Table 1. Characteristics of the included studies.
| First author (published year), country | Study design | Total number of participants/ sexes | Mean age (years) | Study population character | Assessment of blood pressure | Baseline SBP and DBP level (mm Hg) | Intervention type | Intervention description | Study duration | After intervention SBP and DBP level (mm Hg) | Main results outcomes | Quality | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Intervention group | Control group | ||||||||||||
| Silva-Santos (2021), Portugal | RCT | 114/ F, M I:57 C:57 |
I: 47 ± 10 C: 49 ± 11 |
Adults older than 18 years | Portable sphygmomanometer: an average of the values of the two measurements | I: 126.2 ± 18.49, 79.7 ± 12.13 C: 127.7 ± 18.68, 81.2 ± 12.32 |
Self-help material | Using the Salt Control H equipment by the participants at home to control salt quantity for cooking all meals + provision Portuguese food guide |
Provision Portuguese food guide | 8 weeks | I: 123.0 ± 16.17, 74.9 ± 10.98 C: 124.1 ± 15.98, 76.4 ± 10.78 |
SBP and DBP decreased in both groups. The mean difference for SBP was significant in the control group and for DBP, the mean difference was significant in both groups | High |
| Neal (2021), China | C-RCT | 20995/ F, M I:10504 C:10491 |
I: 65.2 ± 8.5 C: 65.5 ± 8.5 |
Adults who had a history of stroke or were 60 years of age or older and had poorly controlled blood pressure | Omron electronic sphygmomanometer: the average of the two measurements | I: 153.8 ± 23.4, 89.1 ± 14 C: 154.2 ± 23.6, 89.4 ± 14 |
Salt substitute | Free of charge replacement of regular salt with salt substitute contained 75% of NaCl, and 25% of KCl | Regular salt | 5 years | I: 143 ± 20, 85 ± 12 C: 147 ± 21, 86 ± 12 |
• Significant difference in SBP, and DBP between two group after the intervention | Medium |
| Yu (2021), India | RCT | 502/ F, M I: 252 C:250 |
I: 61.5 ± 11.1 C: 61.6 ± 12.0 |
Adults with diagnosed hypertension | Automated digital BP monitor: the mean of the last 2 sitting measurements | I: 132.8 ± 20.3, 83.7 ± 12.0 C: 132.1 ± 22.5, 82.9 ± 13.1 |
Salt substitute | Replacement of regular salt with salt substitute contained 70% of NaCl and 30% of KCl | Regular salt | 3 months | I: 127.6 ± 19.6, 83.0 ± 12.6 C: 131.7 ± 21.7, 83.7 ± 13.3 |
• Significant reduction in SBP (an average reduction of 4.6 mmHg, P < 0.001) and DBP (1.1 mmHg, P = 0.02) in DBP in intervention group | High |
| He (2021), China | C-RCT | 592/ F, M I: 297 C:295 |
I: 8.59 ± 0.34 C: 8.58 ± 0.47 |
School children | Validated automatic machine with the appropriate size of cuff: the average of the last two of the three readings | I: 92.8 ± 9.7, 64.3 ± 8.5 C: 92.5 ± 8.7, 64.0 ± 8.2 |
Education | Salt reduction education and monitoring via the app-based platform (AppSalt), complemented by the creation of supportive environments (eg, salt awareness posters put up in classrooms, campuses, and canteens) and seminars for both children and adults organised by teachers | - | 12 months | I: 94.3 ± 9.9, 64.5 ± 7.8 C: 95.3 ± 8.7, 65.5 ± 7.4 |
• Blood pressure showed an increase from baseline to the end of the trial in both groups, and the mean effect comparing the intervention group with the control group was −1.19 mm Hg (−2.76 to 0.38) for SBP and −1.28 mm Hg (−2.64 to 0.09) for DBP | High |
| 1184/ F, M I: 594 C:590 |
I: 46.73 ± 13.06 C: 44.86 ± 12.61 |
Children’s adult family members | Validated automatic machine with the appropriate size of cuff: the average of the last two of the three readings | I: 132.8 ± 20.3, 83.7 ± 12.0 C: 118.9 ± 16.8, 77.5 ± 10.2 |
Education | - | 12 months | I: 115.7 ± 16.5, 74.7 ± 9.9 C: 118.5 ± 17.5, 76.6 ± 11.0 |
• Blood pressure decreased in both groups, but the extent was greater in the intervention group and the mean effect was −2.53 mm Hg (−3.90 to −1.17) for SBP and −1.19 mm Hg (−2.15 to −0.23) for DBP | ||||
