DOI: https://doi.org/10.21203/rs.3.rs-1480877/v1
Background:
With the accelerated pace of people's life and the changed dietary patterns, the number of chronic diseases is increasing and occurring at a younger age in today's society. The speedily rising patients with hypertension led it to becoming one of the main risk factors for chronic diseases. People should focus on health literacy related to salt consumption and reach a better quality of life. At present, there is a lack of local assessment tools for low salt consumption in mainland China.
Objective:
To develop a short-form version of Chinese Health Literacy Scale For Low Salt Consumption instrument for using in mainland China.
Methods:
A cross-sectional design was conducted in a sample of 1472 people in Liaoxi, China. Participants completed a sociodemographic questionnaire, the Chinese version of the CHLSalt-22, the measuring change in restriction of salt (sodium) in diet in hypertensives (MCRSDH-SUST), the Brief Illness Perception Questionnaire (BIPQ) and the Benefit-Finding Scales (BFS) to test the hypothesis. Exploratory factor analysis and confirmatory factor analyses were performed to examine the underlying factor structure of the CHLSalt-22. One month later, 37 patients who participated in the first test were recruited to evaluate the test–retest reliability.
Results:
The CHLSalt-22 demonstrated adequate internal consistency, good test–retest reliability and satisfactory construct validity, convergent validity and discriminant validity. The CHLSalt-22 count scores were correlated with age, sex, body mass index (BMI), education level, income, occupation, the Measuring Change in Restriction of Salt (sodium) in Diet in Hypertensives (MCRSDH-SUST), the Brief Illness Perception Questionnaire (BIPQ), and the Benefit-Finding Scales (BFS).
Conclusion:
The results indicate that the version of the Chinese Health Literacy Scale For Low Salt Consumption (CHLSalt-22) has good reliability and validity, and that it can be considered a tool to assess health literacy related to salt consumption in health screenings.
The Seventh National Population Census in China showed that the population aged 65 years and above were accounted for 13.50 percent, with an increase of 5.44% from 2010[1]. The increasing number and larger base of the elderly have led to an increasing prevalence of chronic diseases, such as hypertension. According to the standard blood pressure values established by the Chinese Hypertension Association in 2021, the standard blood pressure values were categorized as 130/85. By 2020, the number of people with hypertension had reached 270 million in China, and only 14.5% of these case were well controlled[2] .
The World Health Organization (WHO) has developed several measures to address the increasing number of people diagnosed with hypertension [3, 4]. Among the affected factors, the Dietary Approach to Stop Hypertension (DASH) might be the most effective intervention for lowering BP in adults with prehypertension to establish hypertension [5, 6]. Indeed, a modest reduction in dietary salt intake, in which the use of “low-salt” (i.e., 0.3 g/100g) bread played a key role along with dietary advice [7]. In Organization for Economic Co-operation and Development (OECD) member countries, the measure of salt reduction could be cost-effective in the prevention of hypertension[8]. In India, reduced-sodium added-potassium salt led to a significant reduction of in SBP in patients with hypertension[9]. According to previous studies, dietary modifications that lowered BP include reduced sodium intake, weight loss, moderation of alcohol consumption, and healthy dietary patterns [10, 11]. Cross-sectional studies have showed that salt intake is significantly associated with hypertension[12, 13], and sodium intake is a potential factor independent of other influencing factors [14]. In conclusion, a low-salt diet has been promoted worldwide, which shows that it is necessary to improve abnormal eating behaviors and habits in a person's dietary lifestyle [15].
Several interventions and studies have showed the knowledge, attitudes, and behaviors associated with dietary sodium reduction[16]. However, consumer understanding of salt and salt reduction is still limited in China [17]. Currently, the COVID-19 epidemic may have influenced the salt-related knowledge and behaviors of hypertensive patients in China [18]. According to the results of the China National Nutrition and Health Survey, the average daily salt intake was 9.3 grams per person. Although there was a decrease of 1.2 grams compared to the results published in 2015, which was much higher than the maximum daily salt intake (6 g/d) recommended by “Dietary Guidelines for Chinese Residents” [19]. The World Health Organization’s (WHO) Global Action Plan for the Prevention and Control on Noncommunicable Diseases (2013–2020) said that salt intake should be correspondingly reduced by 30 percent [20]. The study of China’s Zhejiang Province is a population-based survey of 7512 residents, only 12.0% of participants once used or were currently using Salt-Restriction Spoons (SRS) [21]. One study showed that the school-based health education levels significantly reduced systolic BP among parents [22]. However, in another study, the effects of sodium reduction were more evident at higher starting blood pressure levels, older age, and among non-white populations [23]. This shows that reducing salt intake and realizing health literacy of low salt intake are essential for a person's health. Therefore, it is especially significant for Chinese people to know about the health literacy of low salt intake and to control the amount of salt consumed in daily life.
