A recent study conducted by researchers at the University of California San Diego delved into the impact of cannabis smoking practices in households on the detection of cannabis in children. Published on Jan. 23, 2025, in the journal JAMA Network Open, the study revealed a concerning association between in-home cannabis smoking and child exposure to cannabis smoke.
Smoking remains the most prevalent method of cannabis consumption, known to release harmful emissions that can adversely affect those exposed to them. With cannabis often being smoked indoors, non-smokers, particularly children, are at risk of inhaling these harmful substances.
Dr. John Bellettiere, an assistant professor at the Herbert Wertheim School of Public Health and Human Longevity Science at UC San Diego, highlighted the potential health hazards associated with cannabis smoke exposure. He stated, “While the long-term effects of cannabis smoke are still not fully understood, it contains carcinogens, respiratory irritants, and other harmful chemicals.”
The research findings indicated that households where in-home cannabis smoking was reported had a five-fold increase in the likelihood of detectable cannabis biomarkers in children. This exposure to toxic chemicals, including known carcinogens, poses a significant health risk to these children in the long run.
The study involved analyzing in-home cannabis smoking practices in San Diego County to quantify the correlation between such practices and the detection of cannabis biomarkers in children’s urine. The youngest child from each of the 275 participating households, with a median age of three years, was tested.
The results showed that 69% of households where in-home cannabis smoking was reported had children with detectable cannabis biomarker levels, compared to only 24% in households without such smoking practices. However, it’s essential to note that the study’s participants were primarily from low-income households enrolled in the Women, Infants, and Children Supplemental Nutrition Program from 2012 to 2015, potentially limiting the generalizability of the findings to the wider U.S. population.
Dr. Osika Tripathi, a recent graduate of the UC San Diego—San Diego State University Joint Doctoral Program in Public Health, emphasized the importance of reducing in-home cannabis smoking to safeguard children’s health. Tripathi suggested adopting strategies akin to tobacco control measures, such as comprehensive smoke-free laws and policies, to minimize children’s exposure to the harmful chemicals present in cannabis smoke.
Dr. Bellettiere concluded by stressing the necessity of further research to determine the long-term health risks associated with second-hand cannabis smoke exposure. As evidence on the health effects of cannabis continues to emerge, implementing preventive measures to protect children from the potential harms of cannabis smoke exposure becomes imperative.
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
