Problematic cannabis use is associated with reduced rectal microbial species richness and diversity among a pilot sample of young men who have sex with men

Compared to young heterosexual men, young sexual and gender minorities (YSGM) have elevated systemic inflammation and unique intestinal microbial profiles, influenced by HIV infection and substance use. However, links between cannabis use and microbial dysbiosis in this population have not been well described. In this pilot study, we aimed to characterize the complex interrelationships between cannabis use and microbial community structure in YSGM in relation to HIV status.Cannabis use was assessed by self-administered Cannabis Use Disorder Identification Test (CUDIT) questionnaires and rectal microbial community alpha-diversity metrics were assessed via 16s rRNA sequencing in a subset of YSGM (n=42) in the RADAR cohort (aged 16-29) in Chicago. Multivariable regression models were used to assess the relationship between cannabis use and microbiome alpha-diversity metrics, adjusting for HIV status and other risk characteristics, including inflammation, which was evaluated by plasma levels of C-reactive protein (CRP). Problematic cannabis use, but not general use, was significantly inversely associated with microbial community richness (Adj. Beta = -8.13; 95% CI: -15.68, -0.59) and Shannon diversity (Adj. Beta = -0.04; 95% CI: -0.07, 0.009). No significant association was observed between CUDIT score and community evenness, nor was any significant moderation observed by HIV status.We observed that problematic cannabis use was associated with reduced microbial community richness and Shannon diversity, adjusting for within population differences in inflammation and HIV status. Future research should aim to assess how cannabis use contributes to microbiome-related health factors among YSGM and if decreasing cannabis use can restore gut microbial community structure.