A new study from Washington University School of Medicine in St. Louis and the Veterans Affairs (VA) St. Louis Health Care System suggests that outdoor air pollution is increasing diabetes on a global scale. With over 420 million people on the planet suffering from diabetes, motivation to better understand the disease is high. Though the main causes of Type 2 diabetes are an unhealthy diet and inactive lifestyle, scientists are now beginning to understand the effect that air pollution may be contributing to the growing number of diagnosed cases.
"Our research shows a significant link between air pollution and diabetes globally," said Ziyad Al-Aly, MD, the study's senior author. "We found an increased risk, even at low levels of air pollution currently considered safe by the U.S. Environmental Protection Agency (EPA) and the World Health Organization (WHO). This is important because many industry lobbying groups argue that current levels are too stringent and should be relaxed. Evidence shows that current levels are still not sufficiently safe and need to be tightened."
The team established that air pollution exceeding 2.4 micrograms per cubic meter of air results in an increased risk of diabetes. Currently, the US sets its standards at 12 micrograms per cubic meter. Even though the US has overall pretty low levels of air pollution when compared to some other countries, the researchers know that that number is too high.
It is already known that air pollution can cause diseases like heart disease, stroke, cancer and kidney disease, but this new investigation plays into the consequences of particulate matter. Published in The Lancet Planetary Health, the research consolidated data about particulate matter, airborne microscopic pieces of dust, dirt, smoke, soot and liquid droplets and determined that these particles can reduce the production of insulin as well as cause inflammation. Researchers overlapped data from 1.7 million US veterans who did not have histories of diabetes with data from the EPA's land-based air monitoring systems and some NASA satellites.
They found that in the United States, 150,000 new cases of diabetes per year resulted due to air pollution; this was a total of 350,000 years of healthy life lost annually. Globally, the numbers soared, with 2016 results showing 3.2 million new diabetes cases attributed to air pollution, or 14% of all new diabetes cases globally that year.
This information gives hope for the future. If we can successfully reduce air pollution worldwide, the number of new cases of diabetes (and other health conditions) may drop. However, this may not be easy for all countries. Unsurprisingly, findings from the study show that there are more cases of polluted-attributed diabetes in lower-income countries. India, Afghanistan, Papua New Guinea and Guyana had particularly higher numbers while countries that have more money and prioritize clean-air policies, like France, Finland and Iceland, show lower numbers.