Association of urinary sodium/creatinine ratio and urinary sodium/specific gravity unit ratio with blood pressure and hypertension: KNHANES 2009–2010

Abstract

Abstract BACKGROUND: We investigated the association between urinary sodium/creatinine ratio (U[Na(+)]/Cr) or urinary sodium/specific gravity unit ratio (U[Na(+)]/SGU), estimated from spot urine, and blood pressure (BP) and hypertension. METHODS: The study population consisted of a total of 9674 adults (4478 men, 5196 women) who participated in the Korea National Health and Nutrition Examination Surveys conducted in 2009 and 2010. Urine levels of sodium and creatinine, urine specific gravity (SG), and BP were measured along with other risk factors of hypertension. SGU is the calculated parameter of (SG-1)×100. RESULTS: There were significant trends of increasing mean systolic and diastolic BPs and prevalence of hypertension with increasing quartile of U[Na(+)]/Cr and U[Na(+)]/SGU. After adjusting for age, total cholesterol, alcohol drinking, obesity, current smoking, mild renal dysfunction, and diabetes mellitus, the odds ratios (ORs) for hypertension in the top quartile of U[Na(+)]/Cr compared with the bottom quartile were 1.40 in men and 2.68 in women. Similarly, the ORs for hypertension in the top quartile of U[Na(+)]/SGU were 1.29 in men and 3.02 in women after adjustment. CONCLUSIONS: U[Na(+)]/Cr and U[Na(+)]/SGU are associated with BP and hypertension, supporting the possible clinical value of U[Na(+)]/Cr and U[Na(+)]/SGU in general medical facilities.