Insight into the Infection Dynamics of the AIDS Epidemic: A Birth Cohort Analysis of New York City AIDS Mortality

The authors analyzed the secular trends of New York City acquired immunodeficiency syndrome (AIDS) mortality from 1980 through the first quarter of 1991 using birth cohort techniques to provide insight into reasons for temporal changes in growth of the epidemic. By disaggregating AIDS mortality data into composite birth cohorts, the authors determined that the slowing in the growth of the epidemic is a result of a leveling or decline in AIDS deaths in male birth cohorts bom before 1950 and a continued growth in younger male and all female birth cohorts. This phenomenon is believed to largely reflect earlier human immunodeficiency virus type 1 (HIV-1) infection patterns associated with age-related risk behaviors; however, to some lesser extent, it could also reflect age-related host factors or therapies that may influence the time from HIV-1 infection to death. The findings support the hypothesis that the early infection dynamics of the epidemic were differentially related to age and sex, which resulted in a diffusion of infection from older to younger cohorts and from males to females over time. The future growth of the epidemic will largely depend upon the infection patterns of younger birth cohorts. This method of analyzing AIDS incidence or mortality data may contribute to a better understanding of earlier patterns of HIV-1 infection within a defined population, which will be useful for targeting prevention efforts and improving AIDS forecasting methods.