to review literature in order to calculate regional estimates of the average duration of time individuals maintain a specific high-risk behaviour.
  
  
  METHODS
  The review targeted the key populations of female sex workers (FSW), male clients of female sex workers (MCFSW), people who inject drugs (injecting drug users (IDU)) and high-risk men who have sex with men (MSM). To be included in the review the study had to provide information on (1) the time a person spent at risk until death or cessation of the risk behaviour, (2) the percentage of the sample who initiated the risk behaviour in less than a year or (3) the mean or median duration of the behaviour from a representative sample.
  
  
  RESULTS
  49 papers were found for the FSW population describing the period of time FSW stay in sex work to be between 2.9 years (Asia) and 12 years (Latin America). Eight papers were found for MCFSW showing the duration of the risk behaviour in this category varying from 4.6 years in Africa to 32 years in Asia. 86 papers were reviewed for the population of IDU showing that the average time a person injects illegal drugs varies from 5.6 years (Africa) to 21 years (South America). No information was found for duration of high-risk behaviour among MSM; instead, the definitions found in the literature for high- and low-risk behaviour among MSM were described.
  
  
  CONCLUSIONS
  There is high variability of estimates of duration of high-risk behaviours at regional level. More research is needed to inform models and prevention programmes on the average duration of time individuals maintain a specific high-risk behaviour.
authors.affiliation: University of Brasília, 26 Chemin Colladon, 1209 Genève, Suisse, Brasília, Brazil. erikafazito@gmail.com
authors.forename: Erika
authors.initials: E
authors.lastname: Fazito
authors.forename: Paloma
authors.initials: P
authors.lastname: Cuchi
authors.forename: Mary
authors.initials: M
authors.lastname: Mahy
authors.forename: Tim
authors.initials: T
authors.lastname: Brown
mesh_terms: D000349:Africa; D000569:Americas; D001208:Asia; D055030:Drug Users; D005260:Female; D006801:Humans; D008297:Male; D012309:Risk-Taking; D060386:Sex Workers; D013997:Time Factors