Dietary Sodium and Cardiovascular Disease Risk
- Cogswell ME, Mugavero K, Bowman BA, et al.
- Dietary Sodium and Cardiovascular Disease Risk — Measurement Matters. N Engl J Med 2016;375:580-586.
The following are key points to remember about dietary sodium and cardiovascular disease (CVD) risk and why measurement matters:
- Hypertension is a common and major risk factor for CVD, the leading US killer. Reducing excess dietary sodium can lower blood pressure, with a greater response among persons with hypertension.
- Many leading medical and public health organizations recommend reducing dietary sodium to a maximum of 2300 mg/day on the basis of evidence indicating a public health benefit. Yet this benefit has been questioned, mainly on the basis of studies suggesting that low sodium intake is also associated with an increased risk of CVD.
- Studies that measure sodium intake vary widely in their methods and should be judged accordingly. Accurate measurement matters. Paradoxical findings based on inaccurate sodium measurements should not stall efforts to improve the food environment in ways that enable consumers to reduce excess sodium intake.
- Analyses showing a J- or U-shaped relationship between sodium intake and one or more CV outcomes in general population samples used convenient but potentially biased methods to estimate individual intake.
- Multiple, nonconsecutive, 24-hour urine collections are the gold standard for assessing sodium intake. Some sodium measures such as spot urine tests unacceptably overestimate individual intake at low levels and underestimate intake at high levels, by plus or minus 3000 mg, even while being unbiased at the average level.
- In association studies, individual-level accuracy matters. Having large numbers of participants does not trump concerns about ascertainment bias and misclassification.
- There is strong evidence of a linear, dose–response effect of sodium reduction on blood pressure. In addition, the evidence shows that sodium reduction prevents CVD.
- Undue emphasis on observational studies with large numbers of participants but invalid measurement of sodium intake and other methodological limitations can lead to erroneous conclusions and delay effective public health action to reduce blood pressure and save lives.
- Gradual, stepwise sodium reduction, as recommended by the Institute of Medicine, remains an achievable, effective, and important public health strategy to prevent tens of thousands of heart attacks and strokes and save billions of dollars in health care costs annually.
- Reducing population sodium intake, through reducing excess sodium in manufactured and restaurant food in the United States, represents an important opportunity to prevent heart disease and stroke and reduce health care costs significantly.
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