EXPOSURE to traffic fumes can set children on the road to diabetes, a study has shown.
Living near a busy road and increased levels of pollution from cars and lorries significantly raises the risk of insulin resistance in 10-year-olds.
The condition, which reduces the body's ability to control blood sugar with the hormone insulin, is a recognised precursor of Type 2 diabetes.
German researchers looked at the effect of two kinds of traffic pollution on 397 children.
Blood tests were taken and measurements made of pollution emissions in areas where the children lived.
For every defined step-rise in levels of nitrogen dioxide (NO2) and sooty particulate matter (PM) from diesel exhausts, the risk of insulin resistance increased by 17pc and 19pc respectively.
Dr Joachim Heinrich, from the German Research Centre for Environmental Health, said: "To our knowledge, this is the first study that investigated the relationship of long-term traffic-related air pollution and insulin resistance in children.
"Insulin resistance levels tended to increase with increasing air pollution exposure, and this observation remained robust after adjustment for socio-economic status, body mass index and passive smoking."
Previous research has linked air pollution, especially sooty particulates, with heart disease and premature death.
However, studies looking at associations between long-term exposure to traffic pollution and Type 2 diabetes in adults have been inconclusive.
"Oxidative stress caused by exposure to air pollutants may ... play a role in the development of insulin resistance," Dr Heinrich said.
Environmental health expert Professor Frank Kelly, from King's College London, pointed out that children were especially vulnerable to air pollution.
"They have a larger lung-to-body volume ratio, their airway epithelium is more permeable to air pollutants, and the lung defence mechanisms against particulate matter pollution and gaseous pollution are not fully evolved," he said.
"Breathing the same pollutant concentrations, children may have a two- to four-fold higher dose reaching the lung compared with adults."