Population Health Research Institute, DBCVS Research Institute, McMaster University, 237 Barton St East, Hamilton, ON L8L 2X2, Canada
HRB-Clinical Research Facility, Galway University Hospital, NUI Galway, Galway, Ireland.
BMJ. 2019 Mar 13;364:l772. doi: 10.1136/bmj.l772.
To evaluate the joint association of sodium and potassium urinary excretion (as surrogate measures of intake) with cardiovascular events and mortality, in the context of current World Health Organization recommendations for daily intake (<2.0 g sodium, >3.5 g potassium) in adults.
International prospective cohort study.
18 high, middle, and low income countries, sampled from urban and rural communities.
103 570 people who provided morning fasting urine samples.
Association of estimated 24 hour urinary sodium and potassium excretion (surrogates for intake) with all cause mortality and major cardiovascular events, using multivariable Cox regression. A six category variable for joint sodium and potassium was generated: sodium excretion (low (<3 g/day), moderate (3-5 g/day), and high (>5 g/day) sodium intakes) by potassium excretion (greater/equal or less than median 2.1 g/day).
Mean estimated sodium and potassium urinary excretion were 4.93 g/day and 2.12 g/day, respectively. After a median follow-up of 8.2 years, 7884 (6.1%) participants had died or experienced a major cardiovascular event. Increasing urinary sodium excretion was positively associated with increasing potassium excretion (unadjusted r=0.34), and only 0.002% had a concomitant urinary excretion of <2.0 g/day of sodium and >3.5 g/day of potassium. A J-shaped association was observed of sodium excretion and inverse association of potassium excretion with death and cardiovascular events. For joint sodium and potassium excretion categories, the lowest risk of death and cardiovascular events occurred in the group with moderate sodium excretion (3-5 g/day) and higher potassium excretion (21.9% of cohort). Compared with this reference group, the combinations of low potassium with low sodium excretion (hazard ratio 1.23, 1.11 to 1.37; 7.4% of cohort) and low potassium with high sodium excretion (1.21, 1.11 to 1.32; 13.8% of cohort) were associated with the highest risk, followed by low sodium excretion (1.19, 1.02 to 1.38; 3.3% of cohort) and high sodium excretion (1.10, 1.02 to 1.18; 29.6% of cohort) among those with potassium excretion greater than the median. Higher potassium excretion attenuated the increased cardiovascular risk associated with high sodium excretion (P for interaction=0.007).
These findings suggest that the simultaneous target of low sodium intake (<2 g/day) with high potassium intake (>3.5 g/day) is extremely uncommon. Combined moderate sodium intake (3-5 g/day) with high potassium intake is associated with the lowest risk of mortality and cardiovascular events.
评估钠和钾尿排泄（作为摄入量的替代指标）与心血管事件和死亡率的联合关联，这是在世界卫生组织目前建议的成年人每日摄入量（<2.0 克钠，>3.5 克钾）的背景下进行的。
国际前瞻性队列研究。
18 个高、中、低收入国家，从城市和农村社区中抽取样本。
提供早晨空腹尿液样本的 103570 人。
使用多变量 Cox 回归评估 24 小时估计尿钠和钾排泄（摄入量的替代指标）与全因死亡率和主要心血管事件的关系。通过钾排泄（>2.1 克/天或等于或小于中位数）生成了一个关于钠和钾联合的六类变量：钠排泄（<3 克/天、3-5 克/天和>5 克/天的低、中、高钠摄入量）。
平均估计钠和钾尿排泄分别为 4.93 克/天和 2.12 克/天。在中位数为 8.2 年的随访后，7884 名（6.1%）参与者死亡或发生主要心血管事件。随着尿钠排泄的增加，尿钾排泄也呈正相关（未校正 r=0.34），只有 0.002%的人同时有<2.0 克/天的尿钠排泄和>3.5 克/天的尿钾排泄。观察到钠排泄呈 J 形关联，而钾排泄与死亡和心血管事件呈负相关。对于钠和钾联合排泄类别，在中等钠排泄（3-5 克/天）和较高钾排泄（队列的 21.9%）的组中，死亡和心血管事件的风险最低。与这个参考组相比，低钾与低钠排泄的组合（风险比 1.23，1.11 至 1.37；队列的 7.4%）和低钾与高钠排泄的组合（1.21，1.11 至 1.32；队列的 13.8%）与最高风险相关，其次是低钾与高钠排泄（1.19，1.02 至 1.38；队列的 3.3%）和高钠排泄（1.10，1.02 至 1.18；队列的 29.6%）在钾排泄大于中位数的人群中。较高的钾排泄减轻了与高钠排泄相关的心血管风险增加（P 交互=0.007）。
这些发现表明，低钠摄入（<2 克/天）与高钾摄入（>3.5 克/天）的同时目标极不常见。中等钠摄入（3-5 克/天）与高钾摄入相结合与死亡率和心血管事件的风险最低相关。