| Payne Riches (2021), United Kingdom | RCT | 47/ F, M I: 31 C:16 |
I: 64 ± 12 C: 67 ± 7 |
Patients with an elevated blood pressure | - | I: 134 ± 16, 81 ± 10 C: 137 ± 15, 80 ± 8 |
Self-help material | Behaviour change advise session with provision of the SaltSwap app to help individuals identify lower-salt options when grocery shopping and provide feedback on swaps made + usual care | Usual care in the form of a postal copy of the publicly available British Heart Foundation Cut Down on Salt booklet or its successor Taking Control of Salt | 6 weeks | I: 133.2 ± 16.9, 80.2 ± 10.7 C: 136.2 ± 15.9, 82.0 ± 10.5 |
• No significant effects on blood pressure • No significant between-group difference |
Medium |
| Dorsch (2020), United States | RCT | 50/ M, F I:24 C:26 |
I: 56.6 ± 10 C: 58.2 ± 11 |
Adults aged ≥18 years who were under treatment for hypertension | Automated blood pressure monitor: An average of 3 measurements was used as the participants’ blood pressure | I: 129.1 ± 20, 84.4 ± 12 C: 128.3 ± 14, 81 ± 8 |
Self-help material | Using LowSalt4Life, a just-in-time adaptive mobile app intervention that recommends lower dietary sodium food alternatives at home, restaurants, and grocery stores | Usual dietary advice | 8 weeks | I: 121.52 ± 7.2, 80.73 ± 5.33 C: 127.78 ± 7.08, 81.56 ± 5.25 |
• The SBP change from baseline to week 8 in the App group was –7.5 mmHg while that in the No App group was –0.7 mmHg (P = .12) | Medium |
| Humalda (2020), Netherlands | RCT | 99/ F, M I:52 C:47 |
I: 55.1 ± 11.5 C: 58.2 ± 13.2 |
Patients with chronic kidney disease (CKD) | Automated oscillometric device: the mean of the second and third reading | I: 139.6 ± 18.03, 83.9 ± 10.09 C: 139.2 ± 17.82, 83.3 ± 10.28 |
Education | Routine care plus a web-based self-management dietary sodium reduction intervention delivered through individual e-coaching and group meetings | Routine care | 9 months | I: 131.5 ± 18.03, 79.2 ± 10.82 C: 135.3 ± 17.82, 80.1 ± 10.28 |
• Significant reduction in SBP and DBP at baseline to 9 months postbaseline in the intervention group • No significant difference in BP between groups after intervention |
High |
| Bernabe-Ortiz (2020), Peru | Stepped-wedge cluster randomized trial | 2376/ F, M I: 3605.3 person-years C: 2547.2 person-years |
43.3 ± 17.2 | Community-based Adults older than 18 years with no heart disease |
Automatic blood pressure monitor: the average of the second and third measurements | - | Salt substitute | Replacement of regular salt with salt substitute contained 75% of NaCl and 25% of KCl | Common salt | 6 months | - | An average reduction of 1.29 mm Hg (95% CI: −2.17, −0.41) in SBP and 0.76 mm Hg (95% CI: −1.39, −0.13) in DBP | High |
| Yasutake (2019), Japan | RCT | 124/ F I:62 C:62 |
Total: 20.8 ± 0.9 I: 20.9 ± 0.8 C: 20.7 ± 0.9 |
Female college students without hypertension | Digital automatic sphygmomanometer: mean of 4 consecutive measurements | I: 100.9 ± 7.7, 63.2 ± 6.5 C: 101.9 ± 7.3, 63.9 ± 6.6 |
Self-help material | Provision of self-monitoring urinary salt excretion measurement device | The control group was asked to behave as they usually did | 4 weeks | I: 100.9 ± 8.1, 62.2 ± 7.0 C: 99.3 ± 6.9, 61.5 ± 6.7 |
• No difference in SBP and DBP at end line in both groups • Significant change in SBP and DBP from baseline to end line in the control group |
Medium |
| Rahimdel (2019), Iran | RCT | 140/ M, F I:70 C:70 |
Total: 42.5 ± 5.2 I: 42.43 ± 4.9 C: 42.61 ± 5.5 |
Subjects at risk of developing hypertension (having SBP and DBP of 120–139 mmHg and 80–89 mmHg respectively). | Mercury sphygmomanometer: mean of 2 readings | I: 126.47 ± 6.9, 75.32 ± 8.1 C: 126.82 ± 7.1, 73.68 ± 7.2 |
Education | Education program based on the theory of planned behavior (TPB) for salt intake reduction | No intervention | 3 months | I: 127.6 ± 6.5, 76.59 ± 7.4 C: 125.83 ± 10.8, 74.66 ± 9.7 |
