Linan Wang; Jin-Ah Seok; Yeon-Kyung Lee

doi:10.5720/kjcn.2025.00318

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Research Article
The association between sodium index and the risk of obesity in Korean and Chinese university students: a cross-sectional study: Linan Wang¹⁾, Jin-Ah Seok²⁾, Yeon-Kyung Lee^3),†; Korean Journal of Community Nutrition 2025;30(6):419-430.
DOI: https://doi.org/10.5720/kjcn.2025.00318
Published online: December 31, 2025

¹⁾Student, Department of Food Science and Nutrition, Kyungpook University, Daegu, Korea

²⁾Lecturer, Department of Food Science and Nutrition, Kyungpook University, Daegu, Korea

³⁾Professor, Department of Food Science and Nutrition, Kyungpook University, Daegu, Korea

†Corresponding author: Yeon-Kyung Lee Department of Food Science and Nutrition, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu 41566, Korea Tel: +82-53-950-6234 Fax: +82-53-950-6229 E mail: yklee@knu.ac.kr

• Received: October 31, 2025 • Revised: December 1, 2025 • Accepted: December 11, 2025

This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Abstract
INTRODUCTION
METHODS
RESULTS
DISCUSSION
NOTES
SUPPLEMENTARY MATERIALS
REFERENCES

Abstract

Objectives
Korea and China have the highest sodium intakes globally. The sodium index is a quantitative measure of the estimated sodium intake, calculated using a regression equation with proven validity and reliability in individuals aged 19–69 years. This study aimed to compare the sodium index of Korean and Chinese university students and analyze the association between the sodium index and the risk of obesity.
Methods
A total of 218 university students—110 Korean (63 males, 47 females) and 108 Chinese (60 males, 48 females)—participated in this study in 2019. Sodium-related awareness, nutritional knowledge, and sodium index were compared between Korean and Chinese students. Obesity indicators were compared according to three criteria for the sodium index of Korean and Chinese students: “moderate,” “careful,” and “severe”. The association between sodium index levels and risk of obesity was analyzed using multiple logistic regression analysis adjusted for age and sex.
Results
Overall, 84% of students recognized that they consumed large amounts of sodium. Korean students demonstrated higher nutritional knowledge scores than Chinese students. The average estimated sodium intake was 3,751 mg, and no significant difference was observed between Korean (3,857 mg) and Chinese (3,643 mg) students. The overall average sodium index was 187, which falls under the “careful” level. As the sodium index levels increased, the students’ body mass index, waist-hip ratio (WHR), and fat-related indicators significantly increased. At the “severe” level of the sodium index, Korean and Chinese students had 2.402-fold and 1.636-fold increases in the risk of obesity based on body fat percentage, and 3.682-fold and 1.622-fold increases based on WHR, respectively.
Conclusion
This study demonstrated an association between sodium index and obesity risk, showing that excessive sodium intake affects body fat-related indicators in university students.
Keywords: obesity; body mass index; waist-hip ratio; sodium; index

INTRODUCTION

Excessive sodium intake is closely associated with diseases such as hypertension, cardiovascular disease, stroke, gastric cancer, and diabetes [1-5]. It was identified as a major cause of mortality and disability-adjusted life years in 2017 [6]. According to the 2017 Global Burden of Disease study [6] that involved 195 countries, East Asian countries, including Korea, China, and Japan, have the highest sodium intake levels worldwide. In East Asia, 30% of the mortality is attributed to an inappropriate diet, with excessive sodium intake representing the highest proportion among dietary factors.

According to the World Health Organization (WHO)’s “Global Report on Sodium Intake Reduction” [7], as of 2019, the daily sodium intake of Koreans was 4,854 mg, which is higher than the average of 4,310 mg among 194 WHO member countries, whereas China showed the highest sodium intake among 194 countries at 6,954 mg.

In Korea, because of implementing government-level sodium reduction policies since 2012, according to Korea Health Statistics [8], the average sodium intake decreased continuously from 4,831 mg in 2010 to 3,124 mg in 2020 and further to 3,092 mg in 2023. However, this represents an intake ratio of 139.4% compared with the chronic disease risk reduction (CDRR) intake of 2,300 mg [9].

In China, the mortality from cardiovascular disease due to an inappropriate diet was 20.8%, with excessive sodium intake (17.3%) representing the highest proportion among dietary factors causing death [10]. The salt intake among Chinese adults was 9.6 g during 2010–2012, with adult males consuming 10.4 g and adult females 8.8 g, which is approximately twice the WHO-recommended standard [11]. According to a meta-analysis [12] on 24-hour urinary sodium and potassium levels in Chinese individuals, the average sodium intake across all regions and age groups in China was approximately twice the recommended standard. For this reason, the Chinese Nutrition Society [13] recommended a daily salt intake of 5 g or less in 2022.

The high sodium intake in Korea and China can be attributed to Korean food culture [14], which involves consuming large amounts of soup-based dishes such as guk, tang, and jjigae, and Chinese food culture [15, 16], which consists of stir-fried vegetables and meat dishes prepared using seasonings such as soy sauce and salt at every meal.

The sodium index is a quantitative measure of estimated sodium intake calculated from a regression equation developed through investigations of 24-hour urine analysis, 24-hour recall, and dietary habits among Korean adults aged 19–69 years during 2014–2015. It is a tool with validated reliability [17]. The sodium index facilitates easy and rapid estimation of sodium intake by investigating sex, age, body mass index (BMI), and sodium-related dietary habits and behaviors. It can be utilized as a useful tool in public sodium reduction education by categorizing sodium intake levels into three stages: moderate, careful, and severe.

University students are frequently exposed to eating out, processed foods, and fast food in their daily diet and have nutritional problems related to irregular lifestyle patterns, improper dietary habits, incorrect nutritional knowledge, and excessive weight control [18-22]. Additionally, a study [23] on lifestyle and overweight/obesity risk among British university students reported that the prevalence of overweight/obesity based on body fat percentage was 14.4% and that unhealthy lifestyle habits coexist and interact with each other to increase the risk of overweight/obesity.

Therefore, this study aimed to compare sodium-related awareness, nutritional knowledge, and the sodium index between Korean and Chinese international students residing in Daegu, Korea. Furthermore, this study aimed to analyze differences in obesity indicator levels according to the sodium index and the risk of obesity indicators according to the sodium index, thereby demonstrating that excessive sodium intake increases the risk of obesity.

METHODS

Ethics statement

The informed written consent was obtained from each participant. The study protocol was approved by the Institutional Review Board of Kyungpook National University (approval number: KNU2019-0141).

1. Study design

This was a cross-sectional study and reported in accordance with the STROBE statement (https://www.strobe-statement.org/).

