HIV in injecting drug users in Edinburgh: prevalence and correlates.

A citywide sample of injecting drug users (IDUs) who had injected in the previous 6 months was recruited in Edinburgh. Interviewers administered a questionnaire enquiring about drug use, sharing of injecting equipment, sexual behavior, and imprisonment. A specimen of saliva was assayed for human immunodeficiency virus (HIV) IgG. HIV antibody prevalence in 346 IDUs recruited between June 1992 and October 1993 was 19.7% (95% confidence limits, 15.5 and 23.9%). Univariate analyses indicated that infection was significantly associated with being 27 to 36 years of age, starting to inject between 1975 and 1980, injecting in 1980-1987 and, particularly, 1982-1984, injecting in more than 7 years since 1979, reusing injecting equipment already used by another IDU in 1980-1987, being imprisoned, using equipment used by a fellow prisoner, and residing in north Edinburgh. Multivariate analysis showed that being 27-36 years of age, injecting in 1982-1984, and being imprisoned were independently related to being HIV positive. The risk of being infected increased with the number of times of imprisonment. A quarter of the sample said that they had used injecting equipment already used by another person in the 6 months before interview, and 70% said that they had ever done so. Of IDUs who started injecting after 1986, 4.5% were HIV positive. These findings suggest that the potential for HIV transmission by contaminated equipment still exists in Edinburgh. This is particularly so in prison, where IDUs do not have access to new needles and syringes.