Air pollution can heighten risk of diabetes – study

Living with, and inhaling, air pollution can raise the risk of also having type 2 diabetes, a study has argued.

The research conducted in the Indian cities of Delhi and Chennai concluded that inhaling air containing high amounts of PM2.5 particles led to higher blood sugar levels and increased type 2 diabetes incidence.

The study, published in the journal BMJ Open Diabetes Research & Care, is part of ongoing research into chronic diseases in India and is believed to be the first study to focus on the link between exposure to ambient PM2.5 and type 2 diabetes.

It has come as air pollution levels in Delhi in November spiked to 100 times the limit deemed healthy by the World Health Organization.

The study found average annual PM2.5 levels in Delhi were 82-100μg/m³ and in Chennai were 30-40μg/m³, many times the WHO limits of 5μg/m³.

The researchers then followed a cohort of 12,000 men and women in Delhi and Chennai from 2010 to 2017 and measured their blood sugar levels periodically.

Using satellite data and air pollution exposure models, they determined the air pollution in the locality of each participant in that timeframe.

They found that one month’s exposure to PM2.5 led to elevated levels of blood sugar and prolonged exposure of one year or more led to an increased risk of diabetes. For every 10μg/m³ increase in annual average PM2.5 level in the two cities, the risk for diabetes increased by 22%, they concluded.

“Given the pathophysiology of Indians – low BMI with a high proportion of fat – we are more prone to diabetes than the western population,” Siddhartha Mandal, lead investigator of the study and a researcher at Centre for Chronic Disease Control, Delhi, told The Guardian newspaper.

The combination of air pollution with lifestyle changes in the past 20 to 30 years was fuelling the increasing burden of diabetes, he added.

Another study on the same cohort in Delhi found average annual exposure to PM2.5 in Delhi (92μg/m³) led to an increase in blood pressure levels and higher likelihood of developing hypertension.