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Passive smoking dulls children's brains

Research by the US Children's Environmental Health Center team found that children exposed to passive smoking are likely to do worse at school than their peers.

The study found that the greater the exposure the worse the decline was and even slight exposure to tobacco smoke in the home notably lowered test results for reading and maths.

The researchers studied nearly 4400 children and, although they did not look at the effects over time as the children grew up, they did take into account other individual differences that might have skewed the results, such as parental education.

The researchers say that the findings support propositions that smoking in public places should be banned.

To measure exposure to environmental tobacco smoke, the scientists measured levels of cotinine, a substance produced when nicotine is broken down by the body. Children were included in the study if their readings were at or below 15 ng/ml - a level consistent with environmental tobacco smoke exposure.

The team, lead by Dr Kimberly Yolton, then looked at the children's cognitive and academic abilities in relation to skills such as maths, reading, logic and reasoning. The results showed a decline in the scores for each test in relation to the levels of cotinine.

Similarly, passive smoking was linked with nearly a two-point decline in a standardised maths test.

Dr Yolton said, "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."

She said more studies looking at the effects of passive smoking over time as children grow would be useful, but said she was confident that their findings stood.

She also said they added further incentive for countries to set public health standards to protect children from exposure to environmental tobacco smoke.

Last week, the UK government launched a series of hard-hitting TV advertisements to encourage smokers to quit, aimed particularly at those who are parents.

Amanda Sandford, research manager at Action on Smoking and Health, (ASH) said, "This shocking study strengthens the case for protecting children from second-hand smoke in all indoor environments.

"Banning smoking in all public places where children have access should be a priority, but all adults should refrain from smoking when children are present and that includes the home environment."

Dr Lawrence Whalley of the University of Aberdeen, who has led research showing that smokers' cognitive ability decreases with time, said the current study findings were very important.

"This fits in with what we know about the effects of tobacco smoke, even though it is not conclusive.

"Smoking is bad for children. Smoking in pregnancy causes low weight babies who do not fare as well in later years. It also causes respiratory diseases."

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