Sodium Sensitivity, Sodium Resistance, and Incidence of Hypertension: A Longitudinal Follow-Up Study of Dietary Sodium Intervention

Cross-sectional studies have reported that high sodium sensitivity is more common among individuals with hypertension. Experimental studies have also reported various animal models with sodium-resistant hypertension. It is unknown, however, whether sodium sensitivity and resistance precede the development of hypertension. We conducted a feeding study, including a 7-day low-sodium diet (1180 mg/day) followed by a 7-day high-sodium diet (7081 mg/day), among 1718 Chinese adults with blood pressure (BP) <140/90 mm Hg. We longitudinally followed them over an average of 7.4 years. Three BP measurements and 24-hour urinary sodium excretion were obtained on each of 3 days during baseline observation, low-sodium and high-sodium interventions, and 2 follow-up studies. Three trajectories of BP responses to dietary sodium intake were identified using latent trajectory analysis. Mean (SD) changes in systolic BP were -13.7 (5.5), -4.9 (3.0), and 2.4 (3.0) mm Hg during the low-sodium intervention and 11.2 (5.3), 4.4 (4.1), and -0.2 (4.1) mm Hg during the high-sodium intervention (P<0.001 for group differences) in high sodium-sensitive, moderate sodium-sensitive, and sodium-resistant groups, respectively. Compared with individuals with moderate sodium sensitivity, multiple-adjusted odds ratios (95% CIs) for incident hypertension were 1.43 (1.03-1.98) for those with high sodium sensitivity and 1.43 (1.03-1.99) for those with sodium resistance (P=0.006 for nonlinear trend). Furthermore, a J-shaped association between systolic BP responses to sodium intake and incident hypertension was identified (P<0.001). Similar results were observed for diastolic BP. Our study indicates that individuals with either high sodium sensitivity or sodium resistance are at an increased risk for developing hypertension.

Automated summary

This study found that individuals with either high sodium sensitivity or sodium resistance are at an increased risk for developing hypertension. There is a J-shaped association between systolic blood pressure responses to sodium intake and incident hypertension. These findings are based on a longitudinal study spanning 7.4 years.