NEEDLE TRANSFER AMONG INJECTION-DRUG USERS - A MULTILEVEL ANALYSIS

Objective: The purpose of the study described here is to extend our un derstanding of needle transfer behaviors among injection drug users (I DUs) by combining both micro and macro variables in a multilevel model . Methods: A sample of 8,404 IDUs interviewed at 18 sites of the Natio nal Institute on Drug Abuse (NIDA) Cooperative Agreement for AIDS Comm unity-Based Outreach/Intervention Program (COOP) was used for the stud y. A multilevel model was employed to deal with intraclass correlation in the sample and to evaluate the impact of micro and macro variables on needle transfer among IDUs. Results: A significant intraclass corr elation was detected in the sample. Needle transfer was associated wit h both the individual characteristics and the features of the social s etting in which they were embedded. Some of the micro slopes were fixe d, while some varied from site to site, depending on the values of mac ro variables. The micro intercept and the micro slope of ethnicity var y randomly across social settings, while they are partially determined by macro variables. Conclusion: Considering the intraclass correlatio n in the data and the effects of contextual features on individual beh aviors, multilevel analysis of HIV risk behaviors should be considered when combining data from micro and macro levels (e.g., individual and project site levels).