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 Table of Contents  
Year : 2021  |  Volume : 8  |  Issue : 3  |  Page : 155-158

Material needs insecurity and dietary salt – Role in uncontrolled hypertension: A case–Control study

1 Department of Medicine, Christian Medical College, Vellore, Tamil Nadu, India
2 Department of Clinical Epidemiology Unit, Christian Medical College, Vellore, Tamil Nadu, India
3 Department of Biochemistry, Christian Medical College, Vellore, Tamil Nadu, India
4 Department of Biostatistics, Christian Medical College, Vellore, Tamil Nadu, India
5 Department of Medicine; Clinical Epidemiology Unit, Christian Medical College, Vellore, Tamil Nadu, India

Date of Submission18-Dec-2019
Date of Decision22-Feb-2020
Date of Acceptance27-Feb-2020
Date of Web Publication04-Mar-2022

Correspondence Address:
Thambu David Sudarsanam
Medicine Unit2 and CEU, Christian Medical College, Vellore - 632 004, Tamil Nadu
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/cjhr.cjhr_124_19

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We performed a case control study of 108 patients for the risk of uncontrolled hypertension Housing insecurity, a part of material needs insecurity is an independent predictor of uncontrolled hypertension (adjusted odds ratio 29.9, 1.2-734). Food insecurity, cost related medication underuse and housing instability were seen in 32.4%, 33.3%.and 39.8% of our study subjects respectively. On average patients had 6 stressful life events, which was not different among those with different levels of blood pressure control. We did not find correlation with 24-urine sodium excretion, a reflection of salt intake and hypertension control. The average hypertensive subject was taking more than 10 grams of sodium per day, far higher than recommended.

Keywords: Hypertension, material needs insecurity, salt intake

How to cite this article:
Kaki AR, Muliyil J, Nellickal AJ, Jeyaseelan V, Turaka VP, Zachariah A, Hansdak SG, Jagannati M, Sudarsanam TD. Material needs insecurity and dietary salt – Role in uncontrolled hypertension: A case–Control study. CHRISMED J Health Res 2021;8:155-8

How to cite this URL:
Kaki AR, Muliyil J, Nellickal AJ, Jeyaseelan V, Turaka VP, Zachariah A, Hansdak SG, Jagannati M, Sudarsanam TD. Material needs insecurity and dietary salt – Role in uncontrolled hypertension: A case–Control study. CHRISMED J Health Res [serial online] 2021 [cited 2022 Jul 7];8:155-8. Available from: https://www.cjhr.org/text.asp?2021/8/3/155/339039

  Introduction Top

Poor blood pressure (BP) control is known to cause poor cardiac, cerebral, and renal outcomes. Other than traditional risk factors, poor education and lower social capital have been related to poor BP control.[1] Among diabetic patients, material need insecurities (MNIs) have been associated with poor control.[2] MNI include food insecurity (FI), housing instability (HI), social stress, and cost-related medication underuse (CRMU).

FI is defined as limited or uncertain availability of nutritionally adequate and safe foods or limited or uncertain ability to acquire acceptable foods in socially acceptable ways. FI has been associated with hypertension and hyperlipidemia.[3]

CRMU can be defined as taking less-than-prescribed medication or not taking at all due to cost. HI is defined as “having difficulty paying rent, spending more than 50% of household income on housing, having frequent moves, living in overcrowded conditions, or doubling up with friends and relatives.” It is associated with poor health outcomes.[4]

Stress levels have been traditionally thought to affect hypertension control. A study has found a significant association between mental stress and hypertension in men.[5]

Recent studies including data from India suggest that the role of salt intake and hypertension may be more nuanced than previously thought.[6] A recent meta-analysis suggests racial differences in salt reduction and BP.[7]

In order to study the role of MNI insecurity, stress, and actual sodium intake in BP control along with traditional risk factors, we performed this case–control study.

  Methods Top

Study setting

The study was performed in the internal medicine department of a university tertiary care hospital in South India. Patients were mostly from lower to middle and lower socioeconomic strata.

