Event-level studies measure substance use and sexual behaviors happening during a specific sexual encounter, ensuring that both variables are temporally paired. This study explored the event-level associations between a range of sexual behaviors (masturbation, anal sex, oral sex, rimming, fisting, sex toys, and group sex) and five sexualized substances (poppers, methamphetamine, GHB, ecstasy/MDMA, and ketamine) used during 11,582 sexual events reported by 762 gay, bisexual, and other men who have sex with men (GBMSM) in Vancouver, Canada. Data were obtained from a prospective cohort of GBMSM who self-reported their behaviors via computer-based questionnaires on their last sexual encounter with up to five of their most recent partners in the past six months. These clustered data were analyzed with multivariable generalized linear mixed models. Participants reported popper use in 16.1% of sexual encounters, methamphetamine in 8.6%, gamma-hydroxybutyrate (GHB) in 4.1%, ecstasy/3,4-methylenedioxymethamphetamine (MDMA) in 3.3%, and ketamine in 1.5%. Condomless receptive anal sex (25.0% of events) was associated with increased odds of using poppers, methamphetamine, GHB, and ecstasy/MDMA. Group sex (13.1% of events) and sharing sex toys (2.0% of events) were more likely with the use of all five substances. Receiving money/drugs/goods in exchange for sex (2.5% of events) was associated with increased odds of poppers, methamphetamine, GHB, and ecstasy/MDMA use. GBMSM living with HIV (29.9% of participants) had higher odds of using poppers, methamphetamine, and GHB, but lower odds of using ecstasy/MDMA. In conclusion, these event-level results suggest public health strategies are needed to address the possible negative impacts of sexualized substance use among GBMSM.

事件级研究测量特定性接触期间发生的物质使用和性行为，确保两个变量在时间上配对。本研究探讨了一系列性行为（手淫、肛交、口交、性交、拳交、性玩具和群交）与五种性化物质（罂粟碱、甲基苯丙胺、GHB、摇头丸/摇头丸和氯胺酮）在加拿大温哥华的 762 名男同性恋、双性恋和其他男男性行为者 (GBMSM) 报告的 11,582 次性事件中使用。数据来自 GBMSM 的前瞻性队列，他们通过基于计算机的问卷调查自我报告了他们在过去六个月中与最多五个最近的伴侣发生的最后一次性接触的行为。这些聚类数据用多变量广义线性混合模型进行分析。参与者报告在 16.1% 的性接触中使用 popper，8.6% 使用甲基苯丙胺，4.1% 使用 γ-羟基丁酸 (GHB)，3.3% 使用摇头丸/3,4-亚甲二氧基甲基苯丙胺 (MDMA)，1.5% 使用氯胺酮。不带安全套的肛交（事件的 25.0%）与使用 poppers、甲基苯丙胺、GHB 和摇头丸/摇头丸的几率增加有关。使用所有五种物质更有可能发生群体性行为（占事件的 13.1%）和分享性玩具（占事件的 2.0%）。接受金钱/毒品/商品以换取性行为（占事件的 2.5%）与使用罂粟碱、甲基苯丙胺、GHB 和摇头丸/摇头丸的几率增加有关。感染 HIV 的 GBMSM（29.9% 的参与者）使用 poppers、甲基苯丙胺和 GHB 的几率较高，但使用摇头丸/摇头丸的几率较低。综上所述，