• No significant change in SBP and DBP from baseline to end line in either group • No significant difference in change of SBP and DBP between two group |
Medium |
| Cashman (2019), Ireland | Cross-over RCT | 97/ M, F I:47 C:50 |
47.8 ± 9.3 | Apparently healthy adults with slightly to moderately elevated BP (pre-hypertension to stage 1 hypertension: minimum >120/80 mmHg) | Automatic digital blood-pressure monitor: the average of the last two measurements | Not reported | Food reformulation | The replacement of bread and a limited number of other foods with equivalent foods which had lower salt content | Usual-salt diet | 5 weeks | I: 131.0 ± 11.0, 84.6± 8.2 C: 134.3± 12.1, 84.7±8.5 |
• Significantly lower SBP during the reduced-salt dietary period compared to the usual-salt dietary period (by 3.3 mmHg on average; p < 0.0001) • No significant difference in DBP |
Medium |
| Yasutake (2018), Japan | RCT | 123/ M, F I:61 C:62 |
Total: 58.1 ± 17.4 I: 56.7 ± 17.5 C: 59.6 ± 17.5 |
Community-based Adults older than 21 years Without history of hypertension |
Digital, upper-arm, automatic BP measuring instrument: mean of 4 consecutive measurements | I: 124.3 ± 15.6, 76.1 ± 10.8 C: 124.4 ± 18.3, 74.3 ± 10.9 |
Self-help material | Self-monitoring of 8h overnight urine extraction using the urinary salt excretion measurement device | No intervention | 4 weeks | I: 123.9 ± 18.1, 75.7 ± 10.1 C: 126.4 ± 17.6, 73.9 ± 9.3 |
• No significant change in BP in either group • No significant difference between the two groups in term of SBP and DBP at end line |
Medium |
| Yang (2018), China | RCT | 51/ M, F I:24 C:27 |
I: 67.8 ± 5.34 C: 65.9 ± 6.17 |
Hypertensive patients with isolated systolic hypertension | The average of the two measurements | I: 161 ± 11.0 80.6 ± 4.94 C: 157 ± 10.4 81.3 ± 4.97 |
Salt substitute | Replacement of regular salt with salt substitute contained 65% NaCl, 30% KCl, and 5% calcium |
Normal salt | 6 months | I:153 ± 7.51 80.4 ± 5.92 C:159 ± 10.7 81.6 ± 5.00 |
• Significant reduction in SBP in intervention group after follow-up | Medium |
| 75/ M, F I:38 C:37 |
I: 67.3 ± 5.62 C: 65.4 ± 6.75 |
Hypertensive patients with non-isolated systolic hypertension | The average of the two measurements | I: 159 ± 12.2 85.0 ± 8.82 C: 157 ± 13.8 83.8 ± 8.21 |
Salt substitute | Replacement of regular salt with salt substitute contained 65% NaCl, 30% KCl, and 5% calcium |
Normal salt | 6 months | I: 155 ± 14.5 84.4 ± 9.00 C:159 ± 13.1 85.9 ± 9.00 |
• No changes in SBP and DBP in either the intervention or control groups | |||
| Takada (2018), Japan | C-RCT | 158/ M, F I:79 C:79 |
I: 62.0 ± 13.0 C: 63.9 ± 11.8 |
Family based adults aged 20 years old or older | Automatic monitor: mean of 2 readings | I: 138.2 ± 21.2, 77.8 ± 11.6 C: 138.5 ± 19.8, 77.3 ± 12.3 |
Self-help material | Holding lecture and handed out leaflets about salt reduction + Provision of self-monitoring device that estimates salt intake |
Holding lecture and handed out leaflets about salt reduction | 4 weeks | I: 135.0 ± 20.9, 77.6 ± 11.9 C: 138.2 ± 21.2, 77.8 ± 11.6 |
• Significant difference in SBP between two group after the intervention | High |
| Musso (2018), Italy | RCT | 291/ M, F I:240 C:51 |
I: 63.2 ± 12.2 C: 64.1 ± 8.9 |
Patients on antihypertensive treatment | Digital Automatic BP Monitor | I: 144.5 ± 18.1, 85.9 ± 11.8 C: 145.4 ± 12.3, 84.5 ± 8.7 |
Education | Simple recommendations printed on a single A4 sheet of paper included on instruction to avoid salty foods and switch from regular bread to salt-free bread | Generic dietary advice | 2 months | I: 135.7 ± 12.6, 80.8 ± 9.5 C: 143.3 ± 10.8, 85.3 ± 6.7 |
• Significant reduction in SBP and DBP in intervention group • Significant difference in SBP and DBP between two groups after intervention |
