Objective: To assess endothelial function and sympathetic nervous activity in individuals with low sodium intake along the glucose continuum.

Research Designs and Methods: In this prospective observational study, participants (n=54) with low sodium intake (single 24hour urine sodium excretion <150mmol/24h) were recruited and categorized based on an oral glucose tolerance test as: controls (n=10), with impaired glucose tolerance (IGT) (n=15) and with untreated (n=12) type 2 diabetes and were then compared to individuals with treated type 2 diabetes (n=17) with established cardio-metabolic risk factors. We assessed pulse amplitude tonometry (PAT) derived measures of endothelial function using the reactive hyperemic index and arterial stiffness using augmentation index; muscle sympathetic nerve activity (MSNA) using microneurography; cardiac baroreflex; heart rate; blood pressure; fasting glucose; glycosylated hemoglobin A1c (HbA1c) and lipid profile.

Results: The mean (SD) sodium excretion was 110.6 (26) mmol/24hour. Compared to individuals from the other groups, the treated type 2 diabetes group had a lower PAT ratio (p=0.04), lower baroreflex (p=0.0002) and higher heart rate (p=0.02) suggestive of sympatho-vascular dysfunction. This occurred despite lower MSNA (p=0.005) and appropriate glycemic (mean +/-SD): HbA1c 7.2 (1.72)% (55mmol/mol), total cholesterol 4.2 (1.0) mmol/L, LDL 2.2 (1.0) mmol/L) and blood pressure (mean +/-SD) 136 (13) systolic and 78 (12) diastolic pressure (mmHg) control.

Conclusion: In individuals with treated type 2 diabetes, despite a low sodium intake and appropriately managed cardio-metabolic risk factors, endothelial and baroreflex function were impaired. Whether sodium restriction may be associated with an attenuated sympatho-vascular response in individuals with diabetes requires further investigations.


S. Baqar: None. E.I. Ekinci: None.

Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. More information is available at http://www.diabetesjournals.org/content/license.