Smoking can cause heart attacks and strokes. Many smokers don’t know that

Smoking cigarettes doesn’t just cause lung cancer . The toxic smoke affects nearly every organ in the body — yet some of its most serious consequences may be less widely recognized.

Smoking is a major cause of cardiovascular disease, including heart attacks and strokes, and exposure to secondhand smoke puts people who don’t smoke at risk, too.

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A recent study published in the journal BMJ Open found major gaps in how well people who smoke understand these risks. While more than 9 in 10 people surveyed across 46 countries knew that smoking causes lung cancer, substantially fewer knew of its cardiovascular effects. Awareness of the cardiovascular dangers of secondhand smoke was even lower.

Why does smoking have such profound effects on the heart and blood vessels? How dangerous is secondhand smoke, and what should people who smoke and those around them know?

To guide us through this research and the questions it raises, I spoke with CNN wellness expert Dr. Leana Wen. Wen is an emergency physician and clinical associate professor at George Washington University. She previously served as Baltimore’s health commissioner.

CNN: How well do people understand the health risks of smoking?

Dr. Leana Wen: The researchers in this study analyzed data from two major international tobacco surveys. One was the International Tobacco Control Project, which included surveys from 26 countries conducted between 2002 and 2022. The other was the Global Adult Tobacco Survey, which used surveys from 32 countries conducted between 2008 and 2020. Some countries participated in both; overall, 46 countries were represented.

Participants, who were smokers age 18 and older, were asked whether they knew or believed that smoking causes lung cancer, heart disease or heart attack, and stroke. They were also asked whether secondhand smoke causes lung cancer and heart disease or heart attack in people who do not smoke.

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The researchers analyzed the two survey datasets separately, and the results were consistent. About 92% of people who smoked knew that smoking can cause lung cancer. By comparison, 85% of survey participants in one analysis knew about the connection with heart disease, and 80% in the other knew about the link with heart attack. Just 75% and 66%, respectively, knew that smoking is associated with stroke.

The gaps were even greater for secondhand smoke. Depending on the survey, 77% to 82% knew that secondhand smoke causes lung cancer, while only 62% to 73% knew it causes heart disease or heart attack.

Another eye-catching finding was how little overall progress there had been over time. Across the five health effects studied, the average increase in knowledge was just 0.14 percentage point per year.

CNN: So many people who smoke don’t know about the cardiovascular risks. Is that concerning?

Wen: Smoking is one of the major preventable causes of cardiovascular disease. In fact, the researchers point out that worldwide, heart disease and stroke together accounted for about 2.6 million deaths attributable to smoking in 2019. That was twice the 1.3 million smoking-attributable deaths from cancers of the lung, trachea and bronchus. Someone who thinks the primary danger of cigarettes is lung cancer is missing a major part of the picture.

Knowledge influences behavior. Someone who understands all the risks may be more motivated to quit. This really matters for secondhand smoke, too. If people who smoke do not realize that their smoke increases cardiovascular risk in those around them, they may not be taking precautions to protect family members, friends and coworkers from exposure.

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CNN: How does smoking cause heart attacks and strokes?

Wen: Cigarette smoke contains thousands of chemicals, including many that damage the cardiovascular system by injuring the inner lining of blood vessels and promoting inflammation. These toxins also contribute to the buildup of plaque inside arteries.

In addition, smoking also makes blood more likely to clot . A heart attack commonly occurs when a clot blocks blood flow through an artery supplying the heart. An ischemic stroke occurs when blood flow to part of the brain is blocked.

Smoking has other cardiovascular effects, too. Nicotine raises heart rate and blood pressure. Carbon monoxide released by combustion reduces the amount of oxygen that the blood can carry. Over time, smoking can narrow and stiffen blood vessels and accelerate cardiovascular disease.

These effects are not limited to people who have smoked heavily for decades. Cardiovascular damage begins early, and relatively low levels of cigarette smoking can carry substantial risk.

CNN: How dangerous is secondhand smoke to the heart and brain?

Wen: People exposed to secondhand smoke inhale many of the same toxic chemicals as the person smoking. These chemicals can cause similar types of damage to blood vessels, increase inflammation and thus increase the risk of coronary heart disease.

Here, the public health impact is also substantial. The study cites estimates that secondhand smoke caused about 1.3 million deaths worldwide in 2021 among people who did not smoke. Yet, in several high-income countries, including the United States, Canada, England, Australia and Germany, fewer than half knew about this risk.

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CNN: Why might people know so much more about the link between smoking and lung cancer than about heart disease and stroke?