Medium |
| Iwahori (2017), Japan | RCT | 92/ M, F I:49 C:49 |
I: 55.0 ± 8.14 C: 54.0 ± 8.14 |
Healthy individuals or individuals with primary hypertension | Automated BP monitor: mean of 4 measurements | I: 125.9 ± 17.1, 79.3 ± 12.2 C: 125.8 ± 15.5, 77.9 ± 9.6 |
Self-help material | Provision brief dietary education and a leaflet as usual care + Provision of self-monitoring urinary salt excretion measurement device | Provision brief dietary education and a leaflet as usual care | 1 months | I: 122.5 ± 17.6, 77.6 ± 12.0 C: 123.6 ± 14.8, 76.9 ± 9.6 |
• No significant difference in changes in SBP and DBP between two groups • No significant reduction in SBP and DBP after intervention |
High |
| Borah (2018), India | RCT | 393/ M, F I:199 C:194 |
I: 44.5 ± 14.4 C: 40.4 ± 15.5 |
Tea garden workers | Electronic BP monitor: average of last 2 reading | I: 140.4 ± 26.9, 84.8 ± 14.5 C: 141.6 ± 19.5, 84.2 ± 12.0 |
Education | Counselling (individual and group) and motivational campaign, meetings, posters, small booklet, health rally and audio-visual aids in the form of documentary film based on trans-theoretical model for behavior change |
Appropriate medical advices as per existing medical practices for hypertensive participant | 1 year | I: 134.6 ± 15.47, 77.6 ± 8.64 C: 141.1 ± 15.83, 83.3 ± 8.64 |
• Significant reduction in SBP and DBP in intervention group after follow-up • Significant different change in SBP and DBP between two groups |
Medium |
| Eyles (2017), New Zealand | RCT | 66/ M, F I:33 C:33 |
I: 64 ±7 C: 65±8 |
Adults with diagnosed cardiovascular disease and aged 40 years or over | Not reported | I: 131 ± 15, 80 ± 10 C: 134 ± 15, 79±9 |
Self-help material | Using SaltSwitch app: scanning the barcode of a packaged food using smartphone camera to receive an immediate interpretive, traffic light nutrition label on screen, along with a list of lower salt alternatives to ‘switch’ to. | access usual care cardiac rehabilitation services for people with CVD | 4 weeks | I: 129 ± 11.5 C: 131 ± 11.5 |
• No significant difference in SBP between groups | High |
| Allaert (2017), France | RCT | 41/ M, F I:22 C:19 |
Total: 51.0±16.0 | Prehypertensive volunteers (120–139 mmHg SBP and/or 80–89 mmHg DBP) older than 18 years old and less than 70 years old | Fully automatic upper arm BP monitor: mean of 3 readings | I: 130.8 ± 5.7, 79.5 ± 6.8 C: 136.6 ± 10.3, 82.6 ± 7.8 |
Salt substitute | Provision of NaCl + Chitosan 3% (Symbiosal) plus a measuring spoon of a dose of 0.5 g of salt | Standard NaCl | 8 weeks | I: 126.1 ± 6.5, 74.7 ± 6.4 C: 140.4 ± 8.3, 85.3 ± 9 |
• Significant decrease in SBP and DBP in intervention group • Significant difference in SBP and DBP between two groups at the end of intervention |
High |
| Zhou (2016), China | RCT | 462/ M, F I:224 C:238 |
I: 45.63 ± 13.72 C: 47.05 ± 13.46 |
Community-based patients with hypertension plus family members aged 18 years over |
Automatic sphygmomanometer: mean of 2 readings | I: 154.02 ±28.26 91.46±14.75 C: 149.53 ± 23.67 89.07±13.78 |
Salt substitute | Replacement of regular salt with salt substitute contained 65% of NaCl, 25% of KCl and 10% MgSO2 | Normal salt with 100% NaCL | 3 years | I: 143.14 ±47.67 88.73 ±29.15 C: 148 ±55.64 90.99 ±29.78 |
• Significant different change in SBP and DBP between the two groups | High |
| Takada (2016), Japan | CRCT | 35/ F I:18 C:17 |
I: 63.0 ± 10.3 C: 64.8 ± 11.5 |
Housewives aged 40 years over | Automatic BP monitor: average of 2 measurements | I: 135.6 ± 18.5 74.6 ±11.4 C: 131.9 ± 18.7 74.1±10.3 |
Education | Practical course for evaluating the amount of salt in a meal and instruction on salt-reduced cooking | lectures about healthy living | 2 months | I: 138.0 ±17.6 76.8 ±9.08 C: 140.3 ±11.3 78.7 ±7.95 |
• No significant difference in SBP and DBP between two groups | Medium |
