An investigation of concurrent sex partnering in two samples of drug users having large numbers of sex partners.

The objective of this study was to quantitatively measure the nature of concurrent sex partnering in two samples of drug users having large numbers of sex partners. The purpose of this study was to measure concurrent sex partnering and overlap in concurrent sex partners in two samples of drug users in which some or all participants were trading sex-for-money. Two samples having large numbers of sex partners were used to conduct the analyses: drug-using male sex workers (MSW) and male and female crack cocaine smokers (CS) having vaginal sex. To reflect the quality of concurrent partnering, three measures were used: the proportion of the samples having concurrent partners; the proportions of the samples having intimate, casual, and sex-for-money of partners; and overlap in concurrent partners. Proportions of each sample having concurrent partners were essentially the same. However, the kinds of concurrent partners and overlap in concurrent partners were significantly different. Concurrent partners in the MSW sample were mostly sex-for-money or sex-for-drugs partners. Most concurrent partners in the CS sample were initimate or casual sex partners. Overlap in concurrent partners was also significantly different. The measure of overlap for the CS sample was three times higher than that of the MSW sample. These data suggest that concurrent sex partnering in the two samples, beyond the proportion having concurrent partners, was different. The patterns of concurrent sex partners in each sample may reflect different reasons for engaging in concurrent partnering. Different reasons for engaging in concurrent partnering may also be reflected in different overlap scores between the two samples. Efforts should be made in future studies to better capture the complexities of concurrent partnering and to examine the implications of these for disease spread and control.