One of the leading causes of death for women of reproductive age is acquired immunodeficiency syndrome (AIDS).1 Certain groups of women are disproportionately affected by HIV/AIDS, including women of color and homeless women.2, 3 The greatest cause of these infections among women is high-risk heterosexual sex, which is estimated at 80 percent of reported cases.4 Women are at higher risk of contracting HIV from heterosexual intercourse than men because of their greater likelihood of engaging in unprotected sex with an infected partner.5 Impoverished women, in particular homeless women, are at even greater risk due to high rates of risky sexual behavior and substance abuse.6-8 In a recent probability sample of sheltered homeless women in Los Angeles County, 19% engaged in unprotected sex with casual partners, 31% drank heavily, and 48% used illicit drugs in the past year.9
The elevated risk of becoming infected by HIV for impoverished women through heterosexual sex emphasizes the importance of continued research that uncovers and explains factors leading to homeless women’s use and non-use of male condoms. A focus on impoverished women’s use of male condoms is important because condoms remain the most effective method against the spread of HIV and heterosexual intercourse is the primary means of HIV transmission for women.10 Understanding the factors that contribute to greater condom use among impoverished women is needed in order to design interventions that are successful at increasing condom use in this population and ultimately slowing the spread of the HIV epidemic.
Factors that predict unprotected sex have been studied for decades, in many populations, using a variety of analytic approaches and focusing on a broad range of different types of variables.11 Some of the most commonly studied predictors of unprotected sex that may be particularly relevant to impoverished women include perceptions of the riskiness of partners,12 psychological factors, such as positive or negative attitudes about condoms 11, and perceived susceptibility of getting HIV.13 The potential influence of drug and alcohol use on risky sexual behavior is another active area of study, although results have been mixed. Some studies suggest that alcohol misuse or drug use increases the likelihood of high-risk sexual behavior by reducing behavioral inhibitions and risk perceptions.14-17 Alternatively, alcohol or drugs may deliberately be used prior to sex to provide an excuse for engaging in high-risk behavior or to reduce conscious awareness of risk,18-20 or because these substances are believed to enhance sexual arousal and performance.14, 18, 21, 22 Other studies have found no association between alcohol use and condom use.23-25
A growing area of study is the effect of interpersonal relationships on the use or non-use of condoms in heterosexual sex. Recent research has shown an association between unprotected sex and social network factors. For example, the perception of risky sexual behavior as normative and a lack of communication about HIV and condom use among social network members have been shown to result in ignorance about protective behaviors and subsequent engagement in risky sex.26 Latkin and colleagues also have shown that more connections among social network members (density) is, by itself, a predictor of unprotected sex.26 They argue that this finding suggests that density contributes to a “spiral of silence” in which discussion or adoption of novel behaviors is discouraged because they are perceived as threatening and disruptive. Other studies of sexual relationships have found associations between consistent condom use and the risky characteristics of the sex partner, such as injection drug use, having had sex with men, and being HIV+,27 characteristics of the relationship such as age difference between women and their sex partners and the type of relationship with the partner (casual vs. primary),28 the level of commitment to the relationship,29 and the amount of violence and sexual coercion that women experience in their sexual relationships with men.9, 30 Several studies have discussed the need to better understand the association between romantic partnership relationship dynamics and condom use, especially the contradiction between desires for close, intimate partnerships which require assumptions about trust and fidelity, and protective behaviors, which imply distrust and infidelity.31-33
Although a growing number of studies have focused on the relationship aspect of unprotected sex, most of the research on risky sexual behavior has investigated risky sex as a characteristic of individuals. Even studies that have focused on relationships often explore associations between variables that summarize an individual’s multiple relationships or focus on one relationship at a time.29 However, unprotected sex is an aspect of relationships and characteristics of these relationships influence condom use. Also, individuals have a variety of numbers and types of relationships. Therefore, summarizing data across relationships or focusing on one partner at a time suggests a loss of information that may be essential in understanding variation in unprotected sex. Despite this loss of information, investigations of unprotected sex are dominated by analysis designs that focus on individuals. This emphasis on the individual level of analysis is common throughout social science despite the fact that many research questions are actually about relationships between individuals rather than independent individuals. Kenny and colleagues suggest that one possible explanation for this limited analytic approach to relationship centered research is that traditional research methods used in the social sciences, such as ANOVA or multiple regression, make an independence assumption.34 Therefore, in order to use these methods, researchers must either summarize relationship information on the individual level, which loses information, or they must analyze relationships, which would break the independence assumption because multiple relationships would be nested within individuals.
Kenny and colleagues also recommend methodological alternatives to either ignoring non-independence or losing analytic power by summarizing information at the individual level.34 One recommendation is to use multi-level modeling (MLM) to estimate data that come from multiple dyads nested within individuals. MLM allows for investigation of variables at different levels of analysis. This approach has had limited use in the condom use literature. For example, Sherman and Latkin investigated condom use among drug users and their sex partners.35 They found that condom use differed based on characteristics of relationships between members of a sexual dyad (financial inter-dependence, living together) as well as characteristics of individuals (being HIV+). Another study of women attending urban clinics used an MLM approach to demonstrate the relationship between partner type (regular and intimate partnerships) and unprotected sex.16 To the best of our knowledge, no prior study has used an MLM design to explore factors associated with consistent condom use among homeless women and their partners.
In this study, we address the need for greater understanding of the factors that predict unprotected sex between impoverished homeless women living in Los Angeles County, California, and the sex partners that they identified through a social network interview that generates personal network data for a sample of focal individuals.36 We use a one-to-many analysis design to account for the “assortive mating” type of non-independence that is inherent in data collected through personal networks.37 We use these data collection and analytic techniques to address the following hypotheses generated through our review of the literature on factors that predict unprotected heterosexual sex. First, we expect that characteristics of women’s attitudes about condoms and HIV will be associated with their engagement in unprotected sex: if women believe that condoms are effective and that they are in danger of becoming infected by HIV,11, 27 they will be more likely to use condoms consistently. Perception of the riskiness of their partners is expected to be associated with women’s condom use: if women perceive their partners as being risky, they will be more likely to use condoms.27 In addition, we expect that relationship characteristics will play a part in women’s unprotected sex with these partners: more commitment to the relationship,29 the existence of violence in the relationship,30, 33, 38 receipt of tangible support,39 lengthy relationships,5, 40, 41 age difference between women and their partners,16 frequency of co-occurrence of drugs or alcohol and sexual intercourse by either the women or their partners14, 15, 17, 28 and higher frequency of sex with the partner42 are each expected to be associated with a higher likelihood of unprotected sex. Finally, we expect that characteristics of women’s social networks will play a role in influencing their risky behavior: women are expected to be less likely to use condoms consistently with their partner if risky sex is normative among their network members,26 if women are not discussing HIV with their social networks,26 and if these networks are very densely connected.26