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Marijuana chemicals found in urine of children exposed to smoke :

December 7, 2016

Psychoactive chemicals were found in children exposed to secondhand marijuana smoke, according to a new study.

The findings come as an increasing number of states legalize medical or recreational marijuana, often without prohibitions on adults’ use when children are present.

“While documenting the presence of metabolites of THC (tetrahydrocannabinol) in children does not imply causation of disease, it does suggest that, like tobacco smoke, marijuana smoke is inhaled by children in the presence of adults who are using it,” authors said in the study “Detecting biomarkers of secondhand marijuana smoke in young children” (Wilson KM, et al. Pediatr Res. Dec. 2, 2016,

While previous research has found toxic chemicals in marijuana smoke, studies have not been done on the impact of secondhand marijuana smoke on children, according to the report whose lead author, Karen M. Wilson, M.D., M.P.H., FAAP, is chair of the AAP Section on Tobacco Control Executive Committee and an investigator with the AAP Julius B. Richmond Center of Excellence.

The team studied children’s exposure by analyzing urine samples from 43 children ages 1 month to 2 years who were hospitalized with bronchiolitis in Colorado from 2013-’15.

Using a new highly sensitive assay from the Centers for Disease Control and Prevention, researchers looked for THC metabolite 11-nor-9-carboxy-THC (COOH-THC) and cotinine, which indicates exposure to tobacco smoke.

They found that 16% of the children had COOH-THC in their urine with concentrations of 0.03 nanograms per milliliter (ng/mL) to 1.5 ng/mL. Among children whose parents indicated marijuana use in the home or by a caregiver, 75% had COOH-THC in their urine compared to 10% of peers.

These children “were also more likely to be exposed to tobacco smoke, which increases their risk for cognitive deficits and respiratory illness,” according to the report.

“More study is warranted to investigate if marijuana smoke exposure adds additional risk,” authors wrote.

In 2015, the Academy released a policy statement on marijuana opposing legalization, use by children and use in the presence of children. It noted unknown effects of secondhand marijuana smoke and “the important influence of role modeling by adults on child and adolescent behavior.”

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