Introduction: Type 2 diabetes (T2D) is characterised by accelerated vascular ageing, which changes arterial wall structure and hence artery mechanics (e.g., pressure-area (P-A)). Pulse wave velocity (PWV) is affected by both blood pressure and changes in wall mechanics. To better capture underlying changes in wall mechanics in T2D, we aimed to disentangle the vascular ageing phenomena (characterised by PWV) from pressure effects.

Methods: We studied young (<55y) and older (>70y) individuals without and with T2D matched at the group level for age, sex and MAP (n=29 each) from the Maastricht Study. Non-linear P-A curves were derived from carotid tonometry and echo-tracking, using Langewouters-model fits. Isobaric PWV (Bramwell-Hill) was determined at MAP.

Results: In individuals without T2D, the average P-A curve in older, as compared to younger individuals, was shifted rightward (diastolic area (A_d), mean±SD: 48.8±10.3 vs. 42.5±8.3mm², p=0.003), which led to higher PWV (9.9±2.0 vs. 7.4±1.6m/s, p<0.001). Next, in younger individuals with T2D, as compared to those without, a similar pattern was found (A_d: 45.7±9.6 vs. 42.5±8.3mm², p=0.068 and PWV: 8.2±1.6 vs. 7.4±1.6m/s, p=0.072). Finally, in older individuals with T2D, as compared to those without, the P-A curve was again shifted rightward (A_d: 53.1±10.4 vs. 48.8±10.3mm², p=0.034), but PWV was not significantly different (10.1±1.7 vs. 9.9±2.0m/s, p=0.29).

Conclusion: Independently of blood pressure, both ageing and T2D have a dilatory effect on carotid arteries, with ageing also clearly demonstrating stiffening. Although T2D is associated with additional stiffening in individuals younger than 55y, this was not observed in individuals older than 70y.