Researchers at University of California San Diego analyzed cannabis smoking practices in San Diego County to assess whether in-home smoking was associated with cannabis detection in children. The study, published on Jan. 23, 2025 in the journal JAMA Network Open, found that in-home cannabis smoking increased the odds of child exposure to cannabis smoke.
Smoking is the most common method of cannabis use and is known to generate emissions that are harmful to those exposed. Cannabis is often smoked indoors, putting non-smokers such as children at risk for exposure.
“While the long-term health consequences of cannabis smoke are not yet well known, cannabis smoke contains carcinogens, respiratory irritants, and other harmful chemicals,” said John Bellettiere, Ph.D., M.P.H., assistant professor in the Herbert Wertheim School of Public Health and Human Longevity Science at UC San Diego.
“In our analysis, the odds of detectable cannabis in children were five times higher in households with reported in-home cannabis smoking. This exposure to toxic chemicals, including known carcinogens, could have long-term health effects in these children.”
The research team analyzed in-home cannabis smoking practices in San Diego County to quantify the relationship between in-home cannabis smoking and cannabis biomarker detection in resident children’s urine. The youngest child in each of the 275 households enrolled in the study was tested, at a median age of three years.
Investigators found that among households reporting in-home cannabis smoking, 69% had a child with detectable cannabis biomarker levels compared to 24% in households not reporting in-home cannabis smoking. Because a large percentage of participants were recruited from low-income households enrolled in the Women, Infants, and Children Supplemental Nutrition Program from 2012 through 2015, findings of the study are not necessarily generalizable to the broader U.S. population, cautioned Bellettiere.
“As young children spend most of their time at home, reducing in-home cannabis smoking could substantially reduce their exposure to the toxic and carcinogenic chemicals found in cannabis smoke,” said Osika Tripathi, Ph.D., M.P.H., a recent graduate of the UC San Diego—San Diego State University Joint Doctoral Program in Public Health.
“As evidence regarding the health effects of cannabis grows, adopting strategies from the tobacco control playbook, such as comprehensive smoke-free laws and policies, could safeguard children’s health,” continued Bellettiere. “Determining the long-term health risks of second-hand cannabis smoke exposure is the absolutely essential next step.”
More information:
Osika Tripathi et al. Exposure to Secondhand Cannabis Smoke Among Children. JAMA Network Open (2025). DOI: 10.1001/jamanetworkopen.2024.55963, jamanetwork.com/journals/jaman … /fullarticle/2829482
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University of California – San Diego
Citation:
Smoking cannabis in the home can increase odds of detectable levels in children (2025, January 23)