ABSTRACT
The relationship between time factors of elevated blood pressure (BP) and carotid atherosclerosis (CA) is still unclear. The associations between time-weighted average 24 h ambulatory systolic BP (TWA-SBP), duration of hypertension in years (hypertension-year), and CA were investigated in a petrochemical company sample of 95 executives and 91 gender- and age-matched non-executives employees. Intima-media thickness (IMT) and plaque scores of extracranial carotid artery (ECCA) were determined bilaterally by high-resolution B-mode ultrasound. The determinants of segment-specific carotid IMT and odds ratios for CA, in terms of thicker IMT (IMT > or = 75th percentile) and ECCA score > or = 3, were evaluated by multivariate regression analysis. Results revealed TWA-SBP and hypertension-year were two major determinants of IMT at common carotid artery (CCA) and carotid bulb by using mixed regression models. However, TWA-DBP was a negative determinant of IMT at CCA and carotid bulb. Meanwhile, the executives were found to be a negative association with IMT at carotid bulb. Measurements at both internal carotid artery and bulb identified duration of diabetes mellitus as significant determinant of IMT. After controlling covariates, multivariate logistic regression analysis identified TWA-SBP and hypertension-year as the important determinants for thicker IMT and ECCA > or = 3. And, TWA-DBP was found as a negative determinant for CA. In conclusion, both TWA-SBP and hypertension-year were two major determinants for carotid IMT and CA, which seem to imply that both short-term and long-term durations of elevated BP are probably crucial in the pathogenesis of CA.
