Blood pressure (BP) responses to dietary sodium and potassium interventions vary among individuals (salt- and potassium-sensitivity). However, it is unknown whether salt- and/or potassium-sensitivity is a reproducible trait. We repeated the dietary sodium and potassium intervention among 488 Han Chinese who participated in the Genetic Epidemiology Network of Salt Sensitivity (GenSalt) four years after the original dietary intervention. The same dietary intervention protocol, which included a 7-day low sodium-feeding (51.3 mmol/day), a 7-day high sodium-feeding (307.8 mmol/day), and a 7-day high sodium-feeding with an oral potassium supplementation (60 mmol/day), was applied in both the original and repeated studies. Three BP measurements were obtained during each of the 3 days of baseline observation and on days 5, 6, and 7 of each intervention period. Three timed urinary samples were collected to measure sodium and potassium excretion at baseline and during each intervention phase. On average, study participants were 39.7 years old and 49.4% of them were male. Study participants had a mean body mass index of 23.7 kg/m
2
, systolic BP of 118.1 mmHg, diastolic BP of 74.4 mmHg, urinary excretion of sodium of 258.8 mmol/24-hrs, and urinary excretion of potassium of 38.8 mmol/24-hrs. The results from the 24-h urinary excretions of sodium and potassium showed excellent compliance with the study diet. BP responses to dietary intervention in the original and repeated studies were highly correlated. For example, the correlation coefficients for systolic BP between original and repeated studies were 0.7681 at baseline, 0.7902 during low-sodium, 0.8045 during high-sodium, and 0.8232 during high-sodium and potassium supplementation intervention (all p<0.0001). The correlation coefficients for systolic BP changes between original and repeated studies were 0.3659 from baseline to low-sodium, 0.3655 from low to high-sodium, and 0.2850 from high-sodium to potassium supplementation (all p<0.0001). These data indicate that BP responses to dietary sodium and potassium intervention are reproducible traits. Furthermore, our study suggests that identification of individuals who are more sensitive to dietary sodium and potassium intake may improve the efficiency of targeted dietary intervention for hypertension prevention among high-risk individuals.
Metabolic syndrome and salt sensitivity of blood pressure in non-diabetic people in China: a dietary intervention study
