Event-Level Substance Use and Unprotected Sex among Young Adults: A Case-Crossover Analysis

Research Article

J Community Med Health Care. 2017; 2(2): 1011.

Event-Level Substance Use and Unprotected Sex among Young Adults: A Case-Crossover Analysiss

Muchimba M¹*, Burton M², Haberstick BC², Corley RP², Hopfer C3 and McQueen M2,4

¹Department of Health Sciences, Department of Health Sciences, Saginaw Valley State University, USA

²Institute for Behavioral Genetics, University of Colorado Boulder, USA

³Department of Psychiatry, University of Colorado Denver, USA

4Department of Integrative Physiology, University of Colorado Boulder, USA

*Corresponding author: Muchimba M, Department of Health Sciences, Department of Health Sciences, Saginaw Valley State University, USA

Received: January 11, 2017; Accepted: February 10, 2017; Published: February 13, 2017

Abstract

Background: It has been theorized that the use of alcohol and other drugs during a sexual encounter increases the likelihood of unprotected sex. Few studies have examined the relationship between substance use and unprotected sex in clinical samples. This study investigated event-level substance use (alcohol and other drugs) and unprotected sex in community and clinical samples.

Methods: A sample of 2775 community and clinical participants aged 19 to 30 years was surveyed between 2008 and 2011. To assess event-level substance use and unprotected sex, we conducted a case-crossover analysis using conditional logistic regression.

Results: Results revealed no association between substance use and unprotected sex among male and female clinical subjects, and among female community subjects. Among community males, there was a negative association (OR, 0.69; 95% CI, 0.48-0.99).

Conclusion: STI/HIV preventive programs should not focus only on the consequences of engaging in sex while under the influence of alcohol and other drugs. To be more effective, they need to consider other factors which influence the relationship between substance use and unprotected sex, including type and amount of substances, personality, context of sexual encounter and type of relationship.

Keywords: Case-crossover; Event-level; Alcohol; Substance use; Unprotected sex

Introduction

Sexually Transmitted Infections (STIs) remain a public health concern in the United States, with nearly 20 million new Sexually Transmitted Infections (STIs) occurring every year [1]. Untreated STIs can lead to reproductive health complications, such as pelvic inflammatory disease, chronic pelvic pain, and infertility among women, and epididymitis and urethritis among men [2]. Human papillomavirus – the most common STI – can cause genital warts, cervical, and other cancers. STIs can also increase a person’s risk for acquiring and transmitting HIV infection [3].

Correct and consistent use of condom remains one of the most effective methods to protect against STIs, including HIV, and a large body of research has focused on factors are that are associated with non-use of condoms. One factor that has been studied extensively is the use of Alcohol and Other Drugs (AOD). AOD are thought to interfere with judgment and decision-making when consumed, and it is believed that their use during sexual activity increases the likelihood that risky sexual behaviors, such unprotected sex, will occur [4].

Correlational studies have shown that the use of AOD is associated with non-use of condoms. For example, among men who have sex with men, the use of inhalants was associated with failure to use condoms during receptive anal sex [5]; and the use of alcohol, inhalants and non-injection drug use before or during sex were associated with significantly more unprotected anal sex [6]. Similar findings have been reported among young people. Per a Kaiser Family Foundation survey among 998 teens and young adults, 22% said they had unprotected sex because they were drinking or using drugs [7].

Most of the research on the relationship between substance use and condom non-use is correlational, and is therefore limited in that the temporal relationship between the two behaviors is not examined. Thus, it cannot be determined whether substance use occurred shortly before unprotected sex, a condition that is necessary for establishing substance use as a risk factor. Event-level studies represent an improvement over correlational designs in that it temporally pairs use of AOD with condom non-use during a specific sexual encounter. Thus, these studies are better able to demonstrate whether the use of AOD preceded unprotected sex, thereby strengthening the causal interpretation [8]. Event-level studies do not establish causality; however, temporally pairing the two behaviors provides greater insight into whether substance use before sex increases the likelihood that unprotected sex will occur. This allows for a more indepth examination of the hypothesis that being under the influence of substances during sexual activity is associated with increased probability of sexual risk behavior.

Some event-level studies have found an association between the use of AOD and condom non-use while others have not. Findings from studies among general population participants have shown that participants were no more or less likely to use condoms during events involving use of AOD than during those without it [9]. However, positive associations have been found in some populations. Eventlevel use of AOD has been shown to predict unprotected sex among STI patients [10], and adolescents involved with the juvenile justice system [11]. Considering these mixed results, there is need for further exploration of the association of substance use with condom use at the event level.

