Differential associations of dietary sodium and potassium intake with blood pressure: a focus on pulse pressure

Objective Dietary sodium and potassium intakes are factors known to influence blood pressure (BP) through different pathways. These mechanisms likely result in differential effects on parameters characterizing BP. The aim of the study was to evaluate relationships between both sodium and potassium intake and all BP parameters namely systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure (PP) and mean arterial pressure (MAP) - simultaneously in a large general population. Methods The present cross-sectional analysis was performed on 4919 middle-aged men and women, participants in the SU.VI.MAX study. Dietary intake was assessed through at least three 24-h dietary records. SBP and DBP were measured twice at a single visit after 10 min rest and averaged. Analysis of covariance was used to test for difference in BP parameters across tertiles of dietary sodium and potassium intakes. Results In univariate analysis, increased dietary sodium and potassium intakes were both significantly associated with increased BP parameters (P < 0.0001). After relevant adjustments, sodium intake remained positively associated with PP (P = 0.006), whereas potassium intake became negatively associated with SBP, DBP and MAP (P <= 0.02) but was not linked to PP (P = 0.56). Conclusion The positive association between dietary sodium intake and PP observed in the present study provides further evidence for the current concept linking sodium to rise in BP through modification and stiffening of the arterial wall, whereas negative associations between dietary potassium intake and both SBP and DBP, hence MAP, support the vasodilator properties of this latter nutrient. J Hypertens 27:1158-1164 (C) 2009 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.