Changes in blood glucose and insulin sensitivity are evident several years before a patient is diagnosed with type 2 diabetes, according to findings from a team of European researchers (Tabák AG et al. Lancet. doi:10.1016/S0140-6736(09)60619-X [published online ahead of print June 8, 2009]).
The prospective occupational cohort study (called Whitehall II) involved 6538 British civil servants without diabetes at baseline. During a median follow-up period of nearly 10 years, 505 cases of type 2 diabetes were diagnosed. Glucose concentrations increased and insulin sensitivity decreased as much as 3 to 6 years before diagnosis of diabetes. Starting 4 years before diagnosis, beta-cell function increased as the body attempted to compensate for increased glucose levels; it then decreased in the 3 years before diagnosis.
Stephenson J. Foreshadowing Diabetes. JAMA. 2009;302(3):246. doi:10.1001/jama.2009.1016