Sodium Intake and Mortality Follow-Up in the Third National Health and Nutrition Examination Survey (NHANES III)
Sodium restriction is commonly recommended as a measure to lower blood pressure and thus reduce cardiovascular disease (CVD) and all-cause mortality. However, some studies have observed higher mortality associated with lower sodium intake.
To test the hypothesis that lower sodium is associated with subsequent higher cardiovascular disease (CVD) and all cause mortality in the Third National Health and Nutrition Examination Survey (NHANES III).
Observational cohort study of mortality subsequent to a baseline survey.
Representative sample (n = 8,699) of non-institutionalized US adults age ≥30, without history of CVD events, recruited between 1988–1994.
Measurements and main results
Dietary sodium and calorie intakes estimated from a single baseline 24-h dietary recall. Vital status and cause of death were obtained from the National Death Index through the year 2000. Hazard ratio (HR) for CVD mortality of lowest to highest quartile of sodium, adjusted for calories and other CVD risk factors, in a Cox model, was 1.80 (95% CI 1.05, 3.08, p = 0.03). Non-significant trends of an inverse association of continuous sodium (per 1,000 mg) intake with CVD and all-cause mortality were observed with a 99% CI of 0.73, 1.06 (p = 0.07) and 0.86, 1.04 (p = 0.11), respectively, while trends for a direct association were not observed.
Observed associations of lower sodium with higher mortality were modest and mostly not statistically significant. However, these findings also suggest that for the general US adult population, higher sodium is unlikely to be independently associated with higher CVD or all-cause mortality.
KEY WORDSsodium intake mortality cardiovascular disease Third National Health and Nutrition Examination Survey (NHANES III)
The authors wish to acknowledge the NHANES III participants and the investigators as well as the National Center for Health Statistics and its Research Data Center for making available the limited access linked mortality data. However, the authors take full and sole responsibility for the integrity of the data analyses and the contents of this article.
We also wish to thank the Department of Epidemiology and Population Health of the Albert Einstein College of Medicine for financial support for this work.
Conflicts of Interest
Michael H. Alderman has been an unpaid consultant to the Salt Institute, a trade organization. He has never received research support, consulting fees or speaker honoraria from either the Salt Institute or any other commercial entity related to use of sodium. Hillel W. Cohen and Susan M. Hailpern have no conflicts of interest to disclose.
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