Study design

This is a prospective, case–control study of men and women, over 40 years of age, diagnosed to have hypertension attending medicine outpatient department. Hypertension was defined according to the JNC 7 criteria[8] (systolic BP >140 mmHg/diastolic >90 mmHg). Those with secondary hypertension were excluded from the study.

Study period

Recruitment was from February to June 2016.

Cases were patients with uncontrolled BP, BP ≥160/100 mmHg, while controls were those with BP ≤systolic BP 140–159 mmHg and diastolic BP 90–99 mmHg.

Sample size calculation: in the general population, FI of any form is estimated at 75%. Based on expert opinion, we estimated the prevalence of MNIs at 90% among poorly controlled hypertensive participants. With a power of 80% and a two-sided alpha error of 5%, we estimated a sample size of 100 cases and 100 controls.

Data collection and analysis

Data were collected on a study-specific clinical research form. 24-h urinary sodium excretion urine was used to assess salt intake in addition to diet history. The 24-h urine sodium was divided by 17 to get the estimated oral sodium consumption. We did not separately analyze nonsalt sources of sodium. Data were entered on EpiData entry 3.1 software and analyzed using SPSS Statistics for Windows, Version 21.0., IBM Corp., Armonk, NY, USA.

Statistical methods

Descriptive data were described with frequencies and percentages, whereas continuous data with mean and standard deviations (SDs) or median and interquartile range. Logistic regression analysis was performed to determine those factors independently associated with poor BP control. Socioeconomic strata were grouped into low, middle, and upper categories; FI was categorized as food secure and food insecure.


After institutional review board (IRB) approval (IRB number 9559), recruitment was done after taking informed consent.

The Household Food Insecurity Access Scale (HFIAS) was used for FI.[9] CRMU was assessed using the method described by Piette et al.[10] HI was determined using the method described by Vijayaraghavan et al.[11] Mental Stress Score was calculated on the basis of this Presumptive Stressful Life Event Score.[12] Socioeconomic strata were described using the modified Kuppuswamy's socioeconomic scale.

  Results Top

We recruited 108 participants (34 cases and 66 controls) during the course of the study [Table 1]. The average age was 53.8 years (SD – 10.8), with 53.7% being men. Nearly 15% were illiterate, while 13.9% had attended only primary school. The socioeconomic strata distribution of upper-lower 28.7%, lower-middle 28.7%, and upper-middle 37% were predominant.
Table 1: Comparison of cases and controls

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The mean duration of hypertension was 8 years (SD – 8.2), and the mean body mass index was 24.6 (3.9). Ten percent were smokers, 19.4% were oral tobacco users, and 12% were regular alcohol users. Based on diet history, 49.1% followed a low-salt diet, while 31.5% were advised low-salt diet but did not follow this. Forty-two percent were compliant on medications, whereas only 46.3% exercised regularly. Heart disease was seen in 20% of participants, stroke in 5.6%, chronic kidney disease in 13%, diabetes in 43.5% (mean HBA1c 6.8), 37% had dyslipidemia, and 3.7% of the participants were obese.

FI strata analysis showed that 68.2% were food secure, 6.5% were mildly food insecure, 24.3% had moderate FI, and only one (0.9%) participant had severe FI. CRMU was seen in 33.6% of the participants. HI was seen among 40.6% of the participants. Overall, the average number of presumptive life events in using the stress score was 6.2/person.

The overall 24-h urine sodium excretion was 175.4 mmol/24 h, which corresponds to 10.32 g of sodium per day. This was 176 mmol/day (10.39 g of sodium) in cases and 174.1 (10.24 g) among controls [Table 2]. The difference between those who claimed to have low-salt diet on history (166.1 (80]) and those who did not (187.7 (68.5]) was 21.6 mmol (−12.64 to +55.84). This was not statistically significant.
Table 2: Salt intake based on 24-h urine sodium excretion between cases and controls

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Logistic regression analysis [Table 3] showed that only HI was found as an independent predictor of poor BP control (odds ratio 29.9 and confidence interval [CI] 1.2–734).
Table 3: Multivariate logistic regression for factors predicting poor blood pressure control

