Low sodium intake and cardiovascular disease mortality among adults with hypertension

BACKGROUND: Though high sodium intake is linked to an increased risk of hypertension and cardiovascular diseases, the relationship between sodium intake and mortality remains controversial. Given that medications used to treat hypertension can potentially lower blood sodium levels and alter electrolyte balance, it begs the question whether a further reduction in dietary sodium below the recommended daily intake of 2300 mg is beneficial among adults with hypertension. OBJECTIVE: To evaluate the effect of low sodium intake on cardiovascular disease (CVD) mortality and all-cause mortality among adults with hypertension. DESIGN: A retrospective cohort study was conducted using data from the Continuous NHANES (1999–2010) linked to mortality files from the National Death Index. Using sodium intake categorized as low <2300 mg/day and high ≥2300 mg/day, the baseline demographic and health characteristics of participants were determined. Hazard ratios (HR) for CVD and all-cause mortality were determined through cox proportional hazard regression analysis adjusted for age, sex, race, total dietary calories, body mass index, physical activity, smoking, diabetes, alcohol consumption, and total serum cholesterol while considering the complex survey design. RESULTS: Of the 8542 adults with hypertension, 71.01% consumed sodium higher than the recommended daily intake of 2300 mg. The mean age was 54 years, 52.3% were female and 73.1% were white. Over 12.7 years of follow-up, there were 971 deaths, with 232 deaths from CVD. The low sodium intake group had a nonsignificant 5% higher risk of CVD mortality, [Adjusted HR 1.05,95% CI (0.7–1.6), p-value 0.82]. Similarly, there was a nonsignificant 17% higher risk for all-cause mortality for the low sodium intake group, [Adjusted HR 1.17,95% CI (1.0–1.4), p-value 0.10]. There was no effect modification by age, race, or sex. CONCLUSION: The findings of an inverse association between sodium intake and mortality among adults with hypertension seen here, though not statistically significant warrant further investigation.