2. Participant selection

The participants were university students residing in Daegu, South Korea. They were recruited after a sufficient explanation of the purpose, content, and process of this study was provided on the university’s website, SNS, and department bulletin boards. Those who wanted to participate in the study were asked to apply via email or telephone, and applications were accepted based on sex ratio and BMI as the criteria for obesity. Specifically, the participants were an allocated sample of 220 calculated by G*Power, with the number of Korean and Chinese male and female students adjusted to 55 ± 10 each, and that of participants with obesity (with a BMI of 25 or above) adjusted to account for 15%–25% of the Korean-Chinese male-female groups. After excluding respondents with incomplete questionnaire items, 218 participants—110 Korean university students (63 males, 47 females) and 108 Chinese university students (60 males, 48 females)—were surveyed between October and December 2019.

3. Anthropometric measurements

The height and weight of the study participants were measured using an automatic height-weight scale (Phonix HM-201; Phonix Co.), and BMI was calculated using height and weight. A body composition analyzer (InBody XBIA 900; InBody Co.) was used to measure body fat mass, body fat percentage, waist-hip ratio (WHR), visceral fat area, visceral fat level, visceral fat mass, subcutaneous fat mass, and muscle mass.

The obesity criteria based on BMI followed the Korean Society for the Study of obesity clinical practice guidelines [24] and the WHO Asia-Pacific guidelines [25], with a BMI of 25 or above classified as obese. Additionally, body fat percentage was classified as obese using the criteria presented in Lee and Nieman’s study [26]: 25% or above for males and 30% or above for females.

4. Sodium-related awareness survey

The sodium-related awareness survey items were based on previous studies [27, 28] and consisted of three items: awareness of sodium intake, necessity of reducing sodium intake, and willingness and practice of reducing sodium intake.

5. Sodium-related nutritional knowledge survey

Sodium-related nutritional knowledge was based on previous studies [29, 30], with items modified and supplemented for use in this study. The items consisted of 10 questions on “daily sodium intake standard,” “relationship between sodium intake and disease,” “alternative foods for salt,” and “awareness of sodium-containing foods.” Respondents selected one of “correct,” “incorrect,” or “don’t know” for each item, with “correct” answers scored as 1 point and “incorrect” or “don’t know” answers scored as 0 points, for a total of 10 points. Higher scores indicated higher nutritional knowledge.

6. Sodium index survey

The sodium index was calculated according to the method described by Lee et al. [17], which involved investigating the participants’ sex, age, BMI, and sodium-related dietary habits and behaviors, and then calculating the estimated sodium intake using the sodium intake estimation regression equation before conversion, as shown in Table 1 (also Supplementary Table 1). Sodium index judgment criteria were as follows: “moderate” for 75–150 points when the sodium intake estimation regression equation value was 1,500–3,000 mg; “careful” for < 75 or > 150–250 points when < 1,500 or > 3,000–5,000 mg; and “severe” for > 250 points when > 5,000 mg. When Lee et al. [17] originally developed the sodium index and established its judgment criteria, they distinguished between “very moderate” for estimated sodium intake of 1,500–2,000 mg and “moderate” for > 2,000–3,000 mg. However, as the proportion corresponding to “very moderate” was very low at 0% for ages 19–29 years [17] and 0.8% [31], and the 2020 CDRR intake was set at 2,300 mg [9], “very moderate” and “moderate” were combined and designated as “moderate.”

7. Statistical analysis

The results were analyzed using IBM SPSS Statistics 30 (IBM Corp.) and expressed as mean ± standard deviation and frequency (percentage). Cross-tabulation analysis was performed to evaluate sodium intake-related awareness among Korean and Chinese university students. T-tests were used to verify the significance of nutritional knowledge and sodium index analysis between Korean and Chinese university students. Comparisons of anthropometric measurements among the four groups based on nationality and sex, and comparisons of obesity indicators among the three stages of the sodium index (moderate, careful, and severe) were analyzed using analysis of variance and Duncan’s multiple range test. The risk of obesity according to the sodium index was analyzed using multiple logistic regression analysis. All significance levels were set at P < 0.05.

RESULTS

1. Comparison of anthropometric measurements between Korean and Chinese university students

The results of the comparison of anthropometric measurements between the Korean and Chinese university students are shown in Table 2. BMI was significantly higher in Korean and Chinese male students (23.2 and 23.6, respectively) than in Chinese female students (21.5) (P < 0.05). The rate of obesity based on BMI was 25% for Korean and Chinese male students, 19.1% for Korean female students, and 14.6% for Chinese female students, with no significant difference. The body fat percentage was significantly higher in Korean and Chinese female students (25.8% and 26.4%, respectively) than in Korean and Chinese male students (19.6% and 20.1%, respectively) (P < 0.001). However, no significant difference was observed in the obesity rate based on body fat percentage among these groups. Additionally, WHR, visceral fat level, visceral fat area, and muscle mass were significantly higher in Korean and Chinese male students than in Korean and Chinese female students (each P < 0.001). However, visceral fat mass and subcutaneous fat mass showed no significant differences between the sexes.

2. Comparison of sodium-related awareness between Korean and Chinese university students

The results of the sodium-related awareness survey of the university students are presented in Table 3. The proportion recognizing high sodium intake was 84.0% overall, with Korean university students (92.8%) showing a higher rate than Chinese university students (75.0%) (P < 0.001). Survey results on the awareness of the necessity of sodium reduction showed that 73.4% recognized it as necessary, with no significant difference between Korean university students (75.5%) and Chinese university students (71.3%).

The survey results on sodium reduction practice showed differences in practice rates between Korean and Chinese university students (P = 0.001). Specifically, 62.7% of Korean university students and 37.0% of Chinese university students had never considered reducing sodium intake. Meanwhile, 8.2% of Korean university students and 25.0% of Chinese university students were already practicing sodium reduction, although for less than six months. Additionally, 10.0% of Korean university students and 14.8% of Chinese university students had been practicing sodium reduction for more than six months.

3. Comparison of sodium-related nutritional knowledge between Korean and Chinese university students

The results of the sodium-related nutritional knowledge survey of Korean and Chinese university students are shown in Table 4. The sodium-related nutritional knowledge score of university students was 6.43 out of 10 points, with Korean university students (6.96 points) showing higher nutritional knowledge levels than Chinese university students (5.87 points) (P < 0.001).

Five out of 10 total items showed higher nutritional knowledge scores for Korean university students than Chinese university students: “Noodles, bread, etc. are not salty, so they do not contain sodium” (P = 0.003), “Using flavor foods such as mustard instead of salt can reduce salt intake” (P < 0.001), “Using a lot of soy sauce instead of salt during cooking can reduce sodium” (P = 0.002), “Blanching processed foods (ham, fish cakes, canned goods) can reduce sodium intake” (P < 0.001), and “Consuming fresh fruits helps sodium excretion” (P = 0.002).

