Effect of South Africa's interim mandatory salt reduction programme on urinary sodium excretion and blood pressure

Hypertension in sub-Saharan Africa: the current profile, recent advances, gaps, and priorities

Recent global and regional reports consistently confirm the high and increasing prevalence of hypertension in sub-Saharan Africa (SSA), with poor detection, treatment, and control rates. This narrative review summarises the burden of hypertension in SSA and recent findings from community-based hypertension management strategies. We further outline prominent risk factors according to recent data and associated underlying mechanisms for hypertension development. An extensive review of literature showed that most countries have reported on the prevalence of hypertension during 2017-2023, despite limitations linked to the lack of nationally representative studies, heterogeneity of sampling and data collection methods. Task-shifting approaches that assign roles to model patients and community health workers reported improved linkage to healthcare services and adherence to medication, with inconsistent findings on blood pressure (BP)-lowering effects over time. The regularly reported risk factors include unhealthy diet, sedentary lifestyle, increased adiposity and underweight, ageing, level of education, and/or income as well as psychosocial factors. Newer data on the pathophysiological mechanisms leading to hypertension and potential areas of intervention are reported from children and adults and include, among others, salt-handling and volume overload, endothelial function, BP dipping patterns and the role of human immunodeficiency virus . To conclude, significant strides have been made in data reporting from SSA on the burden of hypertension in the region as well as biomarker research to improve understanding and identification of areas of intervention. However, gaps remain on linkage between knowledge generation, translation, and implementation research. Coordinated studies addressing both discovery science and public health are crucial to curb hypertension development and improve management in SSA.

A review of the world's salt reduction policies and strategies - preparing for the upcoming year 2025

Excessive consumption of dietary sodium is a significant contributor to non-communicable diseases, including hypertension and cardiovascular disease. There is now a global consensus that regulating salt intake is among the most cost-effective measures for enhancing public health. More than half of the countries worldwide have implemented multiple strategies to decrease salt consumption. Nevertheless, a report on sodium intake reduction published by the World Health Organization revealed that the world is off-track to meet its targeted reduction of 30% by 2025. The global situation regarding salt reduction remains concerning. This review will center on domestic and international salt reduction policies, as well as diverse strategies, given the detrimental effects of excessive dietary salt intake and the existing global salt intake scenario. Besides, we used visualization software to analyze the literature related to salt reduction research in the last five years to explore the research hotspots in this field. Our objective is to enhance public awareness regarding the imperative of reducing salt intake and promoting the active implementation of diverse salt reduction policies.

Consumption of Discretionary Salt and Salt from Bouillon among Households, Women, and Young Children in Northern Region, Ghana: A Mixed-Methods Study with the Condiment Micronutrient Innovation Trial (CoMIT) Project

Background

Information on salt consumption patterns is needed to inform the need for and design of salt reduction strategies.

Objectives

In northern Ghana, this study aimed to estimate household consumption of salt, including salt from bouillon, and compare (estimated) women and children's salt intake to global recommendations; to estimate the proportion of salt consumed from bouillon; and to identify factors, including knowledge, attitudes, and practices, associated with household salt consumption.

Methods

Employing mixed-methods methodology, we conducted a pilot survey (n = 369 households enrolled) and focus group discussions (FGDs; n = 20) in Tolon and Kumbungu districts (14 urban, 14 rural clusters) (clinicaltrials.gov registry: NCT04632771). Households reported purchases of discretionary salt (DS, "table salt") and bouillon cubes. DS and total salt (TS; DS+salt from bouillon) consumption for women (15-49 y) and children (2-5 y) were estimated using the Adult Male Equivalent method and compared with global recommendations (<5 g/d women; <3.75 g/d children). Women's salt intake was also predicted from urinary sodium excretion (INTERSALT equation). Associations between DS and TS consumption, as well as household and women's characteristics, were tested with minimally adjusted and multivariable linear mixed-effects models. Qualitative FGD themes were generated using the Framework Method.

