A new study has found that in the United States there has been a sharp increase in marijuana exposure among young children.

This increase of exposure has come as more states have begun to legalize the drug for both medical or recreational use, the study's researchers say. Generally, marijuana exposure in young children comes when a child breathes in the smoke or accidentally swallows the drug.

"The high percentage of ingestions may be related to the popularity of marijuana brownies, cookies and other foods," says study co-author Henry Spiller, director of the Central Ohio Poison Center at Nationwide Children's Hospital. "Very young children explore their environments by putting items in their mouths, and foods such as brownies and cookies are attractive."

For the study, researchers used information from the National Poison Database System and found that marijuana exposure among children age 5 and younger had risen more than 147 percent across the nation from 2006 through 2013.  Overall, researchers found that almost 2,000 cases of marijuana exposure of young children were reported to the Poison Control Centers in the United States from 2000 through 2013.

This exposure rate increased by almost 610 percent among children in states where marijuana has been legalized for medical use before 2000.  Even states that had not legalized the drug for medical use by 2013 saw a rise with an increase of 63 percent among young children between 2000 and 2013.  More than 75 percent of the children exposed were under 3 and most exposure was the result of the child swallowing the drug, the researchers say.

The study authors found that in most cases the children suffered only minor problems, but some suffered breathing problems, seizures and even comas as a result of their exposure. More than 18 percent of the children exposed were hospitalized for treatment.

The findings are cause for concern, said study senior author Dr. Gary Smith, director of the Center for Injury Research and Policy.

"Any state considering marijuana legalization needs to include child protections in its laws from the very beginning" Smith says. "Child safety must be part of the discussion when a state is considering legalization of marijuana."

Debates about legalizing marijuana have tended to focus on crime rates, economic benefits and health effects of adults. But this new study highlights the fact that more than just adults should be considered by lawmakers before deciding whether legalizing marijuana is best for their state.