Synergistic relationship between changes in the pulse wave velocity and changes in the heart rate in middle-aged Japanese adults: a prospective study

OBJECTIVES: Temporal associations between rates of increases in pulse wave velocity (PWV), a marker of arterial stiffness, and heart rate (HR) indices (baseline HR and changes in HR) as well as inflammatory markers were examined. METHODS: In 1795 apparently healthy Japanese individuals (mean age 39 +/- 8 years old), brachial-ankle PWV (baPWV) and serum C-reactive protein (CRP) levels were measured at the baseline and at the end of a 5-6-year follow-up period. RESULTS: Heart rate at the baseline examination and changes in HR during the follow-up period were significantly associated with the corresponding changes in baPWV during the study period (nonstandardized co-efficient = 0.14, 95% confidential interval = 8.14 x 10-0.19, P < 0.01) even after the adjustment for atherogenic risk factors. When individuals were divided into four groups categorized by baseline HR (higher or lower than median HR) and increase/decrease in HR during the study period, serum CRP levels and atherogenic risk factors were significantly worse in the individuals with high baseline HR accompanied by increased HR during the study period. There was no significant relationship between the changes in the baPWV and the changes in the serum CRP levels. Even after the adjustment for confounding factors, changes in baPWV were significantly higher in this group than the other three groups (P < 0.01). CONCLUSIONS: The study results suggest a synergistic role of high baseline HR and increase in HR during the study period in accelerating age-associated increases in PWV. Inflammation might not be a major factor for this relationship.