May 6, 2002 -- Children who are exposed to tobacco smoke may suffer in the classroom. A new study shows that even low-level exposure to secondhand smoke can cause drops in mental skills such as reading, math, logic, and reasoning in children and adolescents.
Researchers say it's the biggest study ever to look at the effects of environmental tobacco smoke exposure on children's health. The findings were presented today at the annual meeting of the Pediatric Academic Societies in Baltimore.
The study found many of the children's academic abilities were strongly related to environmental smoke exposure. The greater the exposure to secondhand tobacco smoke, the greater the decline in reading and reasoning skills -- even at very low levels of tobacco exposure.
"We estimate that more than 13 million children in the United States are exposed to levels consistent with the adverse effects seen in this study," says study author Kimberly Yolton, PhD, researcher at the Children's Environmental Health Center at Cincinnati Children's Hospital Medical Center, in a news release.
For the study, environmental tobacco exposure was determined by measuring levels of cotinine, a marker of tobacco exposure, in the blood of 4,400 children between the ages of 6 and 16. The children's thinking and academic abilities were also assessed using standardized intelligence and achievement tests.
As cotinine levels in the children's blood rose, scores on reading and math tests fell. A related decline was also found in reasoning tests.
But researchers say they were surprised to find that the tobacco-related declines were even greater at lower levels of environmental tobacco smoke exposure.
"These declines may not be clinically meaningful for an individual child, but they have huge implications for our society because millions of children are exposed to environmental tobacco smoke in the U.S.," says Yolton.