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Estimations of Na excretion by the three formulas should be used with caution when reporting on Na intake levels. More research is needed to validate and develop a specific formula for the South African context with its different population groups. The WHO's recommendation of using 24 h urine collection until more studies are carried out is still supported.

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These preliminary results indicate that high dietary Na:K ratio may lead to a greater increase in BP and hypertension risk with age. Interventions to increase potassium intakes alongside sodium reduction initiatives may be warranted.

Repeated 24-hour urine collection is considered to be the gold standard for assessing salt intake. This is often impractical in large-population studies, especially in low-middle-income countries. Equations to estimate 24-hour urinary salt excretion from a spot urine sample have been developed, but have not been widely validated in African populations. This study aimed to systematically assess the validity of four existing equations to predict 24-hour urinary sodium excretion (24UNa) from spot urine samples in a nationally representative sample of South Africans. Spot and 24-hour urine samples were collected in a subsample (n = 438) of participants from the World Health Organisation Study on global AGEing and adult health (SAGE) Wave 2 in South Africa in 2015. Measured 24UNa values were compared with predicted 24UNa values from the Kawasaki, Tanaka, INTERSALT and Mage equations using Bland-Altman plots. In this subsample (mean age 52.8 ± 16.4 years; body mass index 30.2 ± 8.2 kg/m 2 ; 76% female; 73% black African; 42% hypertensive), all four equations produced a significantly different population estimate compared with the measured median value of 6.7 g salt/day (IQR 4.4-10.5). Although INTERSALT underestimated salt intake (−3.77 g/d; −1.64 to −7.09), the other equations overestimated by 1.28 g/d (−3.52; 1.97), 6.24 g/d (2.22; 9.45), and 17.18 g/d (8.42; 31.96) for Tanaka, Kawasaki, and Mage, respectively. Bland-Altman curves indicated unacceptably wide levels of agreement. Use of these equations to estimate population level salt intake from spot urine samples in South Africans is not recommended.

ObjectiveThe WHO’s global targets for non-communicable disease reduction recommend consumption of<5 g salt/day. In 2016, South Africa was the first country to legislate maximum salt levels in processed foods. South Africa’s salt iodisation fortification programme has successfully addressed iodine deficiency but information is dated. Simultaneous monitoring of sodium reduction and iodine status is required to ensure compatibility of the two public health interventions.Design/setting/participantsA nested cohort design within WHO’s 2015 Study on global AGEing and adult health (n=2887) including individuals from households across South Africa. Randomly selected adults (n=875) provided 24-hour and spot urine samples for sodium and iodine concentration analysis (the primary and secondary outcome measures, respectively). Median 24-hour urinary iodine excretion (UIE) and spot urinary iodine concentrations (UIC) were compared by salt intakes of <5g/day, 5–9g/dayand >9 g/day.ResultsMedian daily sodium excretion was equivalent to 6.3 g salt/day (range 1–43 g/day); 35% had urinary sodium excretion values within the desirable range (<5 g salt/day), 37% had high values (5–9 g salt/day) and 28% had very high values (>9 g salt/day). Median UIC was 130 µg/L (IQR=58–202), indicating population iodine sufficiency (≥100 µg/L). Both UIC and UIE differed across salt intake categories (p<0.001) and were positively correlated with estimated salt intake (r=0.166 and 0.552, respectively; both p<0.001). Participants with salt intakes of <5 g/day were not meeting the Estimated Average Requirement for iodine intake (95 µg/day).ConclusionsIn a nationally representative sample of South African adults, the association between indicators of population iodine status (UIC and UIE) and salt intake, estimated using 24-hour urinary sodium excretion, indicate that low salt intakes may compromise adequacy of iodine intakes in a country with mandatory iodisation of table salt. The iodine status of populations undergoing salt reduction strategies needs to be closely monitored to prevent re-emergence of iodine deficiency.

Changes in the work environment can influence employees' perception of the employment relationship, their psychological contracts, and consequently, their work-related attitudes and behaviour. The study aimed to demonstrate the mechanism through which the state of employees' psychological contract impacts employees' intention to leave employment and the role of employee well-being as a mediator. Cross-sectional data were obtained from employees representing various organisations (N = 246). Structural equation modelling demonstrated that employee well-being mediates the relationship between the state of the psychological contract and an employee's intention to leave the organisation. The study stresses the importance of designing individual-level interventions to enhance well-being in the workplace, which should form part of the retention strategy of any organisation.

Background High sensitivity cardiac troponin T (hs-cTnT) is a validated marker of myocardial damage and may reflect the degree of silent myocardial ischaemia (SMI) and ventricular strain. Our aim was to compare hs-cTnT levels in black and white South Africans taking SMI into consideration. We further explored the capability of hs-cTnT to predict the presence of compensatory systolic hypertension in this South African cohort. Methods A bi-ethnic sex cohort ( n = 404) with similar socioeconomic status (198 black participants and 206 white participants, aged 20-65 years) participated in this target population study where 24 h ambulatory blood pressure, electrocardiogram and overnight fasting cardiometabolic variables were measured. Results Hypertension, higher glycated haemoglobin levels and more frequent and longer SMI events were observed more often in the black participants. Multivariate linear regression analysis showed positive associations between SMI events [Adj. R= 0.19; β 0.35 (0.08-0.62); p < 0.01], SMI event maximum duration [Adj. R= 0.17, β 0.43 (0.16-0.70), p < 0.01], SMI total duration [Adj. R= 0.12; β 0.37 (0.10; 0.65), p = 0.05] and hs-cTnT in black males only.] A lower hs-cTnT cut-point ≥4.2 pg/ml for 24 h systolic hypertension was predicted in the black participants compared with ≥5.6 pg/ml in the white participants (area under the curve 0.66-67 (95% CI: 0.57-0.75), p < 0.001) with a respective sensitivity/specificity of 64/68% and 61/71%. Conclusions hs-cTnT may be a potential marker of SMI in the prediction of systolic blood pressure increases, as well as clusters of risk factors for cardiovascular disease. Ethnic- and possibly sex-specific references values for hs-cTnT should be considered for risk stratification.