Secondhand smoke is a health threat to children. Not only has secondhand smoke been linked to increased risks of asthma, as well as bronchitis, pneumonia and other respiratory infections; new research shows it may also impact school grades.
A study of Hong Kong students suggests children and teenagers exposed to secondhand smoke at home may get poorer grades than their peers from smoke-free homes.
Some 23,000 children and young adults were asked about smoking and their home environment. The study in the Journal Pediatrics found exposure to secondhand smoke was linked to a 14 percent to 28 percent greater risk of poor school performance.
Studies have also found a connection between smoking during pregnancy and higher risks of childhood behavior problems and attention-deficit/hyperactivity disorder. Some research has also found that children exposed to cigarette smoke in the womb or at home may trail their peers when it comes to cognitive abilities like reasoning and remembering.
The findings do not prove smoke was the reason for the bad grades. But the researchers say it's possible that the toxic compounds in tobacco smoke (including lead, arsenic and ammonia) could affect children's cognitive abilities.
In the new study, researchers found 11- to 20-year-old non-smoking students, the one-third who lived with at least one smoker were more likely to describe their own school performance as poor.
Of students who said they were exposed to smoking at home at least five days a week, 23 percent said their school performance was poor compared with their classmates. That rate was 20 percent among kids who had less frequent secondhand-smoke exposure at home and 17 percent among those from smoke-free homes.
The researchers were able to account for other factors, like parents' education levels and the type of housing (markers of socioeconomic status). They found students' exposure to secondhand smoke was linked to a 14 percent to 28 percent greater risk of poor school performance (based upon frequency of exposure).