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

Abstract

ObjectivesThe 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. MethodsA 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. ResultsAge 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. ConclusionThe 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.