Long-term exposure to air pollution may be a diabetes risk factor, researchers find

Researchers at the Helmholtz Zentrum Muenchen (HZM) have found that exposure to local air pollution increases the risk of developing insulin resistance for people with prediabetes or type 2 diabetes.
Along with colleagues from the German Centre for Diabetes Research (DZD), the scientists studied the link between increased air pollution in the Augsburg area and the risk prevalence ratio of type 2 diabetes.
Earlier this month, scientists from the University of Massachusetts Amherst suggested that early pollutants exposure could predispose people to diabetes but haven’t been able to demonstrate that the relationship is real.
This current epidemiology study, published in the journal Diabetes, provides evidence that the development of type 2 diabetes is not only due to lifestyle or genetic factors, but also due to traffic-related air pollution.
Professor Annette Peters from HZM and her colleagues analysed data from a two-year population based study (KORA) of nearly 3,000 participants who live in the city of Augsburg and two adjacent rural counties in Southern Germany.
In people with pre-existing type 2 diabetes, the researchers took fasting blood samples, in which they assessed various biomarkers for insulin resistance and inflammation.
These include beta cell function and insulin resistance (HOMA-IR), insulin secretio, HbA1c levels, and the appetite regulating hormone, leptin.
Non-diabetic individuals underwent an oral glucose tolerance test to detect whether their glucose metabolism was impaired.
The researchers then compared the data collected with the concentrations of air pollutants at the place of residence of each participant. They estimated the latter by taking particle measurements at 20 different sites and nitrogen dioxide readings in 40 sites.
At the time, air pollution levels in Augsburg were in the EU range but still above the proposed guidelines of the World Health Organisation (WHO).
The results revealed that those classified as having prediabetes are particularly vulnerable to the effects of air pollution.
The research team noted a 15.6 per cent increase in markers of abnormal beta cell function and insulin resistance, as well as 14.5 per cent higher insulin levels for every 7.9μg/m3 increment in air particle matter.
Similarly, elevations in nitrogen dioxide load correlated to higher HOMA-IR, blood glucose, insulin and leptin levels. However, no changes were seen for HbA1c.
The effect was found to be much more statistically significant for prediabetic individuals than with type 2 diabetes patients.
Commenting on the results, the researchers urged to consider outdoor air pollution as a more serious environmental factor causing diabetes and called for new government policies on acceptable air pollution threshold globally.