From the available studies, it is known that several scholars have developed tools for the assessment of various aspects of salt. Based on an extension of the Theory of Planned Behavior (TPB), the instrument was used to study the determinant factors of salt consumption among hypertensive subjects. The final tool, comprises three different behaviors related to salt consumption [24]. Roghayeh Chenary developed an instrument based on the same TPB to measure the factors affecting salt-restriction behaviors among women. There are three different salt intake behaviors, including adding salt during cooking, at the table and purchasing salty food [25]. The dietary sodium restriction questionnaire (DSRQ) of 15-item is composed of three subscales: attitude, subjective norm and perceived behavioral control [26]. The Scored Sodium Questionnaire (SSQ) is used in the routine clinical care of patients with chronic kidney disease (CKD) [27]. The Dietary Sodium Reduction Self-Care Agency Scale (DSR-SCA Scale) of 24 items measures the capability or self-care agency of lowering salt consumption in older adults with hypertension [28].
According to the literatures, there are many studies on the influence of salt intake (sodium) on hypertension and other chronic diseases. However, there are not only a few surveys about knowledge, attitudes, and dietary practices related to low salt consumption but also a validated scale on health literacy related to low salt consumption in mainland China. Therefore, this study conducted cultural adjustment of CHLSalt-HK and revised the low-salt healthy element nutrition scale adapted to mainland China. To this end, we will revise CHlSalt-HK and apply it to the mainland Chinese population to measure their low salt health literacy level. Furthermore, we provide a theoretical basis and data support for healthy quality and low salt.
Design and participants
A cross-sectional survey was conducted in Liaoning Province, China, from August to December 2021. The participants were hypertensive patients from Fuxin, Chaoyang, Panjin and Jinzhou. All patients provided informed consent before participating in the study. The research procedures complied with the ethical standards of the Ethics Committee of Jinzhou Medical College, as well as the 1964 Helsinki Declaration and its later amendments. A total of 1577 hypertensive patients took part in the survey. During the survey, the authors and investigators explained the study’s purpose and methods of the study to patients. The questionnaires were individually delivered to each participant and completed in the presence of the authors and the investigator. The participants were encouraged to give truthful answers. Subjects who had not fully completed the scale and provided questionnaires with obvious logical errors were excluded. The remaining 1472 patients (93.34%) were retained. The survey was anonymous, except that 37 patients in Jinzhou were required to write their names as the test–retest participants. One month later, 37 patients who participated in the first test were recruited to evaluate the test–retest reliability.
Revision process
The first step
We obtained permission from Dr PH Chau to revise and verify the Chinese Health Literacy Scale For Low Salt Consumption.
The second step
We then compared the questions with the corresponding culture together with the researchers, companies and professors. Revising some items to conform to the diet. Considering the different food preferences between Hong Kong and the mainland in China, we replaced some food examples with this scale. Finally, a pilot study was conducted among 37 patients with hypertension. They were invited to complete the scale and then were asked about their understanding of the scale’s introduction section, items, and options. We communicated with the survey respondents, who reported that they had no difficulty understanding the content of each item of the scale, and the revised version of the scale was obtained.
The third step
The revised scale was investigated in 469 older. Through statistical analysis, experts and group discussions and literature studies, the official scale was finally obtained. The scale was tested in 300 non-hypertensive subjects to determine its explanatory degree and stability.
The fourth step
We applied the CHLSalt-22 scale and investigated 1003 questionnaires.
Measurements
All participants completed the CHLSalt-HK [29], the measuring change in restriction of salt (sodium) in diet in hypertensives (MCRSDH-SUST) [30], the Brief Illness Perception Questionnaire (BIPQ) [31] and the Benefit Finding Scales(BFS) [32]. Participants were also asked to complete a checklist assessing sociodemographic variables (e.g., sex, age, and income). Height and weight were also self-reported to calculate the body mass index (BMI) of each participant. Participants were categorized as underweight (<18.5kg/m2), normal weight (18.5-23.9kg/m2), overweight (24-27.9kg/m2), and obese (≥28kg/m2) based on Chinese criteria of weight for adults [33].
Modified the Chinese Health Literacy Scale For Low Salt Consumption (CHLSalt-22)
In the research process, many people said that it was very complicated to complete the questionnaire, which took a long time and had many questions. When filling in the questionnaire, the patients felt that their functional literacy and knowledge of international standards were similar. After experts and a literature review, the two dimensions were combined into one dimension. In terms of statistics, experts said that a scale should have no more than seven dimensions. According to the relevant experts and group discussion, the appropriate items were selected, and finally, 22 items were formed.
