New York – Children exposed to second-hand smoke at home may be more likely to have learning and behavioural problems, according to a US study.Of more than 55 000 US children younger than 12 years, 6% lived with a smoker – and those children were more likely to have ADHD compared to children in smoke-free homes, the study, published in Paediatrics, found.Even after accounting for a number of possible explanations, such as parents’ income and education levels, second-hand smoke was still tied to a higher risk of behavioural problems, said Hillel Alpert at the Harvard School of Public Health, one of the researchers.

The findings don’t prove a smoke-filled home is to blame, because there are other factors that the study didn’t look at that may also be to blame – but it may give parents yet another reason to keep their homes smoke-free.

Health experts already recommend that children be shielded from second-hand smoke for health reasons, since it can increase their risk of respiratory infections, severe asthma and sudden infant death syndrome.