Smoking kills about 440,000 people prematurely in the United States each year, the American Cancer Society says. Nearly one in five deaths is attributable to smoking. Smoking affects every organ and is responsible for more early deaths than any other factor in the United States, the National Cancer Institute says. The Centers for Disease Control and Prevention estimates that male smokers live an average of 13 years less, and female smokers 14 years less, than if they had never smoked.
Cardiovascular Disease
Smoking has many negative effects on the cardiovascular system, which include the heart and blood vessels. Cardiovascular disease is the main cause of death related to smoking, according to NetDoctor. Smoking increases blood pressure. Atherosclerosis, or narrowing of the arteries, starts earlier in smokers; the risk of developing blood clots is two to four times higher in smokers. Thirty percent of blood clots in the blood vessels of the heart are caused by smoking. Nine of 10 heart bypass patients are smokers, NetDoctor says. Blood clots in the legs can lead to gangrene and amputation. Blocked blood vessels from clots to the brain cause stroke.
Cancer
Although lung cancer is the cancer most people associate with smoking, smoking also increases the risk of mouth, throat, bladder, cervical and kidney cancer. Esophageal and pancreatic cancer are also more common in smokers. Ninety percent of lung cancer cases are directly caused by cancer, NetDoctor says. Nonsmokers have a 0.5 percent chance of developing lung cancer, and 10 percent of moderate smokers and almost 20 percent of people who smoke more than 15 cigarettes a day die of lung cancer. The chance of developing mouth cancer, which includes cancer of the lips and tongue, is four times higher in smokers than nonsmokers. Throat and mouth cancer are rarely seen in nonsmokers.
It takes about 15 years for ex-smokers to decrease their risk of lung cancer to the level of nonsmokers. But it's still beneficial to quit. The National Cancer Institute (NCI) reports that smokers who quit by age 30 decrease their risk of dying from smoking-related diseases by 90 percent; those who quit by age 50 reduce their risk of premature death by 50 percent.
Respiratory Disease
Cigarette smoking affects the lungs in a number of ways. Chronic obstructive pulmonary disease, known as COPD, includes emphysema and bronchitis. Eighty percent of COPD cases are attributable to smoking, NetDoctor says. More than 90 percent of heavy smokers have evidence of COPD during an autopsy. COPD makes breathing difficult and in some cases leads to a need for constant oxygen supplementation. Emphysema damages the small air sacs in the lungs known as alveoli. Lung damage from COPD is permanent, but quitting at any age helps reduce the lung capacity decline. The NCI says lung function improves significantly within several weeks of quitting smoking. Asthma is also worsened by smoking; children whose parents smoke have an increased risk of developing it.
Other Diseases
Smoking can cause several eye problems. Overweight smokers are twice as likely to develop macular degeneration than the general population and have an increased risk of cataracts. Fertility problems are more common in smokers than non-smokers, and men who smoke are 50 percent more likely than non-smokers to be impotent or unable to maintain an erection. Women who smoke are more likely to have osteoporosis.
