ReutersAir pollution could be responsible for 3.2 million new cases of type 2 diabetes every year globally, suggests a new analysis.
“We estimate that about 14 percent of diabetes in the world occurs because of higher levels of air pollution, that’s one in seven cases,” said senior study author Dr. Ziyad Al-Aly of Washington University and the VA Saint Louis Health Care System in Missouri.
“Risks exist at levels that are below what’s now currently considered safe by the Environmental Protection Agency (EPA) in the United States and also by the World Health Organization,” he told Reuters Health in a phone interview.
The tiniest form of particulate matter pollution, known as PM 2.5, is already associated with increased risk of heart disease, lung disease, kidney disease, and other noncommunicable diseases “and contributed to about 4.2 million premature deaths in 2015,” the study team writes in The Lancet Planetary Health. PM 2.5 is the mix of solid fragments and liquid droplets suspended in air that’s sometimes visible to human eyes as haze.
To look for a link between air pollution and type 2 diabetes, researchers analyzed data on 1.7 million U.S. veterans without diabetes, comparing PM 2.5 levels where they lived to their risk of being newly diagnosed with the disease during the next eight and a half years, on average. The researchers separated out the independent effect of air pollution by taking other diabetes risk factors, like obesity, into account.
Veterans’ annual average daily PM 2.5 exposure ranged from 5 to 22.1 micrograms per cubic meter (mcg/m3) of air. A 10-point increase in PM 2.5 concentration was associated with a 15 percent higher risk of developing diabetes, and an 8 percent higher risk of death. Risk of diabetes started to rise when pollution levels exceeded 2.4 mcg/m3, well below the EPA’s current standard of 12 mcg/m3 and the World Health Organization guideline of 10 mcg/m3.
Al-Aly and his colleagues then looked at worldwide PM 2.5 levels to estimate the total burden of diabetes due to air pollution. About 3.2 million new cases of diabetes, 8.2 million years of life lost to disability and more than 200,000 deaths annually were attributable to breathing dirty air, the authors calculated. Low-income and low-to-middle income countries bore the largest burden of air pollution-related diabetes.