Figure 1
Flow chart of included studies.
Table 1
Characteristics of included studies and results.
| LITERATURE | COUNTRY | MEAN AGE (YEARS) | PARTICIPANTS | INTERVENTION DESCRIPTION | INTERVENTION DURATION | BASELINE SBP (MMHG) | CHANGES FROM BASELINE | ||
|---|---|---|---|---|---|---|---|---|---|
| SBP (MMHG) | DBP (MMHG) | URINARY SODIUM (MMOL/24 HOURS) | |||||||
| Kumanyika 2005 | USA | 43.7 ± 6.2 | 1159 participants (956 white and 203 black adults) with overweight (577 control, 582 intervention) | C: usual care;I: received comprehensive education and counseling about how to reduce sodium intake | 36 months | 127.5 ± 6.5 | C: 0.62 ± 8.61;I: –0.58 ± 9.06 | C: –2.85 ± 6.63;I: –3.04 ± 6.51 | C: –10.50 ± 88.5;I: –50.90 ± 86.30 |
| Chen 2013 | China | 53.5 ± 12.9 | 403 participants between 40 and 49 years of age (177 control, 226 intervention) | C: no measures;I: received salt restriction spoon+health education | 6 months | NA | NA | NA | C: –33.65 ± 98.53;I: –34.84 ± 100.07 |
| He 2015 | China | 10.1 ± 0.5 | 279 healthy primary school students in grade 5 (138 control, 141 intervention) | C: no measures;I: received salt reduction education | 3.5 months | 106.2 ± 11.8a | C: 4.40 ± 11.75;I: 3.80 ± 11.87 | C: 3.40 ± 12.92;I: 2.40 ± 13.06 | C: 20.50 ± 61.09;I: –12.00 ± 60.56 |
| 43.8 ± 12.2 | 553 adult family members of students (275 control, 278 intervention) | C: no measures;I: received the salt reduction education by children | 3.5 months | 125.6 ± 25.0 | C: 5.00 ± 24.87;I: 3.40 ± 25.01 | C: 3.30 ± 17.47;I: 2.70 ± 16.67 | C: 13.20 ± 111.95;I: –36.60 ± 111.71 | ||
| Irwan 2016 | Indonesia | 66.5 ± 6.1 | 45 participants with hypertension/prehypertension (17 control, 13 SRT, 15 SREM) | C: no measures;SRT: received salt reduction educational trainingSREM: received salt reduction educational training and a maintenance meeting | 1.5 months | 145.8 ± 23.3 | C: –6.30 ± 20.26;SRT: –9.40 ± 16.52;SREM: –7.70 ± 27.14 | C: 0.50 ± 10.41;SRT: –2.80 ± 11.14; SREM: –4.40 ± 13.58 | NA |
| Takada 2016 | Japan | 63.8 ± 10.84 | 68 participants (35 housewives and 33 family members) (32 control, 36 intervention) | C: no measures;I: received cooking classes focusing on salt reduction | 2 months | 133.8 ± 18.6a | C: 7.88 ± 11.01;I: 5.05 ± 12.75 | C: 3.81 ± 10.47;I: 2.91 ± 7.03 | NA |
| Iwahori 2018 | Japan | 54.5 ± 8.1 | 92 participants between 40 and 49 years of age (46 control, 46 intervention) | C: brief dietary education+receive a leaflet as usual care;I: self-monitoring urinary sodium-to-potassium ratio device+brief dietary education+a leaflet as usual care | 1 month | 125.9 ± 2.2a | C: –2.20 ± 8.50;I: –3.4 ± 9.70 | C: –1.00 ± 4.20;I: –1.70 ± 6.00 | C: –8.70 ± 82.2;I: –18.50 ± 63.60 |
| Yasutake 2018 | Japan | 58.1 ± 17.4 | 78 local resident volunteers (36 control, 42 intervention) | C: without any measures;I: used the self-monitoring urinary salt-excretion device | 4 weeks | 124.3 ± 16.8 | C: 2.00 ± 17.96;I: –0.4 ± 16.99 | C: –0.40 ± 10.19;I: –0.40 ± 10.47 | C: –2.30 ± 65.52;I: –21.17 ± 66.83 |
| Yasutake 2019 | Japan | 20.8 ± 0.9 | 100 healthy female college students (49 control, 51 intervention) | C: without any measures;I: used the self-monitoring urinary salt-excretion device | 4 weeks | 101.4 ± 7.5 | C: –2.60 ± 7.11;I: –0.30 ± 7.91 | C: –2.40 ± 6.65;I: –1.00 ± 6.76 | C: 2.65 ± 52.00;I: –13.70 ± 44.76 |
| Silva 2021 | Portugal | 48 ± 11 | 114 workers from a public university (57 control, 57 intervention) | C: no measures;I: used the Salt Control H equipment at home to control salt quantity for cooking all meals | 8 weeks | 127.0 ± 18.1 | C: –3.70 ± 13.94;I: –3.20 ± 14.32 | C: –4.80 ± 7.16;I: –4.80 ± 7.16 | C: 2.17 ± 61.86;I: –14.61 ± 63.41 |
| He 2022 | China | 8.6 ± 0.4 | 592 healthy primary school students in grade 3 (295 control, 297 intervention) | C: no measures;I: received salt reduction education and monitoring via the app-based platform | 12 months | 93.9 ± 9.4a | C: 2.80 ± 9.30;I: 1.50 ±9.80 | C: 1.50 ±7.83;I: 0.20 ±8.17 | C: 9.00 ± 37.16;I: 2.80 ± 36.2 |
| 45.8 ± 12.9 | 1184 adult family members of students (590 control, 594 intervention) | C: no measures;I: received salt reduction education and monitoring via the app-based platform | 12 months | 118.7 ± 17.1 | C: –0.40 ± 17.16;I: –3.00 ± 17.08 | C: –0.90 ± 10.62;I: –2.20 ± 10.27 | C: –4.00 ± 64.19;I: –20.10 ± 57.49 | ||
[i] *SBP, systolic blood pressure; DBP, diastolic blood pressure; I, intervention group; C, control group; NA, not applicable; a: reporting using standard validated devices measuring blood pressure.
