Division of Cardiology, Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, California.
Departments of Medicine and Computational Medicine, David Geffen School of Medicine at University of California, Los Angeles, California.
Am J Physiol Heart Circ Physiol. 2020 Sep 1;319(3):H547-H556. doi: 10.1152/ajpheart.00307.2020. Epub 2020 Jul 31.
Tobacco cigarette (TC) smoking has never been lower in the United States, but electronic cigarette (EC) vaping has reached epidemic proportions among our youth. Endothelial dysfunction, as measured by flow-mediated vasodilation (FMD) is a predictor of future atherosclerosis and adverse cardiovascular events and is impaired in young TC smokers, but whether FMD is also reduced in young EC vapers is uncertain. The aim of this study in otherwise healthy young people was to compare the effects of acute and chronic tobacco cigarette (TC) smoking and electronic cigarette (EC) vaping on FMD. FMD was compared in 47 nonsmokers (NS), 49 chronic EC vapers, and 40 chronic TC smokers at baseline and then after EC vapers ( = 31) and nonsmokers ( = 47) acutely used an EC with nicotine (ECN), EC without nicotine (EC0), and nicotine inhaler (NI) at ~4-wk intervals and after TC smokers ( = 33) acutely smoked a TC, compared with sham control. Mean age (NS, 26.3 ± 5.2 vs. EC, 27.4 ± 5.45 vs. TC, 27.1 ± 5.51 yr, = 0.53) was similar among the groups, but there were more female nonsmokers. Baseline FMD was not different among the groups (NS, 7.7 ± 4.5 vs. EC:6.6 ± 3.6 vs. TC, 7.9 ± 3.7%∆, = 0.35), even when compared by group and sex. Acute TC smoking versus control impaired FMD (FMD pre-/postsmoking, -2.52 ± 0.92 vs. 0.65 ± 0.93%∆, = 0.02). Although the increase in plasma nicotine was similar after EC vapers used the ECN versus TC smokers smoked the TC (5.75 ± 0.74 vs. 5.88 ± 0.69 ng/mL, = 0.47), acute EC vaping did not impair FMD. In otherwise healthy young people who regularly smoke TCs or ECs, impaired FMD compared with that in nonsmokers was not present at baseline. However, FMD was significantly impaired after smoking one TC, but not after vaping an equivalent "dose" (estimated by change in plasma nicotine) of an EC, consistent with the notion that non-nicotine constituents in TC smoke mediate the impairment. Although it is reassuring that acute EC vaping did not acutely impair FMD, it would be dangerous and premature to conclude that ECs do not lead to atherosclerosis. In our study of otherwise healthy young people, baseline flow-mediated dilation (FMD), a predictor of atherosclerosis and increased cardiovascular risk, was not different among tobacco cigarette (TC) smokers or electronic cigarette (EC) vapers who had refrained from smoking, compared with nonsmokers. However, acutely smoking one TC impaired FMD in smokers, whereas vaping a similar EC "dose" (as estimated by change in plasma nicotine levels) did not. Finally, although it is reassuring that acute EC vaping did not acutely impair FMD, it would be premature and dangerous to conclude that ECs do not lead to atherosclerosis or increase cardiovascular risk.
在美国，烟草卷烟（TC）吸烟率从未如此之低，但电子烟（EC）蒸气在我们的年轻人中已经达到了流行的程度。血流介导的血管舒张（FMD）测量的内皮功能障碍是未来动脉粥样硬化和不良心血管事件的预测指标，并且在年轻的 TC 吸烟者中受损，但年轻的 EC 蒸气者的 FMD 是否也降低尚不确定。本研究旨在比较急性和慢性 TC 吸烟和 EC 蒸气对 FMD 的影响，研究对象为其他方面健康的年轻人。在基线时，将 47 名不吸烟者（NS）、49 名慢性 EC 蒸气者和 40 名慢性 TC 吸烟者进行比较，然后比较 31 名 EC 蒸气者和 47 名不吸烟者在 4 周间隔内急性使用含尼古丁的 EC（ECN）、不含尼古丁的 EC（EC0）和尼古丁吸入器（NI）以及 33 名 TC 吸烟者急性吸烟 TC 后 FMD 的变化，与假对照相比。各组之间的平均年龄（NS，26.3 ± 5.2 岁 vs. EC，27.4 ± 5.45 岁 vs. TC，27.1 ± 5.51 岁，= 0.53）相似，但不吸烟者中女性更多。基线 FMD 在各组之间无差异（NS，7.7 ± 4.5%∆ vs. EC：6.6 ± 3.6%∆ vs. TC，7.9 ± 3.7%∆，= 0.35），即使按组和性别进行比较也是如此。与对照相比，急性 TC 吸烟会损害 FMD（吸烟前/后 FMD，-2.52 ± 0.92%∆ vs. 0.65 ± 0.93%∆，= 0.02）。尽管 EC 蒸气者使用 ECN 后和 TC 吸烟者吸烟后血浆尼古丁的增加相似（5.75 ± 0.74 vs. 5.88 ± 0.69 ng/mL，= 0.47），但急性 EC 蒸气不会损害 FMD。在其他方面健康的经常吸烟 TC 或 EC 的年轻人中，与不吸烟者相比，基线时 FMD 受损的情况并不存在。然而，吸烟一支 TC 后 FMD 明显受损，但吸食等效“剂量”（通过血浆尼古丁水平变化估计）的 EC 后 FMD 未受损，这与 TC 烟雾中的非尼古丁成分介导损伤的观点一致。尽管令人欣慰的是，急性 EC 蒸气不会急性损害 FMD，但过早得出 EC 不会导致动脉粥样硬化的结论是危险的。在我们对其他方面健康的年轻人的研究中，与不吸烟者相比，吸烟的 TC 吸烟者或 EC 蒸气者在不吸烟时的血流介导扩张（FMD），一种动脉粥样硬化和心血管风险增加的预测指标，没有差异。然而，吸烟一支 TC 会损害吸烟者的 FMD，而吸食类似 EC“剂量”（如血浆尼古丁水平的变化所估计）则不会。最后，尽管令人欣慰的是，急性 EC 蒸气不会急性损害 FMD，但过早和危险地得出 EC 不会导致动脉粥样硬化或增加心血管风险的结论是危险的。
