Factors Associated with Sexual Risks and Risk of STIs, HIV and Other Blood-Borne Viruses Among Women Using Heroin and Other Drugs: A Systematic Literature Review

Age There seemed to be a relationship between age and condom use. Six papers found that age was significantly correlated with engaging in condomless sex [50, 51, 61, 62, 66, 74]. However, data from another paper indicated that this correlation was non-significant [52]. The nature of the association between age and condom use was unclear. In one study, women over 35 years old were significantly more likely to have condomless sex, compared to younger women [61], whereas condom use was marginally and positively associated with age in another study [74]. Among women who engaged in transactional sex, those who were 36 years old or older were more likely to use condoms inconsistently³ followed by women between 26 and 30, women between 31 and 35, and 25-year-old women and younger [51].

Education Data on formal education and condom use were conflicting. Evidence from one paper indicated that graduating from high school was negatively correlated to condom use [62]. Education attainment was found to be non-significantly correlated to using condoms in another study [52].

Ethnicity There were differences in condom use and reported barriers for condom use among women from different ethnicities. White women were more likely to engage in condomless sex with a main partner than Black women [50]. Compared to African Americans, Latina women were more likely to report partner’s dislike of condoms as a barrier for condom use. In turn, African American women reported greater lack of skills using and negotiating condom use, difficulties to get condoms, and discomfort using condoms [61]. Compared to Latinas, there were more reports of African American women not considering using condoms when they were under the influence of drugs [61]. African Americans were also more likely to believe that their partner did not have AIDS, and that they could not transmit HIV to their partners compared to Latinas [61]. These beliefs were associated with having condomless sex.

Marital Status Only one study reported a relationship between marital status and condom use. The findings from this study indicated that there was a non-significant positive correlation [52].

Housing Conditions Higher reports of condomless sex were made by homeless women who injected drugs, compared to those in drug recovery programmes [61]. Women who were cohabiting were more likely, than those who were not, to have condomless sex with steady partners,⁴ and reported more condomless anal sex [50].

Employment and Financial Aspects Transactional sex was associated with an increased likelihood to use condoms inconsistently in the previous 6 months if women perceived great economic pressure due to drug using practices and living expenses [51, 52]. There was also a direct impact of economic pressure on general HIV-related sexual risk and on inconsistent condom use in the past 6 months [51]. One study suggested a non-significant correlation between self-rated financial situation and consistent condom use⁵ [52].

Condom use was predicted when women perceived control over condom use, and using a condom made women feel responsible [65]. A frequent barrier to condom use was the belief that women did not need protection for sex [65].

The fertility of WHOD was perceived to be significantly reduced as a result of their heroin use. The use of condoms was dependent on whether women wanted to have a child or prevent pregnancy. As expected, condomless sex was common among women who wanted to become pregnant [55], had a partner that wanted a child [61], or had a tubal ligation [65]. On the contrary, condom use was higher among those women who wanted to prevent pregnancy [61, 65]. On the other hand, condomless sex was frequent among mothers involved in transactional sex. This was to maintain regular clients and earn more money to provide for their children [57].

The number of male sexual partners was positively correlated with a lack of condom use [62]. These differences were however not significant over a 3-year period [61]. Having had two or more sexual partners in the last 30 days was negatively correlated with the risk of having condomless sex [74]. When adjusting for other variables, having more than two sexual partners was not significantly associated with condomless sex [74].

In romantic relationships, condomless sex was habitual as it was positively associated with feelings of love [77] and trust [58, 59]. Women expressed that suggesting condom use in steady relationships could raise concerns of infidelity and suspicion [58, 59], and that condoms created an emotional barrier with their partners [58]. However, although non-significant and inconsistent to the relationship between love and condomless sex, another study found that a predictor of condom use was women’s perception of closeness to the partner [65]. Yet, when considering the risk of infection, women had a sense of shared destiny and fatalism. Trust and love in romantic relationships translated into inconsistent condom use and an increased sense of security as women only had condomless sex with their partner. The likelihood of transmission was often perceived as unavoidable as part of their relationship and drug-using lifestyle [59]. Embarrassment talking about sex and difficulties negotiating condom use with intimate partners also hindered condom use [58].

Among women engaging in transactional sex, condoms were used to emotionally differentiate sexual encounters with clients and non-clients. Whereas condoms were used with clients, condomless sex was only reserved for romantic relationships [53]. In fact, love and trust were negatively correlated with never or rarely using condoms with clients in the previous month [77].

