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Year : 2022  |  Volume : 20  |  Issue : 2  |  Page : 57-62

Impact of perceived self-efficacy among hypertensives in adapting to low salt diet

1 Department of Community Medicine, ESIC Medical College and PGIMSR, Chennai, Tamil Nadu, India
2 Indian Institute of Public Health-Hyderabad, Hyderabad, Telangana, India

Date of Submission25-Oct-2021
Date of Decision28-Nov-2021
Date of Acceptance15-Dec-2021
Date of Web Publication07-May-2022

Correspondence Address:
Dr. A Y Nirupama
Indian Institute of Public Health-Hyderabad, Masthan Nagar, Kavuri Hills, Hyderabad - 500 033, Telangana
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/cmi.cmi_90_21

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Background: Hypertension is a crucial health problem worldwide, and its snowballing epidemiology demands stern caution to increase the focus on this silent disease. Evidence exists that a considerable decline in salt consumption decreases blood pressure (BP) by around 5–7 mm of Hg systolic, in patients with increased BP. Materials and Methods: A cross-sectional study was conducted among known hypertensive patients attending a health-care setting for routine check-up. This included patients of both genders, diagnosed with hypertensive at least 3 months prior, irrespective of their adherence to medication. Thus, convenient sampling was used to recruit participants after obtaining informed consent. The participants, who did not consent or cases of emergency such as myocardial infarction, malignant hypertension or arrhythmias and association with confirmed diabetes mellitus, were excluded. The study tool consisted of prevalidated and semistructured interview schedule.Results: Median (inter-quartile range) age of the study participants was 60 (15) years with 59% of the population constituting of females. The consumption of dietary sodium was observed to be 2–4 g/day among 74.3% (78) of the study participants, and >5 g among 22.8% (23) of the study participants. Nearly 70% of the participants had higher to moderate perceived self-efficacy scores indicating an overall higher self-efficacy among participants in adapting to the practice of salt restriction. Perceived self-efficacy scores negatively correlated with dietary sodium intake by Spearman's correlation (rho = −0.667, P < 0.001). Conclusion: The perceived self-efficacy scores of the participants showed a strong negative correlation with the dietary sodium intake, this may be an indication of need for self-motivation and patient participation in the control of factors such as restricted salt intake in patients with hypertension and warrants further research.

Keywords: Hypertension, Pender's model, perceived self-efficacy, salt restriction

How to cite this article:
Elangovan V, Nirupama A Y. Impact of perceived self-efficacy among hypertensives in adapting to low salt diet. Curr Med Issues 2022;20:57-62

How to cite this URL:
Elangovan V, Nirupama A Y. Impact of perceived self-efficacy among hypertensives in adapting to low salt diet. Curr Med Issues [serial online] 2022 [cited 2023 Jun 6];20:57-62. Available from: https://www.cmijournal.org/text.asp?2022/20/2/57/344938

  Introduction Top

Hypertension has always been an important public health challenge in developing as well as developed countries and its snowballing epidemiology demands stern caution to increase the focus on this silent sickness.[1] A substantial body of evidence exists which strongly supports the concept of multiple dietary factor involvement in blood pressure (BP) changes such as reduced fat intake, protein rich diet, and salt reduction.[2] Positive reforms in diet have been widely considered as a lifestyle modification tactic with vast probability for preventing as well as controlling hypertension at a lesser cost as compared to that of the current pharmacological interventions.[3]

Salt restriction has always been regarded as a key player in lifestyle modification and a modest decline in salt consumption by 6 g/day was observed to lower the systolic BP (SBP) by around 4–7 mm of Hg in hypertensive patients.[4],[5] There is considerable evidence suggesting that a significant drop in salt consumption lowers BP in both hypertensives and normotensives. Similarly, a few studies have also considered the effect on ethinicity and inferred that blacks experienced a greater fall in BP when compared to whites.[6] Age old history paints a per capita average salt consumption of 1–5 g/day, which has escalated in recent times to 10.98 g/day in India.[7] A technical report from the World Health Organization (WHO) and Food and Agriculture Organization of United Nations has recommend an average daily consumption of <5 g of salt as the population nutrient intake goal.[4],[8]

Recognition of high salt consumption as a significant behavioral cause for elevated BP and hypertension and the implementation of an effort to reverse these habits is a pivotal aspect of recommended lifestyle changes for hypertension prevention and control.[9],[10] Unfortunately, only 20% of patients are accepting and following the accepted dietary practices for salt restriction.[11] Bandura (1986) defined self-efficacy as an individual's confidence in their own capability to perform behavior and went on to identify it as a necessary driving force for self-care.[12] Self-efficacy was found to be the most salient predictor of all health-promoting practices followed by the general public.[5] Assessing self-efficacy in known hypertensives is an important step toward achieving BP control at individual as well as population level.[13]

Primary objective

The present study was envisioned to estimate the average per-capita daily salt consumption status and the perceived self-efficacy (score) in adapting salt restricted behavior among the study participants with a secondary objective to correlate the perceived self-efficacy scores with the average per-capita daily salt consumption.