Results

From household purchase data, estimated TS consumption exceeded global recommendations for 44% of children [median: 2.9 (IQR: 1.9, 5.2) g/d] and 60% of women [6.0 (4.0, 10.2) g/d]; 35% of children and 50% of women exceeded recommendations from DS alone. Bouillon contributed <25% of households' TS consumption. Few characteristics were associated with DS or TS consumption. Salient qualitative themes that shaped salt consumption behaviors included salt's ubiquity as a seasoning, key household members' influence on food procurement and preparation, and perceptions about health.

Conclusions

Purchase data suggest salt consumption among women and children exceeds recommendations, even when excluding salt from bouillon; food prepared outside the home likely further contributes. Salt reduction interventions may be warranted in this context.

Determining food industry compliance to mandatory sodium limits: successes and challenges from the South African experience

OBJECTIVE

To provide an update on the compliance to the Na reduction regulation (R.214) and to highlight some challenges and successes experienced by South Africa in the implementation of a mandatory Na regulation.

DESIGN

The study design was observational. Nutritional information of packaged food (specified in the R.214 regulation) was collected between February 2019 and September 2020, before and after the implementation date of the final Na targets in the regulation. Six supermarket chains that accounted for more than 50 % of the grocery retailer market share in South Africa were included. The Na content (per 100 g) of products was extracted from photographs. Products were classified according to the thirteen food categories included in R.214. The percentage of targeted food categories that met the pre and post-regulation targets as well as the percentage by which Na limits were exceeded was calculated.

SETTING

Low-and-middle-income suburbs in Cape Town, South Africa.

PARTICIPANTS

N/A.

RESULTS

A total number of 3278 products were analysed. After the final implementation date, none of the categories targeted by the R.214 regulation fully complied. However, nine out of the thirteen food categories targeted by R.214 were above the 70 % compliance mark.

CONCLUSIONS

The compliance to R.214 in South Africa is good, although not 100 % compliant. This research also highlights the complexities regarding the monitoring and evaluation of a national regulation. Findings from the current study could aid by providing valuable information to countries in the process of implementing a Na reduction strategy.

Estimated Dietary and Health Impact of the World Health Organization's Global Sodium Benchmarks on Packaged Foods in Australia: a Modeling Study

BACKGROUND

In 2021, the World Health Organization (WHO) set sodium benchmarks for packaged foods to guide countries in setting feasible and effective sodium reformulation programs. We modeled the dietary and health impact of full compliance with the WHO's sodium benchmarks in Australia and compared it to the potential impact of Australia's 2020 sodium reformulation targets.

METHODS

We used nationally representative data on food and sodium intake, sodium levels in packaged foods, and food sales volume to estimate sodium intake pre- and post-implementation of the WHO and Australia's sodium benchmarks for 24 age-sex groups. Using comparative risk assessment models, we then estimated the potential deaths, incidence, and disability-adjusted life years averted from cardiovascular disease, chronic kidney disease, and stomach cancer based on the reductions in sodium intake.

RESULTS

Compliance with the WHO's sodium benchmarks for packaged foods in Australia could lower mean adult sodium intake by 404 mg/day, corresponding to a 12% reduction. This could prevent about 1770 deaths/year (95% uncertainty interval 1168-2587), corresponding to 3% of all cardiovascular disease, chronic kidney disease, and stomach cancer deaths in Australia, and prevent some 6900 (4603-9513) new cases, and 25 700 (17 655-35 796) disability-adjusted life years/year. Compared with Australian targets, the WHO benchmarks will avert around 3 and a half times more deaths each year (1770 versus 510).

CONCLUSIONS

Substantially greater health impact could be achieved if the Australian government strengthened its current sodium reformulation program by adopting WHO's more stringent and comprehensive sodium benchmarks.

