Air pollution 'a diabetes risk for children'
10th May 2013 - Children growing up in areas where there are high levels of air pollution may be at increased risk of insulin resistance and pre- diabetes, according to new German research.
However, one UK expert cautions that it is too early to draw firm conclusions that being exposed to traffic fumes could lead to an increased risk of diabetes.
Normally, food is absorbed into the bloodstream in the form of sugars such as glucose and other basic substances. The increase in sugar in the bloodstream signals the pancreas to increase the secretion of a hormone called insulin. This hormone attaches to cells, removing sugar from the bloodstream so that it can be used for energy.
In insulin resistance, the body's cells have a diminished ability to respond to the action of the insulin hormone. To compensate for the insulin resistance, the pancreas secretes more insulin.
People with insulin resistance, over time, can develop diabetes as even the high insulin levels can no longer compensate for elevated levels of sugar in their blood.
Health risks from pollution
Previous studies have identified links between air pollution and other chronic conditions such as heart disease and atherosclerosis, also known as hardening of the arteries. However, studies into whether long-term exposure to traffic-related air pollution could be associated with type 2 diabetes in adults have produced inconsistent results, while studies on insulin resistance in children are scarce.
The researchers set out to explore the possible association between air pollution and insulin resistance in children. They collected fasting blood samples from 397 10-year-old children who were enrolled on two German health studies. They estimated how much pollution these children were exposed to by checking the addresses where they were born and analysing emissions of traffic fumes in those areas.
The researchers found that levels of insulin resistance were greater in children with higher exposure to air pollution. For instance, insulin resistance increased by 17% for every 10.6 µg/m3 rise in nitrogen dioxide (NO2) and 19% for every 6 µg/m3 increase in particulate matter of up to 10 μm in diameter.
They found that proximity to the nearest major road increased insulin resistance by 7% per 500 metres.
Co-author Joachim Heinrich from the German Research Centre for Environmental Health says in a statement: "To our knowledge, this is the first prospective 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 several confounding factors, including socioeconomic status, BMI [body mass index] and passive smoking."
The study is published in Diabetologia, the journal of the European Association for the Study of Diabetes.