Marijuana and Tobacco Coexposure in Hospitalized Children

The impact of secondhand marijuana smoke exposure on children is unknown. New methods allow for the detection of marijuana smoke exposure in children.

We studied children who were hospitalized in Colorado and had a parent participating in a smoking cessation study; all children had urine samples remaining from the original study as well as consent for future research. Parents completed a survey and urine samples were analyzed for cotinine and marijuana metabolites, including 11-hydroxy-Δ9-tetrahydrocannabinol (COOH-THC), by using liquid chromatography-tandem mass spectrometry.

The median age of the children was 6.0 years (range 0-17 years); 57% were boys. Half (55%) were white, 12% were African American, and 33% were of another race; 39% identified as Hispanic. Approximately 46% had detectable COOH-THC, and 11% had detectable THC. Of those with detectable THC, 3 were teenagers, and 6 were <8 years of age. There were no significant differences in urinary COOH-THC concentrations by age, sex, race and/or ethnicity, or socioeconomic status. Children with positive results for COOH-THC were more likely to have parents who use marijuana daily, smoke marijuana versus other forms of use, use daily in the home, and smoke marijuana in another room if the children are around compared with smoking outside.

Approximately half of the children who qualified for our study had biological evidence of exposure to marijuana. Researchers in studies such as this provide valuable data on secondhand exposure to children from parents using tobacco and marijuana and can inform public health policies to reduce harm.