| Literature DB >> 26963805 |
Stella Kagwiria Muthuri1, Samuel Oji Oti1, Richard James Lilford2, Oyinlola Oyebode2.
Abstract
BACKGROUND: Salt intake is associated with hypertension, the leading risk factor for cardiovascular disease. To promote population-level salt reduction, the World Health Organization recommends intervention around three core pillars: Reformulation of processed foods, consumer awareness, and environmental changes to increase availability and affordability of healthy food. This review investigates salt reduction interventions implemented and evaluated in sub-Saharan Africa (SSA).Entities:
Mesh:
Substances:
Year: 2016 PMID: 26963805 PMCID: PMC4786148 DOI: 10.1371/journal.pone.0149680
Source DB: PubMed Journal: PLoS One ISSN: 1932-6203 Impact factor: 3.240
Search strategies.
| 1. Exp Sodium Chloride, Dietary/ or exp Sodium, Dietary/ | |
| 2. Salt or sodium | |
| 3. Exp Africa/ | |
| 4. 1 OR 2 | |
| 5. 3 AND 4 | |
| 6. Limit to humans | |
| (Africa Angola Benin Botswana "Burkina Faso" Burundi Cameroon "Cape Verde" "Central African Republic" Chad Comoros Congo "Cote d'Ivoire" Djibouti "Equatorial Guinea" Eritrea Ethiopia Gabon Gambia Ghana Guinea Guinea-Bissau Kenya Lesotho Liberia Madagascar Malawi Mali Mauritania Mauritius Mozambique Namibia Niger Nigeria Reunion Rwanda "Sao Tome and Principe" Senegal Seychelles "Sierra Leone" Somalia "South Africa" Sudan Swaziland Tanzania Togo Uganda "Western Sahara" Zambia Zimbabwe) AND (salt sodium) AND (intervention reduction) |
Fig 1PRISMA Flow Diagram showing inclusion and exclusion of identified papers.
From: Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group (2009). Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement. PLos Med 6(6): e1000097. doi: 10.1371/journal.pmed1000097 For more information, visit www.prisma-statement.org.
Included articles.
| Reference | Country | Data Collection Period | WHO Pillar | Study Design | Quality Score |
|---|---|---|---|---|---|
| Charlton et al., 2008 [ | South Africa | May 2004–July 2005 | Product Reformulation | RCT | Moderate |
| Mtabaji et al., 1990 [ | Tanzania | Not reported | Product Reformulation | RCT | Weak |
| Adeyemo et al., 2002 [ | Nigeria | Not reported | Consumer Awareness | Cohort (before-after) | Moderate |
| Cappuccio et al., 2000 [ | Ghana | 1999 | Consumer Awareness | Cohort (before-after) | Moderate |
| Cappuccio et al., 2006 [ | Ghana | June 2001–June 2002 | Consumer Awareness | Cluster RCT | Weak |
| Forrester et al., 2005 [ | Nigeria | Not reported | Consumer Awareness | Randomised crossover trial | Weak |
| An et al., 2013 [ | South Africa | Feb 2009–Nov 2011 | Environmental Change | Observational | Moderate |
Acronyms: Randomised Control Trial (RCT)
Details of included studies.