The CHLSalt-22 consists of 22 items: three items assess Functional literacy, four items assess Salty food knowledge, three items assess Disease knowledge, three items assess Myths about salt intake, three items assess Salt intake attitudes,three items assess Salty food consumption and three items assess Nutrition label practices. For the Likert-scale questions, a score of 2 was assigned to the most favorable option, a score of 1 was assigned to the following profitable option, and a score of 0 was assigned to the remaining three options. For the multiple-choice questions, a score of 2 was assigned to the correct answer, and a score of 0 was assigned to the remaining options. The total score was calculated by summing up the scores for each item [29].
The measuring change in restriction of salt (sodium) in diet in hypertensives (MCRSDH-SUST)
The Continuous Behavior Change Sub-scale (McRsdh-sust) includes nine items, including emotional change (three items), behavior change practice (three items) and social environment change (three items). Likert 5 rating method was used for this scale, 0 = "very uncertain”, 1 = "uncertain”, 2 = "not certain", 3 = "certain", 4 = "very certain". The higher the McRsdh-sust total score, the more likely the hypertensive patients were to change the behavior of the salt-restriction diet [30].
The Brief Illness Perception Questionnaire(BIPQ)
The Brief Illness Perception Questionnaire (BIPQ) was compiled by Broadben et al., which included the symptoms of cognitive diseases and the degree of understanding of patients with emotional disorder dimensions, a total of 8 items, for the self-assessment questionnaire, cognitive disease representation, including disease influence course, symptom recognition, individual control, treatment control, emotional disease representation, including disease worry and mood, and each item was rated from 0 to 10, with a total score of 80 points [31]. The higher the score, the stronger was the negative perception.
The Benefit Finding Scale( BFS)
The Chinese scale includes 19 items, all of which are scored on a Likert level 4, with 1 to 4 points assigned from none to very much. The total score was 19-76, and the higher the score was, the higher the perceived benefit level of the participant. The Cronbach’s α coefficient of the scale in this study was 0.910 [32].
Statistical analysis of data
Data analysis was performed using SPSS 26.0, JASP 0.16, and Mplus 8.0. Given that all the items were dichotomous, Kuder-Richardson’s α (KR-20) was used to assess the internal consistency of the CHLSalt-22. The test–retest correlation coefficient (intraclass correlation coefficient, ICC) was used to calculate the scale’s stability. Values of ICC were interpreted as follows: >0.75 was excellent, between 0.40 and 0.75 was fair to good, and<0.40 was poor [34]. Content validity index (CVI) and Pearson’s correlation coefficients between items and total scores were used to evaluate the content validity of the scale. The CVI includes item-level content validity index (I-CVI) and average S-CVI (S-CVI/Ave) [35]. Each expert chose the relevance of each item to the corresponding dimension. A 4-point rating scale was used to calculate CVI (1=no relevance, 2=low relevance, 3=strong relevance, 4=very strong relevance).EFA and CFA were used to examine the construct validity of the CHLSalt-22. Data were divided into two groups. Sample 1 consisted of 469 hypertensive patients (53.3% women, mean BMI=26.61, SD=3.12), while sample 2 consisted of 1003 hypertensive patients (32.2% women, mean BMI=26.89, SD=3.61). The factor ability of the correlation matrix was assessed with the Kaiser–Meyer–Olkin (KMO) statistic and Bartlett’s test for sphericity [36], and EFA was conducted on sample 1. A scree plot was used to constructed to determine the number of factors. CFA was performed on Sample 1 and 2, and the test level was α=0.05. To assess the quality of the factor model, the following indices were estimated: minimum function chi-square (χ2), comparative fit index (CFI), Tucker-Lewis index (TLI), standardized root mean residual (SRMR), and the root mean square of approximation (RMSEA). An acceptable model should have a χ2/df<3, an RMSEA and an SRMR<0.08 [37], and a CFI and a TLI>0.9 [38]. To assess convergent validity and discriminant validity, we used the path coefficient of CFA to analyze composite reliability (CR) and average variance extract(AVE). An acceptable model should have a CR＞0.7, and an AVE＞0.45 [39]. Through SPSS 26.0 to analyze the predictive validity of the CHLSalt-22 scale. The area under the ROC curve was＞0.70, and the best cut-off points for the CHLSalt-22 scale was analyzed. An AUC of 0.5 represents a test with no discriminating ability, while an AUC of 1.0 represents a test with perfect discrimination [40]. Independent sample t-tests or single-factor ANOVA of the difference in the total score of symptom counts between sociodemographic classifications and Bonferroni’s test were used to calibrate the inspection level for pairwise comparisons. The correlation between the CHLSal-22t count score and MCRSDH-SUST, BIPQ, and BFS was evaluated by calculating the Pearson’s correlation coefficient. The CHLSalt-22 count score was taken as the dependent variable, and the classified and continuous variables were used as independent variables for multivariate linear regression analysis. The multi-classified disordered variables were set as dummy variables according to the requirements of multivariate linear regression for independent variables. The significance level was set at p<0.05.
