The Centers for Disease Control and Prevention (CDC) said adult male smokers lose an average of 13.2 years of life while female smokers lose 14.5 years of life.

How much damage smoking does to your body depends on the type of tobacco, the form it is smoked, the temperature it is burned, the length of time you have been smoking and your general state of health. Experts say cigarette smoking is the most dangerous form and every cigarette you smoke shortens your life.

Cigarette smokers are twice as likely to die before middle age and the average smoker aged 35 has a life expectancy five and a half years shorter than a non-smoker. In many cases, these deaths are caused by cancer.

"Cigarette smoking accounts for at least 30 percent of all cancer deaths. It is a major cause of cancers of the lung, larynx (voice box), oral cavity, pharynx (throat), esophagus (swallowing tube connected to the stomach), and bladder, and it contributes to the development of cancers of the pancreas, cervix, kidney, stomach, and also some leukemias," according to the American Cancer Society (ACS).

"Smoking is responsible for about 87 percent of lung cancer deaths. Lung cancer is the leading cause of cancer death in both men and women, and is one of the most difficult cancers to treat. Lung cancer is a disease that can in many cases be prevented. Groups that promote non-smoking as part of their religion, such as Mormons and Seventh-day Adventists, have much lower rates of lung cancer and other smoking-related cancers," it added.

Aside from lung cancer, smoking damages the cardiovascular, respiratory and digestive systems of the body. The irritating substances found in a cigarette can disturb the bronchial passages and fill the lungs with mucus.

Normally, glands in the interior lining of the lungs constantly produce mucus. Together with dirt and bacteria, the mucus is expelled from the lungs by the action of cilia or small hair-like projections.

Inhaled smoke, however, interferes with the action of cilia and stimulates mucus production. Because of this, mucus, tar and other bacteria are trapped in the lungs. Smoker's cough is a sign that the lungs are clogged with mucus and coughing is the body's attempt to get rid of tar and phlegm.

Bacteria in the lungs can later lead to bronchitis (the Inflammation of the bronchial tubes) or emphysema in which the air passages of the lungs are enlarged. This makes breathing difficult and can damage the heart. Atherosclerosis (the hardening of the arteries) and thrombosis (the formation of blood clots) are common in smokers because the level of fatty acids and cholesterol in the blood is raised.

In the fourth part of this series, we'll tackle the other harmful effects of smoking. Don't miss it! To strengthen your body, take Immunitril - your first line of defense in maintaining a healthy immune system. For details, visit