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  Discussion Top

The only independent risk factor for uncontrolled hypertension was housing insecurity, after adjusting for all other known risk factors including other MNIs. Is this a causal association? The level of odds seems significant, and the wide CI is probably due to the small sample size. HI adds to chronic stress, and this could biologically explain higher BP. A qualitative study found a relationship between urban housing stress and hypertension[13] It is likely that HI came before the onset of high BP. We cannot demonstrate a dose–response relationship with our study. Other studies have shown a relationship between HI and high BP (HBP),[11] and the analogy of the relationship of developing diabetes and HI has been documented.[2] We cannot claim that all participants with HI develop HBP because many with HBP do not have HI. Thus, using the Hills criteria of causation,[14] HI and HBP is probably an association. We would be cautious to suggest its role as a causative factor.[15]

The presence of FI (32.4%) was lower than the 75% noted in the population study done in an urban area in our city,[16] perhaps a tertiary care bias. FI has been associated with self-reported hypertension.[3] A study of 58,677 participants found that hypertension was more common among adults reporting FI (prevalence ratio, 1.27; 95% CI, and 1.19–1.36) after adjusting for socioeconomic status.[17]

CRMU (33.3%) is well documented[18] and ranges between 18% and 23.4% in the US patients.[19],[20] The differences could be due to differences in public health expenditure between a developed and a developing nation and predominant out-of-pocket expenditure for health care in India.

HI (40%) has been shown to adversely affect health intervention programs,[21] though not in hypertension. Homelessness (severe form of HI) is thought to affect 1.77 million Indians.[22]

Social stress was of similar numbers in cases and controls in our study. Racial discrimination interacting with genetic predisposition may, however, contribute to increased BP.[23]

The dietary sodium intake (estimated >10 g/day) in cases and controls is very high, which correlates with other data from India.[24] A recent study showed that between 3 and 6 g of salt was associated with better cardiovascular outcomes among hypertensives, with low or high levels being associated with worse outcomes.[6]

In comparison to our study, the study on diabetes and MNI found that 19.1% had FI, 27.6% had cost-related medication underuse, 10.7% had HI, 14.1% had energy insecurity, and 39.1% had at least 1 MNI. HI was associated with increased outpatient visits but not with diabetes control.[2]


Our sample size was smaller than planned due to difficulty in recruitment. While this could have led to beta error, we did not omit any variables on multivariate analysis that were tending toward statistical significance. As mentioned, we have an inherent referral hospital bias.

