Air pollution could link to ADHD in children

A study published in Environmental Health Perspectives by researchers from the University of Cincinnati and Cincinnati Children's Hospital Medical Centre has suggested that there is a link between Attention Deficit Hyperactivity Disorder (ADHD) in children and air pollution.

The study suggests that exposure to high levels of air pollution at a young age can cause ADHD, as particulates narrow blood vessels, and can cause a build-up of toxins in the frontal cortex of the brain.

Doctor Nicholas Newman, from the Cincinnati Children's Hospital Medical Centre, said: "There is increasing concern about the potential effects of traffic-related air pollution on the developing brain. This impact is not fully understood due to limited epidemiological studies. To our knowledge, this is the largest prospective cohort with the longest follow-up investigating early life exposure to traffic-related air pollution and neurobehavioral outcomes at school age."

The research team followed children from birth until the age of seven; although 762 children began the study only 576 of them remained part of the study until its end. The children were chosen to be part of the study based upon their proximity to major roadways or bus routes and their family history.

The researchers used information on air pollution from traffic collected from the Cincinnati Childhood Allergy and Air Pollution Study and parents' Behavioural Assessment System for Children Second Edition, which assesses any symptoms of behavioural, attention and aggression problems and symptoms of ADHD. From this information they concluded that children exposed to high levels of air pollution within early life, especially their first year, were more prone to be 'at risk' of ADHD by the age of seven. These children will then require more monitoring throughout their development to assess whether they will later develop the disorder.

Dr Newman said: "Several biological mechanisms could explain the association between hyperactive behaviours and traffic-related air pollution, including narrowed blood vessels in the body and toxicity in the brain's frontal cortex."