4. Comparison of estimated sodium intake and sodium index between Korean and Chinese university students

The estimated sodium intake and sodium index of university students are shown in Table 5. The estimated sodium intake of all Korean and Chinese university students was 3,751.4 mg, with male students (4,190.0 mg) having a significantly higher intake than female students (3,183.8 mg) (P < 0.001). However, no significant difference was observed between Korean university students (3,857.7 mg) and Chinese university students (3,643.4 mg).

The overall mean sodium index was 187.6, with “moderate” at 128.3, “careful” at 196.9, and “severe” at 263.2, showing significantly increasing sodium index values at each stage (P < 0.001). However, no difference was found between Korean and Chinese university students. Regarding the sodium index distribution, 72.9% of all university students were classified as having “careful” sodium intake, while 20.2% and 6.9% had “moderate” and “severe” sodium intake, respectively. No significant difference in sodium index distribution was observed between Korean and Chinese university students.

5. Comparison of obesity indicators according to the sodium index of Korean and Chinese university students

The results of the comparison of obesity indicators based on the sodium index of university students are shown in Table 6. As the sodium index of Korean and Chinese university students increased from “moderate” to “careful” to “severe,” BMI, body fat mass, WHR, visceral fat level, and visceral fat area increased significantly at each stage (each P < 0.001). Additionally, body fat mass of Korean university students (P = 0.012) was significantly higher at the “severe” sodium index than at “moderate” and “careful.” However, the body fat mass of Chinese university students showed no difference according to the sodium index. Visceral fat mass (each P < 0.001) and subcutaneous fat mass (each P < 0.001) of Korean and Chinese university students were significantly higher at the “severe” sodium index stage than at the “moderate” and “careful” stages.

6. Analysis of obesity risk according to the sodium index of Korean and Chinese university students

The results of the analysis of obesity risk based on the sodium index of university students are shown in Table 7. For all obesity indicators except body fat percentage of university students, risk increased at the “careful” and “severe” stages based on the “moderate” sodium index, both before and after adjusting for sex and age.

After adjustment, the risk at the “severe” stage compared with that at the “moderate” stage increased 3.875-fold (P < 0.001) for BMI in Korean university students and 3.121-fold (P < 0.001) in Chinese university students. Body fat percentage increased 2.402-fold in Korean university students and 1.636-fold in Chinese university students (each P < 0.001). Additionally, after adjustment, the risk at the “severe” stage compared with that at the “moderate” stage increased 3.682-fold (P < 0.01) for WHR in Korean university students and 1.622-fold (P < 0.001) in Chinese university students. Visceral fat level increased 7.704-fold (P < 0.001) in Korean university students and 2.743-fold (P < 0.001) in Chinese university students. Visceral fat area, visceral fat mass, and subcutaneous fat mass showed an increasing risk as the sodium index progressed to “careful” and “severe” stages (each P < 0.001).

DISCUSSION

This study compared sodium-related awareness, nutritional knowledge, and the sodium index among university students from Korea and China, countries with high sodium intake, and analyzed obesity according to sodium index levels.

Korean and Chinese university students demonstrated high rates of recognizing that they eat salty food, and Korean university students had higher nutritional knowledge levels than their Chinese counterparts. However, no difference was observed in the estimated sodium intake and sodium index between Korean and Chinese university students. Additionally, as the sodium index increased from “moderate” to “careful” to “severe,” the risk of obesity increased, confirming the relationship between sodium intake and obesity.

In this study, 84% of university students reported consuming salty food, and the overall proportion recognizing the necessity of sodium reduction was 73.4%. This finding is similar to An’s study [32], which showed that 72.1% of single-person households recognized the need to reduce sodium intake. However, the proportion of university students who acknowledged the importance of consuming a bland diet was lower than the 87% reported in a study of citizens in Daegu, Korea [33] and the 94% reported among office workers in Seoul, Korea [34]. Additionally, the proportion of Chinese university students practicing sodium reduction was higher than that of their Korean counterparts. This finding confirms the need for educational interventions that promote behavioral changes, specifically the adoption of a bland diet, when teaching sodium reduction to Korean university students.

A comparison of sodium-related nutritional knowledge of university students revealed that Korean university students had higher overall nutritional knowledge levels than their Chinese counterparts; however, scores for items related to sodium intake standards and sodium substitute foods were low. University students belong to an age group with a high intake of foods with a high sodium content, such as eating-out meals, delivered meals, and processed foods. As shown in the results of this study, their nutritional knowledge about sodium intake standards and methods to reduce sodium intake during meals was very low, which may explain why their sodium intake was high. Therefore, it is necessary to educate university liberal arts courses on sodium reduction using not only theory but also tools such as salty taste assessment tools [29] and the sodium index [17], which investigate BMI and sodium-related dietary habits and behaviors to change dietary behaviors.

The average estimated sodium intake of Korean and Chinese university students in Daegu, Korea, in 2019 was 3,751.4 mg, corresponding to the “careful” level. This finding is similar to the estimated sodium intake of 3,907.1 mg among Korean university students reported by Jang et al. [31]. Additionally, compared with the average sodium intake of 3,457.6 mg for individuals aged 19–29 years in the 2019 Korea National Health and Nutrition Examination Survey, the estimated sodium intake of university students in this study was slightly higher. However, both belonged to the sodium index “careful” level. Regarding the distribution of sodium index, “careful” showed the highest overall prevalence, at 72.9%, among Korean and Chinese university students, consistent with the 76.7% reported in Jang et al.’s study [31] of university students in Daegu.

The results of comparing obesity indicators according to sodium index levels in university students revealed a relationship between excessive sodium intake and increased risk of obesity. Specifically, for both Korean and Chinese university students, as levels increased from “moderate” to “careful” to “severe,” BMI, WHR, and most body fat-related indicators increased significantly. Additionally, for obesity indicators, the risk of obesity increased significantly at the “careful” and “severe” stages compared with the “moderate” stage for both Korean and Chinese university students. Although some values appeared exaggerated, this result is consistent with previous studies [31, 35-39] that showed positive correlations between excessive sodium intake and obesity.

Specifically, a study [31] of university students in Daegu also showed that excessive sodium intake at the severe stage of the sodium index was associated with a 2.182-fold increase in the risk of obesity based on body fat percentage and a 4.073-fold increase based on visceral fat level. In a recent meta-analysis by Grimes et al. [35], sodium intake in adults was associated with a 1.74-fold increased risk of obesity and a 2.04-fold increased risk of abdominal obesity. Additionally, a study [36] on British children and adults analyzing salt intake and obesity risk through 24-hour urine collection showed that a 1 g increase in daily salt intake increased risk of obesity by 1.28-fold in children and 1.26-fold in adults. A study [37] of Chinese university students showed that body fat-related indicators increased significantly with increasing sodium intake. Park et al. [38] also reported positive correlations between sodium intake and body weight in males and body fat percentage in females, supporting the results of this study. A recent systematic review by Lee et al. [39] reported cross-sectional associations between sodium intake and obesity. The results of this study also showed that the risk of obesity increased significantly with increasing sodium index, confirming the relationship between sodium intake and obesity. Additionally, meta-analysis results [40] of dietary sodium intake and cardiovascular disease risk showed that cardiovascular disease risk increased by up to 6% for every 1 g increase in dietary sodium intake.

