Am J Epidemiol. 2013 Jun 1;177(11):1193-5; discussion 1196-8. doi: 10.1093/aje/kwt064. Epub 2013 May 14.
Reduction of dietary sodium intake has been identified as a priority to reduce the worldwide burden of hypertension and cardiovascular disease. Dietary sodium intake is most precisely ascertained by using timed urine collection. Casual urine sodium measurements are relatively easy to perform, but their relationship to timed urine sodium measurements is unclear. In this issue of the Journal, Brown et al. (Am J Epidemiol. 2013;177(11):1180-1192) report the development and validation of equations to estimate 24-hour urine sodium excretion from casual urine samples. Their study included a large number of participants on 2 continents, a well-collected gold standard, separate discovery and validation samples, and relevant covariates. The resulting equations represent the best available methods to estimate dietary sodium intake from casual urine samples. However, the study is limited by evidence of a suboptimal model fit, restriction to people 20-59 years of age in North America and Europe, and exclusion and adjustment that further limit external validity. In addition, individual-level correlations of estimated and measured 24-hour urine sodium excretion were modest. Properly applied, the results will facilitate tracking of dietary sodium intake within populations over time and identification of communities for which dietary sodium restriction is most likely to be beneficial. Further work is needed to extend estimation to additional populations and improve individual-level assessment.
减少膳食钠摄入量已被确定为降低全球高血压和心血管疾病负担的优先事项。通过使用定时尿液收集最准确地确定膳食钠摄入量。偶然的尿钠测量相对容易进行，但它们与定时尿钠测量的关系尚不清楚。在本期《美国流行病学杂志》上，Brown 等人（Am J Epidemiol. 2013;177(11):1180-1192）报告了开发和验证用于从偶然尿液样本估算 24 小时尿钠排泄量的方程。他们的研究包括来自 2 个大陆的大量参与者、精心收集的金标准、独立的发现和验证样本以及相关协变量。由此产生的方程代表了从偶然尿液样本估算膳食钠摄入量的最佳方法。然而，该研究受到模型拟合效果不佳、仅适用于北美和欧洲 20-59 岁人群以及进一步限制外部有效性的排除和调整的限制。此外，估计和测量的 24 小时尿钠排泄量的个体相关性适中。正确应用这些结果将有助于在人群中随着时间的推移跟踪膳食钠摄入量，并确定最有可能受益于膳食钠限制的社区。需要进一步的工作来将估计扩展到其他人群，并改善个体水平的评估。
