Role of social networks in the transition to injection drug use: Actions speak louder than words

Objectives: A key challenge in HIV prevention in China is reducing the transition from non-injection drug use to injection-use through effective interventions. The objective of this study was to examine the influences of social network factors in the transition from non-injection heroin and/or opiate use to heroin-injection. Methods: Respondent-driven sampling was used to recruit young heroin and/or opiate users in an egocentric network study in Yunnan, China. Multivariate logistic regression using hierarchical combinations of social network variables was applied to analyze factors for the transition. Results: A total of 3,121 social network alters were reported by 403 egos with an average network size of 8. Fifty-eight percent of egos transitioned to heroin-injection from non-injection drug-use. This transition was associated with having a larger sex network size (OR = 2.17; 95% CI = 1.26, 3.75; p ≤ 0.01), a larger number of heroin injectors in one's network (OR = 1.69; 95% CI = 1.24, 2.31; p ≤ 0.01), and a higher network density (OR = 2.54; 95% CI = 0.96, 6.73; p = 0.06). No significant associations were found between the transition and tangible support, and the transition and subjective norms regarding injection-use. Conclusions: These findings enhance our understanding of the influence of social networks on the transition to injection drug use. The results suggest that drug users in China are influenced by the actions of their network peers, rather than by verbal persuasion. Accordingly, the development of interventions for heroin and/or opiate users in China should consider social network characteristics.