Donald D Porchia, PhD
University of Florida
Co-Authors: Zhi Zhou1, Eric C Porges1, Smita Ghare2, Shish Barve2, Ronald Cohen1, Yan Wang1, Robert L Cook1, Zhigang Li1
1University of Florida, 2University of Louisville
Background and aims: Cannabis use is widespread with an estimated 19.8% of the North American population reporting use in 2022. Because the gut-brain axis involves bidirectional communication between the gut microbiome and the brain, the ingestion of THC can alter the composition of the microbiota in the gut. Our aim is to examine the association between cannabis consumption and the gut microbiome among persons living with HIV (PLWH).
Methods: Of the participants in the Marijuana Associated Planning and Long-term Effects study, 71 provided fecal samples for this cross-sectional analysis. This under-represented sample population consisted of 71 PLWH (53% Female, 73% Black or Hispanic, mean Age 58) of which 36 (51%) were exclusive flower users, 11 (15%) used a combination of flower and other cannabis products, and 24 (34%) were non-users. Cannabis use was measured through a timeline follow back instrument. For flower, THC content was measured by grams consumed times the percentage of THC in the flower if known, otherwise 15% was assumed. For other products, the most common THC percentage from medical dispensaries was used for each. Non-users were recorded as zero. The fecal samples were sequenced using 16S rRNA sequencing. Each participant contributed one sample in the analyses.
The IFAA method was used to identify genera, out of a possible 253 genera, associated with average milligrams of THC ingested per use day and Permanova was used to compare beta diversity between participants with heavy cannabis use verses those with light to no cannabis use. The association between the Simpson diversity index (SDI) and average THC per use day was also tested. All analyses adjusted for age, gender, and education. All p-values were adjusted for multiple testing.
Results: Genus Dialister (b = – 11.5% change per 50 mg, p = 0.0245) showed a significant, negative association with cannabis consumption. There were no significant differences in the high verses low to no cannabis group in terms of beta diversity (p = 0.35) and the SDI was not significantly associated with cannabis use (p = 0.19).
Conclusion: Genus Dialister is a gram-negative, anaerobic or microaerophilic, non-motile, non-spore forming and non-fermentative bacteria. It was negatively associated with cannabis consumption in the sample population. A decrease in Dialister has been associated with irritable bowel disease. The overall diversity was negatively associated with cannabis consumption although not statistically significant. These findings are consistent with similar findings on younger, all male, HIV populations in the literature.