Do level and variability of systolic blood pressure predict arterial properties or vice versa?

No longitudinal study addressed whether systolic blood pressure level (SBPL) or within-visit variability (SBPV) predict arterial properties or vice versa. In families randomly recruited from a Flemish population, we determined SBPL and SBPV from five consecutive blood pressure readings. The indexes of SBPV were variability independent of the mean, the difference between maximum and minimum SBPL, and average real variability. We measured carotid intima-media thickness and distensibility by ultrasound and carotid-femoral pulse wave velocity by tonometry (SphygmoCor, version 8.2). Effect sizes were computed for 1-s.d. increments in the predictors, while accounting for covariables and family clusters. Among 1087 participants (50.4% women; mean age, 41.8 years), followed up for 2.55 years (median), higher SBPL predicted (P0.019) higher carotid intima-media thickness (+15 μm), lower carotid distensibility (-1.53 10(-3) kPa(-1)) and faster carotid-femoral pulse wave velocity (+0.285 m s(-1)) at follow-up, whereas none of the SBPV indexes predicted the arterial traits at follow-up (P0.11). In a subset of 713 participants, followed up for another 3.14 years, lower carotid distensibility predicted (P