May 9, 2013

expert reaction to new research on air pollution and insulin resistance in children

Research published in Diabetologia implied that growing up in areas where air pollution is increased raises the risk of insulin resistance in children.

Professor Jon Ayres, Professor of Environmental and Respiratory Medicine, University of Birmingham, said:

“These results should be treated with caution.  As the authors point out, their measurements of fasting blood insulin levels and estimations of air pollution levels were not taken at the same time.  Therefore these results should be regarded with caution and a larger and methodologically more secure study needs to be done to confirm the possible link between air pollution from traffic emissions and insulin resistance in children.” 

Professor Frank Kelly, Professor of Environmental Health, King’s College London, said:

“Urbanisation and dependence on motorised transport has increased our exposure to traffic pollution.  These include toxic air pollutants and noise for which there is increasing evidence for adverse health effects. Near-road pollution is a complex mixture of particle and gas phase components that are influenced by both exhaust and non-exhaust vehicle emissions.  

“The study by Thiering and colleagues builds upon an increasing literature which links children’s health with poor air quality. Children are particularly vulnerable to the effects of air pollution because 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. Breathing the same pollutant concentrations, children may have a 2-to 4-fold higher dose reaching the lung compared with adults. Of particular relevance to these new findings are the Southern California Children Health studies, which demonstrate the relationship between long-term exposure to air pollution and decreased lung growth among children.

“From a pollution point of view most attention and focus has been paid to particulate matter (PM) pollution from traffic while the impact of the gaseous pollutant, nitrogen dioxide (NO2), has been largely overlooked.  It is of interest that this new study by Thiering and colleagues demonstrates that both PM and NO2 are linked to increased risk of insulin resistance in children. This finding is especially relevant for cities in the UK such as London which regularly exceeds current EU limit values for NO2.  Only last week the Supreme Court ruled that the UK Government was not doing enough to minimising NO2 pollution and protecting the health of its citizens.

“In attempting to explain their findings of how traffic related air pollutants which enter the body through the lung could have effects on distant organs such as the pancreas and kidney Thiering and colleagues remind us that PM and NO2 both cause oxidative stress – a biological response capable of causing cellular damage which could result in increased insulin resistance.  If correct, this is a timely reminder for Government that as well as improving air quality in our cites they need to ensure children have access to quality school meals which include fresh fruit and vegetables to ensure our children have good supply of antioxidants which will help protect them from the worst effects of traffic pollution.”

‘Long-term exposure to traffic-related air pollution and insulin resistance in children: results from the GINIplus and LISAplus birth cohorts’ by Thiering et al. published in Diabetologia on Thursday 9th May.