American adults who are uninsured or on Medicaid smoke at rates more than double those for adults with private health insurance or Medicare, according to a new study by the Centers for Disease Control and Prevention. About 28% of uninsured adults and 29% of Medicaid recipients were current cigarette smokers when surveyed in 2014, compared with 13% of adults with private insurance or Medicare, the study found. The overall cigarette smoking rate for adults was about 17%, down from 18% in 2013 and 21% in 2005. The findings are from the National Health Interview Survey. “Smoking kills half a million Americans each year and costs more than $300 billion,” said CDC Director Tom Frieden, M.D. “This report shows real progress helping American smokers quit and that more progress is possible.”