Descriptive statistics
In our study, most subjects were men (61.1%, n=899) and the mean BMI was 26.80±3.64 kg/m2. Based on the cut of values of BMI for Chinese adults [33], there were 7 (0.5%) underweight participants, 284 (19.3%) normal weight participants, 683 (46.4%) overweight participants, and 499 (33.9%) obese participants. The other demographic characteristics of the study participants are shown in Table 1.
Table 1 : Sample characteristics (n=1472)
|
Characteristics |
Total (N=1472) N (%)/M±SD |
t/F |
P |
|
Sex |
|
1470 |
0.802 |
|
Man |
899（61.1） |
|
|
|
Woman |
573（38.9） |
|
|
|
Age |
|
3.821 |
0.022 |
|
≤39 |
221（15.0） |
|
|
|
40-59 |
695（47.2） |
|
|
|
≥60 |
556（37.8） |
|
|
|
Education level |
|
20.692 |
0.000 |
|
Primary school and below |
463（31.5） |
|
|
|
Secondary school |
467（31.7） |
|
|
|
High school |
281（19.1） |
|
|
|
University or above |
261（17.7） |
|
|
|
Occupation |
|
28.870 |
0.000 |
|
Self-employ |
278（18.9） |
|
|
|
Worker |
623（42.3） |
|
|
|
Farmer or other |
571（38.8） |
|
|
|
Exercise |
|
2.766 |
0.063 |
|
no |
349（23.7） |
|
|
|
Yes,Once in a while |
803（54.6） |
|
|
|
Yes, less than once a week |
320（21.7） |
|
|
|
Income |
|
17.515 |
0.000 |
|
＜1000 |
184（12.5） |
|
|
|
1000-1999 |
470（31.9） |
|
|
|
2000-2999 |
208（14.1） |
|
|
|
≥3000 |
610（41.4） |
|
|
|
BMI |
26.80±3.46 |
- |
- |
Reliability analysis
The CHLSalt-22 consists of 22 items. The KR-20 and split-half reliability of the CHLSalt-22 were 0.815 and 0.713, respectively. After one month, the test-retest ICC of the CHLSalt-22 was 0.982, which met the recommended criteria [41,42], representing good stability.
Construct validity analysis
The result of the Harman single-factor test analyzes Common Method Biases(CMB) was 26.228 < 40, and the contribution rate was 67.993%>60% [43]. The statistically significant results of Bartlett’s test of sphericity ( χ2(231)=3815.612, p<.001) and the Kaiser-Meyer-Olkin Measure of Sampling Adequacy > 0.80 (KMO=0.815) indicate that the data meet the conditions for using factor analysis. Therefore, the first principal component analysis (PCA) was performed to determine the likely number of factors. As a result, seven f actors that explained a total of 49.709% of the variance had initial eigenvalues >1 each. The scree plot further confirms the seven-factor structure. After varimax orthogonal rotation, these seven extracted factors explained 10.985, 21.925, 32.716, 42.813, 52.232, 61.396 and 67.993% of the variance, respectively. The scree plot is presented in Fig. 1.
Table 2 presents the factor loading of each item. All the correlation coefficients were more prominent than 0.40 and statistically significant at P<0.01. A CFA was performed on Sample 1 (n=469). The two models of the scale in this study were evaluated, and the results showed the fitting index of the seven-factor model (Table 3). The structural equation model and the standardized regression coefficients of the seven-factor model of the CHLSalt-22 are appeared in Fig. 2.
Table 2: Factor loadings of the CHLSalt-22 (n=469, salient factor loadings are indicated in italics.)
