The impact of obstructive sleep apnea and heart rate on arterial stiffness: results from the Tokyo Sleep Heart Study.

We examined whether obstructive sleep apnea (OSA) and elevated heart rates (HR) independently increase the arterial stiffness and also the interaction between the two factors in increasing the arterial stiffness in a large Sleep Cohort. A total of 1611 subjects who underwent polysomnography and brachial-ankle pulse wave velocity (baPWV) measurement were included in the analysis. Apnea-hypopnea index (AHI) and heart rate were each categorized into three groups (non-mild: 0/h ≤ AHI < 15/h; moderate: 15/h ≤ AHI < 30/h; severe: ≥30/h; Low: HR < 70 bpm; Medium: 70 ≤ HR < 80 bpm; High: ≥80 bpm), followed by group comparisons. A significant correlation was observed between the AHI and HR. In subjects with AHI < 15, a significant increase in the baPWV was observed along with an increased HR. In subjects with HR < 70 also, a significant increase of the baPWV was observed, along with an increase of the AHI. In a crude model of mediation analysis, the AHI was found to exert a direct and indirect (via HR) effect on the baPWV. After adjustments for the age, sex, BMI, MBP, and medication status, the analysis identified AHI as showing a significant association with the baPWV mediated by the HR, whereas no significant direct relationship was observed between the AHI and the baPWV. In conclusion, in subjects with OSA, the observed increase in arterial stiffness may be mediated by an elevated HR, and therefore, elevated HR may be one of key to increase arterial stiffness in OSA.