A BIRTH COHORT ANALYSIS OF AIDS IN EUROPE - HIGH-INCIDENCE AMONG YOUNG PERSONS AT RISK

Objectives: To study trends in AIDS incidence in Europe by age and yea r of birth. Design: Age-period-cohort analyses were adopted to disting uish the different time factors of calendar year, age and year of birt h. Methods: Non-aggregate AIDS incidence data from 12 European countri es (1978-1994) were adjusted for reporting delay and expressed per uni t of population (per 100 000 persons or 100 000 person-years). Age-spe cific incidence patterns (absolute level and rate of increase) were co mpared between 5-year birth cohorts for homo-/bisexual men, injecting drug users (IDU) and heterosexual contact cases. Results: Mean age at diagnosis increased strongly amongst IDU, but less so among homo-/bise xual men and heterosexual contact cases. Of a total 110 646 reported c ases (116 311 after adjustment for reporting delay), 87 167 (78.8%) we re among people born in 1950-1974 [91 951 (79.1%) after adjustment for reporting delay]. The relative impact on specific birth cohorts diffe red strongly by exposure group. Incidences at age ranges of 20-24 and 25-29 years among cohorts born in 1965 and after were about the same l evel (homo-/bisexual men, IDU) or higher (heterosexual contact cases) than older birth cohorts when these were in the same age range; rates of increase were less among homo-/bisexual men and IDU, but higher amo ng heterosexuals. There were large differences between counties. Concl usions: Overall, AIDS incidence among cohorts born in 1965 and after i s about the same level (homo-/bisexual men, IDU) or higher (heterosexu al contact cases) than older cohorts when these were in the same age r ange. Rates of increase of AIDS incidence curves suggest reduced HIV t ransmission amongst the most recent cohorts of homo-/bisexual men and IDU, but among young heterosexuals the epidemic is still expanding.