Limitations

This study had several limitations. First, as a study targeting individuals aged 20–24 years, its application is challenging to extend to individuals of various ages. Second, the participants were limited to university students in a specific region, requiring consideration of race and occupation. Third, participants were recruited on a first-come, first-served basis, resulting in an uneven distribution of obesity. Therefore, large-scale follow-up studies that include individuals of various ages, occupations, races, and obesity distributions are needed to secure sufficient data for education related to sodium intake reduction.

Conclusion

The results of this study confirmed that the risk of obesity increased as the sodium index increased in both Korean and Chinese university students, suggesting that excessive sodium intake affects the risk of obesity. The sodium index is expected to be actively utilized as a simple and useful tool not only for nationwide sodium reduction projects but also for obesity management projects in the future.

NOTES

CONFLICT OF INTEREST

There are no financial or other issues that might lead to conflict of interest.

FUNDING

None.

DATA AVAILABILITY

The data supporting the findings of this study are available from the corresponding author upon reasonable request.

SUPPLEMENTARY MATERIALS

Supplementary Table 1.

Dietary behaviors.

kjcn-2025-00318-Supplementary-Table-1.pdf

Table 1.

Criteria of sodium index based on the estimated sodium intake

Estimated sodium intake (mg)	Sodium index	Criteria
1,500–3,000	75–150	Moderate
< 1,500, > 3,000–5,000	< 75 or > 150–250	Careful
> 5,000	> 250	Severe

Estimation equation of 24-hour sodium intake = –191.9 + (–705.2 × sex¹⁾) + (189.6 × G_age²⁾) + (130.6 × BMI³⁾) + (24.2 × eating habit⁴⁾) + (18.5 × dietary behavior⁵⁾).

¹⁾1 = male, 2 = female.

²⁾1 = 19–29, 2 = 30–39, 3 = 40–49, 4 = 50–59, 5 = 60–69.

³⁾Body mass index.

⁴⁾Do you usually eat salty? Unsalty = 10, slightly unsalty = 20, neither unsalty nor salty = 30, slightly salty = 40, salty = 50.

⁵⁾20–100 of a total of 10 dietary behavior items (Supplementary Table 1).

Table 2.

Anthropometric measurements between Korean and Chinese university students

Variables	Korean (n = 110)		Chinese (n = 108)		P-value
Variables	Male (n = 63)	Female (n = 47)	Male (n = 60)	Female (n = 48)	P-value
Age (year)	23.6 ± 2.11^b	21.8 ± 2.04^a	23.2 ± 2.33^b	23.0 ± 2.34^b	0.010
Height (cm)	174.2 ± 5.79^b	162.9 ± 4.84^a	177.3 ± 6.38^c	163.0 ± 5.98^a	< 0.001
Weight (kg)	71.3 ± 10.0^b	58.2 ± 13.7^a	74.2 ± 12.5^b	57.1 ± 9.77^a	< 0.001
Body mass index (kg/m²)	23.2 ± 2.85^bc	21.9 ± 4.8^ab	23.6 ± 3.90^c	21.5 ± 3.53^a	0.008
Obesity (%)	16 (25.4)	9 (19.1)	15 (25.0)	7 (14.6)	0.473
Body fat percentage (%)	19.6 ± 5.27^a	25.8 ± 6.10^b	20.1 ± 6.10^a	26.4 ± 6.28^b	< 0.001
Obesity (%)	12 (19.0)	10 (21.3)	12 (20.0)	16 (33.3)	0.279
Waist-hip ratio	0.80 ± 0.05^b	0.75 ± 0.06^a	0.80 ± 0.62^b	0.76 ± 0.53^a	< 0.001
Visceral fat level	7.13 ± 2.05^b	5.04 ± 3.59^a	7.25 ± 2.58^b	5.33 ± 3.21^a	< 0.001
Visceral fat area (cm²)	64.5 ± 17.4^b	43.0 ± 29.5^a	67.8 ± 29.3^b	43.7 ± 21.2^a	< 0.001
Visceral fat mass (kg)	1.88 ± 0.87^a	1.94 ± 2.37^a	2.11 ± 1.41^a	1.60 ± 0.87^a	0.349
Subcutaneous fat mass (kg)	12.6 ± 4.45^a	13.7 ± 6.34^a	13.5 ± 5.92^a	14.0 ± 5.23^a	0.572
Muscle mass (kg)	52.3 ± 5.92^b	39.2 ± 5.58^a	54.4 ± 6.28^b	38.5 ± 3.84^a	< 0.001

Mean ± SD or n (%).

P-value using the F-test, χ² test.

^a–cMeans with different alphabets in each row are significantly different by Duncan’s multiple range test at P < 0.05.

Table 3.

Awareness of sodium reduction among university students

Variables	Total (n = 218)	Korean (n = 110)	Chinese (n = 108)	P-value
Food saltiness in diet
Very low	1 (0.5)	0 (0.0)	1 (0.9)	< 0.001
Low	4 (1.8)	2 (1.8)	2 (1.9)
Moderate	30 (13.8)	6 (5.5)	24 (22.2)
High	151 (69.3)	74 (67.3)	77 (71.3)
Very high	32 (14.7)	28 (25.5)	4 (3.7)
Necessity of sodium reduction in diet
Very unnecessary	1 (0.5)	0 (0.0)	1 (0.9)	0.745
Unnecessary	12 (5.5)	6 (5.5)	6 (5.6)
Natural	45 (20.6)	21 (19.1)	24 (22.2)
Necessary	127 (58.3)	64 (58.2)	63 (58.3)
Very necessary	33 (15.1)	19 (17.3)	14 (13.0)
Sodium reduction practices in diet
Never thinking about sodium reduction	109 (50.0)	69 (62.7)	40 (37.0)	0.001
Thinking about sodium reduction within the next six months	29 (13.3)	13 (11.8)	16 (14.8)
Having plan about sodium reduction within the next month	17 (7.8)	8 (7.3)	9 (8.3)
Doing sodium reduction already, but no more than six months	36 (16.5)	9 (8.2)	27 (25.0)
Doing sodium reduction already for more than six months	27 (12.4)	11 (10.0)	16 (14.8)

n (%).

