Department of Health Promotion Medicine, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
Division of Clinical Nephrology and Rheumatology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
Kidney Blood Press Res. 2022;47(9):576-585. doi: 10.1159/000526277. Epub 2022 Aug 5.
The urinary sodium-to-potassium ratio is an indicator of dietary sodium intake and has been associated with reduced kidney function. However, less is known about its association with albuminuria, the other key component of chronic kidney disease, in the community-dwelling adult population. We examined the association of the spot urinary sodium-to-potassium ratio with albuminuria and compared spot urinary and dietary sodium-to-potassium ratios.
We quantified the association of the urinary sodium-to-potassium ratio with albuminuria in 6,274 Japanese adults (aged 40-97 years; 50.9% women) based on spot urine samples. We performed linear and logistic regression modeling to account for potential confounders. Elevated albuminuria was defined as a spot urinary albumin-to-creatinine ratio (ACR) ≥30 mg/g. We secondarily evaluated the dietary sodium-to-potassium ratio based on a food-frequency questionnaire.
The median spot urinary and dietary sodium-to-potassium ratios were 2.70 (interquartile interval, 1.87-3.83) and 1.50 (1.21-1.84), respectively. The median ACR was 11.0 (6.0-24.0) mg/g. In a multivariable linear regression model, the spot urinary sodium-to-potassium ratio (per increment) was significantly associated with the natural logarithm of the ACR (regression coefficient, 0.023 [95% confidence interval {95% CI}, 0.007-0.038]). This result was consistent in a multivariable logistic regression model (adjusted odds ratio, 1.08 [95% CI: 1.04-1.12]). The corresponding estimates for the dietary sodium-to-potassium ratio were 0.139 (95% CI: 0.087-0.191) and 1.28 (95% CI: 1.14-1.45), respectively.
Both spot urinary and dietary sodium-to-potassium ratios were associated with elevated albuminuria in community-dwelling Japanese adults. Our findings further support the potential usefulness of the spot urinary sodium-to-potassium ratio as an indicator of sodium intake and suggest a link between sodium intake and kidney damage.
尿钠/钾比值是膳食钠摄入量的指标，与肾功能下降有关。然而，在社区居住的成年人群中，关于其与白蛋白尿（慢性肾脏病的另一个关键成分）的关系知之甚少。我们研究了点尿钠/钾比值与白蛋白尿的关系，并比较了点尿和膳食钠/钾比值。
我们基于 6274 名日本成年人（年龄 40-97 岁；50.9%为女性）的点尿样本，定量研究了尿钠/钾比值与白蛋白尿的关系。我们进行了线性和逻辑回归建模，以考虑潜在的混杂因素。白蛋白尿升高定义为点尿白蛋白/肌酐比值（ACR）≥30mg/g。我们根据食物频率问卷进一步评估了膳食钠/钾比值。
点尿和膳食钠/钾比值的中位数分别为 2.70（四分位间距，1.87-3.83）和 1.50（1.21-1.84），ACR 的中位数为 11.0（6.0-24.0）mg/g。在多变量线性回归模型中，点尿钠/钾比值（每增加一个单位）与 ACR 的自然对数呈显著正相关（回归系数，0.023[95%置信区间（95%CI），0.007-0.038]）。在多变量逻辑回归模型中也得到了一致的结果（调整后的优势比，1.08[95%CI：1.04-1.12]）。膳食钠/钾比值的相应估计值分别为 0.139（95%CI：0.087-0.191）和 1.28（95%CI：1.14-1.45）。
点尿和膳食钠/钾比值均与社区居住的日本成年人白蛋白尿升高有关。我们的研究结果进一步支持点尿钠/钾比值作为钠摄入量指标的潜在有用性，并提示钠摄入与肾脏损害之间存在联系。
