Elevated whole blood arsenic level is associated with type 2 diabetes in coal-burning areas in Guizhou

The potential association between coal-burning arsenic exposure and type 2 diabetes (T2D) was examined through a case control study, conducted in coal-burning arsenic poisoning areas in the Guizhou Province. This study included patients diagnosed with type 2 diabetes. Control subjects without type 2 diabetes were recruited randomly after gender and age 1:1 matching. All subjects completed questionnaire surveys and underwent physical examination and whole blood arsenic level testing. The whole blood arsenic level was associated with a significant increase in the risk of type 2 diabetes (75th versus 25th, adjusted OR = 1.76, 95% CI: 1.03-3.01). However, a nonlinear relationship was observed between the blood arsenic level and type 2 diabetes. The risk of type 2 diabetes increased with blood arsenic levels above 3.69 μg/L (Log As ≥0.57). The subgroup analysis revealed that blood arsenic levels were associated with significantly increased risk of type 2 diabetes in people who ever smoked (P < .05), particularly those who smoked ≥15 years (adjusted OR = 3.15, 95% CI: 1.9-7.28). Therefore, prolonged arsenic exposure, even at a low level, is associated with a higher prevalence of type 2 diabetes in a nonlinear pattern. Blood arsenic levels less than 3.69 μg/L may be considered safe with respect to the risk of T2D. However, smoking, particularly smoking ≥15 years, may be associated with the development of diabetes in patients with arsenic exposure.