DALLAS, Sept. 12 (UPI) -- Even with drastic decreases in the number of Americans who smoke, four out of ten children are still exposed to secondhand smoke, at least partially because it remains prevalent in public spaces and apartment buildings, according to a study published in the journal Circulation.
More than two-thirds of black children, more than one-third of white children and just under one-third of Hispanic children are exposed to secondhand smoke, researchers report in the American Heart Association-sponsored study.
The study recommends more be done to discourage smoking, including raising taxes on cigarettes, banning smoking in more areas and increasing funding to tobacco cessation programs.
Just 15 percent of Americans smoke cigarettes, according to the U.S. Centers for Disease Control and Prevention, but Raghuveer said exposure to smoke outside the home, for the most part, is to blame for the continued exposure.
In reviewing literature for the study, Dr. Geetha Raghuveer said the researchers found incidence of high blood pressure and other cardiovascular symptoms with exposure to cigarette smoke, though these effects develop over time.
"Parents need to be educated -- I think we're doing a good job, especially in the pediatric area -- especially since kids have a higher incidence of lung infestations such as asthma," Raghuveer, a professor of pediatrics at Children's Mercy Hospital and Clinics and an author of the study, told UPI in a phone interview. "The cardiovascular manifestations are not as much among children because they accumulate over time."
Analyzing data from the 2011 to 2012 National Health and Nutrition Examination Survey, the researchers found 41 percent of children between ages 3 and 11 and 34 percent of adolescents between ages 12 and 19 had detectible levels of cotinine, a metabolite of nicotine found in biological fluids and used as a marker of exposure to tobacco smoke.
When broken down demographically, the researchers found 68 percent of black children, 37 percent of white children and 30 percent of Hispanic children are exposed to secondhand smoke.
Socioeconomic status also appears to affect the likelihood of children being exposed to secondhand smoke, with 41 percent of children living below poverty line being exposed, compared to 21 percent of those living above it.
Thirty-seven percent of children whose parents rented their housing were exposed to smoke, while 19 percent of those whose parents own their housing were exposed to smoke, and the researchers expressed concern for those renting in multi-unit buildings where smoke can permeate walls and travel through air-conditioning systems.
Raghuveer echoed the recommendations of the study, saying taxes appear to discourage people from buying cigarettes, as do wider bans on where people can smoke.
Cessation programs are also effective because they prevent third-hand smoke -- toxic elements in smoke can get stuck to clothing and skin, exposing children to the danger of tobacco even in the absence of smoke -- and prevent more people from smoking.
"It's a matter of ramping up current efforts," Raghuveer said. "There is no real evidence supporting one method of reduction [over another]."