Secondhand smoke can affect teens' tests

PHILADELPHIA, Sept. 20 (UPI) -- Teens exposed to secondhand smoke at home are at increased risk of failing tests in school, a U.S. and British study suggests.

Lead author Bradley Collins of Temple University in Philadelphia, and colleagues at Oxford University and University of Bristol in England, found that exposure to secondhand smoke at home decreased the odds of passing standardized achievement tests by 30 percent in high school students 16- and 18-year-olds.

However, the study also found that when examining the effects of prenatal tobacco exposure and secondhand smoke together -- prenatal exposure did not influence test performance, the Journal of Adolescent Health reported.

The researchers analyzed data from 6,380 pregnant women and children from the 1958 British National Child Development Study, and said they found it interesting that secondhand smoke exposure trumped prenatal exposure.

The researchers note that U.S. and British smoking statistics are similar -- approximately one-third of women in their childbearing years are smokers; 10 percent to 15 percent of women report smoking during pregnancy; and up to 60 percent of children may be exposed to secondhand smoke at home.

The study did not reveal why secondhand smoke influenced failure on school tests.