Because of differences that exist between males and females regarding substance use and condom use, gender is an important variable to consider in research on AOD and condom use. Men are more likely than women to use almost all types of illicit drugs [12]. Also, the literature suggests that women are less likely to use condoms than men [13]. Barriers to condom use may also differ by gender. There is evidence that men are more likely than women to be concerned that condoms would interfere with sexual pleasure [14]. However, despite these gender differences, event-level studies that have analyzed data by gender are limited.

Even though substance use disorders increase the likelihood of HIV infection and of engaging risky sexual behaviors such as non-use of condoms and multiple sexual partners [15], few event-level studies have included clinical samples. Injection drug users still accounts for a substantial percentage of HIV infections. They comprise an estimated 2.6% of the U.S. population yet they account for 22% of all persons living with HIV infection [16]. In addition, the literature shows a link between STIs and the use of drugs such as cocaine [17]. This highlights the importance of examining the event-level relationship between substance use and condom use in clinical populations.

The purpose of the current investigation was to examine the relationship between substance use and unprotected sex using eventlevel data. This study will contribute to the research by examining the relationship by gender and by including a clinical sample.

Methods

Sample and materials

Participants included community and clinical samples, which were part of the Center for Antisocial Drug Dependence (CADD), an ongoing, multi-component, collaborative study at the University of Colorado. Community participants who were drawn from the twin, adoption, and family study components of the CADD. Twin participants were recruited from the Colorado Twin Registry [18], which consists of a community-based sample of twin families residing in Colorado. Non-twin participants were drawn from two community-based family samples: the Colorado Adoption Project [19], an ongoing, longitudinal study of the genetic and environmental influences on behavioral, cognitive, and emotional development; and the Colorado Adolescent Substance Abuse family study [20], research participants, aged 19 to 30 years, who completed assessments between September 2008 and March 2011. of the familial transmission of substance abuse and associated psychopathology, which recruits adolescents in treatment and matched community controls. The present study comprised 2775 community and clinical

Participants were interviewed using the modified Risk Behavior Questionnaire (M-RBQ), an instrument developed for the CADD, which includes a series of questions on risky sexual behaviors and substance-related STI/HIV behaviors [21]. All participants provided written informed consent prior to the interviews. This study was approved by the University of Colorado Institutional Review Board.

Study variables

Information on whether AOD were used during a sexual encounter was obtained from two questions. For the first question, participants were asked, “Recall the last time you had unprotected sex and did not use a condom for protection. Were you using alcohol or drugs at the time?” Answer options for this question were 0=No, 1=Yes, 3= I always use condoms so I can’t answer this question yes or no. The second question was “Recall the last time you had unprotected sex and did use a condom for protection. Were you using alcohol or drugs at the time?” Answer options for this question were 0=No, 1=Yes, 3= I never use condoms so I can’t answer this question yes or no. We also obtained information on age, gender, ethnicity and marital status.

Statistical analysis

Event-level associations between substance use and unprotected sex were examined by utilizing a case-crossover analysis. This approach allows each participant to serve as his or her own control, thereby eliminating confounding personal factors that are not time-varying. To be included in the analysis, participants had to report at least one unprotected and one protected sexual encounter. Conditional logistic regression models were fitted to estimate Odds Ratios (ORs)—with their corresponding 95% Confidence Intervals (CIs)—of the likelihood of unprotected sex when substances were used. This was achieved by comparing participants’ condom use when substances were used and their condom use when substances were not used. To observe whether the relationship between substance use and unprotected sex differed between community and clinical participants, and between males and females, we ran the analyses separately for community and clinical participants, and by gender in the two groups. Participants who reported always using condoms or never using condoms were left out of the analysis.

Statistical analysis was performed using R Statistical Software (version 2.15.1; Foundation for Statistical Computing, Vienna, Austria) [22].

Results

Descriptive characteristics

In the entire sample, 2250 (91.9%) were community participants while 225 (8.1) were clinical participants. Females constituted 51.0% of the overall sample (Table 1). In the community sample, 52.8% were female and over two-thirds (69.9%) were aged 22 to 27 years (mean age = 25.0; SD = 2.6). Community participants were largely white (86.6%) and over a third (69.7%) had never been married. Most of the participants (93.3%) were not using drugs at the time of the survey.

Citation:Muchimba M, Burton M, Haberstick BC, Corley RP, Hopfer C and McQueen M. Event-Level Substance Use and Unprotected Sex among Young Adults: A Case-Crossover Analysis. J Community Med Health Care. 2017; 2(2): 1011.