Researchers explored cannabis smoking habits to determine if smoking at home was linked to the presence of cannabis in children.
A team of researchers from the University of California San Diego looked into cannabis smoking habits in San Diego County to see if smoking in the home was connected to cannabis being found in children. The results of this study, published in the Jan. 23, 2025, online edition of the Journal of the American Medical Association Network Open, indicated that smoking cannabis indoors raised the chances of children being exposed to cannabis smoke.
Smoking remains the most popular method of using cannabis and is acknowledged for producing emissions that can be harmful to those in its vicinity. Many people smoke cannabis indoors, which puts non-smokers, including children, at risk of exposure.
“The long-term health effects of cannabis smoke are still not fully understood, but it is known to contain carcinogens, irritants for the respiratory system, and other hazardous substances,” explained John Bellettiere, Ph.D., M.P.H., an assistant professor at the Herbert Wertheim School of Public Health and Human Longevity Science at UC San Diego. “Our analysis revealed that the likelihood of detectable cannabis in children was five times higher in homes where residents reported smoking cannabis. This exposure to harmful substances, which includes known carcinogens, could lead to health issues for these children in the future.”
The research team focused on in-home cannabis smoking patterns in San Diego County to evaluate the link between home smoking and the detection of cannabis biomarkers in the urine of resident children. The youngest child in each of the 275 participating households was assessed, with a median age of three years.
Results indicated that in homes where cannabis was smoked indoors, 69% of children showed detectable levels of cannabis biomarkers, in contrast to only 24% in homes where no in-home smoking was reported. Since many participants were recruited from low-income households enrolled in the Women, Infants, and Children Supplemental Nutrition Program from 2012 to 2015, Bellettiere noted that these findings may not apply to the wider U.S. population.
“Given that very young children are primarily at home, decreasing in-home cannabis smoking could significantly lower their exposure to the toxic and cancer-causing substances found in cannabis smoke,” stated Osika Tripathi, Ph.D., M.P.H., a recent graduate from the UC San Diego — San Diego State University Joint Doctoral Program in Public Health.
“As more information emerges about the health impacts of cannabis, implementing strategies from tobacco control—such as thorough smoke-free legislation and policies—could help protect children’s health,” Bellettiere added. “Understanding the long-term health risks associated with second-hand cannabis smoke exposure is a crucial next step.”
The research received funding from several sources, including the National Heart, Lung, and Blood Institute of the National Institutes of Health (grant # R01HL103684), the National Institutes of Health (grant #T32HL079891-11, grant #T32 GM084896), the Tobacco-Related Disease Research Program (awards # T31KT1501, #T33PC6863, #T32PT6244, #T32PT6042, and #T32IR5208), the National Cancer Institute (#K01 CA234317), the San Diego State University/UC San Diego Comprehensive Cancer Center Partnership (#U54 CA132384 and #U54 CA132379), and the Alzheimer’s Disease Resource Center for Advancing Minority Aging Research at UC San Diego (#P30 AG059299).
