Korean Circ J.  2020 Jul;50(7):555-571. 10.4070/kcj.2020.0042.

Sodium Intake, Blood Pressure and Cardiovascular Disease

• Rhee MY
• Jeong YJ

• KMID: 2504214
• DOI: http://doi.org/10.4070/kcj.2020.0042

Abstract

Sodium intake reduction has been emphasized because sodium adversely impacts health, especially blood pressure (BP), and the cardiovascular (CV) disease risk. However, data obtained from several cohort studies have raised questions regarding the effects of high sodium intake on BP and the CV disease risk. In the present study, we systematically reviewed the literature to evaluate these associations. Studies showing negative associations between urine sodium and BP and CV outcomes relied on estimated 24-hour urine sodium from spot urine that is inappropriate for determining sodium intake at an individual level. Furthermore, controversy about the association between 24-hour urine sodium and BP may have been caused by different characteristics of study populations, such as age distribution, ethnicity, potassium intake and the inclusion of patients with hypertension, the different statistical methods and BP measurement methods. Regarding the association between sodium intake and the CV disease risk, studies showing negative or J- or U-shaped associations used a single baseline measurement of 24-hour urine sodium in their analyses. However, recent studies that employed average of subsequently measured 24-hour urine sodium showed positive, linear associations between sodium intake and CV outcomes, indicating that controversies are caused by the different sodium intake measurement methods and analytic designs. In conclusion, the study shows that positive associations exist between sodium intake and BP, CV outcomes, and mortality, and that the argument that reducing sodium intake is dangerous is invalid. Sodium intake reduction should be recommended to all, and not limited to patients with hypertension or CV disease.

Keyword

Sodium intake; Urine; Blood pressure; Cardiovascular

Figure

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  Figure 1 Comparison between measured and estimated 24HUNa in septile groups divided according to measured 24HUNa. Estimated 24-hour urine sodium was calculated by using previously suggested equations. (A) Kawasaki, and (B) Danish equation. When the 24HUNa is calculated by applying the formulas to groups with smaller 24HUNa than that of formula development population, there is a tendency of overestimation of population mean 24-hour urine sodium. On the other hands, in groups with greater 24-hour urine sodium than that of the formula development population, there is a tendency of underestimation of 24-hour urine sodium.24HUNa = 24-hour urine sodium excretion.

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