Smoking Smoking is defined as the inhaling and exhaling of the fumes of burning plant material, especially tobacco, from a cigarette, cigar, or pipe. First introduced into Europe by early explorers, the habit has become worldwide. Cigarette companies themselves knew decades ago that smoking could kill, but rather than coming clean and risking commercial oblivion, they deployed a barrage of unscrupulous marketing and ingeniously manipulated scientific data to conceal their findings. Their customers continued to be willing co -conspirators in the tobacco delusion because they wanted to believe the image of smokers promoted in advertising. The deleterious health effects of tobacco smoking have long been recognized. As early as the 19th century, isolated reports were circulated that cigar and pipe smoking caused cancer of the mouth. It was not until the 20th century--in fact, until 1950--that firm evidence was established that lung cancer was directly related to cigarette smoking. Lung cancer is now the most common cause of cancer deaths in men of most Western countries. Because cigarette smoking became a popular and fairly widespread habit among men during World War II and because this disease has a long latency period, the rise in the incidence of lung cancer during the second part of the 20th century was expected. In the late 20th century, in many countries, as many as one-third of all cancer deaths in men and 10 percent of those in women are attributed to cigarette smoking. As the current trend of males to give up smoking continues, the male percentage will decline. Less optimistically, however, increasingly more women picked up the habit in the 1950s and '60s ;the proportion of women dying from a tobacco-related cancer thus was increasing. Women who smoke during pregnancy are three times more likely to have a low birth weight baby, 27% more likely to miscarry and a third more likely to suffer still-birth, and smoking while pregnant has also been linked to cot deaths and increased chances of congenital defects. In general, the risk of developing a tobacco-related cancer depends on the intensity of the habit as determined by duration of the smoking habit, number of cigarettes smoked per day, tar content of the cigarette, and the depth of inhalation. Cigarette smoking is not only related to the development of lung cancer but also affects the development of cancer of the bladder, oral cavity, and esophagus. The risk of developing one of these cancer increases with the number of cigarettes smoked per day. Studies have also shown that various cancer sites are affected differently by different tobacco products, as well as by different intensities. However, those sites that come into direct contact with tobacco smoke-the lungs, oral cavity, and larynx--are those that are the most adversely affected by exposure to smoke. Passive smoking, defined as a nonsmoker's inhalation of smoke produced by smokers in an enclosed space--also appears to heighten the risk of developing lung cancer. Several studies have found that, over the long term, the nonsmoking spouses of smokers experience a lung cancer risk that is almost double that of spouses neither of whom smoke. It should be emphasized, however, that smokers continue to have a much higher lung-cancer risk ;the lung-cancer mortality risk for a heavy smoker is 20 to 30 times greater than that of a nonsmoker. Smoking is also a prime risk factor in cardiovascular system diseases. Nicotine is known to contract the blood vessels and to release hormones that raise the blood pressure. Both effects could have an adverse effect on the heart. Smokers have distinctly higher levels of carbon monoxide in their blood than nonsmokers do. Carbon monoxide readily combines with hemoglobin, causing many physiological effects. One is a decrease in the amount of hemoglobin available to carry oxygen and a resulting increase in the affinity for oxygen of the hemoglobin that is available. This in turn reduces the availability of oxygen to the tissues. It has been shown that even minute amounts of carbon monoxide decrease the exercise ability of patients with known coronary artery disease. Another important piece of epidemiological evidence linking smoking to disease is that as individuals give up smoking, the risk of lung cancer, coronary artery disease, chronic bronchitis, emphysema, and other tobacco-related diseases declines. The speed and degree of this decline depends, as would be expected, on the duration and intensity of the smoking habit. Among those who have smoked over 20 cigarettes a day for over 20 years, a minimum of three years must elapse after quitting before a decreased risk for cancer is evident ;more than 10 years of abstinence is necessary before the degree of risk approaches that for those who have never smoked. Public response to the smoking dilemma has recently begun to change. No longer is smoking seen as a sign of masculinity, independence, or fashion. Widespread advertisements outline the negative effects of smoking. Recent multi-billion dollar lawsuits brought against the powerful tobacco companies have begun to yield surprising results in the courts of the nation. Nearly every major city has instituted smoking bans in public areas. It is surprising that something long seen as a fashionable trend is now regarded with disgust. It really is amazing what the threat of death will do.