title: Increasing trends in HIV prevalence among people aged 50 years and older: evidence from estimates and survey data.
abstract: OBJECTIVE
  To present the most recent 2013 UNAIDS estimates of HIV prevalence among people aged 50 years and older, and to validate these estimates using data from national household surveys.
  
  
  METHODS
  Modelled estimates of HIV prevalence were validated against nationally representative household survey measures of HIV prevalence.
  
  
  METHODS
  The UNAIDS 2013 HIV estimates were used to compute HIV prevalence and number of people living with HIV aged 50 years and older. Sex-specific HIV-prevalence rates by the 5-year age group were calculated from nationally representative household surveys conducted between 2003 and 2013, and were compared to prevalence rates from the modelled estimates. The ratios (Spectrum/Survey) of the prevalence rates from the two sources were analysed.
  
  
  RESULTS
  In 2013, an estimated 4.2 million (4.0-4.5 million) people aged 50 years and older were living with HIV. The global HIV prevalence among older individuals more than doubled in almost all the 5-year age groups since 1995. There was a relatively good agreement between the modelled HIV-prevalence rates and the survey-based rates among men and women aged 50-54 years (0.90 and 1.00 median ratio, respectively), whereas for 55-59 year-olds, the differences were more notable (ratios of 0.63 for men and 0.90 for women).
  
  
  CONCLUSIONS
  Both data sources suggest HIV-prevalence rates among people aged over 50 have increased steadily in the recent years. Care and treatment services need to address the specific needs of older people living with HIV. Action is needed to incorporate older age groups into HIV surveillance systems.
authors.affiliation: aUNAIDS, Programme Branch, Geneva, Switzerland bIndependent. *These authors contributed equally to this manuscript.
authors.forename: Mary
authors.initials: M
authors.lastname: Mahy
authors.forename: Christine S
authors.initials: CS
authors.lastname: Autenrieth
authors.forename: Karen
authors.initials: K
authors.lastname: Stanecki
authors.forename: Shona
authors.initials: S
authors.lastname: Wynd
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D062665:Epidemiological Monitoring; D005260:Female; D014943:Global Health; D015658:HIV Infections / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D015995:Prevalence; D017678:Sex Distribution; D055815:Young Adult