The findings come from the 2013 CDC National Youth Tobacco Survey, which included more than 18,000 adolescents in grades 6 to 12 in public and private schools around the country. The students completed written questionnaires about whether they have used tobacco products including cigarettes, e-cigarettes, pipes, hookahs and chewing tobacco. The survey assessed secondhand smoke exposure by asking students whether they had been around someone in the last seven days who smoked tobacco in their home, at school or other locations. It did not ask whether they had been around people using e-cigarettes.
Among the adolescents that reported never using tobacco, 48% had been around secondhand smoke in the past week. The most common places for exposure were public areas, including restaurants and parks, where about 35% of study participants reported being exposed. Another 17% and 27% were exposed at school and work, respectively. Although only 15% were exposed in their home and another 15% in cars, these were the most common sites for daily secondhand smoke exposure.
"The findings reinforce that secondhand smoke is still a problem in this country. Half of middle school and high school students are exposed to something we know is harmful to their health and is completely preventable," said Brian King, deputy director for research translation in the CDC Office on Smoking and Health. King led the research, which was published on Monday in the journal Pediatrics
Children who are exposed to secondhand smoke are at increased risk of asthma, lung infection and ear disease, among other health conditions.
"We still have a far way to go in this country protecting people from secondhand smoke in public areas," King said. To date, 28 states and the District of Columbia have passed laws that prohibit smoking in public places and workplaces such as restaurants and bars. Around 700 communities have also passed local laws. Altogether, about half the U.S. population is covered by state and local smoke-free laws.
There is growing momentum in the last several years to create policies that would at least prevent smoking in multi-unit or apartments buildings, King said. A handful of communities in California have municipal laws prohibiting smoking in all apartment buildings, and most states have some municipal laws that prohibit smoking in publicly owned apartment buildings. Eight states have also banned smoking in cars when children are present.
King and his colleagues were not able to determine from the National Youth Tobacco Survey whether secondhand smoke exposure was lower in states and communities that had smoke-free laws.
Although the researchers did not address how the youth were exposed, "we could surmise that it's family member and friends," King said.
Not surprisingly, the study found that secondhand smoke exposure was greater in adolescents who use tobacco themselves. Among this group, 80% of current and 65% of former tobacco users had recently been exposed to secondhand smoke. Adolescents who used tobacco are more likely to have family and peers that engage in this behavior, King said.
The study found that adolescent girls were more likely than boys to be around secondhand smoke. There could be a couple reasons for this. The authors note that female youth tend to be more aware than their male counterparts of the harms of secondhand smoke, and could thus be more likely to remember any exposure they had. In addition, high school males are more likely than females to use tobacco, and could expose girls they socialize with, King said.
Raising the smoking age?
The rate of secondhand smoke exposure at schools, which was about 17%, was particularly surprising, said Dr. Karen Wilson, an associate professor of pediatrics at Children's Hospital Colorado who was not involved in the current study. "I thought smoking bans on campus were a bit more effective than they are. Schools need to look at their bans and see what they need to be more effective," Wilson said.
States and municipalities vary in whether they prohibit tobacco use on school campus, and often laws that do exist don't cover products such as e-cigarettes, which are becoming increasingly common among youth, King said.
The American Academy of Pediatrics recommends increasing the minimum age to buy tobacco products and e-cigarettes to 21 nationwide
. This would mean that no high school students would be old enough to buy tobacco, said Wilson, who is chair of the Academy's section on tobacco control. "Many children under 18 get tobacco from those over 18 at their school, she said.
Wilson recommends that parents talk with their children about the dangers of secondhand smoke and how they can avoid it, such as simply moving away from area if others are smoking. Exposure to secondhand smoke "can impact their lung and cardiovascular health, possibly even in the short-term," Wilson said.
Adolescents may also face special risks from secondhand smoke as compared with younger children, Wilson said. There is some evidence that the exposure to nicotine primes their brains and makes them more likely to be addicted to nicotine in the future.
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