  Materials and Methods Top

Study design and setting

A cross-sectional descriptive study was carried out in a primary health care center, functioning in the urban field practice area, of a teaching hospital in Tamil Nadu.


The study was carried out over a period of 4 months from January 2, to April 29, 2017, among known hypertensive patients attending the health care centre for routine check-up. All patients of both genders diagnosed with hypertensive at least 3 months prior to the study period, irrespective of their adherence to medication and the level of BP control were included in the study. Thus, convenience sampling was used to obtain the sampling frame and a partial randomization [Figure 1] was done to recruit participants for the study after obtaining informed consent. The exclusion criteria included cases of emergency such as myocardial infarction, malignant hypertension or arrhythmias and those with known history of comorbidities such as diabetes, tuberculosis, bronchial asthma, and dyslipidemias.
Figure 1: Inclusion process for study participants from the sampling frame

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Sample size was worked out to be 105, by means of the OpenEpi software using the result of a similar study by Kamran et al.[14] The study result indicated a high 45% prevalence of perceived self-efficacy scores which was considered for the sample size calculation with 90% confidence limit and 8% allowable error.

The study tool consisted of prevalidated and semi-structured interview schedule designed with the “Pender's health promotion model” at its core.[15] The interview schedule was designed including four sections, namely (1) sociodemographic details, (2) clinical details of hypertension, (3) dietary history, and (4) questions to assess the perceived self-efficacy of the participants regarding salt restriction behaviour. This was done in English, translated into the regional language (Tamil) and back translated to check for consistency. The schedule was validated for its content among three designated faculty members before data collection and a pilot study was conducted among 20 participants attending the center from July 2, 2016. This resulted in an interclass correlation coefficient, for perceived self-efficacy, of 0.88. Therefore, the validity of the schedule was considered fit for the study.

During the interview, the sociodemographic details, clinical history of hypertension, duration, and details regarding treatment regularity were also collected. The dietary sodium intake of the participant was estimated from the diet history for 3 days before the day of interview (including table salt, cooking salt, and beverages) by the recall method. The sodium content of each food item was prelisted in a validated reference from the National Health Research Institute-Sodium food chart and was used in the calculation of total sodium consumed by the individual.[16] Percapita sodium consumption for the study was computed as the final average of reported consumption in 3 days to avoid bias.

From the calculated sodium intake, the average salt intake of each individual was calculated separately considering 2 g of sodium to be equivalent to 5 g of salt.[8] With enough evidence correlating dietary salt intake to urine spot sodium, a spot urine sample was also evaluated for sodium levels to substantiate any bias that could arise from the recall method used for dietary sodium calculation.[17]

The perceived self-efficacy of each participant was assessed by a five-question interview on their attitude toward salt restriction in diet. BP values of all the participants were recorded at the time of data collection using a mercury sphygmomanometer. Three separate recordings, 20 min apart by two different examiners, were recorded and an average was considered to avoid any bias.

Statistical analysis

Data were compiled and entered in Microsoft Excel workbook (V. 97-2003) and then analysed using International Business Machines-Statistical Package for the IBM Corp. Released 2012. IBM SPSS Statistics for Windows, Version 21.0. Armonk, NY: IBM Corp. Normality of the data was assessed using the Shapiro–Wilk test for normality. The qualitative variables are summarized as proportions and quantitative variables are enumerated as mean-standard deviation/median-inter-quartile range (IQR). Significance of P value was taken as P < 0.05 and all required statistical tests were applied (Pearson Chi-square, Fischer Exact, Pearson correlation, and Spearman's rho) during the statistical analysis.

Ethical considerations

This study was approved by the Institutional Human Ethics Committee, approval Ref. No. IHEC/0129/2016 dated 15.03.2016. A written informed consent in Tamil (Regional language) was obtained from all the study participants before their interview.

  Results Top

The age, in years, of participants ranged from 32 to 80 years with a median (IQR) of 60,[15] of which 59% were females. Average per-capita dietary sodium values ranged from 1.77 to 9.0 g/day with a median value of 3 and an IQR of 1.20 g/day, consequently the spot urine sodium values ranged from 50.7 to 192 mEq/L with a median value of 138 and an IQR of 26.5 mEq/L. A dietary sodium intake of 2–4 mg/day was noted among 74.3% of the study participants; followed by 22.8% taking >5 g of sodium (equivalent to 12.5 g of salt intake). Median (IQR) SBP and diastolic BP value were 140 (30) and 90 (10), respectively. A low perceived self-efficacy score (a score ≤25 out of 50) was obtained by 31.43% of the study participants.

