Dyer A R, Shipley M, Elliott P
Department of Preventive Medicine, Northwestern University Medical School, Chicago, IL 60611.
Am J Epidemiol. 1994 May 1;139(9):927-39. doi: 10.1093/oxfordjournals.aje.a117099.
This is the first of two reports dealing with the reliability of measurements of 24-hour urinary electrolyte excretion and blood pressure and estimates of electrolyte-blood pressure associations in INTERSALT, an international study of the relations of electrolyte excretion and other factors to blood pressure, involving more than 10,000 persons from 52 centers in 32 countries. This first report describes methods for estimating reliability, taking into account age and sex, and provides estimates for several urinary variables, blood pressure, and pulse rate. The second report (Am J Epidemiol 1994; 139:940-51) uses these estimates of reliability and multivariate procedures to correct multiple regression coefficients from regressions of blood pressure on 24-hour urinary sodium and potassium excretion, body mass index, and alcohol intake for "regression dilution bias." Age- and sex-adjusted estimates of reliability were computed from data on 805 INTERSALT participants with repeat measurements. These estimates ranged from 0.37 to 0.40 for 24-hour urinary sodium, from 0.47 to 0.52 for potassium, from 0.32 to 0.36 for the sodium:potassium ratio, from 0.64 to 0.69 for calcium, from 0.59 to 0.65 for creatinine, from 0.49 to 0.57 for urinary volume, from 0.49 to 0.51 for magnesium, from 0.58 to 0.62 for pulse, from 0.69 to 0.74 for systolic blood pressure, and from 0.63 to 0.67 for diastolic blood pressure. In addition, estimates of within- and between-person covariances among electrolytes indicated that about half of the observed covariance for sodium and potassium excretion in a single 24-hour urine collection was due to within-person covariation in excretion.
这是关于24小时尿电解质排泄量及血压测量可靠性以及电解质与血压关联估计值的两份报告中的第一份。INTERSALT是一项关于电解质排泄及其他因素与血压关系的国际研究，涉及来自32个国家52个中心的10000多人。本第一份报告描述了考虑年龄和性别的可靠性估计方法，并给出了几个尿变量、血压和脉搏率的估计值。第二份报告（《美国流行病学杂志》1994年；139:940 - 51）使用这些可靠性估计值和多变量程序，对血压与24小时尿钠和钾排泄量、体重指数及酒精摄入量的回归中的多元回归系数进行校正，以消除“回归稀释偏倚”。根据805名有重复测量数据的INTERSALT参与者的数据，计算了年龄和性别调整后的可靠性估计值。这些估计值范围为：24小时尿钠为0.37至0.40，钾为0.47至0.52，钠钾比为0.32至0.36，钙为0.64至0.69，肌酐为0.59至0.65，尿量为0.49至0.57，镁为0.49至0.51，脉搏为0.58至0.62，收缩压为0.69至0.74，舒张压为0.63至0.67。此外，电解质的个体内和个体间协方差估计表明，在单次24小时尿液收集的钠和钾排泄量中，约一半的观察到的协方差是由于排泄量的个体内协变。
