(P25-034-25) The Association Between Sodium-to-Potassium Intake Ratio and Vascular Endothelial Function, and the Role of Insulin Resistance

Objectives: Dietary sodium-to-potassium ratio (Na:K) is a better predictor of cardiovascular disease (CVD) risk than Na⁺ or K⁺ intake alone. However, the link between Na:K and vascular endothelial function assessed via flow-mediated dilation (FMD), a subclinical precursor to CVD, is unknown. Further, insulin resistance is associated with higher Na⁺ intake, lower K⁺ intake, and greater CVD risk; whether it affects the relation between Na:K and FMD is unknown. The aim of our pilot data analysis was to examine the association between Na⁺, K⁺, and Na:K versus FMD, and to explore the role of insulin resistance.

Methods: A secondary analysis was conducted using cross-sectional data. Participants recorded their dietary intake for ≥3 days to assess Na⁺ and K⁺ intake. Plasma glucose and insulin were measured from fasting blood samples, with insulin resistance quantified via the Homeostatic Model Assessment for Insulin Resistance (HOMA-IR). Seated blood pressure and FMD were captured at the brachial artery. Pearson correlations were conducted to assess the relation between Na⁺, K⁺, and Na:K versus FMD. Partial correlations were conducted to control for HOMA-IR.

Results: Complete data were collected from 8 participants (4M/4F; age 22.4±2.1 y). Mean BMI was 27.3±6.5 kg/m²; blood pressure was 111±12/63±6 mmHg. Mean Na⁺ intake was 3452±1481 mg/d and mean K⁺ intake was 2231±1490 mg/d. Neither Na⁺ (r=0.08, p=0.43) or K⁺ (r=0.06, p=0.44) intake was correlated with FMD. While not significant, Na:K was weakly inversely associated with FMD before (r=-0.31, p=0.23) and after adjusting for HOMA-IR (r=-0.28, p=0.27).

Conclusions: These preliminary findings suggest Na:K, but not Na⁺ or K⁺ intake alone, is weakly inversely associated with FMD among young adults independent of HOMA-IR. These results should be confirmed with a larger sample.

Funding Sources: Florida State University Graduate School Legacy Fellowship (CD); National Institutes of Health; American Heart Association.