The syndemic of substance abuse, violence and AIDS, initially conceptualized by Singer
, has been studied extensively among impoverished, urban women in the United States
. In their review of the literature, Meyer et al.
 found that women who experienced intimate partner violence faced barriers to negotiating condom use, that substance abuse was associated with increased violence and sexual risk-taking and that women who experienced violence were more likely to abuse substances. Despite the significance of substance abuse and violence in contributing to the burden of HIV, little research has examined its effects among female sex workers (FSWs) in countries with a high prevalence of HIV, particularly within their regular, non-paying partnerships.
Previous studies in the U.S. and China have identified associations between FSWs’ drug and alcohol abuse and experiences of physical and sexual violence perpetrated by both clients and regular, non-paying partners
[3, 4]. FSWs are subjected to high rates of physical and sexual abuse both prior to and during their engagement in sex work. Violence against FSWs may be perpetrated by regular, non-paying partners; clients; police; managers; and others
[3–13]. Research has tended to look cross-sectionally at the coexistence of alcohol abuse and victimization, limiting the ability to determine causality. However, one longitudinal study in the U.S.
 found that women’s alcohol abuse did not increase the odds of a new assault, but that experiencing a new assault significantly increased the odds of subsequent alcohol abuse by the victim.
The associations between FSWs’ experiences of violence and exposure to HIV risk within their client and regular, non-paying partnerships are well-documented. Studies have shown that FSWs who have ever been sexually or physically abused are more likely to report sexually transmitted infections (STIs) and inconsistent condom use with clients
[5, 15]. All types of violence (sexual, physical and emotional) perpetrated by clients or regular, non-paying partners have been associated with STIs
. In particular, the fear of victimization constituted a significant barrier to condom use negotiation
There is a paucity of data on the links between violence and HIV risk within regular, non-paying partnerships in the developing world. One recent study in southern India examining the link between physical and/or sexual violence and inconsistent condom use found no association in non-paying partnerships, while observing a positive relationship in regular and occasional client partnerships
. A study in China examining physical, sexual and emotional violence found the reverse: all types of violence were associated with inconsistent condom use with regular, non-paying partners, but not with clients
Other literature suggests the importance of lifetime gender-based violence (verbal, physical and/or sexual) among FSWs in relation to STIs and inconsistent condom use with clients and other partners
, suggesting that experiences of violence impact women’s HIV risk beyond immediate partnerships. However, the link between FSWs’ violent work environments and HIV risk with regular, non-paying partners has not been investigated. The current study examined whether experiencing any physical, sexual or emotional violence in relation to one’s work was associated with inconsistent condom use in regular, non-paying partnerships.
Heavy alcohol consumption among FSWs has been documented globally
. Alcohol use by FSWs can be partially explained by its wide availability at venues where FSWs operate
[23–26] and the fact that FSWs are often obliged to drink with clients
[7, 27–29]. Alcohol use by FSWs may also have a psychological component, and has been reported as a possible coping mechanism in several settings
[5, 8, 30].
In addition to the effects on FSWs’ general mental and physical health, alcohol abuse has the potential to increase HIV risk in an already vulnerable population. Though FSWs operate in highly diverse environments, the association between alcohol use and increased odds of inconsistent condom use and STIs has been found in studies among FSWs in many developing countries
[24, 26, 27, 31–33]. In qualitative work conducted in Ethiopia and Cambodia, FSWs explained how alcohol use created a barrier to ensuring condom use with clients; it reduced their level of control
 and intoxicated clients tended to refuse to use condoms
Along the transport corridors of Ethiopia, the prevalence of HIV among women in the general population is 8.6%; among FSWs, it is 25.3%
. FSWs’ reported condom use with clients has increased dramatically over the past two decades, from 5.3% in 1989 to 99.4% in 2009, though condom use at last sex with regular, non-paying partners is significantly lower at 65.7%
. Although FSWs’ regular, non-paying partnerships sometimes begin as client relationships, a large discrepancy in condom use between the two partnership types has been identified in numerous studies worldwide
[15, 37–42]. In a qualitative study of FSWs in two Ethiopian towns, many participants reported that they did not deem it necessary to use condoms with sexual partners outside of their work
Unprotected sex with regular, non-paying partners may put both FSWs and their partners at higher risk of HIV infection. For example, research in Benin found that regular, non-paying partners of FSWs had particularly large numbers of partners, concurrent partnerships with other FSWs, low rates of condom use, and higher HIV prevalence as compared to the new and regular clients of sex workers
. Studies on the risk of HIV within FSWs’ regular, non-paying partnerships in Ethiopia have not yet been conducted. However, research in Ethiopia has shown that these partnerships may arise from FSW-client relationships
. Demographic Health Survey data
 indicate that HIV prevalence among clients of FSWs is substantially higher than in the general population (4.3% and 1.5%, respectively). Considering the high prevalence of HIV among Ethiopian FSWs
 and their clients, the evolution of clients to regular, non-paying partners, and the low rate of condom use with the latter, it is likely that these partnerships present considerable risk.
While there is an increasing understanding of the synergistic effects of substance abuse, violence and HIV, little research has examined these associations as they relate to FSWs’ condom use with regular, non-paying partners, and to date, no such studies have been conducted in Ethiopia. Intimate partner violence is common in Ethiopia, with women’s reported lifetime prevalence ranging from 51-78%
. Qualitative work has indicated that in communities studied, intimate partner violence is considered acceptable under certain circumstances and social disincentives prevent reporting
. While research has suggested that FSWs in Ethiopia experience violence perpetrated by clients, establishment owners and other women
, such work-related violence has not yet been examined as a contributor to HIV risk within regular, non-paying partnerships. This study aimed to investigate the influences of establishment-based FSWs’ alcohol abuse and experiences of violence on inconsistent condom use with regular, non-paying partners in Adama City, Ethiopia. Regular, non-paying partners are defined as boyfriends, husbands, or any other regular partners who do not pay directly for sex. Due to the high rate of consistent condom use with new and regular clients reported by respondents in this study (99.4%), we do not examine correlates of condom use within these partnerships.