Tobacco use is a major risk factor for many chronic diseases, including cancer, lung disease, cardiovascular disease, and stroke. It accounts for at least 30 percent of all cancer deaths and 80 percent of lung cancer deaths. Recent data indicates that by 2025, there will be seventeen million new cancer cases worldwide, with three-fourths of cancer-related deaths occurring in developing countries.
Tobacco-related cancers (TRCs) constitute a significant portion of all cancer cases. If current trends in smoking and population growth continue, the number of smokers worldwide is expected to reach 2 billion by 2030. The harmful effects of tobacco are not limited to smokers but also affect nearby individuals, particularly family and friends. Inhaling second-hand smoke is extremely harmful.
Long-term exposure to second-hand smoke causes lung cancer, coronary heart disease, and cardiac death. Non-smokers who live with smokers have a 25%-30% increased risk of coronary heart disease and a 20%-30% increased risk of lung cancer. Each puff of cigarette smoke contains more than 7,000 compounds, at least 60 of which are known carcinogens. These include benzene, formaldehyde, aromatic amines, nitrosamines, and polycyclic aromatic hydrocarbons. Lung cancer, primarily caused by smoking, is one of the leading causes of cancer death in both men and women. The process of carcinogenesis in the lungs due to tobacco smoke is multifactorial.
Tobacco smoke not only directly damages DNA but also causes oxidative stress and persistent inflammation in lung tissues. It also weakens the body’s immune system. The immunosuppressive properties of tobacco smoke reduce the effectiveness of T lymphocytes, which are essential for recognizing and eliminating cancer cells. Smoking has been directly associated with almost 18 types of cancers, including head and neck cancers, leukaemia, and cancers of the esophagus, bladder, pancreas, kidney, liver, stomach, colorectum, cervix, uterus, and ovaries.
In conclusion, tobacco use (both smoking and smokeless) continues to be a rising menace across all age groups and is a leading cause of many cancers.