Air pollution and temperature variability are associated with higher blood glucose levels
A European study involving GCAT identifies associations between air pollution, temperature variability and blood glucose levels in people without diabetes.
Diabetes is one of the most common metabolic diseases, and understanding the factors that may contribute to its development is important for improving prevention. Beyond diet and physical activity, there is growing evidence of the role of environmental exposures, although little is still known about how these factors may act together and be associated with changes in blood glucose levels.
To explore this question further, a new study published in Environment International has examined the relationship between air pollution, temperature, green spaces and glycated haemoglobin (HbA1c) levels -an indicator of average blood glucose levels over the previous two to three months. The analysis focused on people without diabetes, aiming to investigate the relationship between these environmental exposures and blood glucose levels before the onset of the disease.
The research was conducted as part of the European project EXPANSE, an initiative investigating how the urban exposome influences cardiometabolic and respiratory diseases, with the participation of the GCAT|Genomes for Life team at the Germans Trias i Pujol Research Institute (IGTP). Led by researchers from the Swiss Tropical and Public Health Institute (Swiss TPH) and the University of Basel, the study analysed data from 21,259 participants across nine European cohorts, including 5,464 from GCAT.
The findings show that greater exposure to air pollution, particularly PM10 particles, and increases in both temperature and temperature variability are associated with higher HbA1c levels. The analysis also identified interactions between these exposures, highlighting the importance of studying different environmental factors together. In contrast, no consistent associations were found with the presence of green spaces.
The authors also examined different environmental scenarios and estimated that improvements in air quality could be associated with reductions in HbA1c levels, while certain temperature changes linked to climate change could have the opposite effect. However, these two exposures are not independent, and the findings suggest that improving air quality becomes even more important in the context of climate change. In other words, the same reduction in air pollution has a greater beneficial effect on blood glucose levels under warmer temperature scenarios.
Regarding the potential mechanisms involved, the authors suggest that inflammation and insulin resistance may play a role, in line with previous scientific evidence. However, the study did not directly assess β-cell function or insulin secretion, but rather the relationship between environmental exposures and HbA1c levels.
"This study highlights the association between air pollution, temperature variability and HbA1c levels in people who have not yet developed diabetes. Including temperature in this approach is particularly relevant in the current context of climate change, where environmental exposures cannot be understood in isolation", explains Natàlia Blay, a postdoctoral researcher at GCAT and co-author of the study.
This perspective aligns with GCAT's research into the combined contribution of genetic and environmental factors to the risk of type 2 diabetes (T2D), led by Sílvia Bonàs-Guarch, principal investigator of GCAT's T2D research line and a Ramón y Cajal researcher.
Bonàs-Guarch comments: "These types of studies are essential for understanding the role of the exposome in the clinical heterogeneity of type 2 diabetes and investigating the mechanisms through which environmental factors may contribute to metabolic changes before the disease develops. In this context, at GCAT we are working to develop approaches that will allow us to assess how genetic predisposition, together with environmental exposures, may influence key physiological processes involved in the development of type 2 diabetes, such as the insulin secretory capacity of pancreatic beta cells".
The authors conclude that the findings reinforce the importance of improving air quality in the context of climate change, particularly in urban environments where high temperatures, air pollution and diabetes risk may coincide.
Reference
Jeong A, Edstorp J, Lovison G, Pickford R, Bergström A, Blay N, Bussalleu A, Dadvand P, Dalecka A, Imboden M, Kress S, Shen Y, Sochacka-Tatara E, Thiering E, Thorand B, Wolf K, Yu Z, de Cid R, Gehring U, Ljungman P, Magnusson P, Mikeš O, Pac A, Pikhart H, Rizzuto D, Schikowski T, Standl M, de Hoogh K, Melén E, Vermeulen RC, Vlaanderen JJ, Pershagen G, Peters A, Probst-Hensch N. Joint effects of air pollution and temperature on glycemia: an exposome analysis in European cohorts. Environ Int. 2026;216:110538. DOI: 10.1016/j.envint.2026.110538.