Nutr Res Pract.  2022 Jun;16(3):366-378. 10.4162/nrp.2022.16.3.366.

Development and application of the sodium index to estimate and assess sodium intake for Korean adults

• Lee YK
• Hyun T
• Ro H
• Heo YR
• Choi MK

• KMID: 2530397
• DOI: http://doi.org/10.4162/nrp.2022.16.3.366

Abstract

BACKGROUND/OBJECTIVES
The purpose of this study was to develop a sodium index, which is a tool for estimating and assessing sodium intake easily and quickly, to assist in the prevention of various diseases induced by excess sodium intake in Korean adults.
SUBJECTS/METHODS
The 24-h urine collection and dietary behavior surveys were performed on 640 healthy people in 4 regions of South Korea, and an equation for the estimation of 24-h sodium intake was developed. The validity and reliability of the equation were verified with 200 adults. The sodium index was developed by converting the estimated sodium intake using the equation. Finally, the sodium intake status of 1,600 adults was assessed using the sodium index.
RESULTS
The equation included sex, age, body mass index, eating habit and dietary behaviors related to sodium intake. In validity test of the equation, the mean bias between sodium intake using 24-h urine analysis and using the equation from the Bland-Altman plots was −1.5 mg/day. The sensitivity and specificity of the equation for estimation of sodium intake were 80.5% and 64.4%, respectively. In the reliability test of the equation, there was no significant difference between the first and second sodium intakes calculated using the equations, and Spearman's correlation coefficient between the 2 sodium intakes was 0.98. Sodium intake can be assessed as ‘very moderate’ for 75–100 on the sodium index, ‘moderate’ for 100–150, ‘careful’ for less than 75 or 150–200, and ‘severe’ for 250 or more. When sodium intake was assessed using the sodium index in 1,600 subjects, 54.3% and 24.3% of the subjects were assessed to be in the ‘careful’ and ‘severe’ categories, respectively.
CONCLUSIONS
Using a simple questionnaire, the sodium index can be used to monitor and assess sodium intake status, assisting in nutrition education and counseling in a large population.

Keyword

Sodium index; reliability and validity; diet; urine

Figure

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  Fig. 1 Bland-Altman plots of measured 24-h urinary sodium intake and estimated 24-h sodium intake (validation set, n = 200).

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  Fig. 2 Receiver operating characteristic curve for validation of the equation to estimate sodium intake (validation set, n = 200).AUC, area under the receiver operating characteristic curve.

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