Association between trunk flexibility and renal flow pulsatility in middle-aged and older adults

BACKGROUND: Recent clinical studies have indicated that poor trunk flexibility is associated with arterial stiffness in the aged. Arterial stiffness leads to elevated renal flow pulsatility, which accelerates age-related renal dysfunction and damages. However, data indicating the potential link between flexibility fitness and renal flow pulsatility are lacking. This study examined the cross-sectional association between trunk flexibility and renal flow pulsatility in middle-aged and older adults. METHODS: A total of 175 middle-aged and older adults (aged 63 ± 9 years) were included in this study. Sit-and-reach tests (SRT) were performed to assess their trunk flexibility. Using a Doppler ultrasound, renal pulsatility index (PI) and resistive index (RI) were measured as parameters of renal flow pulsatility. RESULTS: The study found that, in middle-aged and older adults, the SRT score was an independent determinant of renal PI (β = -0.134, P = 0.027) and RI (β = -0.135, P = 0.027). In the one-way analysis of covariance (ANCOVA), the renal PI and RI in the older group with a lower SRT score were found to be significantly higher than those in the middle-aged group. CONCLUSIONS: Trunk flexibility is an independent determinant of renal flow pulsatility in middle-aged and older adults.