Urinary sodium excretion measures and health outcomes – Authors' reply

24 h urine collection is a reference method, rather than the gold standard for measuring sodium intake. A key test of whether different measures of sodium intake are valid is to compare each measure with an independent biomarker, such as blood pressure (BP)—an association upon which current recommendations for reducing sodium intake are based. Large epidemiological studies with 24 h urine collections have shown a weak1INTERSALT Cooperative...