Most women reported having experienced physical and sexual violence by men, which significantly increased sexual risks such as having condomless sex [56, 64]. Physical violence was often interlinked with sexual violence, and sexual violence most commonly involved condomless sex. Surprisingly, another study found a non-significant relationship between condom use and experiencing sexual violence [71]. Gender-based violence was rooted in gender roles and power dynamics between men and women, in which men were dominant over women. Some women were opposed to losing power and taking a submissive role in relation to men [56, 59]. One strategy used by some women as a way to overcome their vulnerable position was to use condoms with casual and steady sexual partners [59].

Alcohol Use Using alcohol was associated with a decreased frequency in condom use [62, 65]. The evidence regarding the impact of alcohol use before sex among women in transactional sex was contradictory. Two studies suggested that alcohol use before sex was not found to be a predictor of condom use [52, 60]. However, the findings from another paper indicated that alcohol use before sex and weekly alcohol consumption were significantly and negatively associated with consistent condom use with both regular and casual clients [52]. The frequency and quantity of alcohol use were significantly and positively associated with using condoms after using drugs [60]. This finding contrasts with another study, in which weekly alcohol use was found to be significantly and negatively associated with condom use with transactional sex clients [52].

Drug Use Condom use was found to be marginally and positively associated with polydrug use [62]. Condomless sex was more likely among women who used heroin with sexual partners [74]. A higher number of needle-sharing partners was related to condomless sex [62].

Transactional sex appeared to be associated with a decreased likelihood of condom use when using drugs [51, 52, 65]. Among transactional sex workers, drug use before sex and daily injecting were negatively associated with consistent condom use [52]. Longer duration and higher severity of drug use were positively correlated with inconsistent condom use and general HIV-related risk [51]. Another study indicated that self-reported severity of heroin and cocaine dependence, and the use of condoms for vaginal sex with transactional sex clients were not significantly correlated [60]. There was also a non-significant association between typical doses of heroin and cocaine, and condom use with clients, nor between typical doses and transactional sex participation [60]. In addition, no association was found between frequency (days per week) of heroin or cocaine use and condom use with clients [60].

There were no significant differences in condom use between women engaging in transactional sex and those who did not [67]. Some women were unwilling to have condomless sex with clients for more money [60]. Other women involved in transactional sex reported to be in a more vulnerable position to refuse condomless sex with clients [56, 57, 59]. In some cases, transactional sex workers engaged in condomless sex to avoid losing clients over other transactional sex workers. Women were usually offered larger amounts of money to have condomless sex with clients, which could result in a higher likelihood of having sex without using condoms [55]. Also, even though women selling sex generally had to negotiate condom use as part of the exchange [57], some women resisted carrying condoms as they were afraid of being identified as transactional sex workers by the police and have legal problems [58]. Women working in indoor venues (i.e., bar, hotel or brothel) were significantly more likely to use condoms consistently with both regular and casual transactional sex clients, compared with women working outdoors (i.e., street, clients’ vehicles, shooting galleries, other public spaces) or in low-price guest houses [51, 52]. Positive interactions with clients facilitated condom use [57], although some women did not use condoms with trusted regular clients [57].

Several barriers to condom use were related to characteristics of sexual partners. Known health status, personal characteristics (e.g., marital status), physical appearance (i.e., age, attractiveness and apparent hygiene), and sexual history were associated with condom use and seemed to lead women to refuse certain sexual acts such as anal or oral sex with non-clients [54, 55] and clients of transactional sex [57]. Women expressed how some men insisted on having condomless sex as they felt that condoms reduced sexual pleasure and were inconvenient [58]. Moreover, it was more unlikely for women to use condoms when the sexual partner had similar health conditions to them, denied being HIV positive or when women perceived partners as ‘similar to me’ [55].

Self-reported condom use with transactional sex clients was higher when women had vaginal and anal sex, and less likely for oral sex and masturbation [60]. Condom use was also found to be more likely when the partner or woman performed oral sex and, although non-significant, sex occurred at the woman’s home or on a special occasion (e.g., birthday, anniversary) [65]. Other predictors of condom use were having had sex with the same sexual partner in the past, length of time women knew the partner, and having sex with a steady or casual partner (only with a steady partner in multiple regression analyses) [65]. However, most women reported to ‘never’ use condoms with non-clients in another study [60]. Condom use was also hindered when condoms were unavailable [55]. Besides, there was a non-significant relationship between condom use and receiving social support from a sex partner [74].

