From the Department of Epidemiology, Fielding School of Public Health.
Department of Health and Mental Health Services, Los Angeles LGBT Center.
Sex Transm Dis. 2019 Feb;46(2):105-111. doi: 10.1097/OLQ.0000000000000919.
Among men who have sex with men (MSM) the relationship between sexually transmitted infections (STIs) and cannabis use is not well established. We assessed cannabis use, sexual behavior, and STIs including human immunodeficiency virus (HIV) in a diverse cohort of young MSM.
In Los Angeles, the mSTUDY cohort conducted visits every 6 months with 512 MSM between 2014 and 2017 collecting demographics, sexual behaviors, and reports of frequency of substance use. Each visit conducted testing for gonorrhea, chlamydia, and syphilis via blood, urine, and pharyngeal and rectal swabs by PCR, Human immunodeficiency virus was assessed using rapid tests for HIV-negatives and viral load for HIV-positives. We analyzed the relationship between cannabis use, sexual behaviors and STIs/HIV across 1535 visits.
Significantly fewer participants tested positive for STIs at visits when reporting the previous 6 months use of only cannabis (11.7%) compared with no drugs (16.3%) or other drugs (20.0%, P = 0.01). Fewer MSM reporting only cannabis use than no or other drug use had been incarcerated, had incarcerated partners, experienced interpersonal violence, and were HIV-positive. In multivariable analyses visits with positive STIs were associated with other drug use (adjusted odds ratio, 1.69; 95% confidence interval, 1.03-2.78) but not use of cannabis only or no drug use after controlling for age, HIV status, new sex partners, and number of sex partners.
When MSM reported using cannabis exclusively fewer STIs were detected and lower risk sexual engagements reported than when MSM reported no drug or other drug use.
在男男性行为者（MSM）中，性传播感染（STI）与大麻使用之间的关系尚未得到充分证实。我们评估了不同队列中年轻 MSM 的大麻使用、性行为以及包括人类免疫缺陷病毒（HIV）在内的 STI。
在洛杉矶，mSTUDY 队列在 2014 年至 2017 年间每 6 个月对 512 名 MSM 进行一次访问，收集人口统计学、性行为以及物质使用频率报告。每次访问均通过血液、尿液以及咽拭子和直肠拭子进行淋病、衣原体和梅毒的聚合酶链反应（PCR）检测，对于 HIV 阴性者采用快速检测，HIV 阳性者进行病毒载量检测。我们分析了在 1535 次访问中，大麻使用、性行为与 STI/HIV 之间的关系。
与未使用任何药物（16.3%）或其他药物（20.0%）相比，报告过去 6 个月仅使用大麻的参与者在访问时 STI 检测阳性的比例显著较低（11.7%，P=0.01）。与未使用任何药物或其他药物相比，报告仅使用大麻的 MSM 入狱、有入狱伴侣、经历人际暴力和 HIV 阳性的可能性较低。在多变量分析中，与其他药物使用（调整后的优势比，1.69；95%置信区间，1.03-2.78）相比，只有大麻的使用与阳性 STI 访问相关，而在控制年龄、HIV 状态、新性伴侣和性伴侣数量后，与未使用任何药物或其他药物的情况无关。
当 MSM 报告仅使用大麻时，与报告未使用任何药物或其他药物相比，检测到的 STI 较少，报告的风险性行为较少。