No significant association was noted between sociodemographic factors and perceived self-efficacy scores [Table 1] but a statistically significant association was established between perceived self-efficacy scores and certain factors in the history of hypertension such as the duration of illness and the regularity of drug intake.
Table 1: Association between sociodemographic factors and perceived self-efficacy scores

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A positive correlation was established between dietary salt intake calculated and the urinary spot sodium measurement showing an increase in spot urine sodium with increase in dietary sodium calculated and substantially proving that any associations established with the calculated dietary sodium intake is fairly reliable [Table 2].
Table 2: Correlation using Spearman's rho and Pearson's correlation

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Perceived self-efficacy scores negatively correlated with dietary sodium intake by Spearman's correlation (rho = −0.667, P < 0.001). Relation between perceived self-efficacy scores and dietary sodium intake when plotted showed a negative slope with maximum values falling within the 95% confidence interval [Figure 2] showing that an individual's perceived self-efficacy increased with reduction in his/her dietary salt intake.
Figure 2: Spot diagram showing relation between perceived self-efficacy scores and dietary sodium intake

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An additional query was made regarding the lifestyle modifications and dietary advice received at the time of diagnosis [Figure 3], in order to have a better understanding regarding the impact of health-care advice and nonpharmacological interventions. Even though salt restriction, reductions in fatty foods and avoiding smoking were given emphasis, other vital factors such as the need for physical activity, stress reduction, and high fruits intake did not receive requisite importance.
Figure 3: Lifestyle modifications and dietary advice received at the time of diagnosis

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  Discussion Top

The present study highlights the role of self-efficacy among hypertensive patients in following restriction of salt in diet. Nearly half of the participants showed low self-efficacy and those who were more likely to take action toward sodium reduction were the ones who perceived themselves at risk of consuming excess sodium than the ones who claim ignorance of the prevailing risks of high salt diet. This leads to less likely chances of sodium reduction practices among those who harbor unfavorable attitudes toward sodium reduction.[11] A number of modern studies have emphasized the need for health promoting behavioral changes in chronic disease management; one such being the “Self-efficacy” (defined as the confidence in one's capability to partake in a given behavior).[18] It is a widely used psychosocial concept and is closely connected with the capacity to manage chronic disease.[19]

High salt intake (>5 g/day) was observed in 97.14% of the participants, which is higher than the recommended daily intake of salt by the WHO even for nonhypertensive patients. Observed per-capita salt intake was as high as 22.5 g/day with a mean of 7.5 g/day. This mean value was however lower than a mean of 8.5 g/day reported by Radhika et al. in Chennai, 12 g/day reported in the Tamil Nadu Heart Study and much lesser than the 9-12 g/day as per the WHO global report.[8],[20],[21] At the same time, the global mean sodium intake estimation of 66 countries was reported as 3.95 g/day by Mclean et al.[22]

A significant negative correlation was noted between perceived self-efficacy and dietary salt intake in the present study similar to the findings of Cornelio et al. but also there were studies by Chen et al. and Nastaskin et al. which reported no significant relationship between the two.[1],[23],[24] This may be attributed to the difference in the composition of the study population.

The present study signifies the changing pattern of self-efficacy of hypertensive patients based on the duration of their illness. According to the study, participants having duration of hypertension more than 5 years are found to have poor self-efficacy than those with duration of illness lesser than 5 years. This study supports the theory of giving in to temptations and desires of individual in due course of disease as reported by Chen et al.[1]

Sociodemographic factors showed no significant association with dietary sodium intake or perceived self-efficacy/salt restriction behavior similar to the reports by Radhika et al. and Chen et al. while in a study by Miyaki et al., higher salt intake was significantly noted among the elderly, males, those with high energy intake, poor levels of education, and lower economic status.[1],[20],[25]

Therefore, it is necessary to improve knowledge, attitudes, skills, and self-efficacy among the elderly. The ideal plan of action being educational interventions for the elderly to independently adhere to low-salt diets.[12] BP control by teaching associated self-care skills may not be enough to bring about behavior change. Sense of self-efficacy or self-confidence to perform self-care behaviors needs to be improved by integrating these skills into everyday life.[13]

  Conclusion Top

The mean dietary salt intake was observed to be 7.5 g/day, which is way higher than the WHO prescribed 5 g/day for nonhypertensive patients. It was significantly observed that as an individual's perceived self-efficacy increased his/her dietary salt intake reduced. Perceived self-efficacy had a significant negative correlation with duration of illness and a significant association with regularity of medication showing that as duration of illness increased people were less likely to adhere to salt restriction behavior and also participants who were motivated enough to take their medicines regularly usually ended up adhering to a salt restricted diet. Self-efficacy needs to be backed by integration of self-care skills for BP control and results from this study point toward the need for further investigation in the field.

Research quality and ethics statement

All authors of this manuscript declare that this scientific study is in compliance with standard reporting guidelines set forth by the EQUATOR Network. The authors ratify that this study required Institutional Human Ethics Committee review and hence prior approval was obtained vide IHEC approval Ref. No. IHEC/0129/2016 dtd. 15.03.2016. A written informed consent in Tamil (Regional language) was obtained from all the study participants before their interview. We also declare that we did not plagiarize the contents of this manuscript and have performed a Plagiarism Check.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

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  [Figure 1], [Figure 2], [Figure 3]

  [Table 1], [Table 2]


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