Vascular Ageing Physiology in the Nigerian Population: Arterial Stiffness Trajectories and Their Determinants Across the Adult Lifespan

Arterial stiffness is a fundamental marker of vascular ageing and a superior predictor of cardiovascular events compared to conventional risk factors, yet population-specific trajectories and their determinants have not been characterised in Nigeria. This study investigated arterial stiffness progression across the adult lifespan and its physiological determinants in a multi-geopolitical zone Nigerian sample, making a foundational scientific contribution to African vascular physiology. A large-scale cross-sectional design with longitudinal substudy enrolled 600 adults aged 20 to 75 years stratified across six decades of age from community samples in Lagos, Kano, Enugu, Abuja, Calabar, and Maiduguri, representing all six geopolitical zones. Arterial stiffness was measured by carotid-femoral pulse wave velocity as a gold standard. Augmentation index, central blood pressure, and peripheral flow-mediated dilation were also assessed. Determinants including hypertension, diabetes, smoking, physical activity, dietary patterns, and kidney function were systematically measured. Age-stiffness trajectory modelling using piecewise linear regression and multilevel modelling was applied. Results showed that pulse wave velocity increased non-linearly with age, with an inflection point of accelerated stiffening beginning at age 45. Hypertension, diabetes, and central obesity were the strongest age-independent determinants. Stiffness trajectories differed significantly by geopolitical zone, suggesting regional lifestyle and environmental modifiers. This study provides the first nationally distributed characterisation of arterial stiffness ageing in Nigeria, establishing reference trajectories and identifying modifiable determinants. Population-wide vascular health surveillance is recommended. Keywords: arterial stiffness, pulse wave velocity, vascular ageing, cardiovascular risk, Nigeria.