Institut Universitaire de Médecine Sociale et Préventive, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.
Am J Hypertens. 2009 Oct;22(10):1054-61. doi: 10.1038/ajh.2009.133. Epub 2009 Jul 23.
In this study, we assessed whether the white-coat effect (difference between office and daytime blood pressure (BP)) is associated with nondipping (absence of BP decrease at night).
Data were available in 371 individuals of African descent from 74 families selected from a population-based hypertension register in the Seychelles Islands and in 295 Caucasian individuals randomly selected from a population-based study in Switzerland. We used standard multiple linear regression in the Swiss data and generalized estimating equations to account for familial correlations in the Seychelles data.
The prevalence of systolic and diastolic nondipping (<10% nocturnal BP decrease) and white-coat hypertension (WCH) was respectively 51, 46, and 4% in blacks and 33, 37, and 7% in whites. When white coat effect and nocturnal dipping were taken as continuous variables (mm Hg), systolic (SBP) and diastolic BP (DBP) dipping were associated inversely and independently with white-coat effect (P < 0.05) in both populations. Analogously, the difference between office and daytime heart rate was inversely associated with the difference between daytime and night-time heart rate in the two populations. These results did not change after adjustment for potential confounders.
The white-coat effect is associated with BP nondipping. The similar associations between office-daytime values and daytime-night-time values for both BP and heart rate suggest that the sympathetic nervous system might play a role. Our findings also further stress the interest, for clinicians, of assessing the presence of a white-coat effect as a means to further identify patients at increased cardiovascular risk and guide treatment accordingly.
在这项研究中，我们评估了白大衣效应（诊室血压与日间血压的差异）是否与非杓型血压（夜间血压无下降）相关。
数据来自塞舌尔群岛基于人群的高血压登记处选择的 74 个家系中的 371 名非洲裔个体和瑞士基于人群的研究中随机选择的 295 名白种人个体。我们在瑞士数据中使用了标准的多元线性回归，在塞舌尔数据中使用了广义估计方程来解释家族相关性。
在黑人中，收缩压和舒张压非杓型（夜间血压下降<10%）和白大衣高血压（WCH）的患病率分别为 51%、46%和 4%，在白人中分别为 33%、37%和 7%。当白大衣效应和夜间下降被视为连续变量（mmHg）时，收缩压（SBP）和舒张压（DBP）下降与白大衣效应呈负相关且独立相关（P<0.05），这在两个群体中都是如此。类似地，办公室和白天的心率差与两个群体中白天和夜间的心率差呈负相关。在调整了潜在的混杂因素后，这些结果没有改变。
白大衣效应与血压非杓型有关。办公室-白天值与血压和心率的白天-夜间值之间的相似关联表明，交感神经系统可能起作用。我们的发现还进一步强调了临床医生评估白大衣效应存在的重要性，这是一种识别心血管风险增加的患者并相应指导治疗的方法。