| Li (2016), China | C-RCT | 2566/ F, M I: 1294 C:1272 |
I: 55 ± 15 C: 55 ± 14 |
Random sample of adults |
Automated electronic sphygmomanometer: mean of 2 readings | Not reported | Education | Community-based health education through public lectures, and the display and distribution of promotional materials and availability of reduced-Na, added-K salt substitute at shops | usual practices without the introduction of any of the sodium reduction initiatives | 18 months | I: 141 ± 22 86 ± 14 C:142 ± 23 86 ± 14 |
• No significant difference in SBP and DBP between two groups at the end of the study | Medium |
| Irwan (2016), Indonesia | RCT | 34/ M, F I:17 C:17 |
67.9 ± 6.9 66.1 ± 5.7 |
Older people aged 60 years over with Hypertension or prehypertension | Sphygmomanometer | I: 147.5±17.3 88.0±12.8 C: 144.8±21.1 85.2±10.2 |
Education | Salt-reduction educational training, that applied self-care and self-efficacy theories (SRT) | Monthly health check-ups as usual care | 2 weeks |
I: 142.3±16.2 85.6±8.9 C: 143.5±16.9 87.3±7.5 |
• No significant difference in SBP and DBP among two groups after intervention | High |
| 34/ M, F I:17 C:17 |
65.8 ± 5.9 66.1 ± 5.7 |
Older people aged 60 years over with Hypertension or prehypertension | Sphygmomanometer | I: 145.5±30.5 87.5±15.5 C: 144.8±21.1 85.2±10.2 |
Education | Salt-reduction training and efficacy-maintenance meeting (SRTM) | Monthly health check-ups as usual care | 1.5 months | I: 137.8±21.5 83.1±9.8 C: 138.5±19.3 85.7±10.6 |
• Significant reduction in SBP in SREM after training | |||
| Pinjuh Markota (2015), Bosnia and Herzegovina | RCT | 150/ M, F I: 76 C:74 |
I: 59.4 ± 13 C: 59.3 ± 12 |
Hypertensive adults | Mercury sphygmomanometry | I: 142.9 ± 20.6 84.7±10.3 C: 143.7±18.1 84.1±8.9 |
Self-help material | informational leaflets + Warning labels placed on home salt containers | individual information leaflet about the harmful effects of excessive salt intake | 2 months | I: 137.6±16.1 81.8±8.5 C: 143.3±18.5 83.2±8.9 |
• Significant reduction in SBP and DBP in intervention group | High |
| He (2015), China | C-RCT | 279/ M, F I:141 C:138 |
Total:10.1±0.5 I: 10.0±0.5 C: 10.2±0.5 Total:43.8±12 |
Schoolchildren | Automatic blood pressure monitor: mean of last 2 measurements |
I: 106.2±11.79 67.0±12.97 C: 106.2±11.62 66.8±12.78 |
Education | Multiple theory-based education programme for behavior change to low-salt diet within the schools’ usual health education lessons |
Usual health education lessons as in the curriculum | 3.5 months | I: 110.0 ± 11.79 69.4 ± 12.97 C: 110.6 ± 11.62 70.2 ± 12.78 |
• No significant effect on BP in children | High |
| 553/ M, F I:278 C:275 |
.2 I:43.9±12.5 C:43.6±11.8 |
Children’s family members | Automatic blood pressure monitor: mean of last two measurementsل |
I: 127.1±24.69 81.4±16.46 C: 124.1±24.23 79.9±16.15 |
Education | Transmitting messages through children and delivering educational materials in the form of a newsletter | 3.5 months | I: 130.5±24.69 84.1±16.46 C: 129.1±24.23 83.2±17.77 |
• Significant mean effect of intervention on SBP in adults | ||||
| Barros (2015), Brazil SE |
RCT | 38/ F, M I:19 C:19 |
Total: 55.5 ± 7.4 | Uncontrolled hypertensive patients | Semi-automatic Blood Pressure Monitor: (BP measured at least three times and at 1-minute intervals, until the differences between the measurements were lower than 4 mmHg) mean of last 2readings |
I: 142.95±14.86 89.79±9.10 C: 143.44±13.99 91.19±9.10 |
salt substitute | Replacement of regular salt with the light salt contained (per gram) 130 mg of sodium, 346 mg of potassium and 44 mcg of iodine |
Regular salt contained (per gram) 390 mg of sodium and 25 mcg of iodine | 4 weeks | I: 127.11±15.64 75.95±9.47 C: 137.19±20.22 82.75±12.12 |