Top Sodium Food Sources in the American Diet-Using National Health and Nutrition Examination Survey

Reducing population-level sodium intake can reduce hypertension, an important preventative strategy to lower the risk of cardiovascular diseases, the leading cause of death in the United States. Considering that most dietary sodium is derived from prepackaged foods, this study quantitatively estimates the proportion contribution and mean sodium intake from key food category contributors to total sodium intake in the US population. Data from the 2017-2018 National Health and Nutrition Examination Survey, which collected interviewer-administered 24 h dietary recalls from Americans (n = 7081), were analyzed. Based on the average proportion contributed, the top 15 sources of sodium were identified overall and by age/sex, poverty-income and race/ethnicity. More than 50% of US population-level dietary sodium intake was contributed by: pizza (5.3%); breads, rolls and buns (4.7%); cold cuts and cured meats (4.6%); soups (4.4%); burritos and tacos (4.3%); savoury snacks (4.1%); poultry (4.0%); cheese (3.1%); pasta mixed dishes (2.9%); burgers (2.5%); meat mixed dishes (2.5%); cookies, brownies and cakes (2.4%); bacon, frankfurters and sausages (2.4%); vegetables (2.2%); and chicken nuggets (1.5%), with the results remaining consistent among population subgroups. The results identified the top sources of sodium in the American population overall, as well as in key population subgroups, which can inform policies and programs aimed at reducing sodium intake.

Early evidence for the effectiveness of South Africa's legislation on salt restriction in foods: the African-PREDICT study

South Africa was among the first countries to adopt mandatory regulation in 2016 to lower the salt content in processed foods, aiming to reduce population salt intake to <5 g/day. To assess the effectiveness of this regulation in 20-30 year-old adults, we determined the change in salt intake over a mean follow-up time of 4.56-years spanning the implementation of the regulation. This observational study included baseline (2013-2016; N = 668; 24.9 ± 3 years; 47.8% black; 40.7% men) and follow-up data (2018-ongoing; N = 311; 25.4 ± 3.05 years; 51.1% black; 43.4% men) for participants of the African-PREDICT study. Salt intake was estimated from 24-h urinary sodium excretion. Median salt intake at baseline (N = 668) was 7.88 g/day (IQR: 5.67). In those followed (N = 311), salt intake reduced from baseline [median (IQR): 7.91 g/day (5.83)] to follow-up [7.26 g/day (5.30)] [unadjusted median: -0.82 g/day]. After adjusting for baseline salt intake to address regression to the mean, the mean salt reduction was -1.2 g/day. The greatest reductions were in men [mean difference: -1.47 g/day], black adults [mean difference: -2.04 g/day], and participants from low [mean difference: -1.89 g/day] or middle [mean difference: -1.84 g/day] socio-economic status groups, adjusting for baseline salt intake. Our preliminary findings suggest that South Africa's salt regulation has been effective in lowering salt intake in young adults by ~1.2 g salt/day. Our study supports the effectiveness of upstream interventions to lower population salt intake, particularly for vulnerable groups who may typically consume more processed foods. It needs to be determined if the legislation has the anticipated population health gains.

Estimating Canadian sodium intakes and the health impact of meeting national and WHO recommended sodium intake levels: A macrosimulation modelling study

BACKGROUND

Cardiovascular diseases (CVDs) are the second leading cause of total deaths in Canada. High blood pressure is the main metabolic risk factor for developing CVDs. It has been well established that excess consumption of sodium adversely affects blood pressure. Canadians' mean sodium intakes are well above recommended levels. Reducing dietary sodium intake through food reformulation has been identified as a cost-effective intervention, however, dietary sodium intake and the potential health impact of meeting recommended sodium intake levels due to food reformulation have not been determined in Canada.

OBJECTIVE

This study aimed to 1) obtain robust estimates of Canadians' usual sodium intakes, 2) model sodium intakes had foods been reformulated to align with Health Canada's sodium reduction targets, and 3) estimate the number of CVD deaths that could be averted or delayed if Canadian adults were to reduce their mean sodium intake to recommended levels under three scenarios: A) 2,300 mg/d-driven by a reduction of sodium levels in packaged foods to meet Health Canada targets (reformulation); B) 2,000 mg/d to meet the World Health Organization (WHO) recommendation; and C) 1,500 mg/d to meet the Adequate Intake recommendation.