|
Item |
Estimate |
|
1.Which of the following statements best describes the relationship between salt and sodium? |
0.699 |
|
2.What is the daily limit of salt intake (in grams)that is recommended by the World Health Organization for an adult? |
0.895 |
|
3. Which type of biscuits would you choose if you wish to minimize salt intake? |
0.746 |
|
4.How much the salt content of Lunch meat(100g)? |
0.784 |
|
5.How much the salt content of Instant noodles with seasoning powder(100g)? |
0.560 |
|
6.How much the salt content of Ketchup or Salad dressing (100g)? |
0.888 |
|
7.How much the salt content of Oyster sauce(100g)? |
0.770 |
|
8.Do you agree that the high blood pressure can be caused by high salt intake？ |
0.720 |
|
9.Do you agree that the cardiovascular disease can be caused by high salt intake？ |
0.626 |
|
10.Do you agree that the diabetes mellitus can be caused by high salt intake？ |
0.719 |
|
11.Sodium intake can be reduced by replacing salt with plenty of Chicken essence during cooking. |
0.744 |
|
12.Most foods available at restaurants（e.g,Chinese restaurants,fast food restaurants）are high in salt. |
0.738 |
|
13.Drinking more water can neutralize salt intake from my diet. |
0.783 |
|
14.Most low salt foods taste bad. |
0.433 |
|
15.I feel too much pressure to eat a healthy diet . |
0.960 |
|
16.Limiting the amount of salt intake is important to my health. |
0.896 |
|
17.Add salt or sauce or condiments at the table. |
0.504 |
|
18.Consume canned foods. |
0.700 |
|
19.Consume salted fish, salted vegetables, salted duck eggs. |
0.761 |
|
20.Pay attention to whether the food is labeled as “No added salt” or “Low in salt”. |
0.655 |
|
21.Read the sodium content stated on the nutrition labels on food packages. |
0.707 |
|
22.Purchase foods according to the sodium content stated on the nutrition labels. |
0.859 |
Table 3: Confirmatory factor analysis of the CHLSalt-22 with different models
|
Model |
χ2 |
df |
χ2/df |
CFI |
TLI |
SRMR |
RMSEA[90%CI] |
|
1 |
354.170 |
181 |
1.957 |
0.956 |
0.944 |
0.041 |
0.045[0.038-0.052] |
|
2 |
632.060 |
182 |
3.473 |
0.922 |
0.901 |
0.049 |
0.050[0.045-0.054] |
χ2, chi-square, df, degrees of freedom, CFI, comparative ft index, TLI, Tucker-Lewis index, SRMR, standardized root mean residual, RMSEA, root mean square error of approximation, 90% CI, 90% confidence interval, M1, 469 samples structure model, M2, 1003 samples model
Convergent validity and discriminant validity
The path coefficient of CFA was to analyze the composite reliability (CR) and average variance extract (AVE). The critical ratios among the seven common factors in the CHLSalt-22 were over 0.7, and all of the average variance extraction values were over 0.45 [39,44]. The convergent validity and discriminant validity of the CHLSalt-22 are shown in table 4. The bold numbers on the diagonal lines of the table are the square root of the extraction amount of the mean variance of the corresponding dimensions, and the non-diagonal numbers are the inter-dimensional correlation coefficients.
Table 4: Convergent validity and discriminant validity of the CHLSalt-22
|
Factor |
CR |
AVE |
F1 |
F2 |
F3 |
F4 |
F5 |
F6 |
F7 |
|
F1 |
0.826 |
0.615 |
0.784 |
|
|
|
|
|
|
|
F2 |
0.842 |
0.577 |
0.516** |
0.760 |
|
|
|
|
|
|
F3 |
0.731 |
0.476 |
0.323** |
0.540** |
0.690 |
|
|
|
|
|
F4 |
0.799 |
0.570 |
0.396** |
0.557** |
0.790** |
0.755 |
|
|
|
|
F5 |
0.828 |
0.637 |
0.420** |
0.495** |
0.418** |
0.450** |
0.798 |
|
|
|
F6 |
0.700 |
0.441 |
0.148** |
0.289** |
0.192** |
0.173** |
0.347** |
0.664 |
|
|
F7 |
0.787 |
0.556 |
0.627** |
0.542** |
0.338** |
0.372** |
0.468** |
0.276** |
0.746 |
CR,composite reliability,AVE,average variance extract,**P＜0.01,*:P＜0.05
Content validity
The content validity of the CHLSalt-22 scale was evaluated by an expert evaluation [45]. The expert group is composed of seven experts, including two dieticians, three nursing experts proficient in both Chinese and English, and two psychiatrists. The content validity analysis result shows that the I-CVI of the CHLSalt-22 scale is 0.857-1, and the S-CVI /Ave is 0.968, which has good content validity.
Prediction validity
The ROC curve of the CHlsalt-22 was drawn in this study with hypertension as reference. According to the Youden’s Index (YI) maximization principle [46,47], 16.5＞17 was the best cut off value for the CHLSalt-22 scale. The area under the ROC curve for the scale was 0.774 (p＜.01), with a sensitivity of 0.843, specificity of 0.623, and 95%CI (0.741-0.807). The ROC curve for the CHLSalt-22 is shown in Figure 3.
