Q&A with Karen M. Wilson: Pediatric Health Threat in Legal Marijuana?

September 13, 2016
Carolyn Colwell

Researchers know that cigarette smoke is hazardous to children, even when it is secondhand. But the impact marijuana smoke has on kids in households where adults smoke cannabis been little studied.

Editor’s Note: Colorado has legalized both medical and recreational use of cannabis. Karen M. Wilson, MD, and colleagues at Children’s Hospital Colorado decided to see if there were signs of unintended harm to children whose parents smoke marijuana. They found that most of a small group of children treated for bronchiolitis had marijuana metabolites in their urine.

MD Magazine: What led you to do the study?

KW: When we interviewed parents to screen for smoking, parents started telling us that they were no longer smoking cigarettes, only marijuana.

MD Magazine: You found marijuana metabolites in these children. Did any of the findings of the study surprise you?

KW: Sadly, not really. We know that tobacco smoke in very low levels is detectable in children, so I wasn’t surprised that we could find detectable levels of marijuana smoke.

MD Magazine: Should doctors routinely test for marijuana metabolites in cases of bronchiolitis?

KW: This testing is only available at the CDC and for research purposes, so we don’t have this option yet. If we did, that would be an important conversation.

MD Magazine: What about routinely asking all parents if they use marijuana?

KW: This would be ideal, but there is confusion about how to address marijuana smoking in the home if parents say they use it. There’s no law against smoking in the presence of children, and Colorado laws require recreational marijuana to be smoked in private spaces. People who live in apartments don't have backyards and could be ticketed if they smoke it on the street. So the laws in Colorado, restricting use to private homes, encourages smoking around children since there is nowhere else to go. Kids even in neighboring apartments can be exposed, as happened in a Longmont, Colorado case. Their parents were concerned about their baby when a neighbor's pot smoke leaked into their apartment, possibly through the heating vents. Still, doctors can ask about kids' exposure to marijuana and strongly encourage parents not to smoke in the presence of children.

MD Magazine: Does the legalization of marijuana pose a public health problem for pediatric patients?

KW: It may in two ways. Exposure to second-hand marijuana smoke may normalize the behavior and encourage teens to start using it. Marijuana has a pretty negative effect on the developing teenage brain. The teens who smoke marijuana persistently have an increased risk of declining IQs, structural brain abnormalities and altered neural activity, according to a compilation of recent research. We also are concerned that exposure to secondhand marijuana smoke may cause or exacerbate disease

MD Magazine: What about edible marijuana products, do they pose a pediatric health problem?

KW: Yes there have been some cases of ingestions where children have been hospitalized after eating marijuana products. They are very appealing. When it looks like gummy bears, or pop tarts and brownies and cookies, they're hard to resist. Little kids can't tell the difference. The new Colorado laws about child-proof packaging should help prevent this.

MD Magazine: You found that exposure to marijuana smoke was far more common in non-white households. Was your study large enough to make that a significant finding?

KW: The difference was statistically significant, which means that the study was large enough to detect a difference on a technical basis. But we were looking very imprecisely at white vs. non-white populations (rather than specific racial and ethnic groups). We could not determine if all of that difference was due to other factors, such as socioeconomic status.

MD Magazine: Were any of the kids’ exposures a result of someone using marijuana for a so-called medical purpose?

KW: We don’t have the information to know that. We do know that the 1-month to 2-year-old children enrolled in our study were previously healthy. Therefore, they were highly unlikely to have been given medical marijuana, such as the marijuana tinctures that some parents hope will help control severe seizures. For the kids who were exposed, we don't know if it came from parents smoking medical marijuana or recreational marijuana.

MD Magazine: Where will your research take you next?

KW: We would love to do a cohort study and follow a group of children who are both exposed and not exposed to marijuana, and see if the exposed group has a higher prevalence of lung diseases like asthma and bronchiolitis. We are currently looking for funding.

(Wilson recently left Colorado and is now Chief of General Pediatrics and Vice-Chair for Clinical and Translational Research at Mount Sinai Medical Center in New York City.)