Association of Urinary Sodium/Potassium Ratio with Blood Pressure: Sex and Racial Differences

S. Susan Hedayati, Abu T. Minhajuddin, Adeel Ijaz, Orson W. Moe, Essam F. Elsayed, Robert F. Reilly, Chou Long Huang

Research output: Contribution to journalArticlepeer-review

89 Scopus citations

Abstract

Background and objectives Previous studies reporting an association between high BP and high sodium and low potassium intake or urinary sodium/potassium ratio (U[Na +]/[K +]) primarily included white men and did not control for cardiovascular risk factors. Design, setting, participants, & measurements This cross-sectional study investigated the association of U[Na +]/ [K +] with BP in 3303 participants using robust linear regression. Results Mean age was 43±10 years, 56% of participants were women, and 52% were African American. BP was higher in African Americans than in non-African Americans, 131/81±20/11 versus 120/76±16/9 mmHg (P<0.001). Mean U[Na +]/[K +] was 4.4±3.0 in African Americans and 4.1±2.5 in non-African Americans (P=0.002), with medians (interquartile ranges) of 3.7 (3.2) and 3.6 (2.8). Systolic BP increased by 1.6 mmHg (95% confidence interval, 1.0, 2.2) and diastolic BPby 1.0 mmHg (95% confidence interval, 0.6,1.4) for each 3-unit increase in U[Na +]/[K +] (P<0.001 for both). This association remained significant after adjusting for diabetes mellitus, smoking, body mass index, total cholesterol, GFR, and urine albumin/creatinine ratio. There was no interaction between African-American race and U[Na +]/[K +], but for any given value of U[Na +]/[K +], both systolic BP and diastolic BP were higher in African Americans than in non-African Americans. The diastolic BP increase was higher in men than in women per 3-unit increase in U[Na +]/[K +] (1.6 versus 0.9 mmHg, interaction P=0.03). Conclusions Dietary Na + excess and K + deficiency may play an important role in the pathogenesis of hypertension independent of cardiovascular risk factors. This association may be more pronounced in men than in women.

Original languageEnglish (US)
Pages (from-to)315-322
Number of pages8
JournalClinical Journal of the American Society of Nephrology
Volume7
Issue number2
DOIs
StatePublished - Feb 1 2012

ASJC Scopus subject areas

  • Epidemiology
  • Critical Care and Intensive Care Medicine
  • Nephrology
  • Transplantation

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