Poster Presentation Joint Annual Scientific Meeting of the Nutrition Society of NZ and the Nutrition Society of Australia

Association between urinary sodium intake, sodium-to-potassium ratio and blood pressure in adults (#P54)

Rhoda N Ndanuko 1 , Linda C Tapsell 1 , Karen E Charlton 1 , Elizabeth P Neale 1 , Marijka J Batterham 2
  1. School of Medicine, University of Wollongong, Northfields Avenue, Wollongong , NSW 2522, Australia
  2. Statistical Consulting Service, School of Mathematics and Applied Statistics, University of Wollongong, Northfields Avenue, Wollongong , NSW 2522 , Australia

Background/Aims: Hypertension is a major risk factor for developing cardiovascular disease, stroke and kidney disease. Reducing sodium and increasing potassium intake has been shown to reduce blood pressure (BP). The aim of this study was to determine the association between urinary sodium excretion and sodium-to-potassium ratio and BP in a sample of overweight adults.

Methods: Secondary analysis of baseline data from the 12-month HealthTrack randomised controlled trial (n=327, mean age: 43.6±8.0 years; mean BMI: 32.4±4.2 kg/m2) was conducted. Resting BP and 24-h urine sodium and potassium excretion were measured.

Results: Mean systolic blood pressure (SBP) was 124.9 ± 14.5 mmHg and diastolic blood pressure (DBP) was 73.3 ± 9.9 mmHg. Median urinary sodium excretion was 3197.0 mg/d (7.99g salt) (interquartile range: 2300-4140 mg/d) and median sodium-to-potassium ratio was 1.9 (interquartile range: 1.5-2.4). Urinary sodium was positively correlated with both SBP (r=0.173, p=0.002) and DBP (r=0.134, p=0.015). In multiple linear regression, after adjusting for age, sex, BMI and hypertension medication, urinary sodium (F (3,323) = 33.125, p < 0.0005; adjusted R2 = 0.228) significantly predicted SBP.

Conclusions: These results indicate that the relationship between dietary sodium and SBP can be observed in a clinical sample of overweight adults. These findings are in line with the current dietary recommendations that recommend restriction of salt-containing processed foods. This advice can be translated to clinical practice to include patient groups such as overweight adults.

Funding source(s): Illawarra Health and Medical Research Institute, California Walnut Commission