P-value using χ² test.

Table 4.

Comparison of sodium-related nutrition knowledge of university students

Variables	Total (n = 218)	Korean (n = 110)	Chinese (n = 108)	P-value
Salt intake target per day is 2,000 mg¹⁾	0.20 ± 0.40	0.24 ± 0.42	0.16 ± 0.36	0.144
Consuming too much sodium can lead to high blood pressure, stroke, and cardiovascular disease, etc.	0.94 ± 0.25	0.94 ± 0.24	0.93 ± 0.24	0.972
Using bamboo salt instead of common salt can reduce sodium intake	0.53 ± 0.50	0.58 ± 0.48	0.48 ± 0.50	0.139
Noodles, bread, etc. are not salty, so they do not contain sodium	0.90 ± 0.30	0.96 ± 0.18	0.84 ± 0.36	0.003
Using flavor foods such as mustard instead of salt can reduce salt intake	0.32 ± 0.47	0.44 ± 0.49	0.20 ± 0.40	< 0.001
Using a lot of soy sauce instead of salt during cooking can reduce sodium	0.93 ± 0.26	0.98 ± 0.13	0.87 ± 0.33	0.002
Blanching processed foods (ham, canned goods) can reduce sodium intake	0.65 ± 0.48	0.77 ± 0.42	0.52 ± 0.50	< 0.001
Food additives used in processed food do not contain sodium	0.86 ± 0.35	0.89 ± 0.31	0.83 ± 0.37	0.220
The recommended daily amount of salt by World Health Organization is 10 g	0.31 ± 0.46	0.29 ± 0.45	0.32 ± 0.47	0.598
Consuming fresh fruits helps sodium excretion	0.79 ± 0.41	0.87 ± 0.33	0.70 ± 0.45	0.002
Total	6.43 ± 1.81	6.96 ± 1.48	5.87 ± 1.95	< 0.001

Mean ± SD.

P-value using t-test.

¹⁾1 point if correct, 0 point if incorrect or unknown.

Table 5.

Comparison in estimated sodium intake and sodium index of university students

Variables	Total (n = 218)	Korean (n = 110)	Chinese (n = 108)	P-value
Estimated sodium intake (mg)	3,751.4 ± 834.3	3,857.7 ± 834.3	3,643.4 ± 824.0	0.058
Male	4,190.0 ± 626.5	4,287.7 ± 563.6	4,087.3 ± 676.0	0.076
Female	3,183.8 ± 721.3	3,281.3 ± 793.2	3,088.4 ± 637.2	0.194
P-value	< 0.001	< 0.001	< 0.001
Sodium index	187.6 ± 41.7	192.8 ± 41.7	182.2 ± 41.2	0.059
Moderate	128.3 ± 19.9^a	125.8 ± 21.6^a	130.0 ± 18.8^a	0.492
Careful	196.9 ± 25.2^b	199.6 ± 25.7^b	194.0 ± 24.5^b	0.160
Severe	263.2 ± 20.7^c	258.5 ± 5.9^c	272.6 ± 35.5^c	0.427
P-value	< 0.001	< 0.001	< 0.001
Sodium index
Moderate	44 (20.2)	18 (16.4)	26 (24.1)	0.196
Careful	159 (72.9)	82 (74.5)	77 (71.3)
Severe	15 (6.9)	10 (9.1)	5 (4.6)

Mean ± SD or n (%).

P-value using the t-test, χ² test.

^a–cMeans with different alphabets in each row are significantly different by Duncan’s multiple range test at P < 0.05.

Table 6.

Comparison of obesity indicators according to sodium index levels of university students

Variables	Korean					Chinese
Variables	Total (n = 110)	Moderate (n = 18)	Careful (n = 82)	Severe (n = 10)	P-value	Total (n = 108)	Moderate (n = 26)	Careful (n = 77)	Severe (n = 5)	P-value
Body mass index (kg/m²)	22.7 ± 3.83	19.0 ± 2.34^a	22.9 ± 3.28^b	27.7 ± 3.77^c	< 0.001	22.7 ± 3.87	19.4 ± 2.27^a	23.3 ± 3.00^b	31.1 ± 3.86^c	< 0.001
Body fat mass (kg)	15.1 ± 6.55	10.9 ± 3.63^a	14.9 ± 5.8^b	23.7 ± 9.00^c	< 0.001	15.6 ± 6.75	11.8 ± 3.66^a	16.0 ± 6.10^b	28.8 ± 10.6^c	< 0.001
Body fat percentage (%)	22.3 ± 6.44	20.9 ± 3.78^a	21.9 ± 6.57^a	27.9 ± 6.80^b	0.012	22.9 ± 6.90	22.3 ± 5.55^a	22.7 ± 7.22^a	28.5 ± 6.91^a	0.172
Waist-hip ratio	0.78 ± 0.06	0.72 ± 0.04^a	0.79 ± 0.05^b	0.86 ± 0.04^c	< 0.001	0.78 ± 0.06	0.73 ± 0.04^a	0.79 ± 0.05^b	0.89 ± 0.09^c	< 0.001
Visceral fat level	6.24 ± 2.99	2.72 ± 1.27^a	6.54 ± 2.49^b	10.1 ± 2.73^c	< 0.001	6.40 ± 3.02	3.65 ± 2.00^a	7.04 ± 2.56^b	10.8 ± 3.56^c	< 0.001
Visceral fat area (cm²)	55.3 ± 25.6	27.9 ± 7.39^a	56.5 ± 20.1^b	95.2 ± 30.6^c	< 0.001	57.1 ± 28.6	32.5 ± 9.56^a	61.7 ± 21.2^b	113.6 ± 66.7^c	< 0.001
Visceral fat mass (kg)	1.90 ± 1.67	0.94 ± 0.39^a	1.94 ± 1.72^a	3.38 ± 1.68^b	< 0.001	1.88 ± 0.11	1.08 ± 0.40^a	1.97 ± 0.95^a	4.68 ± 2.83^b	< 0.001
Subcutaneous fat mass (kg)	13.1 ± 5.34	9.95 ± 3.24^a	12.9 ± 4.65^a	20.2 ± 7.39^b	< 0.001	13.7 ± 5.61	10.7 ± 3.27^a	14.1 ± 5.19^a	24.3 ± 7.67^b	< 0.001

Mean ± SD.

^a–cMeans with different letters in each row are significantly different according to Duncan’s multiple-range test at P < 0.05.

Table 7.

