Correlation Between Spot Urine Sodium, 24 Hour Urinary Sodium and Food Frequency Questionnairein Estimation of Salt Intake in Healthy Individuals

Jaafar Maryam Kamiliah, Nordin Nani, Abdul Rahman Abdul Rashid


Background:Salt intake is a known contributor to increased blood pressure. However, it is rarely monitored in clinical practice. 24-hr urinary sodium (24-HrNa) is the gold standard method to estimate salt intake but this method is rather burdensome.

Objective: The objective of this study is to correlate between spot urine sodium (SUNa), 24-HrNa and Na intake estimation by food frequency questionnaire (FFQ) (FFQNa).

Methods : 430 healthy participants aged between 20-40 years old were recruited. Second morning voided urine samples were obtained from all participants to estimate SUNa. 24-HrNa samples were obtained from 77 out of 430 participants. All participants were required to answer a validated FFQ. Urine samples were analysed for Na using indirect ion-selective electrode (ISE) method. Daily sodium intake was calculated from the FFQ.

Results:The mean daily sodium intake from 24-hrNa (n=77) was 155 mmol/day, SUNa (n=430) was 158 mmol/L and FFQNa (n=430) was 271 mmol/day. There was a moderate correlation between SUNa and 24-hrNa (ρ = 0.62, P < 0.000). No correlation was seen between both 24-hrNa and SUNa with FFQNa (ρ = 0.035, P = 0.768 and ρ = 0.026, P = 0.597 respectively).

Conclusion: Spot urine Na is a simple cost-effective method to estimate daily Na intake and has the potential to replace 24-hour urinary Na.

International Journal of Human and Health Sciences Vol. 05 No. 01 January’21 Page: 74-80


Spot urine sodium; 24-hour urinary sodium; salt intake; Second Morning Urine (SMU); FFQ Na; hypertension

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