• Significant reduction in BP among intervention group after using light salt • Significant reduction in casual SBP among control group after using regular salt • Significant difference in casual BP between two groups at the end of study |
Medium |
| Zhao (2014), China | RCT | 282/ M, F I:141 C:141 |
Total:163.1 ± 11.2 I: 62.8 ± 11.1 C: 63.5 ± 11.3 |
Community-based hypertensives aged 40 years over | Automated electronic sphygmomanometer: mean of 3 readings |
I: 176.1±22.4 103.2±12 C: 177.6±23.3 105.8±13.1 |
salt substitute | Free of charge replacement of regular salt with salt substitute contained 65% of NaCl, 25% of KCl and 10% MgSO2 | Regular salt | 3 months | I: 161.0 ±27.0 97.0 ±14.5 C: 170.2 ±26.8 102.6 ± 13.8 |
• Significant reduction in SBP and DBP in both groups • Significant net reduction of SBP and DBP in salt substitute treatment group in comparison with regular salt group |
High |
| Petersen (2013), Australia | RCT | 78/ F, M I:39 C:39 |
Total:63.1 ± 11.2 I: 62.9 ± 10.8 C: 61.6 ± 10.8 |
Hospital-based patients with T2DM aged 18 years over | Digital ambulatory blood pressure monitor: mean of 3 readings |
I: 144 ±10.77 78 ±10.7 C: 138 ±16.15 76 ±10.77 |
Education | Provision of a single education session which focused on label reading | Usual diet | 3 months | I: 136 ± 16.15 74 ± 10.77 C: 132 ± 16.15 73 ± 10.77 |
• No change in SBP and DBP during the intervention phase | Low |
| Cotter (2013), Portugal | RCT | F, M I:58 C:34 |
I: 10.9 ± 0.6 C: 10.8 ± 0.8 |
School children 10–12 years old | Automated oscillometric upper arm BP monitor: 3 separate measurements of BP were carried out at 2 min intervals. The average of the second and third measurements were considered |
I: 115.1 ± 14.8 65.4 ± 8.2 C: 122.1 ± 14.1 73.5 ± 9.6 |
Education | Aromas school gardening club (2 h/week) plus regular lectures on the potential dangers of high salt intake |
- | 6 months | I: 111.3 ±11.6 64.8 ±7.4 C: 113.9 ±9.9 67.0 ±7.4 |
• No significant differences between the final values observed in the two groups and between baseline and final values in each group | Medium |
| F, M I:47 C:34 |
I: 10.9 ± 0.7 C: 10.8 ± 0.8 |
School children 10–12 years old | Automated oscillometric upper arm BP monitor: 3 separate measurements of BP were carried out at 2 min intervals. The average of the second and third measurements were considered |
I: 117.4 ±9.9 66.9 ± 8.0 C: 122.1 ± 14.1 73.5 ± 9.6 |
Education | Regular lectures on the potential dangers of high salt intake | - | 6 months | I: 113.9 ±9.6 66.2 ±8.5 C: 113.9 ±9.9 67.0 ±7.4 |
No significant differences between the final values observed in the two groups and between baseline and final values in each group | |||
| Allaert (2013), France | Cross-over RCT | 40/ F, M I first:21 C first:19 |
I: 59.1 ±11.6 C: 58.0 ±12.7 |
Patient with stage 1 hypertension (SBP 140–159 mmHg or DBP 90–99 mmHg) aged 18 to 85 years | Homologated automated digital sphygmomanometers: the average of the 3 measurements |
I: 149.2±4.9 93.4±3.0 C: 149.7±4.6 93.3±3.4 |
Salt substitute | lifestyle modifications and added salt reduction recommendation plus provision of NaCl + Chitosan 3% (Symbiosal) | lifestyle modifications and added salt reduction recommendation plus Standard NaCl | 8 weeks | I: 136.1±9.5 82.2±7.7 C: 142.9±7.7 86.3±8.2 |
• significant greater reduction in SBP in the intervention group | High |
| 40/ F, M I:19 C:21 |
I: 58.0 ± 12.7 C: 59.1 ± 11.6 |
Patient with stage 1 hypertension (SBP 140–159 mmHg or DBP 90–99 mmHg) aged 18 to 85 years | Homologated automated digital sphygmomanometers: the average of the 3 measurements |
I: 144.0±10.7 87.4±7.2 C: 137.1±9.4 82.3±6.9 |
Salt substitute | Provision of NaCl + Chitosan 3% (Symbiosal) | Standard NaCl | 8 weeks | I: 140.7±11.5 84.8±9.2 C: 136.8±11.6 81.6±9.3 |
• No significant difference in SBP and DBP reduction between two groups | |||
| Sarkkinen (2011), Finland | RCT | 50/ M, F I:25 C:25 |
I: 57 ± 12 C: 54 ± 11 |
