8-hydroxy-2-deoxy-guanosine (8-OHdG) is an early marker for endothelial cells DNA damage associated with oxidative stress in diabetes. Whether endothelial damage precedes increases in cholesterol and associated vascular disease in the early stages of metabolic disease is not known and would provide additional information on the mechanism leading to coronary artery and vascular disease. The study included One-hundred and twenty-seven participants attended the Diabetes Screening Clinic, at Charles Sturt University, Australia. 8-OHdG level was significantly greater in the impaired blood glucose group compared to control group. This increase was not associated with a significant reduction in erythrocyte reduced glutathione, which is an early marker for oxidative stress. Cholesterol levels were in the normal range which is often considered as the primary risk marker for development of cardiovascular disease and hence are actively treated. However, biochemical analysis showed more complicated changes develop much earlier than in the diabetes stage. Endothelial damage and oxidative stress, measured as 8-OHdG have significantly changed in the prediabetes cohort despite non-significant increases in cholesterol levels and lipid peroxidation suggesting that the mechanism of lipid peroxidation leading to oxidative DNA damage needs to be reviewed in conjunction with decreased protection against oxidative stress considered at the prediabetes stage.