METHODS

Foods in the University of Toronto's Food Label Information Program 2017, a Canadian branded food composition database, were linked to nationally representative food intake data from the 2015 Canadian Community Health Survey-Nutrition to estimate sodium intakes (and intakes had Health Canada's reformulation strategy been fully implemented). The Preventable Risk Integrated ModEl (PRIME) was used to estimate potential health impact.

RESULTS

Overall, mean sodium intake was 2758 mg/day, varying by age and sex group. Based on 'reformulation' scenario A, mean sodium intakes were reduced by 459 mg/day, to 2299 mg/day. Reducing Canadians' sodium intake to recommended levels under scenarios A, B and C could have averted or delayed 2,176 (95% UI 869-3,687), 3,252 (95% UI 1,380-5,321), and 5,296 (95% UI 2,190-8,311) deaths due to CVDs, respectively, mainly from ischaemic heart disease, stroke, and hypertensive disease. This represents 3.7%, 5.6%, and 9.1%, respectively, of the total number of CVDs deaths observed in Canada in 2019.

CONCLUSION

Results suggest that reducing sodium intake to recommended levels could prevent or postpone a substantial number of CVD deaths in Canada. Reduced sodium intakes could be achieved through reformulation of the Canadian food supply. However, it will require higher compliance from the food industry to achieve Health Canada's voluntary benchmark sodium reduction targets.

Estimating the changing burden of disease attributable to high sodium intake in South Africa for 2000, 2006 and 2012

Background. Elevated sodium consumption is associated with increased blood pressure, a major risk factor for cardiovascular and chronic kidney disease.Objectives. To quantify the deaths and disability-adjusted life years (DALYs) attributed to high sodium intake in persons aged ≥25 years in South Africa (SA) for 2000, 2006 and 2012.Methods. Comparative risk assessment (CRA) methodology was used and population attributable fractions (PAFs) of high sodium intake, mediated through high blood pressure (BP), for cardiovascular and chronic kidney disease were estimated. This was done by taking the difference between the PAF for elevated systolic BP (SBP) based on the estimated SBP level in the population and the PAF based on the estimated SBP that would result if sodium intake levels were reduced to the theoretical minimum risk exposure level (1 g/day) according to population group and hypertension categories. A meta-regression based on data from nine national surveys conducted between 1998 and 2017 was used to estimate the prevalence of hypertension by age, sex and population group. Relative risks identified from international literature were used and the difference in PAFs was applied to local burden estimates from the second South African National Burden of Disease Study. Age-standardised rates were calculated using World Health Organization (WHO) standard population weights. The attributable burden was also estimated for 2012 using an alternative target of 2 g/day proposed in the National Strategic Plan for the Prevention and Control of Non-communicable Diseases (NSP).Results. High sodium intake as mediated through high SBP was estimated to cause 8 071 (95% uncertainty interval (UI) 6 542 - 15 474) deaths in 2012, a drop from 9 574 (95% UI 8 158 - 16 526) in 2006 and 8 431 (95% UI 6 972 - 14 511) in 2000. In 2012, ischaemic heart disease caused the highest number of deaths in persons (n=1 832), followed by haemorrhagic stroke (n=1 771), ischaemic stroke (n=1 484) and then hypertensive heart disease (n=1 230). Ischaemic heart disease was the highest contributor to deaths for males (27%), whereas for females it was haemorrhagic stroke (23%). In 2012, 1.5% (95% UI 1.3 - 2.9) of total deaths and 0.7% (95% UI 0.6 - 1.2) of total DALYs were attributed to high sodium intake. If the NSP target of <2 g/day sodium intake had been achieved in 2012, ~2 943 deaths and 48 870 DALYs would have been averted.Conclusion. Despite a slight decreasing trend since 2006, high sodium intake mediated through raised BP accounted for a sizeable burden of disease in 2012. Realising SA’s target to reduce sodium intake remains a priority, and progress requires systematic monitoring and evaluation.