Subjects with mildly elevated BP (SBP in the range of 130–159 mmHg and/or DBP in the range of 85–99 mmHg) between 25–75 years old | Automatic sphygmomanometer: mean of two last readings |
I: 140 ±13 89 ±8 C: 134 ±9 88 ±7 |
salt substitute | Replacement of salt used for cooking, salt in the main food sources of salt and table salt with smart Salt contained 50% NaCl, 25% KCl and 25% magnesal; [Mg4K(NH4)3Cl12·24H2O]. | Regular salt consumption | 8 months | I: 132 ±7 86 ±7 C: 138 ±9 90 ±7 |
• Significant reduction in SBP and DBP in the intervention group • Significant net reduction of SBP and DBP in smart salt group in comparison with regular salt group |
Medium |
| Morikawa (2011), Japan | RCT | 41/ M I:22 C:19 |
I: 48.3 ± 8.7 C: 47.1 ± 8.5 |
Hypertensive workers (SBP higher than 130 mmHg and/or DBP higher than 85 mmHg) | Automatic sphygmomanometer: mean of 2 readings |
I: 149.8±14.3 96.9±11.3 C: 149.4±12.0 96.3±6.7 |
Self-help material | Group counselling on lifestyle modification from public health nurses and registered dietitians+ self-monitoring of 8h overnight urine extraction using the electronic salt sensor and sent personalized e-mail advice via cellular phone | Group counselling on lifestyle modification from public health nurses and registered dietitians | 4 weeks | I: 144.4±12.2 90.7±10.2 C: 147.2±12.4 94.7±7.2 |
• Significant reduction in SBP and DBP after intervention compare to baseline in intervention group • Significant difference in change of DBP between two groups |
Medium |
| Ferrante (2011), Argentina | Cross-over RCT | 58/ M, F I:29 C:29 |
I: 41.5 ± 12.4 C: 37.1 ± 9.1 |
Normotensive or hypertensive adults aged 18 years or older | Average of 2 measurements | I: 114.4 ± 11.6 66.3 ±5.4 C: 113.8 ± 10.5 67.4 ± 6.1 |
Food reformulation | Consumption of low-salt bread contained 1.4% salt | Consumption of normal-salt bread contained 2.0% salt | 15 days | - | • Significant reduction in SBP and DBP with the low-salt bread diet | High |
| Fujiwara (2010), Japan | Non-RCT | 36/ M, F I:14 C:22 |
I: 69.0 ± 11.0 C: 75.1 ± 7.2 |
Outpatients with albuminuria no clinical features of RF, ischemic heart disease, or stroke | Mercury sphygmomanometer: mean of 2 measurements |
I: 145.1±13.9 67.1±8.3 C: 134.9±13.1 66.4±12.2 |
Education | Holding a 30-minute session on dietary change for participant and their families at their home and 2-hour health promotion class for participants and their family and neighbors at a public town meeting hall | Usual care, which consisted of monthly visits and physician advice to reduce salt | 3 months | I: 130.9 ±12.9 62.7 ±7.6 C: 130.9 ±14.0 66.8 ±7.8 |
• Significant reduction in SBP and DBP after intervention compare to baseline in intervention group • Significant difference in SBP reduction between two groups |
Low |
| Zhou (2009), China | RCT | 122/ F, M I:57 C:65 |
I: 68.1 ± 8.3 C: 65.4 ± 4.5 |
Community-based normotensive aged 50–80 years | Not reported | I: 125.0 ± 6.8 74.3 ± 6.4 C: 123.8 ± 7.0 74.5 ± 10.2 |
Salt substitute | Compound ion salt (CISalt) contained 65% NaCl, 30% KCl, 5% calcium, and 12mg/kg folic acid |
Normal salt | 6 months | I: 121.6 ± 7.4 71.7 ± 6.7 C: 127.4 ± 8.7 76.5 ± 5.9 |
• Continuous decrease of SBP and DBP over time with CISalt treatment • Significant between-group differences in SBP and DBP changes |
High |
| 126/ F, M I:62 C:64 |
I: 67.5±5.2 C: 65.7 ±6.3 |
Community-based hypertensive aged 50–80 years | Not reported | I: 159.7 ± 11.7 83.3 ± 7.8 C: 157.7 ± 12.9 82.7 ± 7.1 |
Salt substitute | Compound ion salt (CISalt) contained 65% NaCl, 30% KCl, 5% calcium, and 12mg/kg folic acid |
Normal salt | 6 months | I: 150.4±10.7 78.8±8.6 C: 160.2±11.9 84±7.9 |
• Continuous decrease of SBP and DBP over time with CISalt treatment • Significant between-group differences in SBP and DBP changes |
|||
