睡眠时间短可增加卒中风险

波士顿(EGMN)——联合专业睡眠学会(APSS)年会上公布的一项研究显示，持续睡眠不足不仅会导致疲劳，而且还会增加卒中风险。

在这项研究中，美国阿拉巴马大学伯明翰分校的Megan Ruiter博士及其同事采用来自基于全国人群的REGARDS研究的数据，探讨了睡眠时间是否可预测睡眠呼吸暂停或低通气低危患者的卒中风险。REGARDS研究由美国国立神经病与卒中研究所资助，目前还在进行中，纳入超过30,000名45岁以上的志愿者，进行卒中风险和认知健康情况随访。

基于每隔6个月收集的自报告卒中症状，Ruiter博士等人查找到5,666名无卒中史、短暂性脑缺血发作、卒中症状且睡眠障碍性呼吸风险低(根据柏林睡眠问卷评价)的受试者。随后，研究者通过建立区间删失参数生存模型和指数分布来估计预测从测定睡眠时间(6 h以下、6~6.9 h、7~7.9 h、8~8.9 h和9 h以上)至首次出现卒中症状的时间的危险比(HR)。校正人口学资料、胆固醇水平、高血压、体重指数(BMI)、睡眠障碍性呼吸、抑郁症状和焦虑方面的数据。

在BMI处于最佳范围(18.5~24.99 kg/m2)的阻塞性睡眠呼吸暂停低危受试者中，每晚睡眠时间少于6 h者出现卒中症状的风险是每晚睡眠7~8 h者的4倍。具体而言，与对照组相比，每晚睡眠时间少于6 h的BMI正常受试者的卒中症状HR为2.93。在超重和肥胖受试者中未观察到失眠时间短与卒中症状存在类似关联。在校正其他已知卒中危险因素后，仍观察到睡眠时间短与卒中症状(包括突然身体无力、麻木或视力障碍)之间存在显著关联。

在另一项分析中，研究者还发现，黑人往往睡眠时间短，且更易于出现卒中症状。

该研究表明，睡眠时间短是中年人卒中风险的独立预测因素。其局限性在于主要依赖受试者自报告的卒中症状资料，因此存在回忆不准确的可能性。未来尚需开展研究，以进一步明确与卒中症状相关的具体睡眠特征。例如，真正与卒中风险相关的是否并非睡眠时间本身，而是睡眠片段化或个体睡眠感知和睡眠质量相关因素。另外，还需探讨睡眠时间是否与真正的卒中事件相关。这些因素均可通过行为治疗加以干预。

Ruiter博士声明无经济利益冲突。

爱思唯尔  版权所有

BY DIANA MAHONEY
Elsevier Global Medical News
Breaking News

BOSTON (EGMN) –Consistently short sleep duration not only leaves otherwise healthy individuals tired, it also increases their risk of developing stroke, a study has shown.

Previous studies have linked self-reported sleep duration to incident stroke, but none have considered whether sleep-disordered breathing, which itself is associated with adverse cardiovascular outcomes, mediates that risk, said Megan Ruiter, Ph.D., of the University of Alabama at Birmingham. Dr. Ruiter and her colleagues used data from the national, population-based REGARDS (Reasons for Geographic and Racial Differences in Stroke) study to determine whether sleep duration predicts stroke risk among individuals at low risk for sleep apnea or hypopnea.

Funded by the U.S. National Institute of Neurological Disorders and Stroke, the ongoing REGARDS study enrolled more than 30,000 black and white volunteers, aged 45 years and older, to track stroke risk and cognitive health.

Based on self-reported stroke symptoms collected at 6-month intervals, Dr. Ruiter and her colleagues identified 5,666 participants who had been followed for up to 3 years without history of stroke, transient ischemic attack, stroke symptoms, or high risk for sleep-disordered breathing according to the Berlin Sleep Questionnaire. The researchers then conducted interval-censored, parametric survival models with exponential distributions to estimate the hazard ratios predicting time from measurement of sleep duration (less than 6 hours, 6-6.9 hours, 7-7.9 hours, 8-8.9 hours, and 9 or more hours) to first stroke symptoms. Data were adjusted for demographic information, cholesterol levels, hypertension, body mass index (BMI), sleep-disordered breathing, depressive symptoms, and anxiety.

“In people with a low risk for obstructive sleep apnea and a BMI in the optimal range of 18.5-24.99 kg/m2, the risk of stroke symptoms was four times higher in those who had fewer than 6 hours of sleep per night, compared with participants in the same BMI range who reported 7-8 hours of sleep per night,” Dr. Ruiter reported at the annual meeting of the Associated Professional Sleep Societies. Specifically, the hazard ratio for stroke symptoms among individuals within the normal BMI range who reported fewer than 6 hours of sleep nightly was 2.93, relative to the reference group. “We didn’t find any similar association between short sleep duration and stroke symptoms among overweight and obese individuals,” she noted.

The association between shorter periods of sleep and stroke symptoms, including sudden body weakness, numbness, or vision deficits, remained significant after controlling for other known stroke risk factors, Dr. Ruiter said, acknowledging the possibility that “these participants may be late in the development of stroke.”

The findings suggest that habitually short sleep duration may independently predispose middle-age adults to develop major stroke risk factors. “We speculate short sleep is precursor to other traditional risk factors and, once these traditional risk factors are present, they may become stronger risk factors than sleep duration alone,” Dr. Ruiter hypothesized.

In a separate analysis, the investigators also evaluated the association between stroke symptoms and sleep duration by racial group and found a differential risk, according to Dr. Ruiter. “It is possible that sleep duration might partially explain the relationship between ethnic differences in stroke symptoms. For example, African Americans had a greater prevalence of short sleep and were more likely to have stroke symptoms,” she said.

The study is limited by the reliance on self-reporting of stroke symptoms and the potential for recall inaccuracy, Dr. Ruiter said. Further studies are warranted to tease out the specific characteristics of sleep duration that are related to stroke symptoms, she said. For example, “Is it actually sleep fragmentation or one’s perception of sleep and factors that contribute to its quality rather than sleep duration itself?” she proposed. Additionally, “we need to see if sleep duration is related to actual stroke events.” Many of these factors, she noted, are modifiable through behavioral treatment.

Dr. Ruiter had no relevant financial conflicts of interest to disclose.