title: Age differences in sexual partners and risk of HIV-1 infection in rural Uganda.
abstract: OBJECTIVE
  To assess whether differences in age between sexual partners affect the risk of HIV infection in female adolescents and young adults.
  
  
  METHODS
  A total of 6177 ever sexually active women aged 15 to 29 years completed a sociodemographic and sexual behavior questionnaire and provided a blood sample for HIV-1 serology. The age difference between partners was categorized as men 0 to 4 years older (referent group), 5 to 9 years older and 10 or more years older. HIV prevalence and incidence were assessed, and adjusted RR was estimated by multivariate regression.
  
  
  RESULTS
  Prevalent HIV-1 infection in female participants increased with older male sexual partners. Among women aged 15 to 19 years, the adjusted risk of HIV infection doubled (RR = 2.04; 95% CI: 1.29-3.22) among those reporting male partners 10 or more years older compared with those with male partners 0 to 4 years older; among women 20 to 24 years of age, the RR was 1.24 (95% CI: 0.96-1.60). The attributable fraction (exposed) of prevalent HIV infection in women aged 15 to 24 years associated with partners 10 or more years older was 9.7% (95% CI: 5.2-14.0). HIV incidence did not increase with differences in age of partners.
  
  
  CONCLUSIONS
  The age difference between young women and their male partners is a significant HIV risk factor, suggesting that high HIV prevalence in younger women is caused, in part, by transmission from older male partners.
authors.affiliation: Department of Population and Family Health Sciences, School of Hygiene and Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Kelly
authors.forename: Ronald H
authors.initials: RH
authors.lastname: Gray
authors.forename: Nelson K
authors.initials: NK
authors.lastname: Sewankambo
authors.forename: David
authors.initials: D
authors.lastname: Serwadda
authors.forename: Fred
authors.initials: F
authors.lastname: Wabwire-Mangen
authors.forename: Tom
authors.initials: T
authors.lastname: Lutalo
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Wawer
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D005260:Female; D015658:HIV Infections / Q000453:epidemiology*; D015528:HIV Seroprevalence; D006801:Humans; D007223:Infant; D008297:Male; D017533:Marital Status; D015995:Prevalence; D018570:Risk Assessment; D012424:Rural Population; D012747:Sexual Partners / Q000145:classification*; D012959:Socioeconomic Factors; D014454:Uganda / Q000453:epidemiology