But what about the risks related to secondhand marijuana smoke — especially for young children?
A new study that was scheduled to be presented earlier today at the Pediatric Academic Societies 2016 meeting in Baltimore suggests that they're very real.
The main take-away from an American Academy of Pediatrics report about the analysis, entitled "Marijuana Exposure in Children Hospitalized for Bronchiolitis:" "One in six infants and toddlers admitted to a Colorado hospital with coughing, wheezing and other symptoms of bronchiolitis tested positive for marijuana exposure."
The lead researcher for the study was Karen M. Wilson, an associate professor of pediatrics at the University of Colorado School of Medicine. According to the AAP, Wilson and her team "recruited parents of previously healthy children between one month of age and two years old who were admitted to Children's Hospital Colorado between January 2013 and April 2014 with bronchiolitis, an inflammation of the smallest air passages in the lung."
Afterward, the parents filled out a questionnaire that asked about tobacco smoke and, during a later phase, marijuana smoke.
The children of parents who were marijuana smokers tested positive for THC approximately 16 percent of the time.
Moreover, this number rose after legalization of limited recreational marijuana sales took effect on January 1, 2014. Around 10 percent of pot smokers' kids tested registered for traces of THC before legalization, 21 percent afterward — and "non-white children were more likely to be exposed than white children," the study adds.
A statement by Dr. Wilson about the results reads in part: "Our study demonstrates that, as with secondhand tobacco smoke, children can be exposed to the chemicals in marijuana when it is smoked by someone nearby. Especially as marijuana becomes more available and acceptable, we need to learn more about how this may affect children's health and development."
She adds: "Marijuana should never be smoked in the presence of children."
Below, see the abstract from the study.
Marijuana Exposure in Children Hospitalized for Bronchiolitis
K.M. Wilson, M.R. Torok, B. Wei, L. Wang, M. Robinson, C.S. Sosnoff, B.B. Blount. Children's Hospital Colorado, Aurora, CO; AAP Julius B. Richmond Center of Excellence, Elk Grove Village, IL; ACCORDS, University of Colorado School of Medicine, Aurora, CO; National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA.
BACKGROUND: Marijuana is increasingly legal for medical and recreational use. Marijuana smoke contains carcinogenic and psychoactive chemicals. The impact of secondhand marijuana smoke exposure on children is unknown, and most states with legal marijuana use do not restrict its combustion around children.
OBJECTIVE: To determine the prevalence of marijuana exposure in a cohort of children hospitalized with bronchiolitis.
DESIGN/METHODS: This was a secondary analysis of a study of children ages 1 month to 2 years hospitalized with bronchiolitis in Colorado. Subjects were recruited from 1/2013 to 4/2014; recreational marijuana was legalized in Colorado on 1/1/14. Parents completed a survey about their child's health and demographics. We added a question on marijuana use by contacts in 10/2013. Urine samples were sent to the CDC for analysis of cotinine using LC/MS/MS (LOD 0.03 ng/mL) and marijuana metabolites including COOH-THC (LOD 0.015 ng/mL). All analyses were done using SAS, and the study was approved by the Colorado Multiple Institutional Review Board.
RESULTS: We initially enrolled 99 of 180 eligible participants (55%). 43 urine samples were available for testing for this analysis. Most (77%) of the subjects were male, and 58% were less than 1 year of age. All were residents of Colorado. Of the 25 children who were assessed for exposure to marijuana users, 16% reported contact. COOH-THC was detectable in 16% of the samples analyzed (THC+); the range in COOH-THC concentration was .04-1.5 ng/mL, with 2 subjects having levels >1 ng/mL. More subjects were THC+ after legalization (21%) compared with before (10%) but this wasn't significant. Exposure did not differ by gender or age. Non-white children were more likely to be exposed than white children (44% vs. 9%; p<.05). Of those with household contacts using marijuana, 75% were THC+, compared to 10% of those with no reported contact (p<.05). 55% of children with cotinine >2.0 ng/mL were THC+, compared with 6% of those with lower cotinine (p<.01).
CONCLUSIONS: One in six young children in our study was exposed to marijuana. Marijuana should never been smoked in the presence of children. More research needs to be done to investigate secondhand marijuana exposure, and to track the impact of changing marijuana policy on the health and development of children.