Abstract 15025: Lower Levels of Sodium Intake and Reduced Cardiovascular Risk
Background: Recent studies have raised the possibility of adverse effects of low sodium on cardiovascular disease (CVD). However, these paradoxical findings might have resulted from suboptimal measurement of sodium and potential biases related to indication or reverse causality. Uncertainty remains regarding the association of CVD with levels of sodium intake less than 2300 mg/day.
Methods and Results: Phases I and II of the Trials of Hypertension Prevention (TOHP) collected multiple 24-hour urine specimens among pre-hypertensive individuals. In extended post-trial follow-up, CVD endpoints were accrued among 2275 participants not in a sodium reduction intervention (31 in both phases) with 10 (TOHP II) or 15 (TOHP I) years post-trial. Previous analyses found a linear association of the sodium/potassium ratio with CVD. Median sodium excretion was 3630 mg/day, with 1.4% of the participants having intake <1500 mg/day and 10% <2300 mg/day, consistent with national levels. Compared to those with sodium 3600-<4800 mg/day, risk for those with sodium <2300 mg/day was 32% lower after multivariable adjustment (HR=0.68, 95%CI = 0.34-1.37, p for trend = 0.13). There was a linear 17% increase in risk per 1000 mg/day (p=0.05). Spline curves supported a linear association of sodium with CVD (Figure), continuing to descend from 3600 to 2300 and 1500 mg/day, although the data are sparse at the lowest levels.
Conclusion: TOHP was conducted in a low risk group and included several 24-hour urine excretions, thus reducing the possibility of reverse causation and incomplete sodium measurement. These results are consistent with overall health benefits of reducing sodium intake to the 1500 to 2300 mg/day range and support current dietary guidelines.
- © 2013 by American Heart Association, Inc.