Nearly half of nonsmoking Americans are breathing in cigarette fumes, but the percentage has declined dramatically since the 1990s, according to a government study released Thursday.
A main reason for the decline in secondhand smoke is the growing number of laws and policies that ban smoking in workplaces, bars, restaurants and public places, said researchers with Centers for Disease Control and Prevention.
Another factor is the drop in the percentage of adult smokers: It has inched below 20 percent, according to 2007 CDC data.
The new study found about 46 percent of nonsmokers had signs of nicotine in their blood in tests done from 1999 through 2004. That was a steep drop from 84 percent when similar tests were done in the late 1980s and early 1990s.
But health officials stopped short of celebrating. “It's still high,” said Cinzia Marano, one of the study's authors. “There is no safe level of exposure.”
Cigarettes cause lung cancer and other deadly illnesses not only in smokers, but also in nonsmokers who breathe in smoke, studies have shown.
For nonsmoking adults, secondhand smoke increases lung cancer risk by at least 20 percent and their heart disease risk by at least 25 percent. Children exposed to secondhand smoke are at increased risk of asthma attacks, ear problems, acute respiratory infections and sudden infant death syndrome, health officials say.
The new CDC report drew its data from the National Health and Nutrition Examination Survey, a unique government study that sends mobile trailers out to communities. Participants are asked about their health, get blood tests and physical exams.
The new report focused on data collected on about 17,000 nonsmokers in 1988 through 1994, and about the same number in 1999 through 2004. People ages 4 and older were included.
The exposures for children did not decline as dramatically as it did for adults. More than 60 percent of children ages 4 through 11 had recent exposure to cigarette smoke in the 1999-2004 period, the researchers found.