Air pollution linked to 3.2 million diabetes cases in a year

Type 2 diabetes has always been associated with genetic and lifestyle factors such as obesity and lack of exercise. Now, a new study has shown that air pollution, even at levels considered safe, caused one in seven new cases of diabetes in 2016.


While earlier studies have suggested a link between diabetes and pollution, this study published in The Lancet Planetary Health is significant as it quantifies the burden. It estimates that pollution contributed to 3.2 million new diabetes cases (14% of the total) globally in 2016.


What’s worrying is that 14 of the world's 20 most-polluted cities are in India, according to the World Health Organization (WHO). “Air pollution could explain diabetes in patients who otherwise follow a healthy lifestyle,” said diabetes expert Dr Anoop Misra of Fortis.” US researchers found that pollution triggered inflammation which reduces the body's insulin production. Dr Misra says that Indians are more prone to inflammation than people in the West. “Combine this with air pollutants, and the risk becomes much higher,” he adds.

The country is already dealing with a fast-rising incidence of diabetes. The Indian Council of Medical Research found that prevalence had increased by 64% in the past 25 years.

Diabetologist Dr Ambrish Mithal agrees that inflammation is one of the factors in developing diabetes, in addition to other risk factors like poor diet, obesity and sedentary lifestyle. However, he says more studies are needed to establish the link between pollution and diabetes.

The Lancet study examined data from 1.7 million US veterans who did not have a history of diabetes and were followed for 8.5 years. Ziyad Al-Aly, the study's senior author, said the research found an increased risk even with levels of air pollution currently considered safe by the US Environmental Protection Agency (EPA) and the 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.

Mumbai-based endocrinologist Dr Shashank Joshi said pollutants such as suspended particulate matter PM2.5 contain endocrine-disrupting chemicals. "A recent ICMR-INTAB study has shown the increasing rate of diabetes across north Indian cities that have a higher rate of air pollution,'' he added.

However, Dr Joshi wasn't in complete agreement with the Lancet study's hypothesis that reducing pollution would reduce the incidence of diabetes. "Scandinavian countries have the cleanest air and the best environmental laws and while they don't have diabetes type 2, they have high incidence of type I diabetes and other autoimmune conditions. Cleanliness has its own set of problems,'' he said.