Browsing by Author "Thomas A. Gaziano"

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    Estimating population level 24-h sodium excretion using spot urine samples in older adults in rural South Africa
    (2023-02-01) Jacques D. Du Toita; David Kapaonb; Nigel J. Crowtherc; Shafika Abrahams-Gessele; June Fabian; Chodziwadziwa W. Kabudula; Alisha N. Wade; Stephen Tollman; Thomas A. Gaziano
    Background: South Africa has introduced regulations to reduce sodium in processed foods. Assessing salt consumption with 24-h urine collection is logistically challenging and expensive. We assess the accuracy of using spot urine samples to estimate 24-h urine sodium (24hrUNa) excretion at the population level in a cohort of older adults in rural South Africa. Methods: 24hrUNa excretion was measured and compared to that estimated from matched spot urine samples in 399 individuals, aged 40–75 years, from rural Mpumalanga, South Africa.We used the Tanaka, Kawasaki, International Study of Sodium, Potassium, and Blood Pressure (INTERSALT), and Population Mean Volume (PMV) method to predict 24hrUNa at the individual and population level. Results: The population median 24hrUNa excretion from our samples collected in 2017 was 2.6 g (interquartile range: 1.53–4.21) equal to an average daily salt intake of 6.6 g, whereas 65.4% of participants had a salt excretion above the WHO recommended 5 g/day. Estimated population median 24hrUNa derived from the INTERSALT, both with and without potassium, showed a nonsignificant difference of 0.25 g (P = 0.59) and 0.21 g (P = 0.67), respectively. In contrast, the Tanaka, Kawasaki, and PMV formulas were markedly higher than the measured 24hrUNa, with a median difference of 0.51 g (P = 0.004), 0.99 g (P = 0.00), and 1.05 g (P = 0.00) respectively. All formulas however performed poorly when predicting an individual’s 24hrUNa, Conclusion: In this population, the INTERSALT formulas are a well suited and cost-effective alternative to 24-h urine collection for the evaluation of population median 24hrUNa excretion. This could play an important role for governments and public health agencies in evaluating local salt regulations and identifying at-risk populations.
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    Significant Improvement in Blood Pressure Levels Among Older Adults With Hypertension in Rural South Africa
    (2023-08-08) Enrico G. Ferro; Shafika Abrahams-Gessel; David Kapaon; Brian Houle; Jacques Du Toit; Ryan G. Wagner; F. Xavier Gómez-Olivé; Alisha N. Wade; Chodziwadziwa W. Kabudulah; Stephen Tollman; Thomas A. Gaziano
    Background:Sub-Saharan Africa is undergoing an epidemiologic transition from infectious diseases to cardiovascular diseases. From 2014 to 2019, sociodemographic surveillance was performed in a large cohort in rural South Africa. Methods:Disease prevalence and incidence were calculated using inverse probability weights. Poisson regression was used to identify disease predictors. The percentage of individuals with controlled (<140/90 mm Hg) versus uncontrolled hypertension was compared between 2014 and 2019. Results:Compared with 2014 (n=5059), study participants in 2019 (n=4176) had similar rates of obesity (mean body mass index, 27.5±10.0 versus 27.0±6.5) but higher smoking (9.1% versus 11.5%) and diabetes (11.1% versus 13.9%). There was no significant increase in hypertension prevalence (58.4% versus 59.8%; age adjusted, 64.3% versus 63.3%), and there was a significant reduction in mean systolic blood pressure (138.0 versus 128.5 mm Hg; P<0.001). Among hypertensive individuals who reported medication use in 2014 and 2019 (n=796), the proportion with controlled hypertension on medication increased from 44.5% to 62.3%. Hypertension incidence was 6.2 per 100 person-years, and age was the only independent predictor. Among normotensive individuals in 2014 (n=2257), 15.2% developed hypertension by 2019, with the majority already controlled on medications by 2019. Conclusions:The hypertension prevalence and incidence are plateauing in this aging cohort. There was a statistically and clinically significant decline in mean blood pressure and a substantial increase in individuals with controlled hypertension on medication. The prevalence of cardiometabolic risk factors did not decrease over time, suggesting that the blood pressure decrease is likely due to increased medication access and adherence, promoted by local health systems.