Table 5: Pearson’s correlations between the CHLSalt-22 count and MCRSDH-SUST,BIPQ and BFS
|
|
1 |
2 |
3 |
4 |
|
1.CHLSalt-22 |
- |
|
|
|
|
4.MCRSDH-SUST |
0.437** |
|
|
|
|
2.BIPQ |
0.226** |
0.484** |
|
|
|
3.BFS |
0.348** |
0.513** |
0.340** |
- |
CHLSalt-22: revised Chinese Health Literacy Scale For Low Salt Consumption, BIPQ:The Brief Illness Perception Questionnaire, BFS:Benefit Finding Scales, MCRSDH-SUST:The Continuous Behavior Change Sub-scale, ** p<0.01, * p<0.05
Table 6: Results of multiple linear regression models of factors influencing the CHLSalt-22 scores of subjects with different characteristics
|
Variate |
β |
SD |
Β’ |
t |
P |
R2 |
DR2 |
F |
P |
|
Model 1 |
|
|
|
|
|
0.074 |
0.070 |
16.799 |
0.001 |
|
Sex |
1.307 |
0.452 |
0.081 |
2.889 |
0.004 |
|
|
|
|
|
Age |
1.330 |
0.576 |
0.084 |
2.307 |
0.021 |
|
|
|
|
|
BMI |
-0.195 |
0.058 |
-0.086 |
-3.349 |
0.001 |
|
|
|
|
|
Income |
2.317 |
0.630 |
0.103 |
3.676 |
0.000 |
|
|
|
|
|
education level |
2.574 |
0.566 |
0.126 |
4.550 |
0.000 |
|
|
|
|
|
Occupation |
1.461 |
0.493 |
0.092 |
2.966 |
0.003 |
|
|
|
|
|
Model 2 |
|
|
|
|
|
0.212 |
0.211 |
134.649 |
0.001 |
|
MCRSDH-SUST |
0.412 |
0.038 |
0.351 |
10.737 |
0.000 |
|
|
|
|
|
BFS |
0.116 |
0.022 |
0.168 |
5.145 |
0.000 |
|
|
|
|
BMI, body mass index, BFS:Benefit Finding Scales, MCRSDH-SUST:The Continuous Behavior Change Sub-scale, P, P-Value, Bold values correspond to statistically significant correlations (p < 0.05)
Health literacy related to salt consumption and sociodemographic differences
The CHLSalt-22-diagnosed health literacy related to salt consumption count was 17 in patients with hypertension (SD= 17.58, range= 0-44). According to the ROC of the CHLSalt-22 analysis, the higher the low salt health literacy score, the more likely they are to have high blood pressure. This proves that people with hypertension are aware of the prevention of hypertension and other diseases, and pay special attention to the salt content of diet in their daily lives. Many studies have shown that people with high blood pressure have better health literacy [48]. There were no significant differences in the CHLSalt-22 between men and women or between different exercise frequencies. However, there were statistically significant differences in age, education level, occupation, income, and BMI. Table 1 presents the results. There are differences in the level of health literacy, which is similar to the results of previous studies conducted at home and abroad [49,50]. However, a part of the result of the original scale was different [29]. This result is due to all kinds of cultures, customs, and demographic characteristics. Table 5 presents the factors associated with the CHLSalt-22 score: the CHLSalt-22 score was positively correlated with the BIPQ, BFS, and MCRSDH-SUST. The effects of different sociodemographic groups on the CHLSalt-22 score were assessed using bilinear regression. Sociodemographic groups were considered as categorical predictors (with one category being the reference group), and the CHLSalt-22 score represented the continuous outcome variable. The results of the multivariate regression analysis results are shown in Table 6. Sex, age, BMI, income, education level, occupation, BFS, and MCRSDH-SUST were the influencing factors of the CHLSalt-22. This reflects that health literacy is influenced by individual and environmental social determinants [51]. But, BMI was negatively correlated with the CHLSalt-22 and other characteristics were positively correlated with the CHLSalt-22. This suggests that the higher weight of hypertensive patients, the lower the health literacy of low salt intake, and the less attention to salt intake in the normal diet process. The CHLSalt-22 count score increased by 2.317 points for each one-unit increase in income, by 2.574 points for each one-unit increase in education level, by 1.461 points for each one-unit increase in occupation, and decreased by 0.195 points for each one-unit increase in BMI. This trend is consistent with the results of previous studies [52-55]. The degrees of BFS and MCRSDH-SUST were correlated with the CHLSalt-22 count scores. With every increase of one SD in the BFS, the CHLSalt-22 score increased by 0.168 SD. 0.351 SD increased the score increased by the CHLSalt-22 for each increase of one SD in the MCRSDH-SUST.
The CHLSalt-HK is the first validated scale for assessing health literacy related to low salt intake among elderly Chinese adults in Hong Kong. The 49-item scale has a possible score ranging from 0 to 98, with a higher score indicating higher health literacy related to low salt intake. However, the 22-item of the CHLSalt-22 scale has possible scores ranging from 0 to 44. Our sample of Chinese adults had a mean score of 17.58 and a standard deviation of 7.83. The median score was 18.00, the observed minimum score was 2, and the observed maximum score was 41. None of the respondents scored a maximum of 44 or a minimum of 0; therefore, floor or ceiling effects were unlikely to occur. The scale previously studied by the doctor is applied to the elderly. Considering that the population with hypertension is getting younger and younger, this scale was applied to the adult population of any age [29].
