HypertensionCohort study
Sodium Reduction Legislation and Urinary Sodium and Blood Pressure in South Africa
- Prospective cohort study
- population-based
- 3 waves (2014/2015, 2018/2019, 2021/2022)
Authors' conclusion
In this cohort study, following South African regulations limiting sodium in 13 categories of processed foods, there was a significant reduction in 24HrNa excretion among this rural South African population, which was sustained with reductions in blood pressure consistent with levels of sodium excreted.
Study context
- Population
- Adults aged ≥40 years, rural Mpumalanga Province, South Africa (HAALSI cohort), after 2013 regulations limiting sodium in 13 processed food categories
- Participants
- 5,059 adults
- Exposure
- Sodium excretion and BP before vs after mandatory sodium regulations
- Outcome
- Change in estimated 24-hour urine sodium excretion (INTERSALT equation) and BP
Main finding
As reported in the abstract
Estimated 24HrNa excretion
Baseline
3.08
mean · SD 0.78 · g
- First 2 waves · between the first 2 waves
- mean reduction 0.22 g (95% CI −0.27 to −0.17); P < 0.001
- First and third waves · between the first and third waves
- mean reduction 0.23 g (95% CI −0.28 to −0.18); P < 0.001
Observational data: associations, not effects.
Further findings
24-hour urine sodium, participants with samples in all 3 waves
- Reduction for both waves 2 and 3 vs wave 1
- −0.26 g
SBP per gram of sodium reduction
- SBP reduction per gram sodium reduction
- −1.30 mm Hg (95% CI, 0.65-1.96; P = .00)
Ideal sodium consumption (<2 g per day)
- Proportion achieving ideal sodium consumption increased
- from 7% to 17%
Original publication
Sodium Reduction Legislation and Urinary Sodium and Blood Pressure in South Africa. JAMA Cardiol. Published 1 April 2025. doi:10.1001/jamacardio.2024.5410
Summarised from the published abstract; every number is checked against it