title: Category of exposure to HIV and age in the progression to AIDS: longitudinal study of 1199 people with known dates of seroconversion. HIV Italian Seroconversion Study Group.
abstract: OBJECTIVE
  To determine whether rate of development of AIDS is affected by category of exposure to HIV and whether the more rapid development found in older subjects persists for each exposure category.
  
  
  METHODS
  Longitudinal study of people with known date of seroconversion to HIV.
  
  
  METHODS
  16 HIV treatment centres throughout Italy.
  
  
  METHODS
  1199 people infected with HIV through use of injected drugs, homosexual sex, or heterosexual sex.
  
  
  METHODS
  AIDS as defined by 1987 definition of Centers for Disease Control (including and excluding neoplasms) and by 1993 European definition.
  
  
  RESULTS
  225 subjects (18.8%) progressed to AIDS (Centers for Disease Control 1987 definition) during median follow up of 5.8 years. Univariate analyses showed more rapid progression to AIDS for older subjects compared with younger subjects and for homosexual men compared with other exposure categories. The age effect was of similar size in each exposure category and in men and women. In a bivariate model with age and exposure categories simultaneously included as covariates, differences by exposure category disappeared for use of injected drugs and heterosexual sex compared with homosexual sex (relative hazards 1.02 (95% confidence interval 0.71 to 1.45) and 1.07 (0.70 to 1.64) respectively), while the age effect remained (relative hazard 1.55 (1.32 to 1.83) for 10 year increase in age). Analyses using the other definitions for AIDS did not appreciably change these results.
  
  
  CONCLUSIONS
  There was no evidence of differences in rate of development of AIDS by exposure category, while there was a strong tendency for more rapid development in older subjects for all three groups. This supports the view that external cofactors do not play major role in AIDS pathogenesis but that age is of fundamental importance.
authors.affiliation: Centre Operative AIDS, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Pezzotti
authors.forename: A N
authors.initials: AN
authors.lastname: Phillips
authors.forename: M
authors.initials: M
authors.lastname: Dorrucci
authors.forename: A C
authors.initials: AC
authors.lastname: Lepri
authors.forename: N
authors.initials: N
authors.lastname: Galai
authors.forename: D
authors.initials: D
authors.lastname: Vlahov
authors.forename: G
authors.initials: G
authors.lastname: Rezza
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000453:epidemiology; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D015658:HIV Infections / Q000453:epidemiology*; D006679:HIV Seropositivity; D018451:Homosexuality, Male; D006801:Humans; D015994:Incidence; D007558:Italy / Q000453:epidemiology; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012307:Risk Factors; D015819:Substance Abuse, Intravenous / Q000453:epidemiology