Living near a busy road is associated with a dramatic increase in the risk of childhood autism, a US study has shown.
Early exposure to traffic pollution, either in the womb or during the first year of life, more than doubled a child's chances of having the disorder, scientists found.
Children from homes with the highest air pollution levels were three times more at risk than those from less exposed homes.
Experts described the finding as “important” but stressed it did not prove a causal link between pollutant chemicals and impaired brain development.
The findings are published in the latest online edition of the journal Archives of General Psychiatry. However, British experts have said the findings should be interpreted with caution.