Outdoor air pollution even at levels deemed safe may be associated with an increased risk of diabetes globally, with India being at a greater risk due to lack of air cleaning policies, scientists said in a report in Lancet.

The findings showed that air pollution contributes to development of diabetes by reducing insulin production and triggering inflammation, which prevents the body from converting blood glucose into energy that the body needs. 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, Lancet Planetary Health report said.

"Our research shows a significant link between air pollution and diabetes globally," said Ziyad Al-Aly, from the University of Washington in St. Louis, US. "We found an increased risk, even at low levels of air pollution currently considered safe by the US 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," Aly explained. The researchers estimated that pollution contributed to a little more than three million new diabetes cases globally in 2016, which represented about 14 per cent of all new diabetes cases globally that year.

Nearly 10 million years of healthy life were lost in 2016 due to pollution-linked diabetes, representing about 14 per cent of all years of healthy life lost due to diabetes from any cause. According to the UN 2018 Sustainable Development Goals Report, an estimated 4.2 million people died as a result of high levels of ambient air pollution.

In the study, the team analysed data from more than one million participants without a history of diabetes, who were followed for a median of eight and a half years. They also looked at particulate matters, airborne microscopic pieces of dust, dirt, smoke, soot and liquid droplets. 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 study said.