16% of Hospitalized Toddlers in Colorado Had Detectable Marijuana Metabolites in Their Urine
Among 43 children under age 2 hospitalized with bronchiolitis in Colorado, 16% had detectable marijuana metabolites in their urine, with exposure more common in non-white children and those with tobacco smoke exposure.
Quick Facts
What This Study Found
Researchers tested urine from 43 young children (ages 1 month to 2 years) hospitalized with bronchiolitis in Colorado for marijuana metabolites using highly sensitive LC/MS/MS testing.
16% of samples were positive for COOH-THC (the primary marijuana metabolite), with concentrations ranging from 0.03 to 1.5 ng/mL. Two subjects had levels above 1 ng/mL. The exposure was detected through secondhand marijuana smoke, not intentional administration.
Non-white children had significantly more exposure than white children (44% vs. 9%, p < 0.05). Children with higher tobacco smoke exposure (cotinine > 2.0 ng/mL) were more likely to also be positive for marijuana metabolites (40% vs. 7%, p < 0.01), suggesting households with tobacco smoke are also more likely to expose children to marijuana smoke.
Key Numbers
43 children tested. 16% positive for COOH-THC. Range: 0.03-1.5 ng/mL. 2 children had levels > 1 ng/mL. 77% male. 52% under 1 year. Non-white children: 44% vs. 9% exposed (p < 0.05). High tobacco exposure: 40% vs. 7% also marijuana-exposed (p < 0.01).
How They Did This
Cross-sectional study of children aged 1 month to 2 years hospitalized with bronchiolitis in Colorado (2013-2015). Parent survey and urine analysis for cotinine (tobacco metabolite) and COOH-THC (marijuana metabolite) using LC/MS/MS with very low detection limits (0.015 ng/mL for COOH-THC).
Why This Research Matters
This is one of the first studies to objectively document secondhand marijuana smoke exposure in young children. The 16% positivity rate is concerning given that these children were already hospitalized with a respiratory illness. Whether secondhand marijuana smoke contributed to or worsened their bronchiolitis is unknown but raises important questions.
The Bigger Picture
As cannabis legalization expands, secondhand exposure in children becomes a public health concern parallel to secondhand tobacco smoke. This study provides the first biomarker evidence that young children in Colorado are being exposed to marijuana smoke, establishing a baseline for monitoring and motivating research on health effects.
What This Study Doesn't Tell Us
Very small sample (43 children). Single-site study in Colorado. Cannot determine whether the marijuana exposure contributed to the bronchiolitis. The detection of metabolites confirms exposure but cannot determine the magnitude, frequency, or route (could be from clothing or surfaces, not just smoke). No comparison to hospitalized children outside legalization states.
Questions This Raises
- ?Does secondhand marijuana smoke worsen respiratory illness in young children?
- ?What are the developmental effects of chronic secondhand marijuana exposure?
- ?Should pediatric screening for marijuana metabolites become routine in legalization states?
Trust & Context
- Key Stat:
- 16% of hospitalized toddlers had detectable marijuana metabolites; 44% of non-white children were exposed
- Evidence Grade:
- Preliminary evidence from a small, single-site study with biomarker confirmation.
- Study Age:
- Published in 2017. One of the first studies to objectively measure secondhand marijuana smoke exposure in children.
- Original Title:
- Detecting biomarkers of secondhand marijuana smoke in young children.
- Published In:
- Pediatric research, 81(4), 589-592 (2017)
- Authors:
- Wilson, Karen M(5), Torok, Michelle R(2), Wei, Binnian(4), Wang, Lanqing, Robinson, Michelle, Sosnoff, Connie S, Blount, Benjamin C
- Database ID:
- RTHC-01553
Evidence Hierarchy
A snapshot of a population at one point in time.
What do these levels mean? →Frequently Asked Questions
Can secondhand marijuana smoke affect young children?
This study confirmed that marijuana metabolites can be detected in the urine of young children, proving that secondhand exposure occurs. Whether this exposure causes health problems is still unknown, but the finding raises concerns, particularly since these children were hospitalized with respiratory illness.
How are young children being exposed to marijuana?
Through secondhand smoke in the home. This study found that children in households with tobacco smoke were also more likely to have marijuana metabolites, suggesting these exposures often co-occur. The metabolites detected (COOH-THC) confirm systemic absorption, meaning the children are not just smelling smoke but actually absorbing marijuana compounds.
Read More on RethinkTHC
Cite This Study
https://rethinkthc.com/research/RTHC-01553APA
Wilson, Karen M; Torok, Michelle R; Wei, Binnian; Wang, Lanqing; Robinson, Michelle; Sosnoff, Connie S; Blount, Benjamin C. (2017). Detecting biomarkers of secondhand marijuana smoke in young children.. Pediatric research, 81(4), 589-592. https://doi.org/10.1038/pr.2016.261
MLA
Wilson, Karen M, et al. "Detecting biomarkers of secondhand marijuana smoke in young children.." Pediatric research, 2017. https://doi.org/10.1038/pr.2016.261
RethinkTHC
RethinkTHC Research Database. "Detecting biomarkers of secondhand marijuana smoke in young ..." RTHC-01553. Retrieved from https://rethinkthc.com/research/wilson-2017-detecting-biomarkers-of-secondhand
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.