Odds ratio for obesity according to sodium index levels by multiple logistic regression of university students

Variables	Sodium index, OR (95% CI)
	Korean			Chinese
	Moderate (n = 18)	Careful (n = 82)	Severe (n = 10)	Moderate (n = 26)	Careful (n = 77)	Severe (n = 5)
Body mass index (kg/m²)
Unadjusted	1.000	1.964 (1.405–2.745)^^^*	2.690 (1.817–3.981)^^^*	1.000	1.844 (1.410–2.413)^^^*	3.156 (1.960–5.084)^^^*
Adjusted	1.000	1.780 (1.224–2.586)^^	3.875 (2.093–7.176)^^^*	1.000	1.774 (1.296–2.428)^^^*	3.121 (1.843–5.286)^^^*
Body fat mass (kg)
Unadjusted	1.000	1.237 (1.068–1.433)^^	1.446 (1.210–1.728)^^^*	1.000	1.181 (1.063–1.312)^^	1.466 (1.211–1.774)^^^*
Adjusted	1.000	1.403 (1.127–1.747)^^	2.051 (1.483–2.836)^^^*	1.000	1.371 (1.151–1.634)^^^*	1.823 (1.369–2.428)^^^*
Body fat percentage (%)
Unadjusted	1.000	1.029 (0.943–1.122)	1.175 (1.035–1.333)^*	1.000	1.010 (0.945–1.079)	1.145 (0.986–1.328)
Adjusted	1.000	1.481 (1.184–1.852)^^^*	2.402 (1.643–3.514)^^^*	1.000	1.259 (1.104–1.436)^^^*	1.636 (1.277–2.096)^^^*
Waist-hip ratio
Unadjusted	1.000	1.366 (1.178–1.584)^^^*	2.039 (1.549–2.684)^^^*	1.000	1.263 (1.139–1.400)^^^*	1.707 (1.302–2.238)^^^*
Adjusted	1.000	1.317 (1.104–1.571)^^	3.682 (1.593–8.513)^^	1.000	1.238 (1.093–1.402)^^^*	1.622 (1.231–2.137)^^^*
Visceral fat level
Unadjusted	1.000	2.603 (1.647–4.114)^^^*	4.294 (2.472–7.458)^^^*	1.000	1.726 (1.372–2.171)^^^*	2.883 (1.813–4.586)^^^*
Adjusted	1.000	2.279 (1.353–3.838)^^	7.704 (2.891–20.530)^^^*	1.000	1.541 (1.206–1.970)^^^*	2.743 (1.597–4.710)^^^*
Visceral fat area (cm²)
Unadjusted	1.000	1.174 (1.077–1.280)^^^*	1.246 (1.135–1.367)^^^*	1.000	1.120 (1.069–1.173)^^^*	1.169 (1.100–1.242)^^^*
Adjusted	1.000	1.158 (1.047–1.280)^^	1.394 (1.181–1.645)^^^*	1.000	1.088 (1.036–1.143)^^^*	1.133 (1.064–1.207)^^^*
Visceral fat mass (kg)
Unadjusted	1.000	1.343 (1.142–1.579)^^^*	1.381 (1.172–1.629)^^^*	1.000	1.230 (1.111–1.362)^^^*	1.387 (1.206–1.595)^^^*
Adjusted	1.000	1.327 (1.090–1.615)^^	1.399 (1.143–1.713)^^	1.000	1.262 (1.106–1.440)^^^*	1.427 (1.208–1.685)^^^*
Subcutaneous fat mass (kg)
Unadjusted	1.000	1.243 (1.055–1.465)^^	1.516 (1.230–1.869)^^^*	1.000	1.189 (1.058–1.337)^^	1.558 (1.243–1.952)^^^*
Adjusted	1.000	1.481 (1.147–1.911)^^	2.340 (1.591–3.441)^^^*	1.000	1.440 (1.176–1.763)^^^*	2.118 (1.470–3.051)^^^*

Multiple logistic regression for obesity with sodium index adjusted for age and sex.

OR, odds ratio; CI, confidence interval.

^*P < 0.05,

^**P < 0.01,

^***P < 0.001.

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The association between sodium index and the risk of obesity in Korean and Chinese university students: a cross-sectional study

Korean J Community Nutr. 2025;30(6):419-430. Published online December 31, 2025

DOI: https://doi.org/10.5720/kjcn.2025.00318

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The association between sodium index and the risk of obesity in Korean and Chinese university students: a cross-sectional study

Estimated sodium intake (mg)	Sodium index	Criteria
1,500–3,000	75–150	Moderate
< 1,500, > 3,000–5,000	< 75 or > 150–250	Careful
> 5,000	> 250	Severe

Variables	Korean (n = 110)		Chinese (n = 108)		P-value
Variables	Male (n = 63)	Female (n = 47)	Male (n = 60)	Female (n = 48)	P-value
Age (year)	23.6 ± 2.11^b	21.8 ± 2.04^a	23.2 ± 2.33^b	23.0 ± 2.34^b	0.010
Height (cm)	174.2 ± 5.79^b	162.9 ± 4.84^a	177.3 ± 6.38^c	163.0 ± 5.98^a	< 0.001
Weight (kg)	71.3 ± 10.0^b	58.2 ± 13.7^a	74.2 ± 12.5^b	57.1 ± 9.77^a	< 0.001
Body mass index (kg/m²)	23.2 ± 2.85^bc	21.9 ± 4.8^ab	23.6 ± 3.90^c	21.5 ± 3.53^a	0.008
Obesity (%)	16 (25.4)	9 (19.1)	15 (25.0)	7 (14.6)	0.473
Body fat percentage (%)	19.6 ± 5.27^a	25.8 ± 6.10^b	20.1 ± 6.10^a	26.4 ± 6.28^b	< 0.001
Obesity (%)	12 (19.0)	10 (21.3)	12 (20.0)	16 (33.3)	0.279
Waist-hip ratio	0.80 ± 0.05^b	0.75 ± 0.06^a	0.80 ± 0.62^b	0.76 ± 0.53^a	< 0.001
Visceral fat level	7.13 ± 2.05^b	5.04 ± 3.59^a	7.25 ± 2.58^b	5.33 ± 3.21^a	< 0.001
Visceral fat area (cm²)	64.5 ± 17.4^b	43.0 ± 29.5^a	67.8 ± 29.3^b	43.7 ± 21.2^a	< 0.001
Visceral fat mass (kg)	1.88 ± 0.87^a	1.94 ± 2.37^a	2.11 ± 1.41^a	1.60 ± 0.87^a	0.349
Subcutaneous fat mass (kg)	12.6 ± 4.45^a	13.7 ± 6.34^a	13.5 ± 5.92^a	14.0 ± 5.23^a	0.572
Muscle mass (kg)	52.3 ± 5.92^b	39.2 ± 5.58^a	54.4 ± 6.28^b	38.5 ± 3.84^a	< 0.001

