Approximately 20 per cent people in the world are smokers. Smoking is the cause of 20 to 35 per cent of cancers in various countries. Among various cancers, lung is the organ primarily affected by smoking. Smoking causes coronary artery disease, stroke and chronic obstructive pulmonary disease (COPD), apart from cancer, to name a few. Tobacco may have killed more people in 20th century, than both the world wars put together!
Tobacco is also consumed in other forms apart from smoking, such as chewing tobacco, snuff, etc., which are equally dangerous as well. In India and other south Asian countries, tobacco chewing is an important concern, unlike in the west. South Asian counties contribute one third of patients suffering from oral and throat cancers worldwide. In India, oral and throat cancers are among the top five causes of deaths due to cancers.
Smoking causes various diseases in lungs, and commonest are the cancer and COPD. COPD is one of the leading causes of death, and in fact, one of the top five causes in most countries. Smoking is the cause of COPD, except in a very small percentage of patients. Other leading causes of death, Ischaemic heart disease and stroke are also caused and aggravated by smoking. Smoking permanently affects the airways, resulting in the obstruction to airflow, which is the hallmark of COPD. Many patients may also manifest with excessive, persistent sputum production. COPD is a relentless disease, which will invariably progress, once it sets in. Unfortunately, there is no treatment available to stop the progression, leave alone the reversal of the disease. Symptomatic treatments do help to an extent. In fact, the only intervention to slow down the progression of COPD (not to stop the progression), is stoppage of smoking.
Smoking causes premature thickening of arteries all over the body, including the coronary arteries of heart, the carotid vessels of the neck and the cerebral vessels of the brain. Heart attacks in young are most often due to smoking. Smoking also causes peripheral vascular diseases, which may necessitate limb amputations to save the life. Strokes in young are also more often seen in smokers.
Lung cancer is the most common cancer worldwide, accounting and is the leading cancer killer in both men and women in many countries. Around 90% of lung cancers are because of smoking. More than half of people with lung cancer die within 1 year of being diagnosed, despite all treatments. Tobacco smoke contains at least 80 different cancer-causing substances (carcinogenic agents). The more a person smokes, the younger they start, and the longer they keep smoking, all further increase the risk of cancer. Currently tobacco use is responsible for around 22% of all cancer deaths.
Passive smoking, whether at home or work, is also lethal. Non-smokers who reside with a smoker have 20 to 30 per cent increase in risk for developing lung cancer when compared with non-smokers who do not reside with a smoker. To quote BMJ, ‘Cigarette is the deadliest artefact in human civilisation. But unfortunately, as high as one sixth of homo sapiens smoke’.
There are 3 proven ways to reduce the risk of lung cancer— don’t smoke; if you are a smoker, stop smoking; and, avoid second-hand or passive smoke.
Smoking damages nearly every organ in the body. People can significantly reduce their chance of smoking-related disease by giving it up.
Dr. C. Jagadeesh, Senior Consultant in Internal Medicine, Apollo Hospitals