Among adults with children living in the home, cannabis use was more common in states with legalized cannabis use, according to a new study by Columbia University Mailman School of Public Health, Columbia Irving Medical Center and the City University of New York. Legalization for recreational and medical use were both linked with significantly higher prevalence of past-month and daily cannabis use. Until now, most tobacco control and harm reduction efforts protecting youth from exposure to secondhand tobacco smoke focused on parental cigarette smoking, ensuring smoke-free homes, and not smoking in the presence of children. The findings are published in the journal Addiction.