Standard drug tests miss a lot of teen marijuana use, and tobacco smoking strongly predicts it
High-sensitivity urine testing detected THC in 25% of urban adolescents, far more than standard immunoassay screens, and cigarette smokers had 13 times the odds of also using marijuana.
Quick Facts
What This Study Found
The standard immunoassay substantially underestimated THC exposure compared to high-sensitivity chromatographic testing. THC was detected in 25% of 686 adolescents. Prevalence increased with age and was higher among non-Hispanic Black participants. Active tobacco smokers had 80% prevalence of THC use (OR 13.2). Urine cotinine and THC metabolite levels were significantly correlated (r=0.60).
Key Numbers
686 adolescents. THC detected in 25%. Cigarette smokers: 80% THC prevalence, OR 13.2 for predicting THC use. Cotinine-THC correlation: r=0.60. Standard immunoassay had high specificity but only moderate sensitivity.
How They Did This
Cross-sectional study of 686 adolescents aged 12-21 seen at Zuckerberg San Francisco General Hospital (2012-2014). Urine tested using both standard immunoassay and high-sensitivity liquid chromatographic assays for nicotine and THC metabolites.
Why This Research Matters
If standard drug tests underestimate adolescent marijuana use, prevalence data and clinical screening may be systematically inaccurate. The strong tobacco-marijuana concordance suggests screening for one substance should trigger screening for the other.
The Bigger Picture
The quantitative correlation between tobacco and marijuana exposure levels suggests these are not just co-occurring habits but may be dose-related. As dual use becomes more common with vaping products, understanding this relationship becomes increasingly important.
What This Study Doesn't Tell Us
Single urban hospital setting may not represent all adolescent populations. Cross-sectional design cannot determine directionality of the tobacco-marijuana relationship. Urine testing captures recent use but not patterns over time.
Questions This Raises
- ?How much adolescent marijuana use is missed by standard screening?
- ?Does reducing tobacco use reduce marijuana use?
- ?Would high-sensitivity testing change clinical decision-making in adolescent care?
Trust & Context
- Key Stat:
- 13x odds if smoking tobacco
- Evidence Grade:
- Rated moderate because this is a reasonably large study with quantitative biomarker data, though from a single hospital setting.
- Study Age:
- Published in 2019 using 2012-2014 data. Vaping has since changed the dual-use landscape significantly.
- Original Title:
- Quantitative biochemical screening for marijuana use and concordance with tobacco use in urban adolescents.
- Published In:
- Drug and alcohol dependence, 205, 107583 (2019)
- Authors:
- Benowitz, Neal(2), Nardone, Natalie, St Helen, Gideon, Addo, Newton, Jacob, Peyton, Liakoni, Evangelia, Jain, Shonul, Hooshfar, Shirin, Lynch, Kara
- Database ID:
- RTHC-01938
Evidence Hierarchy
A snapshot of a population at one point in time.
What do these levels mean? →Frequently Asked Questions
How common is marijuana use among teens?
Using high-sensitivity testing, 25% of urban adolescents had detectable THC in their urine. Standard drug tests missed a significant portion of this use.
Why are tobacco and marijuana use so linked in teens?
In this study, 80% of teen cigarette smokers also tested positive for THC, and the amounts of each substance in urine were correlated. The reasons may include shared risk factors, social contexts, or nicotine-THC interactions.
Read More on RethinkTHC
Cite This Study
https://rethinkthc.com/research/RTHC-01938APA
Benowitz, Neal; Nardone, Natalie; St Helen, Gideon; Addo, Newton; Jacob, Peyton; Liakoni, Evangelia; Jain, Shonul; Hooshfar, Shirin; Lynch, Kara. (2019). Quantitative biochemical screening for marijuana use and concordance with tobacco use in urban adolescents.. Drug and alcohol dependence, 205, 107583. https://doi.org/10.1016/j.drugalcdep.2019.107583
MLA
Benowitz, Neal, et al. "Quantitative biochemical screening for marijuana use and concordance with tobacco use in urban adolescents.." Drug and alcohol dependence, 2019. https://doi.org/10.1016/j.drugalcdep.2019.107583
RethinkTHC
RethinkTHC Research Database. "Quantitative biochemical screening for marijuana use and con..." RTHC-01938. Retrieved from https://rethinkthc.com/research/benowitz-2019-quantitative-biochemical-screening-for
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.