Condom use and having needle-sharing partners were positively associated [62]. There was no significant association between having transactional sex clients who injected drugs and condom use [71]. However, condomless sex was associated with having sex with men who injected drugs, when these were not transactional sex clients [50, 61, 62]. In romantic relationships formed by a person who injects drugs (PWID) and a person who does not inject drugs (PWNID), condoms were generally used if the PWID in the relationship was HIV positive and the PWNID was HIV negative [55]. In sexual relationships between a PWID and a person who does not use drugs, knowing the partner’s drug using practices was key for HIV infection. When non-using women were not aware of the partner’s drug using practices, they seemed to be more likely to have condomless sex. However, HIV risk concerns increased when women knew that their partner was injecting drugs. In order to avoid partner’s concerns and continue having condomless sex, some drug users hid their drug using practices and health status, which increasingly heightened the risk of infection [59]. On the other hand, disparities on sexual desire were common in PWID-PWNID relationships. In this context, the increased sexual desire of the PWNID led to the rejection of condom use, as a way for the PWID partner (most often men) to please their partner [59].

Condom use was facilitated when it was discussed, and especially when women were more willing to use condoms. Also, when both partners agreed on either using condoms or the partner insisted on using condoms [65]. Lack of skills using and negotiating condom use, dislike of condoms, discomfort [61, 65] and loss of pleasure using condoms were common reported barriers to condom use [65]. Other barriers were that using condoms made sex less intimate, either women or their partners did not feel like using condoms, a partner got angry about using condoms, and when the partner refused to use them [65]. Another study however found a non-significant relationship between condomless sex and having a partner insisting on not using condoms [71]. Condom use was also hindered when partners agreed on not using condoms, sex was unplanned, women could not afford to buy condoms [65], and condoms were unavailable [55, 61, 65]. However, another study suggested that there was no significant association between access to free condoms and consistent condom use [52]. On the other hand, some women expressed discomfort when negotiating condom use. This discomfort appeared to be caused by the fear of offending their partners when suggesting using condoms, and being afraid of getting hurt. These difficulties in negotiating condom use were a barrier to having sex with a condom [61].

Age There was conflicting evidence regarding the relationship between age and transactional sex. Whereas one paper indicated that these were correlated [50], another suggested a non-significant correlation [75].

Education As for age, there was contradictory evidence on the relationship between education and transactional sex. Graduating from high school was found to be negatively correlated to transactional sex [62]. This relationship was however found non-significant in another paper [75].

Ethnicity The likelihood of engaging in transactional sex was higher among Black women, compared to White, Hispanic and women from other ethnicities [50]. In another study, ethnicity was not found to be significantly associated with transactional sex, even though Indigenous Canadian women were less involved in transactional sex [49]. Compared to Black women, White women had more transactional sex clients [69]. Black women were, on average, older the last time they sold sex [69].

Sexual Orientation Both bisexual and lesbian women were more likely to engage in transactional sex, compared to heterosexual women [72]. The engagement in transactional sex was also higher among women who currently had sex with women (CSW), followed by women who had past sexual experiences with women (PSW) and women who never had sex with women (NSW) [68].

Marital Status Single women were more likely to have sold sex, compared to married women. This was significant when looking at the impact of emotional neglect, emotional abuse and physical neglect on transactional sex practices [75]. Extramarital sex was more likely among married women who were selling sex, compared to married women who did not engage in transactional sex [67].

Housing Conditions Being in unstable housing was more prevalent among women involved in transactional sex, who also lived in more deprived urban areas [49].

Employment and Financial Aspects Women who engage in transactional sex were more likely to have another job and were considered to be unemployed [67]. Although non-significant, there were associations between having two or more daily clients in the previous 2 weeks, and perceiving economic pressure due to being in debt, the need to support family members and drug use [51].

Legal Involvement A significant relationship was found between having been in jail in the previous 6 months and transactional sex [49].

Socially constructed gender roles and power dynamics in which men are dominant over women were associated with engaging in transactional sex [56]. In order to avoid assuming a submissive role in relation to men, some women obtained drugs and supported themselves through transactional sex [56].

