Smoking

Smoking tobacco in the form of cigarettes or cigars, or in pipes. Over 100,000 deaths per year in the UK are attributed to smoking. The main harmful effects of smoking are lung cancer, bronchitis, emphysema, coronary artery disease, and peripheral vascular disease. Smoking also increases the risk of mouth cancer, lip cancer, and throat cancer (see pharynx, cancer of). Smoking is extremely harmful during pregnancy. Babies of women who smoke are smaller and are less likely to survive than those of nonsmoking mothers. Children with parents who smoke are more likely to suffer from asthma or other respiratory diseases. There is also evidence that passive smokers are at increased risk of tobaccorelated disorders and also suffer discomfort in the form of coughing, wheezing, and sore eyes. Tobacco contains many toxic chemicals. Nicotine is the substance that causes addiction to tobacco. It acts as a tranquillizer but also stimulates the release of adrenaline into the bloodstream. This can raise blood pressure. Tar in tobacco produces chronic irritation of the respiratory system and is thought to be a major cause of lung cancer. Carbon monoxide passes from the lungs into the bloodstream, where it easily combines with haemoglobin in red blood cells, interfering with oxygenation of tissues. In the long term, persistently high levels of carbon monoxide in the blood cause hardening of the arteries, which greatly increases the risk of coronary thrombosis.