Wen: The connection between smoking and lung cancer has been a central part of public health messaging for decades. The link appears prominently in education campaigns and tobacco warnings and, rightfully so, has become ingrained in public consciousness.

The cardiovascular consequences have not achieved the same level of recognition. This study found large differences between countries, which could reflect differences in mass media campaigns and other educational efforts.

CNN: Does cutting down on cigarettes substantially reduce cardiovascular risk, or does someone need to quit completely?

Wen: Cutting down is not the same as quitting. There is a common misconception that someone who smokes only a few cigarettes a day has a small fraction of the cardiovascular risk of someone who smokes a pack a day. That is not the case . Even low levels of cigarette smoking substantially increase cardiovascular risk.

The goal should be to stop smoking completely. The good news is that the cardiovascular benefits begin to accrue quickly after quitting . Heart rate and blood pressure improve, carbon monoxide levels in the blood decline, and over time the risks of heart attack, stroke and other smoking-related diseases all fall substantially.

No smoker should conclude that the damage is already done and that there is no point to stopping now. Quitting is beneficial at any age, and the sooner someone stops, the more health benefit they gain.

6 steps you can take to quit smoking and live a healthier life

CNN: It may seem obvious, but what should people who smoke do for their health and the health of those around them?

Wen: The single most effective step is to quit smoking. There are effective treatments for tobacco dependence, including nicotine replacement therapy and prescription medications. Combining medication with behavioral counseling increases the chance of successfully quitting.

People should speak with their healthcare provider about which treatment is appropriate for them. It is also common to require multiple attempts before quitting for good. An unsuccessful attempt is not a reason to stop trying; it can help someone identify triggers and determine what additional support they need next time.

In the meantime, people who smoke should protect others from secondhand smoke. Smoking in another room or opening a window does not make indoor smoking safe. Never smoke inside the home, car or other enclosed space, and keep smoke away from children, pregnant people, older adults and anyone with cardiovascular or respiratory disease.

Everyone who smokes should know their habit does not just threaten the lungs. Smoking cigarettes damages blood vessels throughout the body and can cause heart attacks and strokes. Understanding the full range of harms provides another powerful reason to quit, for the sake of their health and the health of their loved ones.

Get inspired by a weekly roundup on living well, made simple. Sign up for CNN’s Life, But Better newsletter for information and tools designed to improve your well-being.

吸烟不仅仅会导致肺癌。有毒烟雾几乎会影响身体的每一个器官——然而，它的一些最严重的后果可能鲜为人知。

吸烟是导致心血管疾病（包括心脏病和中风）的主要原因，接触二手烟也会使不吸烟的人面临风险。

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心脏病死亡人数大幅下降。现在，真正夺走我们生命的是其他什么呢？

近期发表在《英国医学杂志开放版》（BMJ Open）上的一项研究发现，吸烟者对吸烟风险的认知存在显著不足。在对46个国家的受访者中，超过90%的人知道吸烟会导致肺癌，但了解吸烟对心血管疾病影响的人却少得多。而对于二手烟的心血管危害，人们的认知度则更低。

为什么吸烟会对心脏和血管造成如此严重的损害？二手烟的危害有多大？吸烟者及其周围的人应该了解哪些信息？

为了帮助我们更好地理解这项研究及其提出的问题，我采访了CNN的健康专家莉娜·温博士。温博士是乔治·华盛顿大学的急诊医生和临床副教授，她曾担任巴尔的摩市的卫生专员。

CNN：人们对吸烟的健康风险了解多少？

温莉娜博士：这项研究的研究人员分析了两项主要的国际烟草调查的数据。一项是国际烟草控制项目，该项目包含了2002年至2022年间在26个国家开展的调查。另一项是全球成人烟草调查，该调查使用了2008年至2020年间在32个国家开展的调查数据。一些国家同时参与了这两项调查；总共有46个国家参与其中。

参与者均为18岁及以上的吸烟者，他们被问及是否知道或相信吸烟会导致肺癌、心脏病或心脏病发作以及中风。他们还被问及二手烟是否会导致不吸烟者患肺癌、心脏病或心脏病发作。

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研究人员分别分析了这两组调查数据集，结果一致。约92%的吸烟者知道吸烟会导致肺癌。相比之下，在一项分析中，85%的受访者知道吸烟与心脏病有关，在另一项分析中，80%的受访者知道吸烟与心脏病发作有关。而分别只有75%和66%的受访者知道吸烟与中风有关。

