There is a highly significant relationship between frequency and intensity of drug and alcohol use and risky sex among American HIV-negative gay men, a study published in the online edition of the Journal of Acquired Immune Deficiency Syndromes shows.
“HIV risk among MSM [men who have sex with men] increases with both frequency of substance use and the number of substances used,” write the authors. “These practices have a myriad of biologic and cognitive effects that may increase sexual risk taking…using different classes of substances together or in sequence may activate multiple pathways, synergistically increase risk behaviors, and thus explain some of our findings.”
Gay and other MSM are the group most affected by HIV in the US. Many gay men use recreational drugs, often during sex, and previous research has shown a relationship between consumption of drugs or alcohol and increased HIV risk.
Investigators from Project ECHO in San Francisco wanted to see if there was a connection between the frequency of drug and alcohol use (as well as the number of drugs used at any one time) and high-risk sex (defined as unprotected anal sex with a partner of a different or unknown HIV infection status).
They therefore designed a cross-sectional study involving 3173 HIV-negative gay men who were recruited in the San Francisco area between 2009 and 2012. All participants completed a telephone interview enquiring about their substance use and their sexual behaviour.
The investigators focused on the use of cocaine, methamphetamine and poppers and alcohol.
Participants were categorised according to whether they used these substances episodically (less than once a week, weekly) or more frequently. Men who had more than four alcoholic drinks each day were defined as heavy drinkers; individuals reporting the consumption of fewer than four drinks as moderate drinkers.
Data were also collected on the use of other drugs, including cannabis, heroin and erectile dysfunction treatments.
Most of the participants were white (51%) and their mean age was 34 years. Over two-thirds (67%) reported an HIV test in the previous six months. Unprotected anal sex was reported by 45% of participants, with a quarter reporting high-risk sex.
Use of cocaine, methamphetamine and poppers was episodic rather than frequent (27 vs 5%; 12 vs 6%; 27 vs 8%). Moderate drinking was highly prevalent (84%), but few men drank heavily (10%).
The most commonly used substances during unprotected anal sex were alcohol (28%), cannabis (18%), poppers (15%), erectile dysfunction drugs (8%), cocaine (8%) and methamphetamine (8%). Treatment for substance abuse was reported by 5% of participants.
Episodic use of methamphetamine (AOR = 3.31; 95% CI, 2.55-4.28) and cocaine (AOR = 1.86; 95% CI, 1.51-2.29) was associated (compared to non-use) with an increased risk of reporting unprotected anal sex with an HIV-positive or unknown status partner. The risk was even higher (compared to non-use) for men who reported frequent use of these drugs (AOR = 5.46; 95% CI, 3.8-7.83 and AOR = 3.13; 95% CI, 2.12-4.63 respectively).
For poppers, the risk of reporting high-risk unprotected anal sex was similar for episodic and more frequent users (AOR = 2.08; 95% CI, 1.68-2.56 and AOR = 2.54; 95% CI, 1.85-3.48).
Heavy drinkers were more likely to report unprotected sex with HIV-positive men or individuals of unknown status than moderate drinkers (AOR = 1.90; 95% CI, 1.45-2.51).
The investigators also found that the risk of reporting high-risk unprotected anal intercourse increased according to the number of substances used before or during sex (one substance: AOR = 16.81; 95% CI, 12.25-23.08; two substances: AOR = 27.31; 95% CI, 19.93-39.39; three or more substances: AOR = 46.38; 95% CI, 30.65-70.19).
“HIV risk was strongly associated with frequency of use and number of substances used before and during unprotected sex,” write the authors.
They believe their findings have public health implications and that gay men who use substances “may benefit from strategies that build self-efficacy and promote skills for explicit HIV-serostatus communications with partners”.
Santos G-M et al. Dose response associations between number and frequency of substance use and high-risk sexual behaviors among HIV-negative substance-using men who have sex with men (SUMSM) in San Francisco. J Acquir Immune Defic Synd, online edition, doi: 10.1097/QAI.0b013e318293f10b, 2013.