Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America.
PLoS One. 2012;7(4):e35332. doi: 10.1371/journal.pone.0035332. Epub 2012 Apr 9.
The mechanisms by which smoking cessation reduces cardiovascular disease risk are unclear. We evaluated longitudinal changes in carotid intima-media thickness among current smokers enrolled in a prospective, randomized smoking cessation clinical trial.
METHODOLOGY/PRINCIPAL FINDINGS: Subjects were enrolled in a randomized, double-blind, placebo-controlled trial of 5 smoking cessation pharmacotherapies and underwent carotid ultrasonography with carotid intima-media thickness measurement. Subjects were classified as continuously abstinent (biochemically confirmed abstinence at 6 months, 1 year, and 3 years post-quit attempt), intermittently abstinent (reported smoking at one of the three time points), or smoked continuously (reported smoking at all three time points). The primary endpoint was the absolute change (mm) in carotid intima-media thickness (ΔCIMT(max)) before randomization and 3 years after the target quit date. Pearson correlations were calculated and multivariable regression models (controlling for baseline CIMT(max) and research site) were analyzed. Among 795 subjects (45.2 ± 10.6 years old, 58.5% female), 189 (23.8%) were continuously abstinent, 373 (46.9%) smoked continuously, and 233 (29.3%) were abstinent intermittently. There was a greater increase in carotid intima-media thickness among subjects who were continuously abstinent than among those who smoked continuously (p = 0.020), but not intermittently (p = 0.310). Antihypertensive medication use (p = 0.001) and research site (p<0.001) independently predicted ΔCIMTmax--not smoking status. The greatest increase in carotid intima-media thickness among continuous abstainers was related to increases in body-mass index (p = 0.043).
CONCLUSIONS/SIGNIFICANCE: Smoking status did not independently predict ΔCIMT(max); increasing body-mass index and antihypertensive medication use were the most important independent predictors. The rapid reduction in cardiovascular disease events observed with smoking cessation is unlikely to be mediated by changes in subclinical atherosclerosis burden.
ClinicalTrials.gov NCT00332644.
目前尚不清楚戒烟降低心血管疾病风险的机制。我们评估了参加一项前瞻性、随机戒烟临床试验的当前吸烟者的颈动脉内膜中层厚度的纵向变化。
方法/主要发现：受试者参加了一项随机、双盲、安慰剂对照的 5 种戒烟药物治疗试验，并进行了颈动脉超声检查和颈动脉内膜中层厚度测量。受试者被分为持续戒烟者（6 个月、1 年和 3 年戒烟尝试后，通过生物化学方法确认的戒烟）、间歇性戒烟者（在三个时间点之一报告吸烟）或持续吸烟（在所有三个时间点报告吸烟）。主要终点是随机分组前和目标戒烟日期后 3 年的颈动脉内膜中层厚度绝对变化（mm）（ΔCIMT(max)）。计算了 Pearson 相关系数，并进行了多变量回归模型分析（控制基线 CIMT(max)和研究地点）。在 795 名受试者中（45.2 ± 10.6 岁，58.5%为女性），189 名（23.8%）为持续戒烟者，373 名（46.9%）为持续吸烟者，233 名（29.3%）为间歇性戒烟者。持续戒烟者的颈动脉内膜中层厚度增加幅度大于持续吸烟者（p = 0.020），但与间歇性戒烟者无差异（p = 0.310）。抗高血压药物的使用（p = 0.001）和研究地点（p<0.001）独立预测了ΔCIMTmax，而与吸烟状态无关。持续戒烟者颈动脉内膜中层厚度增加最大与体重指数增加有关（p = 0.043）。
结论/意义：吸烟状态不能独立预测ΔCIMT(max)；体重指数增加和抗高血压药物的使用是最重要的独立预测因素。戒烟后观察到心血管疾病事件的迅速减少不太可能是通过亚临床动脉粥样硬化负担的变化介导的。
ClinicalTrials.gov NCT00332644。
