Objective: To describe and quantify changing AIDS incidence trends in New York City.
Methods: Data on 44,400 AIDS cases diagnosed and reported between 1981 and 1992 were analyzed among demographic and HIV transmission categories. Data were grouped into 10-year birth cohorts by sex, race/ethnicity, and mode of HIV transmission. AIDS incidence and rates of change, as well as changes in median age at diagnosis, were analyzed for persons born between 1920 and 1969.
Results: Declining AIDS incidence between 1989 and 1992 was only observed among white men who have sex with men (MSM) born prior to 1960 and among minority MSM born prior to 1940. Between 1989 and 1992 the highest rate of increase in AIDS incidence was observed among female injecting drug users (IDU) and persons born after 1960. Median age at diagnosis increased during the study period by 1 year among white MSM, by 2 years among minority MSM, by 7 and 6 years among male and female IDU, respectively, and by 5 years among women infected through heterosexual contact.
Conclusions: These findings suggest that early HIV infection dynamics of the AIDS epidemic were differentially related to age, sex, and transmission category, which resulted in the diffusion of infection from older to younger cohorts and from men to women. The continuing increase in AIDS incidence among the 1960s cohort suggests that the future growth of the epidemic will be dependent upon infection patterns of younger birth cohorts.