Food (salt) Safety Research Center, Semnan University of Medical Sciences, Semnan, Iran.
Department of Community Nutrition, School of Nutritional Science and Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
Clin Nutr. 2019 Jun;38(3):1092-1100. doi: 10.1016/j.clnu.2018.05.017. Epub 2018 Jun 1.
BACKGROUND & AIMS: The association of high sodium intake with risk of stroke has been accepted. But considering the proposed J/U-shaped association between sodium intake and risk of all-cause mortality, the shape of the dose-response relationship has not been determined yet. This study aimed to test the dose-response association of dietary sodium and sodium-to-potassium ratio with risk of stroke in adults aged 18 years or older.
We performed a systematic search using PubMed and Scopus, from database inception up to October 2017. Prospective and retrospective observational studies reporting risk estimates of stroke for three or more quantitative categories of dietary sodium or sodium-to-potassium ratio were included. Studies that reported results as continuous were also included. Two independent authors extracted the information and assessed the quality of included studies. Pooled relative risk (RR) was calculated using a random-effects model. Publication bias was tested. Sensitivity and subgroup analyses were done.
Of initial 20,412 studies identified, 14 prospective cohort studies, one case-cohort study, and one case-control study (total n = 261,732) with 10,150 cases of stroke were included. The Pooled RRs of stroke were 1.06 (95%CI: 1.02, 1.10; I = 60%, n = 14 studies) for a 1 gr/d increment in dietary sodium intake, and 1.22 (95%CI: 1.04, 1.41; I = 60%, n = 5 studies) for a one-unit increment in dietary sodium-to-potassium ratio (mmol/mmol). The risk of stroke increased linearly with increasing dietary sodium intake, and also along with the increase in dietary sodium-to-potassium ratio. No evidence of a J/U-shaped association was found in the analyses of total stroke, stroke incidence, and stroke mortality. High sodium intake was associated with a somewhat worse prognosis among Asian countries as compared to westerns.
Higher sodium intake and higher dietary sodium-to-potassium ratio were associated with a higher risk of stroke. Reducing dietary sodium-to-potassium ratio can be considered as a supplementary approach in parallel with the decrease in sodium intake in order to decrease stroke risk. The interpretation of the results is limited by observational nature of studies examined.
高钠摄入量与中风风险之间的关联已被认可。但是，考虑到钠摄入量与全因死亡率之间存在提出的 J/U 形关联，剂量反应关系的形状尚未确定。本研究旨在检验成年人饮食钠和钠钾比与中风风险之间的剂量反应关系。
我们使用 PubMed 和 Scopus 进行了系统搜索，从数据库建立到 2017 年 10 月。纳入报告了三种或更多定量类别饮食钠或钠钾比与中风风险的前瞻性和回顾性观察性研究。还包括报告连续结果的研究。两名独立作者提取信息并评估纳入研究的质量。使用随机效应模型计算汇总相对风险（RR）。测试发表偏倚。进行敏感性和亚组分析。
在最初的 20412 项研究中，有 14 项前瞻性队列研究、1 项病例对照研究和 1 项病例对照研究（共 261732 人，有 10150 例中风）纳入其中。饮食钠摄入量每增加 1 克/天，中风的汇总 RR 为 1.06（95%CI：1.02，1.10；I=60%，n=14 项研究），饮食钠钾比每增加 1 个单位，RR 为 1.22（95%CI：1.04，1.41；I=60%，n=5 项研究）。随着饮食钠摄入量的增加，中风风险呈线性增加，随着饮食钠钾比的增加，中风风险也呈线性增加。在分析总中风、中风发生率和中风死亡率时，没有发现 J/U 形关联的证据。与西方国家相比，高钠摄入量与亚洲国家的预后较差有关。
较高的钠摄入量和较高的饮食钠钾比与中风风险增加有关。减少饮食钠钾比可以与减少钠摄入量同时考虑，以降低中风风险。由于所检查研究的观察性质，对结果的解释受到限制。