| Saptharishi (2009), India | RCT | 58/ F, M I:28 C:30 |
I: 22.5 ± 1.47 C: 22.5 ± 1.4 |
Hypertensives and pre-hypertensives young adults | Mercury sphygmomanometer | I: 123.1 ± 8.1 83.7 ± 6.8 C: 123.8 ± 10.8 83.2 ± 7.2 |
Education | Practical suggestions on reducing salt intake to at least half of previous intake | No intervention | 8 weeks | I: 120.8 ± 6.7 80.3 ± 5.3 C: 123.7 ± 10.4 82.8 ± 6.3 |
• Significant reduction in SBP and DBP in intervention group • No significant difference in SBP and DBP reduction between the two groups |
Medium |
| Mu (2009), China | RCT | 215/ F, M I:101 C:114 |
I: 20.3 ± 3.1 C: 21.4 ± 3.9 |
Adolescents with high BP (SBP ≥90th percentile by age and sex) | Mercury sphygmomanometer: mean of 3 readings | I: 123.8 ± 12.9 75.0 ± 11.1 C: 124.3 ± 14.1 77.0 ± 11.8 |
Salt substitute | Provision of salt which KCL and CaCl had been added | No interventions | 2 years | - | • Significant reduction in SBP and DBP in the intervention group • Significant different change in SBP and DBP between two group |
Medium |
| 588/ M, F I:334 C:254 |
- | Family members of hypertensive adolescent | Mercury sphygmomanometer: mean of 3 readings | - | Salt substitute | Provision of salt which KCL and CaCl had been added | No intervention | 2 years | - | • Significant different change in SBP and DBP between two group | |||
| 224/ M, F I:110 C:114 |
I: 20.6 ± 3.1 C: 21.4 ± 3.9 |
adolescents with high BP (SBP ≥90th percentile by age and sex) | Mercury sphygmomanometer: mean of 3 readings | I: 121.5 ± 12.8 75.4 ± 9.9 C: 124.3 ± 14.1 77.0 ± 11.8 |
Education | Health-behavior education about salt-restricted diet | No intervention | 2 years | - | • Significant different change in SBP and DBP between two group | |||
| 592/ M, F I:338 C:254 |
- | Family members of hypertensive adolescent | Mercury sphygmomanometer: mean of 3 readings | education | Health-behavior education about salt-restricted diet | No intervention | 2 years | - | • Significant different change in SBP and DBP between two group | ||||
| CSSSC (2007), China | RCT | 608/ M, F I:306 C:302 |
I: 59 ±10.0 C: 61 ± 9.7 |
Individuals with high risk of future vascular disease | Automatic sphygmomanometer: mean of 2 readings | I: 159 ± 25 93 ± 14 C:159 ± 26 93 ± 14 |
Salt substitute | Replacement of regular salt with salt substitute contained 65% of NaCl, 25% of KCl and 10% MgSO2 | Regular salt | 12-months | I: 141.61 ± 61 93 ± 14 C:148.04 ± 26 93 ± 14 |
• Significant mean difference in SBP between randomized groups • No significant differences between randomized groups for DBP |
High |
| Cappuccio (2006), Ghana | CRCT | 1013/ M, F I:522 C:491 |
I: 54 ± 11 C: 55 ± 11 |
Community-based individuals | Not reported | I: 129.2 ± 24.6 76.9 ± 13.0 C:125.6 ± 25.5 75.2 ± 13.3 |
Education | general health education + more specific education as to how to reduce salt intake | general health education | 6 months | I: 127.9 ± 27.7 76.0 ± 14.2 C:127.4 ± 26.0 78.7 ± 14.3 |
• Significant different change in SBP and DBP between two group | Medium |
| Arcand (2005), Canada | RCT | 50/ M, F I:25 C:25 |
I: 56 ± 3 C: 61 ± 3 |
patients with stable heart failure | Not reported | I: 114 ± 4 71 ± 2 C:114 ± 4 71 ± 2 |
Education | Prescription a 2 g/d sodium-restricted diet as a usual care provision of standardized nutrition education materials as a usual care + holding individualized nutrition-counselling appointments with a registered dietitian | Prescription a 2 g/d sodium-restricted diet and provision of standardized nutrition education materials as a usual care | 3 months | I: 110 ± 4 68 ± 2 C:11 6± 4 74 ± 3 |
• No significant reduction in BP in both group | Medium |
C: Control; I: Intervention; RCT: Randomized controlled-trial; CRCT: Cluster randomized controlled trial; F: Female; M: Male; DBP: Diastolic blood pressure; SBP: Systolic blood pressure