Associations between long-term exposure to ultrafine particles and type 2 diabetes: A large-scale, multicenter study in China.

Few studies have examined the associations between long-term exposure to ultrafine particles (UFP) and type 2 diabetes (T2DM). This study aimed to investigate the impact of long-term UFP exposure on diabetes prevalence and stages, as well as glycemic markers, using data from a large multi-center cohort collected from 2017 to 2021. The health outcomes assessed included diabetes prevalence and stages (normoglycemia, prediabetes, and diabetes), as well as glycemic markers, i.e., fasting blood glucose (FPG) and glycated hemoglobin (HbA1c). The three-year average UFP concentration prior to baseline was used as the long-term UFP exposure level. This cross-sectional study included 93,990 participants, with a diabetes prevalence of 10.97 %. An interquartile range increase in UFP was significantly associated with diabetes prevalence and stages, with ORs of 1.20 (95 % CI: 1.14, 1.26) and 1.11 (95 % CI: 1.07, 1.44), respectively. Specifically, for comparison between normoglycemia and prediabetes, and between prediabetes and diabetes, the corresponding ORs were 1.01 (95 % CI: 0.96, 1.04) and 1.24 (95 % CI: 1.17, 1.31), respectively. UFP exposure was also significantly associated with elevated levels of FPG and HbA1c. These findings suggest that long-term UFP exposure may be a potential risk factor for diabetes with larger risks in the prediabetes population.