Sex-Specific trajectories of arterial stiffness: a large-scale description of 38 million real-world pulse wave velocity measurements.

<h4>Introduction</h4>Arterial stiffness, measured by Pulse Wave Velocity (PWV), is a critical marker of cardiovascular risk. However, current reference values are often derived from limited clinical cohorts. This study aims to establish large-scale normative trajectories for PWV using real-world data.<h4>Methods</h4>We analyzed anonymized data from 38,648,329 measurements collected via Withings smart scales in 1 196 712 unique users (681719 men and 514993 women) between 2023 and 2024, across Japan, North America, and Europe. PWV was estimated using ballistocardiography coupled with impedancemetry. We applied multivariate quantile regression to assess the impact of age, sex, and BMI on PWV.<h4>Results</h4>There was a significant interaction between age and sex (<i>p</i> <i><</i> <i>0.001</i>). Men exhibited higher PWV values in early adulthood after adolescence compared to women. However, a distinct crossover was observed around the fifth decade of life, after which women displayed a steeper rate of arterial stiffening, eventually surpassing men. Age, sex and BMI were independently associated with PWV.<h4>Discussion</h4>This observational study provides the largest real-world dataset on PWV to date. The results illustrate in an observational way the sex dependent "vascular aging crossover" likely associated with hormonal change at adolescence and later menopause. This finding demonstrates the utility of connected devices in large-scale cardiovascular epidemiology.