| Reference | Population | Intervention | Control | Outcomes Measured | Results |
|---|---|---|---|---|---|
| Charlton et al., 2008 [ | 80 Black residents of a Cape Town township aged 50–75 years, with drug-treated mild-to-moderate hypertension but without type 1 diabetes, impaired cognitive function, incontinence, renal impairment, cerebral infarction or haemorrhage, not taking furosemide for cardiac failure, not drinking three or more alcoholic drinks per day, and a BMI under 45. | Sodium, potassium, magnesium and calcium content were modified in 5 commonly consumed food items (brown bread, margarine, stock cubes, aromat (flavour enhancer), and soup mixes. These items plus a salt replacement (solo), fermented milk (maas), and enough food was given to the whole family for 8 weeks (delivered 3 times a week). The subjects were instructed to consume their usual amounts of food. | The same items were provided to a control group of participants, but using the standard commercial compositions, and an artificially sweetened cold drink was given instead of maas. | 24h urinary sodium. Systolic and diastolic blood pressure. | No significant reduction in 24h urinary sodium. Reduction in systolic blood pressure. No significant reduction in diastolic blood pressure. |
| Mtabaji et al., 1990 [ | 30 male normotensive volunteers. | Participants were given a low sodium diet of about 50 mmol/day. | The control arm of participants were given a normal diet supplemented by 250 mmol of sodium in the form of a soup. | 24h urinary sodium. Mean arterial pressure. | Reduction in 24h urinary sodium. Reduction in mean arterial pressure. |
| Adeyemo et al., 2002 [ | 88 participants were randomly selected from a population-based register of adults aged ≥25 years among those who had systolic blood pressure within the top 20% of the population's distribution. Participants were recruited from two rural communities in Idere and Igbo-Ora, and were mainly farmers. | Participants were taken through a counselling and food tasting session teaching them (1) how to reduce salt added during cooking by half, and (2) how to eliminate the use of bouillon cubes and monosodium glutamate seasoning for a 2-week period | Not applicable | 24h urinary sodium. Systolic and diastolic blood pressure. | Reduction of 24h urinary sodium. Reduction in systolic blood pressure. No significant reduction in diastolic blood pressure. |
| Cappuccio et al., 2000 [ | 20 farmers (8 men, 12 women) were selected randomly from households in the village of Odoyefe in the Ashanti region of Ghana. | A week of daily nutrition education (1.5 hours each) was offered, followed by once a week sessions thereafter for 4 weeks. | Not applicable | 24h urinary sodium. Systolic and diastolic blood pressure. | Reduction in 24h urinary sodium. Reduction in systolic blood pressure. Reduction in diastolic blood pressure. |
| Cappuccio et al., 2006 [ | 12 communities (villages) in the Ashanti region, 6 rural and 6 semi-urban. | Community Health Workers delivered sessions using flip charts as the main means of communication. These were held daily for one week and once a week thereafter, each lasting one hour (for both intervention and control arms). The standard health education package included prevention of malaria, infective diarrhoea, roundworm infection, and awareness of diabetes and hypertension. In addition to the standard health education package, additional advice was given to the intervention arm to limit the consumption of 5 salty foods, and when eaten, to soak the items in water overnight beforehand, and not to add salt to food. | Control villages received the standard health education package. | 24h urinary sodium. Systolic and diastolic blood pressure. The intervention was carried out with the whole village. The measurements were only taken in a random sample of 1013 participants from these villages. | No significant reduction in 24h urinary sodium. No significant change in systolic blood pressure. Reduction in diastolic blood pressure. |
| Forrester et al., 2005 [ | 58 participants recruited from the Igbo-Ora and Idere rural communities in South West Nigeria (about 50 miles from Ibadan). They were normotensive men and women aged 25–55 years, who were able to give informed consent, excluding pregnant and breastfeeding women, people with history of diabetes, kidney disease, atherosclerotic vascular disease or obesity (BMI over 40). | For the low-salt diet arm, case managers provided information and counselling to participants to help identify dietary sodium sources and enhance behavioural skills for reducing salt intake. For the high-salt diet arm, participants were instructed to consume their regular diet and take four capsules containing 16 mEq each. Compliance was monitored by a daily log and pill counts at each visit. | A randomisation scheme was constructed in blocks of four. Individuals were allocated to either a low-salt or high-salt diet for 3 weeks, followed by 2 weeks wash-out, then a crossover for an additional 3 weeks. | 24h urinary sodium. Systolic and diastolic blood pressure. | Reduction in 24h urinary sodium. Reduction in systolic blood pressure. Reduction in diastolic blood pressure. |
| An et al., 2013 [ | 351,319 members of a health and life insurance company’s health promotion programme in 169,485 households. | Everyone enrolled in the health promotion programme was eligible for the Healthy Food Benefit, but to receive it, they were required to activate it online or via a phone call. Those who activated the benefit received 10% off healthy food purchases in a specific supermarket chain (“Pick n Pay”) and 25% off if they completed an online health risk assessment questionnaire. | For analysis of survey data, participants were classified into three groups dependent on the level of benefit at the time of survey completion: 0%, 10% and 25%. For analysis of credit card purchases, participants were classified according to their level of benefit at the time of purchase (therefore some households acted as their own control). | Survey data: “How often do you eat a) high sugar food; b) fried food; c) processed meats; d) fast food” “How salty do you like your food? Not salted, slightly salted, or very salty” Food purchases made in “Pick n Pay” with a Visa credit card. | |
Acronyms: Body Mass Index (BMI), 24 hour (24h).
