The role of needle exchanges in modifying sharing behaviour: cross-study comparisons 1989-1993.

In this paper the relationship between sharing behaviour and needle-exchange attendance is examined. Data from three studies of drug misuse carried out consecutively from 1989 to 1993 in the north-west of England are compared. Samples differed in their drug preferences. Analyses of sharing injecting equipment comparing exchange attenders and non-attenders revealed different patterns in each of the studies. Among opiate injectors no differences were observed in the proportions using others' injecting equipment, but attenders not in treatment were more likely to pass on their used equipment. This was attributed to uneven patterns of availability in the early days of exchange provision. Primary amphetamine users attending a needle exchange shared less than non-attenders, although overall levels of sharing were higher. Frequency of sharing was lowest in the third study of polydrug users but proportions sharing were similar to the opiate users. There was no effect of exchange attendance on sharing. Multiple logistic regressions identified other important predictors in these studies, e.g. treatment status, an injecting partner and injecting friends. Interpretations of the relationship between exchanges and sharing should take account of local availability of sterile equipment and the characteristics of exchange clientele.