Table 2
Cochrane risk of bias assessment tool.
| REFERENCE | RISK OF BIAS ASSESSMENT | ||||||
|---|---|---|---|---|---|---|---|
| RANDOM SEQUENCE GENERATION | ALLOCATION CONCEALMENT | BLINDING OF PARTICIPANTS AND PERSONNEL | BLINDING OF OUTCOME ASSESSMENT | INCOMPLETE OUTCOME DATA | SELECTIVE REPORTING | OTHER BIAS | |
| Kumanyika 2005 | Unclear | Low | High | Low | Low | Low | Low |
| Chen 2013 | Unclear | Low | Low | Low | Low | Low | Low |
| He 2015 | Low | Low | Low | Low | Low | Low | Low |
| Irwan 2016 | Unclear | Low | High | Low | Low | Low | Low |
| Takada 2016 | Unclear | Low | High | Low | Low | Low | Low |
| Iwahori 2018 | Low | Low | High | Low | Low | Low | Low |
| Yasutake 2018 | Unclear | Low | High | Low | Low | Low | Low |
| Yasutake 2019 | Unclear | Low | High | Low | Low | Low | Low |
| Silva 2021 | Low | Low | High | Low | Low | Low | Low |
| He 2022 | Low | Low | Low | Low | Low | Low | Low |
Figure 2
Mean net change in SBP (a), DBP (b), and urinary sodium (c) levels and corresponding 95% CI by trial and pooled. SBP, systolic blood pressure; DBP, diastolic blood pressure.
Figure 3
The results of subgroup analysis of SBP and DBP: (a) subgroup analysis of SBP by adult or child subgroup; (b) subgroup analysis of DBP by adult or child subgroup. SBP, systolic blood pressure; DBP, diastolic blood pressure.
Figure 4
The results of subgroup analysis of urinary sodium: (a) subgroup analysis of urinary sodium by adult or child subgroup; (b) subgroup analysis of urinary sodium by invention type subgroup.
Table 3
Certainty of evidence of systolic blood pressure, diastolic blood pressure, and urinary sodium assessment.
| QUALITY ASSESSMENT | NO. OF PATIENTS | EFFECT | QUALITY | IMPORTANCE | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| NO. OF STUDIES | DESIGN | RISK OF BIAS | INCONSISTENCY | INDIRECTNESS | IMPRECISION | OTHER CONSIDERATIONS | BEHAVIORAL INTERVENTION BASED ON SALT REDUCTION | CONTROL | RELATIVE(95% CI) | ABSOLUTE | ||
| Systolic blood pressure (follow-up 1–36 months; better indicated by lower values) | ||||||||||||
| 12 | Randomized trials | Serious1 | No serious indirectness | No serious indirectness | No serious imprecision | None | 2173 | 2154 | – | WMD 1.17 lower (0.49–1.86 lower) | ⊕⊕⊕OModerate | Critical |
| Diastolic blood pressure (follow-up 1–36 months; better indicated by lower values) | ||||||||||||
| 12 | Randomized trials | Serious1 | No serious indirectness | No serious indirectness | No serious imprecision | None | 2173 | 2154 | – | WMD 0.58 lower (0.08–1.07 lower) | ⊕⊕⊕OModerate | Critical |
| Urinary sodium (follow-up 1–36 months; better indicated by lower values) | ||||||||||||
| 10 | Randomized trials | Serious1 | Serious2 | No serious indirectness | No serious imprecision | None | 2314 | 2222 | – | WMD 21.88 lower (11.64–32.13 lower) | ⊕⊕⊕OLow | Critical |
[i] 1Allocation concealment was mentioned in only three articles, and two articles were single-blind.
2High heterogeneity.