ASSOCIATIONS OF SODIUM INTAKE WITH CENTRAL HEMODYNAMICS AND CHANGES IN VASCULAR STRUCTURE AND FUNCTION AT HIGH ALTITUDE LOCALITIES

Abstract

Objective: To investigate the associations of sodium intake with central hemodynamics and changes in vascular structure and function at high altitude localities. Design and method: From December 2018 to January 2019, a total of 383 monks who participated in cardiovascular risk factors screening were enrolled in four temples around Luhuo County, Ganzi Tibetan Autonomous Prefecture with an average elevation of 3,800 meters. Questionnaire, physical examination, blood and urine examination, electrocardiogram, echocardiography, intima-media thickness (IMT), Brachial ankle pulse wave velocity (BaPWV), Ankle brachial index (ABI), Central systolic blood pressure (CSBP), Central diastolic blood pressure (CDBP), Central pulse pressure (CPP), Central mean arterial pressure (CMAP), Augmentation pressure (AP), Augmentation index (AI) and other tests were performed on all participants. Estimated 24-hour urinary sodium excretion was measured by the Kawasaki formula using the urinary sodium/urinary creatinine ratio of the second morning fasting urine. Pearson correlation and multiple linear regression were used to analyze the associations between 24 h urinary sodium and central arterial hemodynamic parameters and BaPWV and IMT. Results: 1. The estimated 24 h urinary sodium excretion in the temple was (5.26 ± 1.61)g, and the estimated salt intake was (13.36 ± 4.09)g. There was no significant correlation between 24 h urinary sodium and CDBP, AP and IMT (P > 0.05). After gender, age, CSBP, body Mass Index (BMI), fasting blood glucose (FBG), estimated glomerular filtration rate (eGFR), triglycerides (TG), high density lipoprotein (HDL) and low density lipoprotein (LDL) were adjusted, 24 h urine sodium was positively correlated with CSBP (P = 0.018) and CPP (P < 0.001). After adjusting for gender, age, CSBP, BMI, eGFR, FBG, TG, HDL, LDL, 24 h urinary sodium was significantly negatively correlated with AIX75 and BaPWV (P = 0.028,P < 0.001, respectively). The line graph of means across the 24 h urinary sodium quartiles and the cubic fitting curve showed that the associations between 24 h urinary sodium excretion with AIX75 and BaPWV presented an approximate ’J’ shape. Conclusions: 24 h urinary sodium was positively correlated with CSBP and CPP in the monks in this region. The associations between 24 h urinary sodium with AIX75 and BaPWV resembled a ’J’ shape.