Ancoli-Israel Sonia, Stepnowsky Carl, Dimsdale Joel, Marler Matthew, Cohen-Zion Mairav, Johnson Sherella
Department of Psychiatry, University of California, San Diego, CA, USA.
Chest. 2002 Oct;122(4):1148-55. doi: 10.1378/chest.122.4.1148.
BP normally drops (or "dips") by approximately 10% at nighttime; however, in a number of illnesses there is an increased amount of "nondipping" of nocturnal BP. This study examined whether nondipping in older African Americans and older white subjects is related to the presence of sleep-disordered breathing (SDB) and hypertension.
Prospective study with a convenience sample.
All data were collected in the subjects' homes.
Seventy self-defined African Americans with complaints of snoring or excessive daytime sleepiness, and 70 age-matched and gender-matched white subjects.
Sleep was recorded for 2 nights, with 1 night of oximetry. BP was recorded on a separate 24-h period. African Americans had higher dipping ratios than white subjects even after accounting for covariates such as respiratory disturbance index (RDI), oxygen desaturation index (ODI), body mass index, and average 24-h mean arterial pressure (p = 0.025). Higher values of RDI (R(2) = 0.0686, p = 0.021) and ODI (R(2) = 0.042, p < 0.03) were correlated with higher dipping ratios in both African Americans and white subjects. However, there was a three-way interaction such that higher RDIs were correlated primarily with nondipping in African Americans receiving antihypertensive medication (R(2) = 0.0373, p = 0.022).
These results demonstrated that African Americans tend to be "nondippers," while white subjects tended to be "dippers." This nondipping was not a result of weight, gender, or of having SDB. The analyses also confirmed that, in both races, the dipping ratio was greatest in those with SDB and hypertension. The third hypothesis, that RDI would be greatest in the nondipping hypertensive subjects, was true only for the African Americans.
血压通常在夜间下降（或“降低”）约10%；然而，在一些疾病中，夜间血压的“非勺型”现象增多。本研究调查了老年非裔美国人和老年白人受试者的血压非勺型现象是否与睡眠呼吸紊乱（SDB）和高血压的存在有关。
采用便利抽样的前瞻性研究。
所有数据均在受试者家中收集。
70名自述有打鼾或日间过度嗜睡症状的非裔美国人，以及70名年龄和性别匹配的白人受试者。
记录2晚的睡眠情况，其中一晚进行血氧饱和度测定。在单独的24小时期间记录血压。即使在考虑了诸如呼吸紊乱指数（RDI）、氧饱和度下降指数（ODI）、体重指数和24小时平均动脉压等协变量后，非裔美国人的血压降低率仍高于白人受试者（p = 0.025）。RDI（R² = 0.0686，p = 0.021）和ODI（R² = 0.042，p < 0.03）的较高值与非裔美国人和白人受试者的较高血压降低率相关。然而，存在三方交互作用，即较高的RDI主要与接受抗高血压药物治疗的非裔美国人的血压非勺型现象相关（R² = 0.0373，p = 0.022）。
这些结果表明，非裔美国人倾向于为“非勺型”，而白人受试者倾向于为“勺型”。这种血压非勺型现象并非体重、性别或患有SDB的结果。分析还证实，在两个种族中，患有SDB和高血压的受试者的血压降低率最高。第三个假设，即血压非勺型的高血压受试者的RDI最高，仅在非裔美国人中成立。
