Secondhand smoke and e-cigarettes: More dangerous than you think

Author: Zhi Xiuyi, Chief Physician of Beijing Tsinghua Chang Gung Hospital affiliated to Tsinghua University

Reviewer: Zhang Yu, researcher at Chinese Center for Disease Control and Prevention

As we all know, smoking poses a huge health risk. According to statistics from the World Health Organization, millions of people die each year from smoking. Among them, lung cancer is one of the most direct consequences of smoking, and its incidence and mortality rates remain high. So, how can you accurately determine whether you are at high risk of lung cancer?

The smoking index plays a vital role in this process. It is an important indicator for assessing an individual's risk of lung cancer. Its calculation method is simple and intuitive: the number of cigarettes smoked per day multiplied by the number of years of smoking. When this value exceeds 400, it is defined as a high-risk group for lung cancer. In other words, if you smoke more than 20 cigarettes a day for more than 20 years, or if you smoke less every day but have been smoking for a very long time, you should be highly alert to the risk of lung cancer.

Figure 1 Original copyright image, no permission to reprint

The importance of this indicator is that it provides us with a quantitative standard to help people more accurately assess their health status. It is worth noting that with the increase of age and the extension of smoking years, the smoking index tends to rise, while the decline of immunity and the accumulation of pathogenic factors make long-term smokers more susceptible to diseases such as lung cancer.

Therefore, it is particularly important for smokers to regularly screen for lung cancer and detect and treat potential lesions early. At the same time, quitting smoking or reducing smoking is also an effective way to reduce the risk of lung cancer.

However, the harm of smoking is not limited to direct smokers. Secondhand smoke is also a health killer that cannot be ignored. Compared with direct smoking, secondhand smoke contains a large number of harmful substances and carcinogens. Although its concentration is lower than that of firsthand smoke, people who are exposed to secondhand smoke for a long time also face higher health risks. Especially for susceptible groups such as children, pregnant women and the elderly, the harm of secondhand smoke is more serious.

In tobacco control propaganda, it is often emphasized that secondhand smoke is more dangerous than firsthand smoke. This is mainly because some heavy metals and harmful substances in secondhand smoke are not easy to completely burn and decompose at low temperatures, which increases its toxicity. In addition, exposure to secondhand smoke is often continuous and hidden, causing victims to be harmed unknowingly.

Figure 2 Original copyright image, no permission to reprint

Therefore, whether at home, in the workplace, or in other public places, we should actively create a smoke-free environment. Smokers should try to smoke in designated areas and avoid exposing others to secondhand smoke. At the same time, all sectors of society should strengthen tobacco control publicity and education efforts to raise public awareness of the hazards of secondhand smoke and prevent it.

In addition, there are many misunderstandings about filters and e-cigarettes. Although filters can theoretically reduce the intake of some harmful substances such as tar, the actual effect of filters is often difficult to evaluate due to the many uncertainties in smoking behavior itself, such as the amount of smoking and the way of smoking.

More importantly, the low tar content of filters often becomes a marketing gimmick for tobacco companies, misleading consumers into thinking that low tar equals low harm, which may cause smokers to relax their vigilance and increase their smoking. However, it has been proven that low tar does not significantly reduce the risk of smoking-related diseases.

As a new tobacco product that has emerged in recent years, the health risks of e-cigarettes cannot be ignored. Although e-cigarettes do not contain harmful substances such as tar in traditional tobacco, their core ingredient nicotine is still addictive. In addition, e-cigarettes may produce new harmful substances such as formaldehyde during the heating process, posing a potential threat to human health.

Therefore, neither filters nor e-cigarettes can be used as an effective means to reduce the harm of smoking. The best option for smokers is still to quit smoking or reduce the amount of smoking. At the same time, all sectors of society should strengthen the supervision and publicity of new tobacco products such as e-cigarettes to raise the public's awareness of their health risks and preventive awareness.