The Journal of Clinical Hypertension (Oct 2021)

Associations of urinary sodium excretion with central hemodynamics and changes in vascular structure and function at high altitude

  • Zhipeng Zhang,
  • Hang Liao,
  • Xin Zhang,
  • Qingtao Meng,
  • Rufeng Shi,
  • Jiayue Feng,
  • Xinran Li,
  • Qiling Gou,
  • Runyu Ye,
  • Xianjin Hu,
  • Xiaoping Chen

DOI
https://doi.org/10.1111/jch.14356
Journal volume & issue
Vol. 23, no. 10
pp. 1907 – 1914

Abstract

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Abstract Research reports on associations of urinary sodium excretion with central hemodynamic parameters and vascular changes are quite limited in general or non‐hypertensive population. The purpose of the current study was to explore such associations in Chinese general Tibetans living at high altitude. This cross‐sectional study was conducted in Luhuo County, Ganzi Tibetan Autonomous Prefecture with average elevation of 3800 meters from December 2018 to January 2019. A total of 294 Tibetans were included in the current study. Twenty‐four hour urinary sodium excretion was estimated by second fasting spot urine in the morning using Kawasaki formula. Central hemodynamic parameters, including central systolic blood pressure (CSBP), central diastolic blood pressure (CDBP), central pulse pressure (CPP), central mean arterial pressure (CMAP), augmentation pressure (AP), and augmentation index standardized for heart rate of 75 (AIx75), were evaluated using the SphygmoCor system. Vascular structures and functions were assessed by carotid intima media thickness (CIMT) test and brachial ankle pulse wave velocity (baPWV), respectively. Estimated mean 24h urinary sodium excretion of Tibetans in Luhuo County was 5.26±1.61 g. After adjustment, estimated 24h urinary sodium was positively associated with CSBP (β = 1.15, p = .008) and CPP (β = 0.87, p = .013). Line graph of means across urinary sodium quartiles showed that associations of 24 h urinary sodium excretion with AIx75 and baPWV presented approximate “J” shape after controlling for confounders. Estimated 24 h sodium excretion was independently and positively associated with CSBP and CPP. Moreover, association between urinary sodium excretion and arterial elasticity, as evaluated by baPWV and AIx75, presented “J” shape. Further studies are needed to verify J‐shaped association and “safe” zone of sodium intake.

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