Quantitative results from included studies.
| Systolic Blood Pressure (mmHg) | Diastolic Blood Pressure (mmHg) | 24h urinary sodium (mmol/day) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Baseline (μ (SD)) | Results (μ (95% CI)) | Baseline (μ (SD)) | Results (μ (95% CI)) | Baseline (μ (SD)) | Results (μ (95% CI)) | |||||||
| Charlton et al., 2008 [ | Intervention | 133.9 (14.6) | Control—Intervention | 6.2 (1.0–11.4) | Intervention | 79.8 (8.6) | Control- Intervention | 0.6 (-1.8–3.0) | Intervention | 171.7 (53.7) | Post-pre intervention (μ (sd)) | -14.6 (54.4) p>0.05 |
| Control | 135.4 (16.7) | Control | 82.3 (7.5) | Control | 173.2 (52.4) | Control—Intervention (μ (sd)) | 8.7 (46.9) p>0.05 | |||||
| Mtabaji et al., 1990 [ | High salt (μ (sd)) | 324 (25.5) | ||||||||||
| Low salt (μ (sd)) | 52.4 (6.9) | |||||||||||
| Adeyemo et al., 2002 [ | Men | 116.8 (15.3) | Post-pre intervention | 4.7 (1.9–7.4) | Men | 74.0 (9.5) | Post-pre intervention | 1.9 (-0.3–4.1) | Men | 140.5 (53.4) | Post-pre intervention | 76.9 (59.7–94.1) |
| Women | 110.1 (14.6) | Post-pre intervention | 7.0 (2.6–11.4) | Women | 69.1 (11.5) | Post-pre intervention | 1.6 (-1.8–5.0) | Women | 132.6 (48.0) | Post-pre intervention | 79.4 (59.4–99.5) | |
| Cappuccio et al., 2000 [ | Total Sample | 135.3 (16.5) | Post-pre intervention | 6.4 (0.5–12.3) | Total Sample | 85.8 (8.6) | Post-pre intervention | 4.5 (-0.3–9.3) | Total Sample | 99.4 (49.4) | Post-pre intervention | 44.1 (22.3–65.9) |
| Cappuccio et al., 2006 [ | Intervention | 129 (25) | Control—Intervention at 6 months | 2.5 (-1.5–6.5) | Intervention | 77 (13) | Intervention—Control at 6 months | 4.0 (0.8–7.1) | Intervention | 99.9 (44.7) | Intervention—Control at 6 months | -6.0 (-16.1–4.1) |
| Control | 127 (27) | Control | 76 (13) | Control | 102.5 (45.3) | |||||||
| Forrester et al., 2005 [ | Total Sample | 114.8 (11.4) | High salt—low salt phase | 4.5 (1.6–7.3) | Total Sample | 73.3 (9.1) | High salt—low salt phase | 2.7 (0.9–4.5) | Pre-intervention/High salt diet | 93.0/127.3 | High—Low salt diet | 93.7 |
Note: 1mmol sodium = 58.5 mg salt. Mean arterial pressure results are presented in the text.