An American Academy of Pediatrics study found about half a group of hospitalized children in Colorado, which allows use of marijuana for recreational purposes, whose parents enrolled in a smoking cessation program tested positive for marijuana exposure.
The study, posted online early last week, determined co-use of tobacco and marijuana in the state could expose children to harmful effects of both.
The results of the study come as Missouri prepares for implementation of its new medical marijuana law. The new law, which goes into effect Dec. 6, establishes a timeline for the Missouri Department of Health and Senior Services to implement the new program.
In Missouri, marijuana will be legal for treatment of symptoms associated with cancer; epilepsy; glaucoma; intractable migraines (those persistent migraines that don't respond to other treatments); chronic medical conditions that cause severe, persistent pain or persistent muscle spasms, including, but not limited to those associated with multiple sclerosis, seizures, Parkinson's disease and Tourette's syndrome; debilitating psychiatric disorders (when diagnosed by a state licensed psychiatrist), including, but not limited to post-traumatic stress disorder; human immunodeficiency virus or acquired immune deficiency syndrome; chronic medical conditions whose treatment could lead to physical or psychological dependence (if a physician determines cannabis would be effective and safer); any terminal illness; or (in the professional judgment of a physician) any other chronic debilitating medical condition.
"Approximately half of the children who qualified for our study had biological evidence of exposure to marijuana," according to the academy. "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."
That biological evidence was shown in positive readings for "bio-markers," such as acute effects on their central nervous systems or changes in their heart rates.
Colorado legalized medical marijuana in 2000. Much like Missouri's new law, the use of cannabis was legal for specific conditions.
In 2012, however, the state legalized recreational use of cannabis. Users must be 21 and have a valid government ID to purchase, smoke and possess marijuana. And, residents may buy up to an ounce in a single transaction.
The researchers studied children who were hospitalized (not necessarily in connection with the second-hand smoke) in Colorado and had a parent participating in a smoking cessation study. The study, therefore looked at those whose parents potentially co-exposed the children to two kinds of smoke.
All children, whose ages range from 0-17 years and whose median age was 6, provided urine samples.
About 10 percent (nine) of the children tested positive for THC, the psychoactive compound I cannabis.
Children with positive results for cannabinoids - including THC - were more likely to have parents who used marijuana daily, smoked the marijuana verse using other delivery methods, used daily in their homes and smoked in another room when children were around rather than going outside to smoke, according to the study.
Despite various other methods of marijuana use, 30.1 percent of parents who use the product chose to smoke it, according to Dr. Karen Wilson, an author of the study. That was followed by edibles (14.5 percent) and vaporizers (9.6 percent).
Three of the nine children were adolescents, and the study did not rule out the possibility they were themselves marijuana users.
Six of the children were ages 7 and younger - most of whom had parents who reported using marijuana some days or every day.
Study authors said children with detectable levels of THC were more likely to have parents who reported smoking in the home and in a different room if their child was there rather than outside.
Marijuana and tobacco smoke contain similar harmful chemicals, they said, and smoking in the home - even if it is in a different room - can result in significant exposure to children.
Parents and caregivers should be encouraged to avoid smoking tobacco, marijuana or both in the home, the report states, to help reduce exposure to infants and children living there.
"Our findings suggest that smoking in the home, even in a different room, results in exposure to children," Wilson said. "The more we understand second-hand smoke exposure," she said, "the better we can protect children in the home in states where marijuana is legal."