Variables	Total (n = 218)	Korean (n = 110)	Chinese (n = 108)	P-value
Food saltiness in diet
Very low	1 (0.5)	0 (0.0)	1 (0.9)	< 0.001
Low	4 (1.8)	2 (1.8)	2 (1.9)
Moderate	30 (13.8)	6 (5.5)	24 (22.2)
High	151 (69.3)	74 (67.3)	77 (71.3)
Very high	32 (14.7)	28 (25.5)	4 (3.7)
Necessity of sodium reduction in diet
Very unnecessary	1 (0.5)	0 (0.0)	1 (0.9)	0.745
Unnecessary	12 (5.5)	6 (5.5)	6 (5.6)
Natural	45 (20.6)	21 (19.1)	24 (22.2)
Necessary	127 (58.3)	64 (58.2)	63 (58.3)
Very necessary	33 (15.1)	19 (17.3)	14 (13.0)
Sodium reduction practices in diet
Never thinking about sodium reduction	109 (50.0)	69 (62.7)	40 (37.0)	0.001
Thinking about sodium reduction within the next six months	29 (13.3)	13 (11.8)	16 (14.8)
Having plan about sodium reduction within the next month	17 (7.8)	8 (7.3)	9 (8.3)
Doing sodium reduction already, but no more than six months	36 (16.5)	9 (8.2)	27 (25.0)
Doing sodium reduction already for more than six months	27 (12.4)	11 (10.0)	16 (14.8)

Variables	Total (n = 218)	Korean (n = 110)	Chinese (n = 108)	P-value
Salt intake target per day is 2,000 mg¹⁾	0.20 ± 0.40	0.24 ± 0.42	0.16 ± 0.36	0.144
Consuming too much sodium can lead to high blood pressure, stroke, and cardiovascular disease, etc.	0.94 ± 0.25	0.94 ± 0.24	0.93 ± 0.24	0.972
Using bamboo salt instead of common salt can reduce sodium intake	0.53 ± 0.50	0.58 ± 0.48	0.48 ± 0.50	0.139
Noodles, bread, etc. are not salty, so they do not contain sodium	0.90 ± 0.30	0.96 ± 0.18	0.84 ± 0.36	0.003
Using flavor foods such as mustard instead of salt can reduce salt intake	0.32 ± 0.47	0.44 ± 0.49	0.20 ± 0.40	< 0.001
Using a lot of soy sauce instead of salt during cooking can reduce sodium	0.93 ± 0.26	0.98 ± 0.13	0.87 ± 0.33	0.002
Blanching processed foods (ham, canned goods) can reduce sodium intake	0.65 ± 0.48	0.77 ± 0.42	0.52 ± 0.50	< 0.001
Food additives used in processed food do not contain sodium	0.86 ± 0.35	0.89 ± 0.31	0.83 ± 0.37	0.220
The recommended daily amount of salt by World Health Organization is 10 g	0.31 ± 0.46	0.29 ± 0.45	0.32 ± 0.47	0.598
Consuming fresh fruits helps sodium excretion	0.79 ± 0.41	0.87 ± 0.33	0.70 ± 0.45	0.002
Total	6.43 ± 1.81	6.96 ± 1.48	5.87 ± 1.95	< 0.001

Variables	Total (n = 218)	Korean (n = 110)	Chinese (n = 108)	P-value
Estimated sodium intake (mg)	3,751.4 ± 834.3	3,857.7 ± 834.3	3,643.4 ± 824.0	0.058
Male	4,190.0 ± 626.5	4,287.7 ± 563.6	4,087.3 ± 676.0	0.076
Female	3,183.8 ± 721.3	3,281.3 ± 793.2	3,088.4 ± 637.2	0.194
P-value	< 0.001	< 0.001	< 0.001
Sodium index	187.6 ± 41.7	192.8 ± 41.7	182.2 ± 41.2	0.059
Moderate	128.3 ± 19.9^a	125.8 ± 21.6^a	130.0 ± 18.8^a	0.492
Careful	196.9 ± 25.2^b	199.6 ± 25.7^b	194.0 ± 24.5^b	0.160
Severe	263.2 ± 20.7^c	258.5 ± 5.9^c	272.6 ± 35.5^c	0.427
P-value	< 0.001	< 0.001	< 0.001
Sodium index
Moderate	44 (20.2)	18 (16.4)	26 (24.1)	0.196
Careful	159 (72.9)	82 (74.5)	77 (71.3)
Severe	15 (6.9)	10 (9.1)	5 (4.6)

Variables	Korean					Chinese
Variables	Total (n = 110)	Moderate (n = 18)	Careful (n = 82)	Severe (n = 10)	P-value	Total (n = 108)	Moderate (n = 26)	Careful (n = 77)	Severe (n = 5)	P-value
Body mass index (kg/m²)	22.7 ± 3.83	19.0 ± 2.34^a	22.9 ± 3.28^b	27.7 ± 3.77^c	< 0.001	22.7 ± 3.87	19.4 ± 2.27^a	23.3 ± 3.00^b	31.1 ± 3.86^c	< 0.001
Body fat mass (kg)	15.1 ± 6.55	10.9 ± 3.63^a	14.9 ± 5.8^b	23.7 ± 9.00^c	< 0.001	15.6 ± 6.75	11.8 ± 3.66^a	16.0 ± 6.10^b	28.8 ± 10.6^c	< 0.001
Body fat percentage (%)	22.3 ± 6.44	20.9 ± 3.78^a	21.9 ± 6.57^a	27.9 ± 6.80^b	0.012	22.9 ± 6.90	22.3 ± 5.55^a	22.7 ± 7.22^a	28.5 ± 6.91^a	0.172
Waist-hip ratio	0.78 ± 0.06	0.72 ± 0.04^a	0.79 ± 0.05^b	0.86 ± 0.04^c	< 0.001	0.78 ± 0.06	0.73 ± 0.04^a	0.79 ± 0.05^b	0.89 ± 0.09^c	< 0.001
Visceral fat level	6.24 ± 2.99	2.72 ± 1.27^a	6.54 ± 2.49^b	10.1 ± 2.73^c	< 0.001	6.40 ± 3.02	3.65 ± 2.00^a	7.04 ± 2.56^b	10.8 ± 3.56^c	< 0.001
Visceral fat area (cm²)	55.3 ± 25.6	27.9 ± 7.39^a	56.5 ± 20.1^b	95.2 ± 30.6^c	< 0.001	57.1 ± 28.6	32.5 ± 9.56^a	61.7 ± 21.2^b	113.6 ± 66.7^c	< 0.001
Visceral fat mass (kg)	1.90 ± 1.67	0.94 ± 0.39^a	1.94 ± 1.72^a	3.38 ± 1.68^b	< 0.001	1.88 ± 0.11	1.08 ± 0.40^a	1.97 ± 0.95^a	4.68 ± 2.83^b	< 0.001
Subcutaneous fat mass (kg)	13.1 ± 5.34	9.95 ± 3.24^a	12.9 ± 4.65^a	20.2 ± 7.39^b	< 0.001	13.7 ± 5.61	10.7 ± 3.27^a	14.1 ± 5.19^a	24.3 ± 7.67^b	< 0.001