Modeling global 80-80-80 blood pressure targets and cardiovascular outcomes

As the leading cause of death worldwide, cardiovascular diseases (CVDs) present major challenges for health systems. In this study, we analyzed the effects of better population blood pressure control in the context of a proposed 80-80-80 target: 80% of individuals with hypertension are screened and aware of their diagnosis; 80% of those who are aware are prescribed treatment; and 80% of those on treatment have achieved guideline-specified blood pressure targets. We developed a population CVD model using country-level evidence on CVD rates, blood pressure levels and hypertension intervention coverage. Under realistic implementation conditions, most countries could achieve 80-80-80 targets by 2040, reducing all-cause mortality by 4-7% (76-130 million deaths averted over 2022-2050) and slowing the rise in CVD expected from population growth and aging (110-200 million cases averted). Although populous middle-income countries would account for most of the reduced CVD cases and deaths, low-income countries would experience the largest reductions in disease rates.

Delayed Finalization of Sodium Targets in the United States May Cost Over 250 000 Lives by 2031

BACKGROUND

The US Food and Drug Administration (FDA) proposed 2- and 10-year voluntary sodium-reduction targets for >150 packaged- and prepared-food categories in 2016 and finalized the short-term targets in 2021.

METHODS

We modeled the health benefits of implementing the newly finalized sodium targets, and the net health losses because of the 4.3-year delay in finalizing the sodium targets in different compliance scenarios in adults aged ≥30, using the National Health and Nutrition Examination Survey (NHANES) 2015 to 2016 cycle. The health impact was estimated by multiplying the projected reduction in population sodium intake by the annual health benefits resulting from every 1000-mg reduction in daily sodium intake.

RESULTS

Under certain assumptions, the FDA's finalization of the short-term targets in Oct 2021 and possible finalization of the long-term targets by April 2024 is projected to save up to 445 979 (95% CI, 17 349-787 352) lives in the coming 10 years. The net number of unnecessary deaths because of FDA's delay is projected to be as high as 264 644 (95% CI, 10 295-467 215) according to our prediction.

CONCLUSIONS

These findings highlight the enormous health costs due to the FDA's delay in finalizing the sodium-reduction targets, and the great potential health benefits of industry compliance with the FDA's finalization of its short- and long-term targets in the coming 10 years.

Paediatric Hypertension in Africa: A Systematic Review and Meta-Analysis

BACKGROUND

The burden of cardiovascular disease (CVD) and hypertension is rapidly increasing in low- and middle-income countries. This is evident not only in adults, but also in children. Recent estimates of prevalence in children are lacking, particularly in Africa. As such, we conducted a systematic review and meta-analysis to provide updated estimates of paediatric hypertension in Africa.

METHODS

We searched PubMed and EBSCO to identify articles published from January 2017 to November 2020. Studies were assessed for quality. We combined results for meta-analyses using a random effects model (Freeman-Tukey arcsine transformation). Heterogeneity was quantified using the I² statistic.

FINDINGS

In the narrative synthesis of 53 studies, publication bias was low for 28, moderate for 24, and high for one study. Hypertension prevalence ranged substantially (0·2%-38·9%). Meta-analysis included 41 studies resulting in data on 52918 participants aged 3 to 19 years from ten countries. The pooled prevalence for hypertension (systolic/diastolic BP≥95th percentile) was 7·45% (95%CI 5·30-9·92, I²=98.96%), elevated blood pressure (BP, systolic/diastolic BP≥90th percentile and <95th percentile) 11·38% (95%CI 7·94-15·33, I²=98.97%) and combined hypertension/elevated BP 21·74% (95%CI 15·5-28·69, I²=99.48%). Participants categorized as overweight/with obesity had a higher prevalence of hypertension (18·5% [95%CI 10·2-28·5]) than those categorized as underweight/normal (1·0% [95%CI 0·1-2·6], 4·8% [95%CI 2·9-7·1], p<0·001). There were significant differences in hypertension prevalence when comparing BP measurement methods and classification guidelines.

INTERPRETATION

Compared to a previous systematic review conducted in 2017, this study suggests a continued increase in prevalence of paediatric hypertension in Africa, and highlights the potential role of increasing overweight/obesity.

FUNDING

This research was funded in part by the Wellcome Trust [Grant number:214082/Z/18/Z]. LJW and SAN are supported by the DSI-NRF Centre of Human Development at the University of the Witwatersrand.