Although aortic stiffening is a strong predictor of cardiovascular mortality in diabetes, the underlying mechanisms have yet to be fully determined. In this cross-sectional study, we investigated determinants of aortic stiffness (aortic pulse wave velocity (PWV)) by measuring systemic collagen formation and turnover (plasma concentrations of procollagen type 1 N-propeptide (plasma P1NP)), cardiovascular autonomic function and systemic inflammation (hsCRP), in subjects with type 1 and 2 diabetes, in comparison with impaired glucose tolerance (IGT) subjects.

Fifty males with diabetes (35 type 2, 15 type 1) (age range 39–75yrs) and 21 males with IGT (age range 42–69yrs) were studied. Concentrations of P1NP were higher in type 1 in comparison with type 2 and IGT subjects (40.3±18.3 ug/L versus 28.1±12.5 ug/L versus 30.4±9.8 ug/L respectively, p<0.05) and were positively correlated with aortic PWV in type 1 (r=0.56, p<0.05) and type 2 subjects (r=0.46, p<0.01). Multiple regression analysis revealed age, hsCRP and P1NP to be stronger predictors of aortic PWV in diabetic subjects in comparison with other measured cardiovascular risk factors including autonomic dysfunction.

Our findings highlight the likely importance of increased collagen turnover as a predictor of aortic stiffening in diabetes. P1NP concentration was more strongly predictive of aortic stiffening than conventional risk factors with the exception of age. Further investigation is required to establish whether true differences in collagen turnover exist between type 1 and 2 diabetes.