On the other hand, experiencing physical and/or sexual violence was positively associated with engaging in transactional sex [54, 63, 64]. Physical and sexual violence were associated with having had a HIV-positive partner in the previous 30 days [64]. Specifically, childhood abuse was significantly correlated with transactional sex [64]. Another study found that childhood physical and sexual abuse did not increase the likelihood of being involved in transactional sex as an adult among Black women [75]. Only the severity of emotional and physical neglect, and emotional abuse were associated with an increased likelihood of transactional sex among Black women [75]. No form of abuse was significantly associated with transactional sex among White or Hispanic women [75].

Drug Use Injecting drug use was associated with engaging in transactional sex [50, 66, 67, 76, 78]. In one of the studies, this relationship was found to be significant for non-White women only [50]. The primary drug of use was not a significant predictor for transactional sex practices [75]. Data from one of the included studies indicated that severity of drug dependence was significantly related to having two or more transactional sex partners in the week before taking part in the study [51]. It is important to highlight that no difference was found in this study between self-reported severity of dependence between women who did and did not engage in transactional sex [60]. Other studies found that heroin use was marginally higher among women engaging in transactional sex, although cocaine and crack use was more frequent among women involved in transactional sex [49]. Women who sold sex had been using drugs for a longer time, compared to women who did not engage in transactional sex [66]. Nonetheless, these two studies [49, 66] did not find significant associations between substance use and sexual practices. Sex was generally exchanged for money or drugs and, in some cases, to sustain the partner’s drug habits [53, 56, 59]. Sex-for-drugs exchanges were more common when women experienced withdrawal symptoms, as transactional sex was an accessible drug-seeking behaviour. Men often took advantage of women’s addiction and offered drugs in exchange for sex [56, 57, 59]. Women were also less selective with clients when they experienced withdrawal symptoms [60]. Having withdrawal symptoms was correlated with self-reported severity of dependence upon heroin [60]. Women would often use drugs before transactional sex as a coping mechanism and emotional barrier towards transactional sex. Using drugs before transactional sex increased women’s sexual health risks [56, 57, 59].

Ethnicity and Country of Origin Among women engaging in transactional sex in Mexico, those born in the US who spoke English were more likely to report sexual violence [71].

The high threat of violence led women to take a subordinate role and to rely on men for protection from violence [56]. Women reaching for protection constructed relationships with men based on exchanging resources [56]. In the context of these relationships, the role of women was to attend living and drug use expenses [56, 59], whereas men were expected to offer safety. However, men did not always provide women with protection and were often abusive towards women themselves. Conflicts with partners were associated with drug distribution and with men’s sexual difficulties [56]. Women often felt ‘used for sex’ and stigmatised by men as, because of their drug use, women were regarded as ‘easy’ and worthless [59]. Women then reported that they became even more vulnerable to sexual and physical violence and exploitation, from both their partners and other men [56, 59]. Those who were involved in transactional sex often reported having partners insisting on having sex or condomless sex, which was associated with sexual violence [71]. Among women engaging in transactional sex, those experiencing sexual violence were more likely to have a history of rape [71].

Drug Use Women involved in transactional sex were more likely to experience sexual violence when they used drugs with clients [71].

Selling sex made women particularly vulnerable to sexual and physical violence, and consequently increased sexual health risks [54, 56, 57, 59]. In this context, women’s exposure to violence [56, 57] and sexual health risks was particularly heightened [59]. Despite women’s high risk for HIV, sexual health concerns were less of a priority compared to other dangers of the ‘fear culture’ in which women lived [56]. Even though some women engaged in protective strategies (e.g., having regular clients, offering oral sex rather than vaginal/anal sex, resorting to stealing, working legally, and sometimes relying on welfare) to decrease these risks [56, 57], they were still the target of violent assaults [56]. Those women who reported cases of gender-based violence were disregarded by the police, which contributed to women’s feelings of powerlessness and the perpetuation of the constant threat of violence [56], and consequent sexual health risks.

Women involved in transactional sex usually experienced very poor and unsafe working conditions, which made it difficult for women to be selective with clients, to maintain good hygiene, and to avoid coercive encounters with clients [55]. Transactional sex in hotels or motels, living and working in the same location, and reports of bad/extremely bad working conditions were associated with an increased likelihood of reporting sexual violence [71]. The association between location and working conditions were non-significant in multivariate statistical analyses [71]. Women who had their transactional sex earnings administered by a partner, and those having to pay a manager or a pimp were more likely to have experienced sexual violence [71]. The relationship between sexual violence and having to pay managers or pimps was however not significant [71]. Also, the risk for HIV was related to the position of women engaging in transactional sex in the street hierarchy, where women working for a pimp were the most vulnerable as they usually worked in exploitative conditions [56]. Although some interactions with clients were positive, others turned out to be violent and coercive. In order to prevent violent situations, women involved in transactional sex preferred working with regular clients [56, 57].

