Age and sex-specific relationships between blood pressure variability and carotid intima-media thickness

This study evaluated the association between carotid intima-media thickness (IMT) and 24 h ambulatory blood pressure variability (BPV) in 150 subjects. The subjects were divided into different age groups and gender groups. We found that for the subjects aged less than 45 years, 24 h and daytime diastolic BPV were associated with the increased IMT (r = 0.525, P = 0.018; r = 0.507, P = 0.022). For the middle aged people (46-55 years), daytime (r = 0.377, P = 0.014) and 24 h systolic BPV (r = 0.366, P = 0.017) were more related to the increases in IMT than 24 h diastolic BPV (r = 0.320, P = 0.039). However, no association between carotid IMT and BPV was found in the elderly (>55 years). In addition, the relationships between carotid IMT and BPV were more obvious in males than females. 24 h systolic BPV (P = 0.008) is the independent factor to evaluate the increased carotid IMT for males, but not for females. The findings in our study indicated that age and sex had influences on progression of carotid IMT. We conclude that the relationship between carotid IMT and ambulatory BPV can be modified by age and sex, thus, the regression model using BPV to evaluate the arteriosclerotic progression should take age and sex into account.