Individual and Partnership Factors Associated with Heterosexual Anal Intercourse Among Attendees of Public Sexually Transmitted Disease Clinics in Los Angeles County.

Heterosexual anal intercourse (HAI) is an understudied sexual behavior and poses unique challenges to the prevention of sexually transmitted diseases (STDs). This study aimed to explore individual and partnership characteristics associated with HAI. This study used data collected from 243 young people who attended STD clinics in Los Angeles County between April 2012 and May 2014. Participants reported on sexual behaviors with their last three sexual partners. Hierarchical, mixed effects, repeated-measures analyses were used to assess partner-level (demographic) and individual-level (demographic and behavioral) factors associated with recent (past 6 months) HAI. Thirty-two percent of participants (n = 243) reported HAI with at least one recent sex partner, and 49% reported ever having anal intercourse (AI). After adjusting for demographic characteristics, HAI was more than twice as likely to occur in relationships (n = 503) lasting more than a year compared to relationships lasting less than one month. HAI was also more likely to occur in relationships where intimate partner violence (IPV) was reported either as IPV initiated by the respondent (aOR = 2.18, 95% CI 1.08-4.41) or IPV initiated by the partner (aOR = 2.38, 95% CI 1.27-4.47). Among our participants, a substantial proportion reported HAI in the recent past 6 months and nearly half reported lifetime AI. Notably, our results indicate the importance of relationship contexts for people engaging in HAI and highlight the increased risk of STD/HIV transmission in the context of relationships with intimate partner violence victimization and perpetration.