  Conclusions Top

Housing insecurity, a part of MNI, is an independent predictor of uncontrolled hypertension (adjusted odds ratio 29.9 and 1.2–734). FI, CRMU, and HI were seen in 32.4%, 33.3%, and 39.8% of our study participants, respectively. On an average, the patients had six stressful life events, which was not different among those with different levels of BP control. We did not find correlation with 24-h urine sodium excretion, a reflection of salt intake and hypertension control. The average hypertensive participant was taking more than 10 g of sodium per day, far higher than recommended.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Gupta R, Kaur M, Islam S, Mohan V, Mony P, Kumar R, et al. Association of household wealth index, educational status, and social capital with hypertension awareness, treatment, and control in South Asia. Am J Hypertens 2017;30:373-81.  Back to cited text no. 1
Berkowitz SA, Meigs JB, DeWalt D, Seligman HK, Barnard LS, Bright OJ, et al. Material need insecurities, control of diabetes mellitus, and use of health care resources: Results of the measuring economic insecurity in diabetes study. JAMA Intern Med 2015;175:257-65.  Back to cited text no. 2
Seligman HK, Laraia BA, Kushel MB. Food insecurity is associated with chronic disease among low-income NHANES participants. J Nutr 2010;140:304-10.  Back to cited text no. 3
Kushel MB, Gupta R, Gee L, Haas JS. Housing instability and food insecurity as barriers to health care among low-income Americans. J Gen Intern Med 2006;21:71-7.  Back to cited text no. 4
Jadhav SB, Jatti GM, Jadhav AS, Rajderkar SS, Naik JD, Nandimath VA. Stressing 'mental stress' in hypertension: A rural background study. J Clin Diagn Res 2014;8:JC04-7.  Back to cited text no. 5
O'Donnell M, Mente A, Rangarajan S, McQueen MJ, Wang X, Liu L, et al. Urinary sodium and potassium excretion, mortality, and cardiovascular events. N Engl J Med 2014;371:612-23.  Back to cited text no. 6
Huang L, Trieu K, Yoshimura S, Neal B, Woodward M, Campbell NR, et al. Effect of dose and duration of reduction in dietary sodium on blood pressure levels: Systematic review and meta-analysis of randomised trials. BMJ 2020;24:m315.  Back to cited text no. 7
Chobanian AV, Bakris GL, Black HR, Cushman WC, Green LA, Izzo JL Jr., et al. The seventh report of the joint national committee on prevention, detection, evaluation, and treatment of high blood pressure: The JNC 7 report. JAMA 2003;289:2560-72.  Back to cited text no. 8
Household Food Insecurity Access Scale (HFIAS) for Measurement of Food Access: Indicator Guide. Available from: http://www.fao.org/fileadmin/user_upload/eufao-fsi4dm/doc-training/hfias.pdf. [Last accessed on 2018 Feb 09].  Back to cited text no. 9
Piette JD, Heisler M, Wagner TH. Cost-related medication underuse: Do patients with chronic illnesses tell their doctors? Arch Intern Med 2004;164:1749-55.  Back to cited text no. 10
Vijayaraghavan M, Kushel MB, Vittinghoff E, Kertesz S, Jacobs D, Lewis CE, et al. Housing instability and incident hypertension in the CARDIA cohort. J Urban Health 2013;90:427-41.  Back to cited text no. 11
Singh G, Kaur D, Kaur H. Presumptive Stressful Life Events Scale (PSLES)-A new stressful life events scale for use in India. Indian J Psychiatry 1984;26:107-14.  Back to cited text no. 12
[PUBMED]  [Full text]  
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Hill AB. The environment and disease: Association or causation? Proc R Soc Med 1965;58:295-300.  Back to cited text no. 14
Lucas RM, McMichael AJ. Association or causation: Evaluating links between “environment and disease”. Bull World Health Organ 2005;83:792-5.  Back to cited text no. 15
Gopichandran V, Claudius P, Baby LS, Felinda A, Mohan VR. Household food security in urban Tamil Nadu: A survey in Vellore. Natl Med J India 2010;23:278-80.  Back to cited text no. 16
Preventing Chronic Disease. Available from: https://www.cdc.gov/pcd/issues/2014/pdf/14_0190.pdf. [Last accessed on 2016 Sep 05].  Back to cited text no. 17
Murphy A, Palafox B, O'Donnell O, Stuckler D, Perel P, AlHabib KF, et al. Inequalities in the use of secondary prevention of cardiovascular disease by socioeconomic status: Evidence from the PURE observational study. Lancet Glob Health 2018;6:e292-e301.  Back to cited text no. 18
Piette JD, Heisler M, Wagner TH. Cost-related medication underuse: Do patients with chronic illnesses tell their doctors? Arch Intern Med 2004;164:1749-55.  Back to cited text no. 19
Berkowitz SA, Seligman HK, Choudhry NK. Treat or eat: Food insecurity, cost-related medication underuse, and unmet needs. Am J Med 2014;127:303-10000.  Back to cited text no. 20
Turnbull H, Loptson K, Muhajarine N. Experiences of housing insecurity among participants of an early childhood intervention programme. Child Care Health Dev 2014;40:435-40.  Back to cited text no. 21
Census of India Website : Office of the Registrar General and Census Commissioner, India. Available from: http://www.censusindia.gov.in/2011census/hh-series/hh02.html?q =Homeless. [Last accessed on 2019 Nov 19].  Back to cited text no. 22
Taylor JY, Sun YV, Barcelona de Mendoza V, Ifatunji M, Rafferty J, Fox ER, et al. The combined effects of genetic risk and perceived discrimination on blood pressure among African Americans in the Jackson heart study. Medicine (Baltimore) 2017;96:e8369.  Back to cited text no. 23
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  [Table 1], [Table 2], [Table 3]


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