Exposure to air pollution raises the risk of resistance to insulin, a typical warning sign of diabetes, according to a study of almost 400 German children.
Insulin resistance climbed by 17 percent for every 10.6 micrograms per cubic meter increase in ambient nitrogen dioxide and by 19 percent for every 6 micrograms per cubic meter increase in particulate matter in the study of 10-year-olds. The findings were published today in Diabetologia, the journal of the European Association for the Study of Diabetes.
The study adds to previous research that showed a link between traffic-related air pollution and the development of diabetes in adults. Those studies have shown that exposure to fine pollution particles that invade the breathing system and get into the heart and blood vessels increases inflammation, which may be linked to insulin resistance, said Joachim Heinrich of the German Research Center for Environmental Health, one of the study authors.
“Given the ubiquitous nature of air pollution and the high incidence of insulin resistance in the general population, the associations examined here may have potentially important public health effects,” Heinrich said in the published paper.
Diabetes occurs when blood-sugar levels are too high. In the Type 1 form of the disease, the body is unable to produce insulin, the hormone used to convert blood sugar into energy. In Type 2 diabetes, the body either can’t produce enough insulin or becomes resistant to its effects.
Type 2 diabetes tends to strike later in life, brought on by obesity and sedentary lifestyles. The Type 2 form accounts for 90 percent of the 347 million cases of diabetes globally, according to the World Health Organization in Geneva.
The researchers collected blood samples from the 397 children who were included in two German birth cohort studies. Exposures to air pollutants at their birth addresses were estimated by analyzing emissions from road traffic in the neighborhood, population density and land use in the area.
The measurements of blood insulin levels and estimates of pollution were taken at different times, so the findings “should be regarded with caution,” said Jon Ayres, a professor of environmental and respiratory medicine at the University of Birmingham in England. A larger study should be conducted to confirm the possible link, Ayres said in a statement.
A follow-up study at age 15 will explore how these findings evolve during and after puberty and the effect of moving to a cleaner area, Heinrich and his colleagues said.
The research was funded by the German Federal Ministry of Education and Research and the European Community’s Seventh Framework Program.
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