015 - Association of dietary Sodium Intake and All-Cause and Cardiovascular Disease Mortality: NHANES-Linked Mortality study.

Background: While there is a wealth of evidence on the direct relationship between dietary sodium intake and blood pressure, the evidence of its relationship with risk of cardiovascular diseases (CVDs), and major events, has been inconsistent, due to limitations including confounding, measurement errors, and rarely examining the role of other risk factors, which should be considered to inform solid scientific evidence-based prevention guidelines.
Aim: To assess the association of sodium intake with cardiovascular disease (CVD) and all-cause mortality, among US adults aged 20 years and older.
Method: We used a nationally representative sample of 25,075 US adults, followed from time of survey participation through December 31, 2015. We examined data from the 2015 public-use National Health and Nutrition Examination Survey Linked Mortality File (1999-2014). Incident all-cause, and CVD mortality status were determined by assigned vital status codes and further determination from ICD, 10th Revision (ICD-10), and linked sodium, estimated by single 24-hour dietary recall. Bivariate analyses were performed; and relative risks (RR) for CVD (HD) and all-cause mortality were calculated from multivariate adjusted Poisson regression models, and further stratification models, accounting for the sampling design.
Results: During a mean follow-up period of 135 (33.3) months, 3,371 deaths were documented, including 755 CVD, and 561 HD deaths. After multivariate adjustment, comparing the lowest quartile of sodium consumption, higher sodium intake quartiles were significantly associated with decreased all-cause mortality, quartile 3 (RR=0.712; 95%CI:0.582, 0.871), and quartile 4 (RR=0.767; 95%CI:0.597, 0.984). In stratified models, the findings differed significantly by sex, and age. The risk for all-cause mortality remained consistently decreased across all quartiles: quartile 2 (RR=0.851, 95%CI: 0.731, 0.991), quartile 3 (RR=0.747, 95%CI: 0.608, 0.918), and quartile 4 (RR=0.703; 95%CI: 0.510, 0.970) among older participants, and females (quartile 3 (RR=0.607; 95%CI: 0.456, 0.806); whereas higher sodium intake was associated with increased heart disease (HD) mortality risk among participants who were younger than 65 years (quartile 3 (RR=2.639; 95%CI: 1.094, 6.367), and quartile 4 (RR=3.436; 95%CI: 1.020, 11.578) and among females (quartile 2 (RR=1.927; 95%CI:1.075, 3.457). Risk was also decreased for heart disease mortality in older participants in the third quartile (RR=0.423; 95%CI:0.223, 0.804).
Conclusion: The direct evidence of the harmful effects of high sodium intake among US adult population aged 65years and younger, suggest that a reduction in sodium intake may play a key role in the prevention of non-fatal and fatal CVDs in this population. However, the inverse relation seen for all-cause, and heart disease mortality among older participants raises questions regarding the likelihood of a survival advantage accompanying a lower sodium diet. Further study is warranted to better define the mechanism and role of sodium intake as a potential modifiable risk factor for mortality outcomes.

Cardiovascular disease, heart disease mortality, stroke, dietary

All-cause mortality, sodium intake, salt, behavior, NHANES

Risk factors, CHD

CHF, potassium

blood pressure, hypertension

cardiovascular, health effects.