But exposure remains high among children and those who rent.
The number of people exposed to secondhand smoke dropped by half over the last decade, but one in four nonsmokers, or some 58 million people, are still exposed, a CDC report said today.
Declines in exposure haven't been uniform across the board, with two in five children, and seven in 10 black children still being exposed.
A fuller report was published online in Morbidity and Mortality Weekly Report.
"Secondhand smoke continues to expose too many people," said Tom Frieden, MD, MPH, director of the CDC, during a telephone press briefing. "These are preventable harms, and going smoke-free can prevent a wide range of problems."
Previous studies have found that children exposed to secondhand smoke have respiratory health risks that persist even into adulthood, and that exposure for adults may constitutea greater risk factor for heart disease than other well-known factors such as high cholesterol.
Data for the new report came from the National Health and Nutrition Examination Survey during the years 1999 to 2012.
In 1999-2000, about one in two nonsmokers were exposed to secondhand smoke, but by 2011-2012, the number had dropped to approximately one in four. Exposure was higher in African Americans, among whom about half of nonsmokers were exposed to secondhand smoke. Those who lived below the poverty level were also at increased risk -- two in five poor nonsmokers were exposed. Higher than average exposure was also seen in nonsmokers living in rental housing, of whom more than one in three were exposed.
The report said that state and city officials should help protect children and nonsmokers from secondhand smoke by eliminating smoking in public places like restaurants, bars, casinos, and workplaces, and in multi-unit housing such as apartments, condominiums, and government housing.
Though most states have restrictions on where smoking is allowed, at least 14 states place few or no regulations on where smoking is allowed, an infographic from the report showed.
The CDC also encouraged doctors, nurses, and other healthcare providers to talk with patients about the dangers of secondhand smoke and push smokers to quit.
http://www.medpagetoday.com/PrimaryCare/Smoking/49853
