Sodium and potassium intake present a J-shaped relationship with arterial stiffness and carotid intima-media thickness.

OBJECTIVES: The purpose of this study was to analyse the relationship between sodium and potassium intake and vascular structure and function and to ascertain whether said relationship follows the pattern of a J-shaped curve.

METHODS: A cross-sectional study was carried out in a primary care setting. Three hundred fifty-one subjects from the Vasorisk study were included and ranged in age from 30 to 80 years (mean 54.8, SD 11.7); 219 (62.4%) were females. Sodium and potassium intake were evaluated by means of a food frequency questionnaire. Arterial stiffness was assessed according to pulse wave velocity (PWV), ambulatory arterial stiffness index (AASI, AASI_BPVR), and central and peripheral augmentation index (AIx). Carotid intima-media thickness (C-IMT) was evaluated by ultrasonography.

RESULTS: Age was lower in the quartiles with the highest sodium intake (p < 0.05), and no difference was observed between the sexes. Mean C-IMT, CAIx, AASI and AASI_BPVR were higher in the quartiles with higher sodium intake (p < 0.05 for both AASI and AASI_BPVR). Sodium intake was negatively correlated with C-IMT (r = -0.121, p < 0.05), PWV (r = -0.114, p < 0.05), AASI and AASI_BPVR (r = -0.155, p < 0.01). Potassium intake was positively correlated with Cornell VDP (r = 0.119, p < 0.05), CAIx (r = 0.178, p < 0.01) and PAIx (r = 0.202, p < 0.01). After adjustment, the morphology of the relationship between arterial stiffness parameters and C-IMT with quartiles of sodium intake resembles a J-shaped curve. The relationship between central and peripheral AIx and C-IMT and potassium intake resembles a J-shaped curve.

CONCLUSION: The relationship of sodium and potassium intake with vascular structure and function, as evaluated with C-IMT, PWV, AASI and peripheral and central AIx, resembles a J-shaped curve, which is similar to what has been proposed in the case of cardiovascular morbimortality.