New study says countries like India with no clean air policies particularly vulnerable
With an estimated 70 million diabetics, India is widely touted as the diabetes capital of the world. Rising pollution levels in the country have been making headlines every year.
Turns out, the two could be linked.
New research links outdoor air pollution — even at levels deemed safe — to an increased risk of diabetes globally. The findings are from a study from Washington University School of Medicine in St. Louis and the Veterans Affairs (VA) St. Louis Health Care System.
The study raises the possibility that reducing pollution may lead to a drop in diabetes cases in heavily polluted countries such as India.
Diabetes is one of the fastest growing diseases. The main drivers of diabetes include eating an unhealthy diet, having a sedentary lifestyle, and obesity, but the new research indicates the extent to which outdoor air pollution plays a role.
“Our research shows a significant link between air pollution and diabetes globally,” said Ziyad Al-Aly, MD, the study’s senior author and an assistant professor of medicine at Washington University.
“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,” he added.
The findings have been published in The Lancet Planetary Health.
While growing evidence has suggested a link between air pollution and diabetes, researchers have not attempted to quantify that burden until now. “Over the past two decades, there have been bits of research about diabetes and pollution,” Al-Aly said. “We wanted to thread together the pieces for a broader, more solid understanding.”
To evaluate outdoor air pollution, the researchers looked at particulate matter, airborne microscopic pieces of dust, dirt, smoke, soot and liquid droplets.
Previous studies have found that such particles can enter the lungs and invade the bloodstream, contributing to major health conditions such as heart disease, stroke, cancer and kidney disease. In diabetes, pollution is thought to reduce insulin production and trigger inflammation, preventing the body from converting blood glucose into energy that the body needs to maintain health.
Overall, the researchers estimated that pollution contributed to 3.2 million new diabetes cases globally in 2016, which represents about 14 percent of all new diabetes cases globally that year. They also estimated that 8.2 million years of healthy life were lost in 2016 due to pollution-linked diabetes, representing about 14 percent of all years of healthy life lost due to diabetes from any cause. (The measure of how many years of healthy life are lost is often referred to as “disability-adjusted life years.”)
Overall risk of pollution-related diabetes is tilted more toward lower-income countries such as India that lack the resources for environmental mitigation systems and clean-air policies
The Washington University team, in collaboration with scientists at the Veterans Affairs’ Clinical Epidemiology Center, examined the relationship between particulate matter and the risk of diabetes by first analyzing data from 1.7 million U.S. veterans who were followed for a median of 8.5 years. The veterans did not have histories of diabetes. The researchers linked that patient data with the EPA’s land-based air monitoring systems as well as space-borne satellites operated by the National Aeronautics and Space Administration (NASA).
They used several statistical models and tested the validity against controls such as ambient air sodium concentrations, which have no link to diabetes, and lower limb fractures, which have no link to outdoor air pollution, as well as the risk of developing diabetes, which exhibited a strong link to air pollution. This exercise helped the researchers weed out spurious associations.
Then, they sifted through all research related to diabetes and outdoor air pollution and devised a model to evaluate diabetes risk across various pollution levels.
Finally, they analyzed data from the Global Burden of Disease study, which is conducted annually with contributions from researchers worldwide. The data helped to estimate annual cases of diabetes and healthy years of life lost due to pollution.
The researchers also found that the overall risk of pollution-related diabetes is tilted more toward lower-income countries such as India that lack the resources for environmental mitigation systems and clean-air policies.
For instance, poverty-stricken countries facing a higher diabetes-pollution risk include Afghanistan, Papua New Guinea and Guyana, while richer countries such as France, Finland and Iceland experience a lower risk. The U.S. experiences a moderate risk of pollution-related diabetes.
