The dynamics of injection drug users' social networks

Serial use of drug injection equipment is a well-known route of HIV transmission. The role of needle sharing and other individual risk behaviors in the spread of HIV infection has received considerable attention from public health researchers over the past two decades. Less attention has been given to understanding the determinants of these risk behaviors. Studies that have collected information about injection drug users' (IDUs) social networks have been helpful in this regard. The majority of these studies, however, have characterized IDUs' social networks with cross-sectional data. The current research contributes to the understanding of HIV risk among IDUs by examining the dynamics of their personal social networks and HIV risk behaviors over time.; Using data collected as part of a longitudinal HIV-intervention study in Baltimore, Maryland, this study assessed changes in the personal networks of more than 1,000 IDUs and their social network contacts. In comparison to the findings of much of the ethnographic work in similar populations, the changes occurring in the personal networks of these individuals were less than expected.; The role of broader social environmental conditions in affecting network changes was modeled using multivariate Poisson models. Lack of secure housing and mental and physical health problems were found to have the strongest associations with changes in personal network membership over time. Characteristics of the interpersonal relationships hypothesized to affect relationship persistence were investigated using a multilevel multivariate model. Individuals acting in a manner consistent with building social capital were shown to have more persistent relationships.; Multinomial logistic regression analysis was used to assess the association between changes in personal network membership and simultaneous changes in levels of HIV injection risk behaviors. Changes occurring over time in personal network membership were found to have an important impact on whether an individual increases, decreases or maintains her or his level of risky injection behaviors.; The findings from these analyses suggest that scholars and practitioners interested in ameliorating social ills, such as illicit drug use and HIV, need to pay greater attention to the dynamics of the personal social networks of those residing in impoverished inner-city environments.