Abstract Background Day-by-day home systolic blood pressure variability (BPV) was shown to be associated with increased common carotid artery (CCA) intima-media thickness (IMT) in the hypertensives. Recently, 24 hour ambulatory BPV was revealed to serve as an indicator of higher CCA-IMT only in males. However, there have been no studies that reported the sex-dependent relationship between day-by-day BPV and CCA-IMT. Purpose We assessed the hypothesis that day-by-day BPV was associated with higher CCA-IMT in the Japanese males at high-risk of cardiovascular disease. Methods Among 4310 patients with one or more cardiovascular risks recruited for the Japan Morning Surge-Home Blood Pressure Study, carotid ultrasound in CCA was performed in the 1365 patients (mean age 65.6 years old, male 52%). The home blood pressure (BP) readings during mean 11.2 days were used to calculate home mean levels and variability in morning systolic BP (SBP). Day-by-day BPV was measured as standard deviation [SD] and delta (maximum-minimum) in SBP. Results Average mean CCA-IMT of left and right side was 1.046±0.4mm. Mean (r=0.118, p<0.0001), SD (r=0.120, p<0.0001) and delta (r=0.149, p<0.0001) in morning SBP were significantly correlated with CCA-IMT. In the multiple regression analysis adjustment for confounders including age, gender, body mass index, total cholesterol, high density lipoprotein and mean morning SBP, SD (B: 0.008, 95% CI: 0.001–0.015, p<0.05) or delta (B: 0.004, 95% CI: 0.002–0.006, p<0.001) in morning SBP each had a significant association with CCA-IMT. According to the gender, SD (p<0.01) or delta (p<0.01) in morning SBP each was significantly associated with CCA-IMT only in the male group while neither SD (p=0.4) nor delta (p=0.4) in morning SBP was associated with CCA-IMT in the female group. Conclusions In addition to the conventional risk factors, day-by-day morning SBP variability was a significant indicator of increased CCA-IMT in the high-risk Japanese population. The significant relationship between day-by-day morning SBP variability and CCA-IMT was observed only in the males. Gender specific impact of day-by-day morning home systolic BPV on carotid artery atherosclerosis should be taken into account in the high-risk elderly at cardiovascular disease. Funding Acknowledgement Type of funding source: None
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