Casual sex and concurrent sexual partnerships among young people from an Yi community with a high prevalence of HIV in China.

Liangshan Prefecture in Sichuan province, China, has a high prevalence of HIV infection, which is reflective of a change in the mode of transmission from injection drug use (IDU) to heterosexual intercourse. However, few studies focus on HIV-related heterosexual risk behaviours among the majority Yi population. The objectives of this study were to explore the characteristics of an egocentric sexual network and estimate the prevalence of casual sexual behaviour. Yi villagers (n=108), aged 15-35 years, who reported having had sex within the previous year were interviewed as to their sexual behaviours and networks. In-depth interviews and focus group discussions provided supplementary information on sexual norms. Logistic regression analysis was used to calculate unadjusted odds ratios (ORs) and 95% confidence intervals (CIs). Most of the respondents reported having had casual sex at some time in their life, and 66.7% reported multiple sexual partnerships. Only 21.3% reported ever having used a condom. During the study year, a total of 137 partners were involved in 153 sexual partnerships. Among the reported sexual partnerships, 67.3% originated from a casual sexual relationship. For network members in components of size ≥ 3, 56.9% were involved in concurrent sexual partnerships. Having never been married (OR: 2.11; 95% CI: 1.03-4.33) and younger age (OR: 0.89; 95% CI: 0.83-0.95) were both associated with being in a component of size ≥ 3. Size (OR: 2.99; 95% CI: 1.17-7.66), pair (OR: 0.54; 95% CI: 0.39-0.74), the number of weak components of the egocentric sexual network (OR: 30.04; 95% CI: 6.47-139.46) and gender (OR: 0.19; 95% CI: 0.06-0.67) were all associated with being in concurrent sexual partnerships. HIV-related interventions for the Yi ethnic minority in Sichuan province must therefore address concurrent sexual partnerships and promote condom use.