Tobacco contains nicotine, a substance that is recognized to be addictive by international medical organizations.Nicotine fulfills the key criteria for addiction or dependence, including compulsive use, despite the desire and repeated attempts to quit; psychoactive effects produced by the action of the substance on the brain; and behavior motivated by the “reinforcing” effects of the psychoactive substance. Cigarettes, unlike chewed tobacco, enable nicotine to reach the brain rapidly, within a few seconds of inhaling smoke, and the smoker can regulate the dose puff by puff. Within the next year, tobacco is expected to kill approximately 4 million people worldwide. Already, it is responsible for one in 10 adult deaths; by 2030 the figure is expected to be one in six, or 10 million deaths each year—more than any other cause and more than the projected death tolls from pneumonia, diarrheal diseases, tuberculosis, and the complications of childbirth for that year combined. If current trends persist, about 500 million people alive today will eventually be killed by tobacco, half of them in productive middle age, losing 20 to 25 years of life. However, the toll of death and disability from smoking outside the high-income countries has yet to be felt. This is because the diseases caused by smoking can take several decades to develop. Even when smoking is very common in a population, the damage to health may not yet be visible. A person’s risk of developing lung cancer is affected more strongly by the amount of time that they have been a smoker than by the number of cigarettes
they have smoked daily. Smokers affect not only their own health but the health of those around them. Women who smoke during pregnancy are more likely to lose the fetus through spontaneous abortion. Babies born to smoking mothers in high-income countries
are significantly more likely than the babies of nonsmokers to have a low birth weight and up to 35 percent more likely to die in infancy. They also face higher risks of respiratory disease. The earlier a smoker starts, the greater the risk of disabling illnesses. In high-income countries with long-term data, researchers have concluded that smokers who start early and smoke regularly are much more likely to develop lung cancer than smokers who quit while they are still young. With all the disadvantages listed above, smoking is strongly not recommended and should definitely be avoided.
温馨提示：答案为网友推荐，仅供参考