对于二手烟，认知差距更大。根据不同的调查，77%到82%的人知道二手烟会导致肺癌，而只有62%到73%的人知道它会导致心脏病或心脏病发作。

另一个引人注目的发现是，随着时间的推移，总体进展甚微。在所研究的五种健康影响中，知识水平的平均增长仅为每年0.14个百分点。

CNN：很多吸烟者并不了解吸烟对心血管疾病的风险。这令人担忧吗？

温：吸烟是导致心血管疾病的主要可预防因素之一。事实上，研究人员指出，2019年全球因吸烟导致的死亡人数中，约有260万人死于心脏病和中风。这一数字是因吸烟导致的肺癌、气管癌和支气管癌死亡人数（130万人）的两倍。认为香烟的主要危害是肺癌的人，忽略了问题的关键所在。

知识影响行为。了解所有风险的人可能更有动力戒烟。这一点对于二手烟危害尤为重要。如果吸烟者没有意识到二手烟会增加周围人的心血管疾病风险，他们可能就不会采取预防措施来保护家人、朋友和同事免受二手烟的危害。

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高血压、心脏病与食品中常见的防腐剂有关

CNN：吸烟是如何导致心脏病和中风的？

温：香烟烟雾中含有数千种化学物质，其中许多会损伤血管内壁并引发炎症，从而损害心血管系统。这些毒素还会导致动脉内斑块的积聚。

此外，吸烟还会增加血液凝结的风险。心脏病发作通常发生在血栓阻塞了供应心脏的动脉时。缺血性中风则发生在大脑某部分的血液供应受阻时。

吸烟还会对心血管系统造成其他影响。尼古丁会加快心率、升高血压。燃烧产生的一氧化碳会降低血液的携氧量。长期吸烟会导致血管收缩和硬化，加速心血管疾病的发生。

这些影响并非仅限于长期大量吸烟者。心血管损伤很早就开始发生，即使吸烟量相对较低也可能带来相当大的风险。

CNN：二手烟对心脏和大脑的危害有多大？

温：接触二手烟的人会吸入与吸烟者相同的许多有毒化学物质。这些化学物质会对血管造成类似的损害，加剧炎症，从而增加患冠心病的风险。

二手烟对公众健康的影响也十分显著。该研究援引估计数据称，2021年全球约有130万人死于二手烟，而这些死者并非吸烟者。然而，在包括美国、加拿大、英国、澳大利亚和德国在内的几个高收入国家，只有不到一半的人了解这种风险。

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一项研究表明，吸烟可能会导致腹部脂肪堆积。这令人担忧的原因如下。

CNN：为什么人们对吸烟与肺癌之间的联系了解得比对心脏病和中风之间的联系了解得更多？

温：几十年来，吸烟与肺癌之间的联系一直是公共卫生宣传的核心内容。这种联系在教育宣传活动和烟草警示中都占据显著位置，而且理所当然地，它已经深深植根于公众意识之中。

心血管疾病的后果尚未得到同等程度的重视。本研究发现各国之间存在显著差异，这可能反映了大众媒体宣传和其他教育工作的差异。

CNN：减少吸烟量能否大幅降低心血管疾病风险，还是需要完全戒烟？

温：减少吸烟量并不等同于戒烟。很多人误以为每天只抽几支烟的人患心血管疾病的风险远低于每天抽一包烟的人。事实并非如此。即使是少量吸烟也会显著增加患心血管疾病的风险。

目标应该是彻底戒烟。好消息是，戒烟后心血管益处会很快显现。心率和血压会改善，血液中的一氧化碳水平会下降，随着时间的推移，心脏病发作、中风和其他吸烟相关疾病的风险都会显著降低。

吸烟者不应认为损害已经造成，现在戒烟毫无意义。戒烟在任何年龄都有益，而且越早戒烟，获得的健康益处就越多。

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CNN：这或许显而易见，但吸烟者为了自身及周围人的健康应该怎么做呢？

温：最有效的办法就是戒烟。目前有多种治疗烟草依赖的有效方法，包括尼古丁替代疗法和处方药。药物治疗结合行为咨询可以提高戒烟成功的几率。

人们应该咨询医疗保健提供者，了解哪种治疗方法适合自己。通常需要多次尝试才能彻底戒烟。一次失败的尝试并非放弃的理由；它可以帮助人们识别诱因，并确定下次需要哪些额外的支持。

与此同时，吸烟者应保护他人免受二手烟危害。在另一个房间吸烟或打开窗户并不能使室内吸烟变得安全。切勿在家中、车内或其他封闭空间吸烟，并让儿童、孕妇、老年人以及患有心血管或呼吸系统疾病的人远离烟雾。

所有吸烟者都应该知道，吸烟的危害远不止于肺部。吸烟还会损害全身血管，并可能导致心脏病和中风。了解吸烟的全部危害，是为自身及家人健康戒烟的又一有力理由。

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