RESUMO
Higher levels of sodium intake are reported to be associated with higher bloodpressure. Whether this relationship varies according to levels of sodium or potassiumintake and in different populations is unknown.MethodsWe studied 102,216 adults from 18 countries. Estimates of 24-hour sodium andpotassium excretion were made from a single fasting morning urine specimen andwere used as surrogates for intake. We assessed the relationship between electrolyteexcretion and blood pressure, as measured with an automated device.ResultsRegression analyses showed increments of 2.11 mm Hg in systolic blood pressureand 0.78 mm Hg in diastolic blood pressure for each 1-g increment in estimatedsodium excretion. The slope of this association was steeper with higher sodiumintake (an increment of 2.58 mm Hg in systolic blood pressure per gram for sodiumexcretion >5 g per day, 1.74 mm Hg per gram for 3 to 5 g per day, and 0.74 mm Hgper gram for 55 years of age, 2.43 mm Hg pergram at 45 to 55 years of age, and 1.96 mm Hg per gram at <45 years of age;P<0.001 for interaction). Potassium excretion was inversely associated with systolicblood pressure, with a steeper slope of association for persons with hypertensionthan for those without it (P<0.001) and a steeper slope with increased age (P<0.001).ConclusionsIn this study, the association of estimated intake of sodium and potassium, as determinedfrom measurements of excretion of these cations, with blood pressurewas nonlinear and was most pronounced in persons consuming high-sodium diets,persons with hypertension, and older persons. (Funded by the Heart and StrokeFoundation of Ontario and others).