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Even low levels of air pollution increase risk for diabetes

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July 7, 2018

Exposure to air pollution may contribute to millions of new diabetes cases globally each year, according to a study published in The Lancet Planetary Health.

“Our research shows a significant link between air pollution and diabetes globally,” Ziyad Al-Aly, MD, assistant professor of medicine at Washington University and the study’s senior author, said in a press release. “We found an increased risk, even at low levels of air pollution currently considered safe by the U.S. Environmental Protection Agency and 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.”

To evaluate the association of exposure to particulate matter with aerodynamic diameter less than 2.5 µm (PM2.5) with diabetes, researchers conducted a longitudinal cohort study consisting of 1,729,108 U.S. veterans who had no previous diabetes diagnosis. All participants were followed for a median of 8.5 years and Cox proportional hazard models were used.

According to the press release, researchers also linked the patient data to data from the EPA’s land-based air monitoring systems and NASA’s space-borne satellites.

To broaden the scope of the study from the U.S. population, researchers examined data from the annually conducted Global Burden of Disease study to estimate annual cases of diabetes and the effect pollution has on the loss of healthy years of life.

After adjusting for sociodemographic and health characteristics, researchers found that, in the cohort of U.S. veterans, a 10 µg/m³ increase in PM2.5 was associated with increased risk for diabetes (HR = 1.15; 95% CI, 1.08-1.22) and also with increased risk for death as the positive outcome control (HR = 1.08; 95% CI, 1.03-1.13).

Globally, air pollution contributed to approximately 3.2 million (95% uncertainty interval [UI], 2.2-3.8) incident cases of diabetes, approximately 8.2 million (95% UI, 5.8-11) healthy years lost and 206,105 (95% UI, 153,408-259,119) deaths related to diabetes in 2016, according to the researchers.

It was further determined that the risk for pollution-related diabetes varies geographically and is more prominent in lower-income countries due, in part, to a lack of environmental resources and clean-air policies, with the U.S. experiencing a “moderate risk of pollution-related diabetes,” according to the release.

“Over the past 2 decades, there have been bits of research about diabetes and pollution,” Al-Aly said in the release. “We wanted to thread together the pieces for a broader, more solid understanding.”

The findings follow several studies that have suggested a link between air pollution and diabetes risk. As Endocrine Today previously reported, prolonged ambient exposure, particularly exposure to nitrogen dioxide and PM2.5, increases the risk for development of type 2 diabetes in Hispanic children with overweight or obesity. After adjustment for confounders and body fat percent, higher nitrogen dioxide and PM2.5 exposures had adverse effects on the development of risk factors for type 2 diabetes, including insulin sensitivity, acute insulin response to glucose and disposition index. Beta-cell function fatigue was also evident with prolonged exposure to ambient air pollution. – by Melissa J. Webb

Disclosures: The authors report no relevant financial disclosures.