Dyer A R, Elliott P, Shipley M
Department of Preventive Medicine, Northwestern University Medical School, Chicago, IL 60611.
Am J Epidemiol. 1994 May 1;139(9):940-51. doi: 10.1093/oxfordjournals.aje.a117100.
This is the second 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. The first report (Am J Epidemiol 1994; 139:927-39) described methods of estimating reliability, taking into account age and sex, and provided estimates for several urinary variables, blood pressure, and pulse rate. This second report uses these estimates of reliability and multivariate procedures to correct associations with blood pressure for "regression dilution bias." In these analyses, the estimated mean change in systolic blood pressure associated with a 100-mmol decrease in sodium intake was -3.1 mmHg with adjustment for age, sex, body mass index, and alcohol intake. For potassium, the estimated mean change in systolic pressure associated with a 15-mmol increase in potassium intake was -1.0 mmHg. These estimates are 44%-50% larger than those previously reported in INTERSALT, based on simple corrections for reliability. Furthermore, compared with previously reported INTERSALT values, the estimated mean change in systolic pressure per unit of change in body mass index decreased by about 5% and that for consumption of > or = 300 ml of absolute alcohol per week increased by about 6%. These results further clarify the observed INTERSALT associations of systolic blood pressure with 24-hour urinary sodium and potassium excretion, body mass index, and alcohol intake.
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二份。该研究名为国际盐与血压关系研究（INTERSALT），涉及来自32个国家52个中心的一万多名受试者，主要探讨电解质排泄及其他因素与血压的关系。第一份报告（《美国流行病学杂志》1994年；139:927 - 39）描述了考虑年龄和性别的可靠性估计方法，并给出了多个尿液变量、血压及脉搏率的估计值。本第二份报告运用这些可靠性估计值及多变量方法，对血压关联进行“回归稀释偏倚”校正。在这些分析中，校正年龄、性别、体重指数及酒精摄入量后，钠摄入量每减少100 mmol，收缩压估计平均变化为 -3.1 mmHg。对于钾，钾摄入量每增加15 mmol，收缩压估计平均变化为 -1.0 mmHg。基于简单的可靠性校正，这些估计值比INTERSALT先前报告的值大44% - 50%。此外，与先前报告的INTERSALT值相比，体重指数每单位变化引起的收缩压估计平均变化降低了约5%，每周饮用≥300 ml纯酒精引起的收缩压估计平均变化增加了约6%。这些结果进一步阐明了在INTERSALT研究中观察到的收缩压与24小时尿钠、钾排泄量、体重指数及酒精摄入量之间的关联。