Women engaged in transactional sex were more vulnerable to experiencing sexual violence when they had drug-using (PWID and PWNID) clients, and more non-regular clients [71].

Age According to the data of one of the included papers [66], women who initiated sex at a younger age were more likely to have multiple sexual partners.

Ethnicity African American women were more likely to have multiple sexual partners, followed by acculturated Latinas, and compared to low acculturated Latinas [61]. Compared to Black women, White women had their first sexual encounter at a younger age [69].

Sexual Orientation CSW initiated sex at a younger age, had more than one male sexual partner in the previous 6 months, and reported having had sex daily in the past 6 months, compared to PSW and NSW [68]. Also, CSW were more likely to have vaginal sex more than once a week, oral sex with casual partners, and having had anal sex [68]. PSW reported to engage in oral sex more than CSW and NSW [68].

Housing Conditions Women who were cohabiting were less likely to have more than one sexual partner, compared to women who were not cohabiting [50]. Women who were cohabiting were more likely, than those who were not, to have anal sex [50].

No significant associations were found between recent partner violence and having had sex with more than one partner in the past year [64].

Drug Use Having multiple sexual partners was significantly correlated with higher drug injecting [50, 66] and crack use [76]. The relationship between number of sexual partners and drug injecting was significant for non-White women only in one of the studies [50]. Moreover, women were more likely to engage in a wider variety of sexual practices with clients after taking heroin and cocaine [60].

Overall, women who sold sex had more sexual partners in the previous year and in their lifetime, compared to women who did not engage in transactional sex [62, 67]. Women who worked in hotels and in saloons and massage parlours had more clients than those working in other settings [51]. Women involved in transactional sex were also more likely to have had their first sexual experience at a younger age [67]. Women engaging in transactional sex who experienced sexual violence were younger and had initiated transactional sex at a younger age, compared to those who did not report sexual violence. This relationship was however non-significant [71].

Ethnicity White women were more likely than Black women to have a sexual partner who injected drugs [50]. Although non-significant, White women were younger the last time they had a steady partner [69].

Sexual Orientation Heterosexual women reported less casual sex, compared to bisexual and lesbian women. Bisexual women were more likely to have recent casual sex, and lesbian women were less likely to have sex with steady partners, compared to heterosexual women [72]. CSW were less likely to have steady male partners [68], and more likely to have vaginal sex more than once a week, oral sex with casual partners, having had anal sex, and having had a sexual partner diagnosed with an STI. In contrast with CSW and NSW, PSW engaged in oral sex more than four times a week [68].

Selling sex was associated with women being more likely to have sex with strangers or a friend, rather than with a boyfriend or husband [67]. They were also less likely to have a regular sexual partner [49].

The evidence available indicated that the number of male sexual partners was positively correlated with the number of needle-sharing partners [62].

There were no significant associations between recent partner violence, and having sex with a PWID, having sex with a partner who had sex with someone else in the past year, and having sex with a partner who had an STI in the past year [64].

Drug Use There were very few and robust data on the relationship between drug use and the type and characteristics of sexual partners. The evidence available suggested that crack use and having a partner that is a PWID were not associated [76].

Ethnicity Compared to Black women, White women reported higher use of drugs before and after transactional sex, and higher use of injecting drugs with steady and casual partners [69]. There was a trend for Black women to use more non-injecting drugs when engaging in transactional sex [69].

A non-significant relationship was found between experiencing sexual violence and an increased likelihood of using drugs with clients, among women involved in transactional sex [71].

A wide range of factors, from socio-demographic characteristics to social contexts of violence and power dynamics between women and men, were found to be associated with sexual risks among WHOD. The interplay of these factors remains uncertain, and there were a number of studies presenting contradictory findings. This indicates that there is currently a lack of strong evidence on the links between most factors and sexual risks. This point is further discussed in Aim 2 of the Discussion section. The most salient factors and implications for future research and service development are discussed below.