This study shows that the CHLSalt-22 has a seven-factor structural solution and has good authentic characteristics. The reliability analysis results of this study showed that the internal consistency coefficient of the scale met the statistical requirements, and the CHLSalt-22 test-retest reliability was good, indicating that the scale has good stability over time. Furthermore, the CHLSalt-22 has good construct validity, convergent validity, discriminant validity, content validity, and prediction validity.
A seven-factor structure of the the CHLSalt-22 was confirmed as the best solution for the scale through CFA, which differs from the theoretical conception of the original scale (30). The items removed from 49 to 22, and the factors ranged from 8 to 7. First, during the revision process, items that did not conform to mainland Chinese eating habits were adjusted and cross-culturally adjusted, which affected the original structure to a certain extent. Second, this difference may be related to the sample population and region. The survey samples were mainly from northeast China. Therefore, people from different regions may have different subjective experiences of salt consumption and an understanding of the concept of salt consumption. Other possible reasons for this different living habits, eating habits, and cultures. China has a vast territory with different dietary compositions. Our samples were mainly from Northeast China, where the diet is high in salt [56]. A retrospective study of significant changes in the dietary structure of Chinese adults showed that consumption of cooking oil and salt was substantively far above the recommendations [57]. Dietary differences in the sample population may be an essential reason for the different results. Finally, we measured varying levels of people, shortened the time for people to fill in the questionnaire, and ensured the authenticity of the answers. Repetitive or complex questions were removed to make the scale more universal. In this process, the professor's consent was obtained; from a content point of view, there are relatively reasonable explanations for various factors.
Based on the construct validity analysis,twenty-seven items were removed. From a content point of view, there are relatively reasonable explanations for the various factors. According to the previous studies [21, 58–60], the salt restriction policy was promoted in many countries, including China, and some people used a 2-g salt-restriction spoon for cooking. Therefore, we think of the item (how many grams of salt does one teaspoon of salt have?) should be removed. The 3 item (refer to the following nutrition labels of various biscuits. Which type of biscuits would you choose if you wish to minimize salt intake?) is similar to this item (refer to the following nutrition labels of various canned soups, which of the canned soups has the highest salt content?). They all examined the relevant knowledge of nutrition labels, and we think it is suitable for such a question. We consider ketchup and salad dressing as eating like condiments. According to literature, high salt levels affect a wide range of diseases [8, 61, 62]. However, in recent years, the highest mortality rates in China have been for cerebrovascular disease, hypertension, and diabetes [63]. So, we only left over these three items (8,9,10). The 16 item (limiting the amount of salt intake is important to my health.) and item (I worry about the serious health problems that are caused by eating salty foods.). Although the expression is opposite, the meaning is the same. Considering the actual Chinese diet and table salt is one such condition [64]. We summed up item (add salt at the table.) and item (add sauce, or condiments at the table.) into one item, named 17 item (add salt, or sauce, or condiments at the table.). The 17 item and the item (only by adding salt and sauces while cooking can the taste of food be enhanced.) both refer to the act of adding salt and sauces during cooking. The 17 item is the opposite of the item of minimizing my salt intake, and the reverse of the assignment proves the same. During the investigation, data were removed. The 17 item, the 18 item (consume canned foods) and the 19 item (consume salted fish, salted vegetables, salted duck eggs) are similar to the item (I enjoy eating salty foods.). The 20 item (pay attention to whether the food is labeled as “No added salt”or “Low in salt”.), the 21 item (read the sodium content stated on the nutrition labels on food packages.) and 22 item (purchase foods according to the sodium content stated on the nutrition labels.) are similar to the item (I am concerned about the salt content in foods.) and the item (I am confident that I can control my daily salt intake.). We considered the item (only by adding salt and sauces while cooking can enhance the taste of food be enhanced.), the item (I enjoy eating salty foods.), the item (I enjoy eating salty foods.) and the item (I am confident that I can control my daily salt intake.) were emotionally charged. There is a possibility of misinterpretation or even deviation in the investigation. The items (consume fast food, potato chips, bread, instant oatmeal, sliced cheese and hamburger) do not belonging to the diet of mainland Chinese. In the course of the investigation, we substituted Guangdong BBQ Pork (with sauce) for braised pork with sauce and substituted pizza for scallion pancakes. Respondents realized that they owned different salts by disparate cooking. For people in northern China, BBQ is a common and intangible cultural heritage food that is prone to deviation during its investigation. Due to regional differences, many rural residents or other people do not understand these foods (salted snacks and preserved fruits) well and have deviations in measurement. The revised version of the CHLSalt-22 was also contains the three most common domains of health literacy identified by Frisch et al.: functional literacy, factual and procedural knowledge, and awareness [65].
