31 Aug 2026 (Navroze Bureau) : India’s growing diabetes burden may have another emerging risk factor: climate change. A new review suggests that rising temperatures, air pollution and extreme weather can disrupt the body’s ability to regulate blood sugar and may add to established diabetes risks such as obesity, unhealthy diets and physical inactivity.
The researchers caution that climate-related exposures are not yet proven to be a direct cause of diabetes in every individual. However, the evidence suggests they can create additional metabolic stress, potentially increasing vulnerability to the disease and making diabetes harder to manage.
India Faces a Double Challenge
India already has one of the world’s largest diabetes burdens. The review estimates that around 101 million people in India were living with diabetes in 2023, while adult prevalence is roughly 11%. At the same time, large parts of the country face increasing exposure to extreme heat and unhealthy air.
That combination is important because climate-related stress can interact with existing metabolic risk factors rather than acting in isolation.
Air Pollution May Affect Insulin Signalling
Among the climate-related exposures examined, fine particulate air pollution, particularly PM2.5, has some of the clearest evidence linking environmental exposure with metabolic problems.
PM2.5 particles can travel deep into the lungs and trigger oxidative stress and inflammation. Once these inflammatory processes spread through the body, they may interfere with insulin signalling in tissues such as the liver, muscles and fat tissue, potentially contributing to insulin resistance.
A prospective study involving people in Chennai and Delhi found that every 10 microgram-per-cubic-metre increase in PM2.5 exposure was associated with higher fasting glucose and HbA1c levels and approximately a 22% higher risk of type 2 diabetes. The finding represents an association, not proof that pollution alone caused diabetes.
Heat Puts the Body Under Metabolic Stress
Extreme heat can affect blood-sugar regulation through a different pathway.
When temperatures rise, the body works harder to cool itself. Prolonged heat exposure can cause dehydration, reduced blood volume and electrolyte disturbances. Heat stress can also activate the body’s stress-response systems, increasing hormones such as cortisol, adrenaline and glucagon.
These hormones can stimulate the liver to release more glucose and can worsen insulin resistance. In people who already have diabetes, severe heat and dehydration can therefore contribute to dangerous fluctuations in blood sugar and increase the risk of acute complications.
Extreme Weather Can Disrupt Diabetes Care
The climate-diabetes connection is not only biological.
Floods, storms and other extreme weather events can damage hospitals, roads and pharmacies. Patients may struggle to attend appointments, obtain medicines or maintain regular glucose monitoring.
For people dependent on insulin or other regular medication, even temporary disruption can make disease management substantially harder. The review notes that healthcare interruptions can continue well after an extreme weather event has passed.
Food Security Is Another Link
Climate change can also affect diabetes indirectly by disrupting food systems.
Changes in rainfall, heat and extreme weather can affect crop yields, food prices and the availability of diverse foods. For vulnerable households, these pressures can make healthier diets more difficult to maintain.
This means climate change can potentially influence metabolic health through several connected pathways: heat exposure, pollution, physical activity, food security and access to healthcare.
Why Existing Diabetes Risks Still Matter
The review does not suggest that climate change has replaced conventional diabetes risk factors.
Genetics, ageing, excess body weight, physical inactivity, diet, smoking and socioeconomic conditions remain major contributors to type 2 diabetes.
Instead, researchers describe climate-related exposures as additional risk modifiers that may compound those existing vulnerabilities.
India’s Heat Problem Makes the Issue More Important
India has experienced increasingly frequent episodes of extreme heat, while access to air conditioning remains limited.
The review notes that only around 8–10% of Indian households own an air conditioner, meaning large sections of the population may have limited protection from prolonged high temperatures.
Outdoor workers, people living in poorly ventilated housing and those with existing metabolic or cardiovascular conditions may face particular challenges during severe heat.
The Science Is Still Evolving
Experts caution against interpreting the findings as proof that climate change directly causes diabetes.
The researchers say India needs more long-term studies capable of examining repeated exposure to heat and air pollution together and determining how these factors influence diabetes incidence, blood-sugar control and complications across both urban and rural populations.
Existing research nevertheless supports the broader concern that people with diabetes are especially vulnerable to climate-related heat, pollution and extreme weather.
What This Could Mean for Public Health
The emerging evidence suggests that diabetes prevention may increasingly need to consider environmental conditions.
That could include stronger air-quality monitoring, heat-warning systems, access to cooling and hydration, climate-resilient healthcare facilities and better planning for medicine supplies during floods and other disasters.