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Gender differences in correlations of self-reported marijuana use with a creatinine-normalized urine biomarker among persons with HIV

Donald Porchia
University of Florida

Co-Authors: Yancheng Li, Michael Truver, Bruce Goldberger, Eric C Porges, Yan Wang, Samuel Wu, Robert L Cook
University of Florida

Background: Cannabis use is common among persons with HIV (PWH). However, accurately quantifying cannabis consumption and its components such as THC has been a long-standing challenge due to the variety of cannabis products available, variability in smoking and other consumption behaviors, as well as the reliability and validity of self-reported cannabis measures. Further, the relationship between a timeline follow back (TLFB) and cannabis metabolites/biomarkers in older PWH has been less explored. We sought to determine the correlation between the self-reported quantity of cannabis use in grams per day (overall and flower-specific) with a creatinine-normalized urine biomarker (THC-COOH). We also explored whether the correlations differed by gender at birth, and whether the correlations would improve if we used the self-reported potency to weight the quantity of cannabis consumed.

Method: Data were collected from 2018-2022 from participants in the MAPLE study, a longitudinal study examining health effects of cannabis among persons with HIV in Florida.  This analysis included data from 253 PWH (mean age 49, 41% Female, 16% White, 68% Black, and 13% Hispanic) who used cannabis products. The quantity of daily cannabis use over the past 30 days was collected by a trained interviewer using a self-reported, calendar-based TLFB and pictures to help estimate grams of flower. Using these findings, cannabis quantity was summarized as grams of flower per day and converted to a standardized 15% THC flower grams per day since most flower was obtained from non-dispensary sources. Urine THC-COOH, a biomarker for THC, was determined by mass spectroscopy from 103 samples. Spearman correlation coefficients were used to compare creatinine-normalized THC-COOH levels with grams and potency-adjusted grams per day both overall and flower-specific as stratified by gender. 

Results: Among the 103 PWH with THC-COOH results, grams and potency-adjusted grams per day both overall and flower-specific were all significantly associated with THC-COOH urine biomarkers (r = 0.43-0.45, p < 0.01). When stratified by gender at birth, the correlations showed a stronger relationship for males (r = 0.54-0.58, p < 0.01) than for females (r=0.27-0.32, p=0.08-0.21).

Conclusions: TLFB is a valid instrument to measure self-reported marijuana use. However, the association between self-reported consumption of cannabis with urine THC-COOH biomarkers is stronger in males than in females. It is worth noting that our population consisted of older adults living with a chronic condition, HIV, so further investigation may be needed to explore the association between self-reported cannabis consumption and urine biomarkers among females.