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Impact of salt substitute and stepwise reduction of salt supply on blood pressure in residents in senior residential facilities: Design and rationale of the DECIDE-Salt trial.
Jin, A, Liu, K, Labarthe, DR, Feng, X, Zhang, R, Wang, H, Qiao, Q, Li, H, Li, J, Gao, P, et al
American heart journal. 2020;:198-205
Abstract
BACKGROUND High sodium intake has been considered as the leading dietary risk factor for deaths and disability-adjusted life-years among older adults. High-quality randomized trials to evaluate the effects of practical sodium reduction strategies are needed. METHODS The study is a cluster randomized trial with a 2 × 2 factorial design conducted in 48 senior residential facilities in northern China. These facilities are randomly assigned (1:1:1:1) to 1 of 4 groups: stepwise salt supply control (SSSC) in which 5%-10% of the study salt supply in the institutional kitchens will be reduced every 3 months, replacing normal salt with salt substitute (SS); SSSC only; SS only; or neither SSSC nor SS. The interventions last for 2 years with follow-up every 6 months. The primary outcome is the change in systolic blood pressure from baseline to 24 months. Secondary outcomes include the incidence of hyperkalemia, hyponatremia, cardiovascular events, and death. CURRENT STATUS The study has recruited and randomized 48 senior residential facilities with 1,606 participants. Mean age at baseline was 71 years, and 76% are male. Both types of salt intervention were initiated in the study facilities between January and April 2018. CONCLUSION The study is well placed to define the effects of 2 practical and scalable sodium reduction strategies for blood pressure reduction and will provide important new data about safety of these strategies among older adults in China.
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Resequencing Epithelial Sodium Channel Genes Identifies Rare Variants Associated With Blood Pressure Salt-Sensitivity: The GenSalt Study.
Gu, X, Gu, D, He, J, Rao, DC, Hixson, JE, Chen, J, Li, J, Huang, J, Wu, X, Rice, TK, et al
American journal of hypertension. 2018;(2):205-211
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Abstract
BACKGROUND A resequencing study of renal epithelial sodium channel (ENaC) genes was conducted to identify rare variants associated with blood pressure (BP) salt-sensitivity. METHODS The Genetic Epidemiology Network of Salt-Sensitivity (GenSalt) study was conducted among 1,906 participants who underwent a 7-day low-sodium followed by a 7-day high-sodium feeding-study. The 300 most salt-sensitive and 300 most salt-resistant GenSalt participants were selected for the resequencing study. Three ENaC genes (SCNN1A, SCNN1B, and SCNN1G) were resequenced using capillary-based sequencing methods. Traditional burden tests were utilized to examine association between rare variants and BP salt-sensitivity. Associations of low-frequency and common variants were tested using single-marker analyses. RESULTS Carriers of SCNN1A rare variants had a 0.52 [95% confidence interval (CI): 0.32-0.85] decreased odds of BP salt-sensitivity compared with noncarriers. Neither SCNN1B nor SCNN1G associated with salt-sensitivity of BP in rare variant analyses (P = 0.65 and 0.48, respectively). In single-marker analyses, 3 independent common variants in SCNN1A, rs11614164, rs4764586, and rs3741914, associated with salt-sensitivity after Bonferroni correction (P = 4.4 × 10-4, 1.1 × 10-8, and 1.3 × 10-3). Each copy of the minor allele of rs4764586 was associated with a 1.36-fold (95% CI: 1.23-1.52) increased odds of salt-sensitivity, whereas each copy of the minor allele of rs11614164 and rs3741914 was associated with 0.68-fold (95% CI: 0.55-0.84) and 0.69-fold (95% CI: 0.54-0.86) decreased odds of salt-sensitivity, respectively. CONCLUSIONS This study demonstrated for the first time a relationship between rare variants in the ENaC pathway and BP salt-sensitivity. Future replication and functional studies are needed to confirm the findings in this study. CLINICAL TRIAL REGISTRY Trial Number NCT00721721.
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Blood pressure responses to dietary sodium and potassium interventions and the cold pressor test: the GenSalt replication study in rural North China.
Zhao, Q, Gu, D, Chen, J, Li, J, Cao, J, Lu, F, Guo, D, Wang, R, Shen, J, Chen, J, et al
American journal of hypertension. 2014;(1):72-80
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BACKGROUND In the Genetic Epidemiology Network of Salt Sensitivity (GenSalt) study, we observed that blood pressure (BP) responses to dietary sodium and potassium interventions and the cold pressor test (CPT) varied greatly among individuals. We conducted a replication study to confirm our previous findings among 695 study participants. METHODS The dietary intervention included a 7-day low sodium (51.3 mmol/day), a 7-day high sodium (307.8 mmol/day), and a 7-day high sodium with potassium supplementation (307.8 mmol sodium and 60 mmol potassium/day). BP measurements were obtained during the baseline and each intervention phase. During the CPT, BP was measured before and at 0, 1, 2, and 4 minutes after the participants immersed their right hand in ice water for 1 minute. RESULTS Systolic and diastolic BP responses (mean ± SD (range), mm Hg) were 8.1±8.4 (-39.1 to 18.2) and -3.5±5.1 (-25.1 to 11.1) to low sodium, 9.1±8.4 (-13.3 to 33.1) and 4.0±5.4 (-16.0 to 20.7) to high sodium, and -4.6±5.8 (-31.8 to 11.6) and -1.9±4.3 (-16.9 to 14.2) to potassium supplementation, respectively (all P < 0.0001 for comparison with each former phase). The mean maximum systolic and diastolic BP responses to the CPT were 16.5±10.5 (-15.3 to 63.3) and 7.6±6.1 (-8.7 to 39.3), respectively (all P < 0.0001). CONCLUSIONS Our study indicates that there are large variations in BP responses to dietary sodium and potassium interventions and to the CPT among individuals.