Air pollution increases the risk of diabetes, particularly when exposure is long-term, according to emerging evidence.

A 2025 study from China involving 18,606 middle-aged and elderly adults found that long-term exposure to air pollution – both indoor and outdoor – significantly increased their risk of metabolic disorders like diabetes.

“This national cohort study shows that outdoor air pollution -– particularly PM1, PM2.5, and their chemical components – is an important environmental factor contributing to GMDs [glycolipid metabolic disorders],” according to the study, published in the World Journal of Diabetes.

Long-term exposure results in higher toxicity than short-term exposure.

This is one of a series of studies on the association between diabetes and air pollution produced in the past decade.

But researchers need to factor in several variables that could affect the results, such as sugar consumption, genetics and socio-economic conditions, Arindam Roy, climate science advisor at the Clean Air Fund, told Health Policy Watch.

“It’s difficult in terms of getting the data right, because you need to have a substantial amount of air quality monitors, or by any means, you need air quality information at a very high resolution. You also need health information at a very high resolution,” Roy said.

A 2022 study published in The Lancet concluded that, “in 2019, approximately a fifth of the global burden of type 2 diabetes was attributable to PM2.5 exposure.”

While type 1 diabetes is an autoimmune condition where the body attacks the insulin-producing cells, type 2 diabetes is influenced by environmental factors, diet and exercise.

Solid fuel not linked to higher diabetes risk

The 2025 study from China looked at air pollution as a result of various particle sizes ranging from PM1, PM2.5 and PM10. It studied the health impact over a five-year (long-term) and one-year (short-term) period.

Researchers found that while any kind of exposure to air pollution increases the risk of developing diabetes, the impact of long-term exposure was strongest.

The terms short-term and long-term are not very well defined, but short-term usually refers to episodic high exposure around events like wildfire or a season of high exposure. Long-term duration is usually measured in a timeline of years.

The use of solid fuels for cooking, which is known to push up indoor air pollution, did not appear to increase the risk of developing diabetes in the China study.

The researchers concluded that the lack of any association with air pollution from solid fuels and metabolic disorders like diabetes “underscores the urgent need for targeted interventions to improve outdoor air quality and reduce metabolic risks at the population level.”

This result is also in line with another four-year multi-country trial, the Household Air Pollution Intervention Network (HAPIN), which studied 3,200 households in Guatemala, India, Peru, and Rwanda. Study participants switched from cooking on solid stoves to LPG but did not see any significant health gains – a result that surprised the study’s researchers.

Also read: Switching from Biomass to LPG Failed to Show Health Gains in Four-Country Study of Household Air Pollution

Lack of adequate ground monitors is getting in the way

A 2022 study from Denmark that studied 1.9 million people found that exposure to all air pollutants was associated with a higher risk of diabetes.

Studying the health impacts of air pollution requires two sets of data – one on air pollution, and the other on health. Currently, very few countries have both these datasets at hand.

Air pollution data requires better monitoring on the ground using ground monitors.

“We do have satellite-based or modelled air quality data, which are very high resolution, like one kilometre or so. But again, you need ground-based monitors to validate the data in those particular areas to give you more confidence in your research,” Roy said.

Sharing health data is also often fraught with ethical challenges, apart from the fact that institutions in many countries might not even have them in digital format. Then there is the issue of both health and environmental researchers working in silos.

Evidence is lagging in most parts of the world

High-quality evidence on air pollution’s impact on health is available only in some countries and regions, such as the US, UK, and Europe.

“China is one example of a country where AQ (air quality) data has been improved during the recent past. There are other countries as well where accessibility has improved,” Roy said.

Africa in particular, and much of the developing world in general, suffers from the lack of evidence, researchers told HPW.

“The monitoring is not nationwide. A lot of the monitoring is centered in urban areas, and especially in the capital cities. Most of this monitoring is not national government activities,” said Gordon Dakuu, a Ghana-based analyst with Clean Air Fund.

“These are mostly project-based initiatives using Low-Cost Air Quality Sensors with a few Reference Grid monitoring. So, in Kenya, it is just Nairobi. In South Africa, it is Johannesburg, then when you come to Ghana, [it] is just Accra.”

The US administration’s cuts to the budget of its Environmental Protection Agency (EPA) have further disrupted air quality monitoring in several global locations.

Currently, the awareness of the air pollution-diabetes connection is also low.

“We tried engaging [people] on how air pollution can lead to some of these conditions. And you see, people’s perception of the linkages between air pollution and diabetes is still very weird,” Dakuu said.

“They think diabetes has to do with eating sugar, especially white sugar. So, I think there is still a lot for us to do as far as public health sensitization of people is concerned about the risk factors.”

Image Credits: isensusa/Unsplash, hailegebrael Berhanu/Unsplash.