School of Public Health and Health Systems, University of Waterloo, Waterloo, ON, Canada.
Department of Psychology, University of Waterloo, Waterloo, ON, Canada.
Nicotine Tob Res. 2019 Aug 19;21(9):1259-1266. doi: 10.1093/ntr/nty174.
"Dual use" refers to the concurrent use of tobacco cigarettes (smoking) and electronic cigarettes (e-cigarettes; vaping). Although dual use is common among e-cigarette users, there is little evidence regarding biomarkers of exposure among dual users and how these change under different conditions of product use.
A nonblinded within-subjects crossover experiment was conducted with adult daily dual users (n = 48) in Ontario, Canada. Participants completed three consecutive 7-day periods in which the use of tobacco cigarettes and e-cigarettes was experimentally manipulated, resulting in four study conditions: Dual use, Tobacco cigarette use, E-cigarette use, and No product use. Repeated measures models were used to examine changes in product use and biomarkers of exposure.
Compared to dual use, cotinine remained stable when participants exclusively smoked (p = .524), but significantly decreased when they exclusively vaped (p = .027), despite significant increases in e-cigarette consumption (p = .001). Levels of biomarkers of exposure to toxicants, including carbon monoxide (CO), 1-hydroxypyrene (1-HOP), and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), were significantly lower when participants exclusively vaped than when they engaged in dual use (CO = -41%, p < .001; 1-HOP = -31%, p = .025; NNAL = -30%, p = .017). Similar findings were observed among participants abstaining from both products as compared to dual use (CO: -26%, p < .001; 1-HOP = -14% [ns]; NNAL = -35%, p = .016). In contrast, levels of biomarkers of exposure increased when participants exclusively smoked as compared to dual use (CO = +21%, p = .029; 1-HOP = +23%, p = .048; NNAL = +8% [ns]).
Although dual use may reduce exposure to tobacco smoke constituents to some extent, abstaining from smoking is the most effective way to reduce such exposure.
Public health authorities should clearly communicate the relative risk of e-cigarettes and tobacco cigarettes to the general public, focusing on two salient points: (1) e-cigarettes are not harmless, but they are less harmful than tobacco cigarettes; and (2) using e-cigarettes while smoking may not necessarily reduce health risks; therefore, consumers should stop smoking completely to maximize potential health benefits.
“双重使用”是指同时使用传统香烟（吸烟）和电子烟（蒸气）。尽管电子烟使用者中双重使用很常见，但关于双重使用者的暴露生物标志物以及在不同产品使用条件下这些标志物如何变化的证据很少。
在加拿大安大略省进行了一项针对成年日常双重使用者（n=48）的非盲、个体内交叉实验。参与者连续完成三个为期 7 天的周期，在这三个周期中，香烟和电子烟的使用被实验性地控制，从而产生了四种研究条件：双重使用、仅吸烟、仅蒸气和无产品使用。重复测量模型用于检查产品使用和暴露生物标志物的变化。
与双重使用相比，当参与者仅吸烟时，可铁宁保持稳定（p=0.524），但当参与者仅蒸气时，可铁宁显著下降（p=0.027），尽管电子烟的使用量显著增加（p=0.001）。当参与者仅蒸气时，暴露于有毒物质的生物标志物水平，包括一氧化碳（CO）、1-羟基芘（1-HOP）和 4-（甲基亚硝氨基）-1-（3-吡啶基）-1-丁醇（NNAL），显著低于双重使用时（CO：-41%，p<0.001；1-HOP：-31%，p=0.025；NNAL：-30%，p=0.017）。与双重使用相比，在参与者同时戒除两种产品时也观察到类似的发现（CO：-26%，p<0.001；1-HOP：-14%[无统计学意义]；NNAL：-35%，p=0.016）。相比之下，当参与者仅吸烟时，暴露于生物标志物的水平与双重使用相比增加（CO：+21%，p=0.029；1-HOP：+23%，p=0.048；NNAL：+8%[无统计学意义]）。
尽管双重使用可能在一定程度上降低对烟草烟雾成分的暴露，但完全戒除吸烟是降低这种暴露的最有效方法。
公共卫生当局应向公众明确传达电子烟和香烟的相对风险，重点关注两个要点：（1）电子烟并非无害，但比香烟危害小；（2）使用电子烟同时吸烟不一定能降低健康风险；因此，消费者应彻底戒烟，以最大限度地提高潜在健康益处。
