Serum cystatin C and the incidence of type 2 diabetes mellitus

To examine the association of serum cystatin C with the incidence of type 2 diabetes mellitus over a 15 year follow-up period. The 15 year cumulative incidence of diabetes was measured in a cohort of Beaver Dam Eye Study participants (n = 3,472, 1988-2003). A person was defined as developing diabetes (a positive history of diabetes mellitus treated with insulin, oral hypoglycaemic agents and/or diet, or elevations in glycosylated haemoglobin levels) in the absence of diabetes at baseline. The relation of cystatin C and other risk factors to incident type 2 diabetes was determined using discrete time extension of the proportional hazards model. The 15 year cumulative incidence of diabetes was estimated to be 9.6%. After controlling for age, sex, body mass index, smoking status, glycosylated haemoglobin, proteinuria, chronic kidney disease status and hypertension status, serum cystatin C at baseline was associated with the 15 year cumulative incidence of type 2 diabetes (OR per log of cystatin C unit 2.19, 95% CI 1.02-4.68). These findings show a positive relationship of serum cystatin C levels with the incidence of type 2 diabetes mellitus independently of confounding risk factors. The findings strongly suggest the need for further evaluation of the potential importance of cystatin C in the pathogenesis of type 2 diabetes mellitus.