In our study, sex, age, income,education level and occupation were positively correlated with the CHLSalt-22 count scores: older age, higher income, higher education level, and better occupation were associated with a greater the possibility of health literacy related to salt consumption. Ernsting et al. reported that smartphones and health App users were younger, more likely to report chronic conditions, and were more literate than non-users who had a smartphone [66]. Study has shown that age, sex and education level are all associated with health literacy in older adults[67]. Moreover, Aygun et al. used a cross-sectional study of Fethiye samples, which confirmed that age group, income level,education level, health news reading status, reading a publication about health and level of self-assessment were related to general health literacy levels [68].
In this study, BMI showed a small, passive association with the CHLSalt-22 scores (rs= -0.118, P<0.001). Similar findings have been reported by several studies. For example, in a survey of Olyani S, the negative correlation between the female adolescent students’ health literacy count scores and BMI was − 0.233[69]. Additionally, a previous survey using the Nutrition Literacy Assessment Instrument scale showed that BMI was associated with nutrition literacy and dietary habits [70]. Compared with people in the Risk Assessment and Management Program (RAMP) in a cluster-randomized survey, BMI showed no significant changes and there was a significantly higher BP control rate[71]. Obesity is often associated with salt-sensitive hypertension [72]. Furthermore, for children and students, the level of health literacy of their parents and themselves also plays a crucial role in their weight[73–76]. Nutritional literacy is an important factor in the prevention, prediction, and treatment of certain chronic diseases[70, 77]. Less in the low-fat diet, and had a higher health-related quality of life and health literacy[78]. Given the complexity of these findings, more research is needed to identify interventions for health literacy and to elucidate the associations between BMI, BP, and weight.
We found a positive correlation among the CHLSalt-22 score, BIPQ, BFS and MCRSDH-SUST: the higher BIPQ, BFS, and MCRSDH-SUST scores, the higher the summary score of the CHLSalt-22. MCRSDH-SUST is defined as changes in salt restriction dietary behavior in hypertensive patients, and it may affect quality of life and health[30]. A previous study reported that inconsistent cognition and behavior in patients on a salt-restricted diet. Although patients met the requirements of a salt-restricted diet, some patients did not implement it [79]. Few studies have examined the relationship between low salt health literacy and disease perception and benefit discovery, but many researchers have studied the changes of health literacy on behavior and cognition [80, 81].
Several limitations of this study should be considered when interpreting its findings. First, the sample was conveniently obtained. Our sample had a high proportion of male participants, which may limit the generalizability of our results to other populations. Further investigation into the angle of sex variation could offer valuable insights. Therefore, future studies should assess the reliability and validity of the CHLSalt-22 in other countries and assess the level and characteristics of health literacy related to salt consumption among different samples. Second, bias was inevitable because of the self-reported nature of this investigation.
The CHLSalt-22 scale, which supports a seven-factor structure, was found to be reliable; therefore, it can be used as a short method of assessing health literacy in low-salt screening. Health literacy of low salt is associated with sex, age, BMI, income, education level, and occupation. Future research should examine the psychometric properties of the revised CHLSalt-22 scale across different locations in China. In addition, the potential predictors of low salt intake in hypertension should be further determined, and we think that measurement is only the first step, and how to change behavior is the next step in future research.
a short-form Chinese Health Literacy Scale For Low Salt Consumption
the Measuring Change in Restriction of Salt (sodium) in Diet in Hypertensives
the Brief Illness Perception Questionnaire
the Benefit-Finding Scales
World Health Organization
Dietary Approach to Stop Hypertension
Organization for Economic Co-operation and Development
Salt-Restriction Spoons
Theory of Planned Behavior
nchronic kidney disease
Kuder-Richardson’sα
intraclass correlation coefficient
Content validity index
Tucker-Lewis index
composite reliability
average variance extract
Youden’s Index BMI:Body Mass Index
Principal components analysis
Intraclass correlation coefcient.
Acknowledgements
We appreciate the hypertensive patients who helped us in conducting this research, and we would like to thank Dr PH Chau, the author of the revised Chinese Health Literacy Scale For Low Salt Consumption instrument providing us the tool and CHLSalt-22 for providing us the tool and for his encouragement.
Authors’contributions
All the authors conceived the study, HL designed this study. YZ wrote this article. HZ, SL, and YL collected data and were mentoring the work on the article. YZ, CH, and HZ performed data analysis. YL and HZ revised this article. The authors read and approved the final manuscript.
Funding
This work was supported by the department of Chinese Society of Gerontology and Geriatrics [No.2021-04-01].
Availability of data and materials
The data set is available from the corresponding author upon reasonable request.
Consent for publication
Not applicable
Ethics approval and consent to participate
All procedures performed in studies involving human participants were approved with the ethical standards of the Ethics Committee of the Jinzhou Medical University. In addition to this, we confirmed that the experimental protocol was approved by the Ethics Committee of the Jinzhou Medical University (No.JZMULL2022008) and in accordance with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Informed consent was obtained from all participants included in the study.
Competing interests
The authors declare that they have no competing interests.