Variables	Sodium index, OR (95% CI)
	Korean			Chinese
	Moderate (n = 18)	Careful (n = 82)	Severe (n = 10)	Moderate (n = 26)	Careful (n = 77)	Severe (n = 5)
Body mass index (kg/m²)
Unadjusted	1.000	1.964 (1.405–2.745)^{^{^^}^*}	2.690 (1.817–3.981)^{^{^^}^*}	1.000	1.844 (1.410–2.413)^{^{^^}^*}	3.156 (1.960–5.084)^{^{^^}^*}
Adjusted	1.000	1.780 (1.224–2.586)^{^^}	3.875 (2.093–7.176)^{^{^^}^*}	1.000	1.774 (1.296–2.428)^{^{^^}^*}	3.121 (1.843–5.286)^{^{^^}^*}
Body fat mass (kg)
Unadjusted	1.000	1.237 (1.068–1.433)^{^^}	1.446 (1.210–1.728)^{^{^^}^*}	1.000	1.181 (1.063–1.312)^{^^}	1.466 (1.211–1.774)^{^{^^}^*}
Adjusted	1.000	1.403 (1.127–1.747)^{^^}	2.051 (1.483–2.836)^{^{^^}^*}	1.000	1.371 (1.151–1.634)^{^{^^}^*}	1.823 (1.369–2.428)^{^{^^}^*}
Body fat percentage (%)
Unadjusted	1.000	1.029 (0.943–1.122)	1.175 (1.035–1.333)^*	1.000	1.010 (0.945–1.079)	1.145 (0.986–1.328)
Adjusted	1.000	1.481 (1.184–1.852)^{^{^^}^*}	2.402 (1.643–3.514)^{^{^^}^*}	1.000	1.259 (1.104–1.436)^{^{^^}^*}	1.636 (1.277–2.096)^{^{^^}^*}
Waist-hip ratio
Unadjusted	1.000	1.366 (1.178–1.584)^{^{^^}^*}	2.039 (1.549–2.684)^{^{^^}^*}	1.000	1.263 (1.139–1.400)^{^{^^}^*}	1.707 (1.302–2.238)^{^{^^}^*}
Adjusted	1.000	1.317 (1.104–1.571)^{^^}	3.682 (1.593–8.513)^{^^}	1.000	1.238 (1.093–1.402)^{^{^^}^*}	1.622 (1.231–2.137)^{^{^^}^*}
Visceral fat level
Unadjusted	1.000	2.603 (1.647–4.114)^{^{^^}^*}	4.294 (2.472–7.458)^{^{^^}^*}	1.000	1.726 (1.372–2.171)^{^{^^}^*}	2.883 (1.813–4.586)^{^{^^}^*}
Adjusted	1.000	2.279 (1.353–3.838)^{^^}	7.704 (2.891–20.530)^{^{^^}^*}	1.000	1.541 (1.206–1.970)^{^{^^}^*}	2.743 (1.597–4.710)^{^{^^}^*}
Visceral fat area (cm²)
Unadjusted	1.000	1.174 (1.077–1.280)^{^{^^}^*}	1.246 (1.135–1.367)^{^{^^}^*}	1.000	1.120 (1.069–1.173)^{^{^^}^*}	1.169 (1.100–1.242)^{^{^^}^*}
Adjusted	1.000	1.158 (1.047–1.280)^{^^}	1.394 (1.181–1.645)^{^{^^}^*}	1.000	1.088 (1.036–1.143)^{^{^^}^*}	1.133 (1.064–1.207)^{^{^^}^*}
Visceral fat mass (kg)
Unadjusted	1.000	1.343 (1.142–1.579)^{^{^^}^*}	1.381 (1.172–1.629)^{^{^^}^*}	1.000	1.230 (1.111–1.362)^{^{^^}^*}	1.387 (1.206–1.595)^{^{^^}^*}
Adjusted	1.000	1.327 (1.090–1.615)^{^^}	1.399 (1.143–1.713)^{^^}	1.000	1.262 (1.106–1.440)^{^{^^}^*}	1.427 (1.208–1.685)^{^{^^}^*}
Subcutaneous fat mass (kg)
Unadjusted	1.000	1.243 (1.055–1.465)^{^^}	1.516 (1.230–1.869)^{^{^^}^*}	1.000	1.189 (1.058–1.337)^{^^}	1.558 (1.243–1.952)^{^{^^}^*}
Adjusted	1.000	1.481 (1.147–1.911)^{^^}	2.340 (1.591–3.441)^{^{^^}^*}	1.000	1.440 (1.176–1.763)^{^{^^}^*}	2.118 (1.470–3.051)^{^{^^}^*}

Table 1. Criteria of sodium index based on the estimated sodium intake

Estimation equation of 24-hour sodium intake = –191.9 + (–705.2 × sex¹⁾) + (189.6 × G_age²⁾) + (130.6 × BMI³⁾) + (24.2 × eating habit⁴⁾) + (18.5 × dietary behavior⁵⁾).

1 = male, 2 = female.

1 = 19–29, 2 = 30–39, 3 = 40–49, 4 = 50–59, 5 = 60–69.

Body mass index.

Do you usually eat salty? Unsalty = 10, slightly unsalty = 20, neither unsalty nor salty = 30, slightly salty = 40, salty = 50.

20–100 of a total of 10 dietary behavior items (Supplementary Table 1).

Table 2. Anthropometric measurements between Korean and Chinese university students

Mean ± SD or n (%).

P-value using the F-test, χ² test.

a–c

Means with different alphabets in each row are significantly different by Duncan’s multiple range test at P < 0.05.

Table 3. Awareness of sodium reduction among university students

n (%).

P-value using χ² test.

Table 4. Comparison of sodium-related nutrition knowledge of university students

Mean ± SD.

P-value using t-test.

1 point if correct, 0 point if incorrect or unknown.

Table 5. Comparison in estimated sodium intake and sodium index of university students

Mean ± SD or n (%).

P-value using the t-test, χ² test.

a–c

Means with different alphabets in each row are significantly different by Duncan’s multiple range test at P < 0.05.

Table 6. Comparison of obesity indicators according to sodium index levels of university students

Mean ± SD.

a–c

Means with different letters in each row are significantly different according to Duncan’s multiple-range test at P < 0.05.

Table 7. Odds ratio for obesity according to sodium index levels by multiple logistic regression of university students

Multiple logistic regression for obesity with sodium index adjusted for age and sex.

OR, odds ratio; CI, confidence interval.

P < 0.05,

P < 0.01,

***

P < 0.001.